linux/arch/Kconfig

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Create arch/Kconfig Puts the content of arch/Kconfig in the "General setup" menu. Linus: > Should it come with a re-duplication of it's content into each > architecture, which was the case previously ? The oprofile and kprobes > menu entries were litteraly cut and pasted from one architecture to > another. Should we put its content in init/Kconfig then ? I don't think it's a good idea to go back to making it per-architecture, although that extensive "depends on <list-of-archiectures-here>" might indicate that there certainly is room for cleanup there. And I don't think it's wrong keeping it in kernel/Kconfig.xyz per se, I just think it's wrong to (a) lump the code together when it really doesn't necessarily need to and (b) show it to users as some kind of choice that is tied together (whether it then has common code or not). On the per-architecture side, I do think it would be better to *not* have internal architecture knowledge in a generic file, and as such a line like depends on X86_32 || IA64 || PPC || S390 || SPARC64 || X86_64 || AVR32 really shouldn't exist in a file like kernel/Kconfig.instrumentation. It would be much better to do depends on ARCH_SUPPORTS_KPROBES in that generic file, and then architectures that do support it would just have a bool ARCH_SUPPORTS_KPROBES default y in *their* architecture files. That would seem to be much more logical, and is readable both for arch maintainers *and* for people who have no clue - and don't care - about which architecture is supposed to support which interface... Sam Ravnborg: Stuff it into a new file: arch/Kconfig We can then extend this file to include all the 'trailing' Kconfig things that are anyway equal for all ARCHs. But it should be kept clean - so if we introduce such a file then we should use ARCH_HAS_whatever in the arch specific Kconfig files to enable stuff that is not shared. [...] The above suggestion is actually not exactly the best way to do it... First the naming.. A quick grep shows following usage today (in Kconfig files) ARCH_HAS 51 ARCH_SUPPORTS 4 HAVE_ARCH 7 ARCH_HAS is the clear winner. In the common Kconfig file do: config FOO depends on ARCH_HAS_FOO bool "bla bla" config ARCH_HAS_FOO def_bool n In the arch specific Kconfig file in a suitable place do: config SUITABLE_OPTION select ARCH_HAS_FOO The naming of ARCH_HAS_ is fixed and shall be: ARCH_HAS_<config option it will enable> Only a single line added pr. architecture. And we will end up with a (maybe even commented) list of trivial selects. - Yet another update : Moving to HAVE_* now. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jeff Dike <jdike@addtoit.com> Cc: David Howells <dhowells@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-02-02 20:10:33 +00:00
#
# General architecture dependent options
#
2015-09-09 22:38:55 +00:00
config KEXEC_CORE
bool
config OPROFILE
tristate "OProfile system profiling"
depends on PROFILING
depends on HAVE_OPROFILE
select RING_BUFFER
select RING_BUFFER_ALLOW_SWAP
help
OProfile is a profiling system capable of profiling the
whole system, include the kernel, kernel modules, libraries,
and applications.
If unsure, say N.
config OPROFILE_EVENT_MULTIPLEX
bool "OProfile multiplexing support (EXPERIMENTAL)"
default n
depends on OPROFILE && X86
help
The number of hardware counters is limited. The multiplexing
feature enables OProfile to gather more events than counters
are provided by the hardware. This is realized by switching
between events at an user specified time interval.
If unsure, say N.
config HAVE_OPROFILE
bool
config OPROFILE_NMI_TIMER
def_bool y
depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
config KPROBES
bool "Kprobes"
depends on MODULES
depends on HAVE_KPROBES
select KALLSYMS
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
a probepoint and specifies the callback. Kprobes is useful
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
jump label: Add work around to i386 gcc asm goto bug On i386 (not x86_64) early implementations of gcc would have a bug with asm goto causing it to produce code like the following: (This was noticed by Peter Zijlstra) 56 pushl 0 67 nopl jmp 0x6f popl jmp 0x8c 6f mov test je 0x8c 8c mov call *(%esp) The jump added in the asm goto skipped over the popl that matched the pushl 0, which lead up to a quick crash of the system when the jump was enabled. The nopl is defined in the asm goto () statement and when tracepoints are enabled, the nop changes to a jump to the label that was specified by the asm goto. asm goto is suppose to tell gcc that the code in the asm might jump to an external label. Here gcc obviously fails to make that work. The bug report for gcc is here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226 The bug only appears on x86 when not compiled with -maccumulate-outgoing-args. This option is always set on x86_64 and it is also the work around for a function graph tracer i386 bug. (See commit: 746357d6a526d6da9d89a2ec645b28406e959c2e) This explains why the bug only showed up on i386 when function graph tracer was not enabled. This patch now adds a CONFIG_JUMP_LABEL option that is default off instead of using jump labels by default. When jump labels are enabled, the -maccumulate-outgoing-args will be used (causing a slightly larger kernel image on i386). This option will exist until we have a way to detect if the gcc compiler in use is safe to use on all configurations without the work around. Note, there exists such a test, but for now we will keep the enabling of jump label as a manual option. Archs that know the compiler is safe with asm goto, may choose to select JUMP_LABEL and enable it by default. Reported-by: Ingo Molnar <mingo@elte.hu> Cause-discovered-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Baron <jbaron@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Daney <ddaney@caviumnetworks.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: David Miller <davem@davemloft.net> Cc: Richard Henderson <rth@redhat.com> LKML-Reference: <1288028746.3673.11.camel@laptop> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-29 16:33:43 +00:00
config JUMP_LABEL
static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]() So here's a boot tested patch on top of Jason's series that does all the cleanups I talked about and turns jump labels into a more intuitive to use facility. It should also address the various misconceptions and confusions that surround jump labels. Typical usage scenarios: #include <linux/static_key.h> struct static_key key = STATIC_KEY_INIT_TRUE; if (static_key_false(&key)) do unlikely code else do likely code Or: if (static_key_true(&key)) do likely code else do unlikely code The static key is modified via: static_key_slow_inc(&key); ... static_key_slow_dec(&key); The 'slow' prefix makes it abundantly clear that this is an expensive operation. I've updated all in-kernel code to use this everywhere. Note that I (intentionally) have not pushed through the rename blindly through to the lowest levels: the actual jump-label patching arch facility should be named like that, so we want to decouple jump labels from the static-key facility a bit. On non-jump-label enabled architectures static keys default to likely()/unlikely() branches. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: a.p.zijlstra@chello.nl Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-24 07:31:31 +00:00
bool "Optimize very unlikely/likely branches"
jump label: Add work around to i386 gcc asm goto bug On i386 (not x86_64) early implementations of gcc would have a bug with asm goto causing it to produce code like the following: (This was noticed by Peter Zijlstra) 56 pushl 0 67 nopl jmp 0x6f popl jmp 0x8c 6f mov test je 0x8c 8c mov call *(%esp) The jump added in the asm goto skipped over the popl that matched the pushl 0, which lead up to a quick crash of the system when the jump was enabled. The nopl is defined in the asm goto () statement and when tracepoints are enabled, the nop changes to a jump to the label that was specified by the asm goto. asm goto is suppose to tell gcc that the code in the asm might jump to an external label. Here gcc obviously fails to make that work. The bug report for gcc is here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226 The bug only appears on x86 when not compiled with -maccumulate-outgoing-args. This option is always set on x86_64 and it is also the work around for a function graph tracer i386 bug. (See commit: 746357d6a526d6da9d89a2ec645b28406e959c2e) This explains why the bug only showed up on i386 when function graph tracer was not enabled. This patch now adds a CONFIG_JUMP_LABEL option that is default off instead of using jump labels by default. When jump labels are enabled, the -maccumulate-outgoing-args will be used (causing a slightly larger kernel image on i386). This option will exist until we have a way to detect if the gcc compiler in use is safe to use on all configurations without the work around. Note, there exists such a test, but for now we will keep the enabling of jump label as a manual option. Archs that know the compiler is safe with asm goto, may choose to select JUMP_LABEL and enable it by default. Reported-by: Ingo Molnar <mingo@elte.hu> Cause-discovered-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Baron <jbaron@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Daney <ddaney@caviumnetworks.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: David Miller <davem@davemloft.net> Cc: Richard Henderson <rth@redhat.com> LKML-Reference: <1288028746.3673.11.camel@laptop> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-29 16:33:43 +00:00
depends on HAVE_ARCH_JUMP_LABEL
help
static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]() So here's a boot tested patch on top of Jason's series that does all the cleanups I talked about and turns jump labels into a more intuitive to use facility. It should also address the various misconceptions and confusions that surround jump labels. Typical usage scenarios: #include <linux/static_key.h> struct static_key key = STATIC_KEY_INIT_TRUE; if (static_key_false(&key)) do unlikely code else do likely code Or: if (static_key_true(&key)) do likely code else do unlikely code The static key is modified via: static_key_slow_inc(&key); ... static_key_slow_dec(&key); The 'slow' prefix makes it abundantly clear that this is an expensive operation. I've updated all in-kernel code to use this everywhere. Note that I (intentionally) have not pushed through the rename blindly through to the lowest levels: the actual jump-label patching arch facility should be named like that, so we want to decouple jump labels from the static-key facility a bit. On non-jump-label enabled architectures static keys default to likely()/unlikely() branches. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: a.p.zijlstra@chello.nl Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-24 07:31:31 +00:00
This option enables a transparent branch optimization that
makes certain almost-always-true or almost-always-false branch
conditions even cheaper to execute within the kernel.
Certain performance-sensitive kernel code, such as trace points,
scheduler functionality, networking code and KVM have such
branches and include support for this optimization technique.
jump label: Add work around to i386 gcc asm goto bug On i386 (not x86_64) early implementations of gcc would have a bug with asm goto causing it to produce code like the following: (This was noticed by Peter Zijlstra) 56 pushl 0 67 nopl jmp 0x6f popl jmp 0x8c 6f mov test je 0x8c 8c mov call *(%esp) The jump added in the asm goto skipped over the popl that matched the pushl 0, which lead up to a quick crash of the system when the jump was enabled. The nopl is defined in the asm goto () statement and when tracepoints are enabled, the nop changes to a jump to the label that was specified by the asm goto. asm goto is suppose to tell gcc that the code in the asm might jump to an external label. Here gcc obviously fails to make that work. The bug report for gcc is here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226 The bug only appears on x86 when not compiled with -maccumulate-outgoing-args. This option is always set on x86_64 and it is also the work around for a function graph tracer i386 bug. (See commit: 746357d6a526d6da9d89a2ec645b28406e959c2e) This explains why the bug only showed up on i386 when function graph tracer was not enabled. This patch now adds a CONFIG_JUMP_LABEL option that is default off instead of using jump labels by default. When jump labels are enabled, the -maccumulate-outgoing-args will be used (causing a slightly larger kernel image on i386). This option will exist until we have a way to detect if the gcc compiler in use is safe to use on all configurations without the work around. Note, there exists such a test, but for now we will keep the enabling of jump label as a manual option. Archs that know the compiler is safe with asm goto, may choose to select JUMP_LABEL and enable it by default. Reported-by: Ingo Molnar <mingo@elte.hu> Cause-discovered-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Baron <jbaron@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Daney <ddaney@caviumnetworks.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: David Miller <davem@davemloft.net> Cc: Richard Henderson <rth@redhat.com> LKML-Reference: <1288028746.3673.11.camel@laptop> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-29 16:33:43 +00:00
If it is detected that the compiler has support for "asm goto",
static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]() So here's a boot tested patch on top of Jason's series that does all the cleanups I talked about and turns jump labels into a more intuitive to use facility. It should also address the various misconceptions and confusions that surround jump labels. Typical usage scenarios: #include <linux/static_key.h> struct static_key key = STATIC_KEY_INIT_TRUE; if (static_key_false(&key)) do unlikely code else do likely code Or: if (static_key_true(&key)) do likely code else do unlikely code The static key is modified via: static_key_slow_inc(&key); ... static_key_slow_dec(&key); The 'slow' prefix makes it abundantly clear that this is an expensive operation. I've updated all in-kernel code to use this everywhere. Note that I (intentionally) have not pushed through the rename blindly through to the lowest levels: the actual jump-label patching arch facility should be named like that, so we want to decouple jump labels from the static-key facility a bit. On non-jump-label enabled architectures static keys default to likely()/unlikely() branches. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: a.p.zijlstra@chello.nl Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-24 07:31:31 +00:00
the kernel will compile such branches with just a nop
instruction. When the condition flag is toggled to true, the
nop will be converted to a jump instruction to execute the
conditional block of instructions.
This technique lowers overhead and stress on the branch prediction
of the processor and generally makes the kernel faster. The update
of the condition is slower, but those are always very rare.
jump label: Add work around to i386 gcc asm goto bug On i386 (not x86_64) early implementations of gcc would have a bug with asm goto causing it to produce code like the following: (This was noticed by Peter Zijlstra) 56 pushl 0 67 nopl jmp 0x6f popl jmp 0x8c 6f mov test je 0x8c 8c mov call *(%esp) The jump added in the asm goto skipped over the popl that matched the pushl 0, which lead up to a quick crash of the system when the jump was enabled. The nopl is defined in the asm goto () statement and when tracepoints are enabled, the nop changes to a jump to the label that was specified by the asm goto. asm goto is suppose to tell gcc that the code in the asm might jump to an external label. Here gcc obviously fails to make that work. The bug report for gcc is here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226 The bug only appears on x86 when not compiled with -maccumulate-outgoing-args. This option is always set on x86_64 and it is also the work around for a function graph tracer i386 bug. (See commit: 746357d6a526d6da9d89a2ec645b28406e959c2e) This explains why the bug only showed up on i386 when function graph tracer was not enabled. This patch now adds a CONFIG_JUMP_LABEL option that is default off instead of using jump labels by default. When jump labels are enabled, the -maccumulate-outgoing-args will be used (causing a slightly larger kernel image on i386). This option will exist until we have a way to detect if the gcc compiler in use is safe to use on all configurations without the work around. Note, there exists such a test, but for now we will keep the enabling of jump label as a manual option. Archs that know the compiler is safe with asm goto, may choose to select JUMP_LABEL and enable it by default. Reported-by: Ingo Molnar <mingo@elte.hu> Cause-discovered-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Baron <jbaron@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Daney <ddaney@caviumnetworks.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: David Miller <davem@davemloft.net> Cc: Richard Henderson <rth@redhat.com> LKML-Reference: <1288028746.3673.11.camel@laptop> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-29 16:33:43 +00:00
static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]() So here's a boot tested patch on top of Jason's series that does all the cleanups I talked about and turns jump labels into a more intuitive to use facility. It should also address the various misconceptions and confusions that surround jump labels. Typical usage scenarios: #include <linux/static_key.h> struct static_key key = STATIC_KEY_INIT_TRUE; if (static_key_false(&key)) do unlikely code else do likely code Or: if (static_key_true(&key)) do likely code else do unlikely code The static key is modified via: static_key_slow_inc(&key); ... static_key_slow_dec(&key); The 'slow' prefix makes it abundantly clear that this is an expensive operation. I've updated all in-kernel code to use this everywhere. Note that I (intentionally) have not pushed through the rename blindly through to the lowest levels: the actual jump-label patching arch facility should be named like that, so we want to decouple jump labels from the static-key facility a bit. On non-jump-label enabled architectures static keys default to likely()/unlikely() branches. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: a.p.zijlstra@chello.nl Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-24 07:31:31 +00:00
( On 32-bit x86, the necessary options added to the compiler
flags may increase the size of the kernel slightly. )
jump label: Add work around to i386 gcc asm goto bug On i386 (not x86_64) early implementations of gcc would have a bug with asm goto causing it to produce code like the following: (This was noticed by Peter Zijlstra) 56 pushl 0 67 nopl jmp 0x6f popl jmp 0x8c 6f mov test je 0x8c 8c mov call *(%esp) The jump added in the asm goto skipped over the popl that matched the pushl 0, which lead up to a quick crash of the system when the jump was enabled. The nopl is defined in the asm goto () statement and when tracepoints are enabled, the nop changes to a jump to the label that was specified by the asm goto. asm goto is suppose to tell gcc that the code in the asm might jump to an external label. Here gcc obviously fails to make that work. The bug report for gcc is here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226 The bug only appears on x86 when not compiled with -maccumulate-outgoing-args. This option is always set on x86_64 and it is also the work around for a function graph tracer i386 bug. (See commit: 746357d6a526d6da9d89a2ec645b28406e959c2e) This explains why the bug only showed up on i386 when function graph tracer was not enabled. This patch now adds a CONFIG_JUMP_LABEL option that is default off instead of using jump labels by default. When jump labels are enabled, the -maccumulate-outgoing-args will be used (causing a slightly larger kernel image on i386). This option will exist until we have a way to detect if the gcc compiler in use is safe to use on all configurations without the work around. Note, there exists such a test, but for now we will keep the enabling of jump label as a manual option. Archs that know the compiler is safe with asm goto, may choose to select JUMP_LABEL and enable it by default. Reported-by: Ingo Molnar <mingo@elte.hu> Cause-discovered-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Baron <jbaron@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Daney <ddaney@caviumnetworks.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: David Miller <davem@davemloft.net> Cc: Richard Henderson <rth@redhat.com> LKML-Reference: <1288028746.3673.11.camel@laptop> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-29 16:33:43 +00:00
config STATIC_KEYS_SELFTEST
bool "Static key selftest"
depends on JUMP_LABEL
help
Boot time self-test of the branch patching code.
kprobes: Introduce kprobes jump optimization Introduce kprobes jump optimization arch-independent parts. Kprobes uses breakpoint instruction for interrupting execution flow, on some architectures, it can be replaced by a jump instruction and interruption emulation code. This gains kprobs' performance drastically. To enable this feature, set CONFIG_OPTPROBES=y (default y if the arch supports OPTPROBE). Changes in v9: - Fix a bug to optimize probe when enabling. - Check nearby probes can be optimize/unoptimize when disarming/arming kprobes, instead of registering/unregistering. This will help kprobe-tracer because most of probes on it are usually disabled. Changes in v6: - Cleanup coding style for readability. - Add comments around get/put_online_cpus(). Changes in v5: - Use get_online_cpus()/put_online_cpus() for avoiding text_mutex deadlock. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 13:34:07 +00:00
config OPTPROBES
def_bool y
depends on KPROBES && HAVE_OPTPROBES
kprobes: Introduce kprobes jump optimization Introduce kprobes jump optimization arch-independent parts. Kprobes uses breakpoint instruction for interrupting execution flow, on some architectures, it can be replaced by a jump instruction and interruption emulation code. This gains kprobs' performance drastically. To enable this feature, set CONFIG_OPTPROBES=y (default y if the arch supports OPTPROBE). Changes in v9: - Fix a bug to optimize probe when enabling. - Check nearby probes can be optimize/unoptimize when disarming/arming kprobes, instead of registering/unregistering. This will help kprobe-tracer because most of probes on it are usually disabled. Changes in v6: - Cleanup coding style for readability. - Add comments around get/put_online_cpus(). Changes in v5: - Use get_online_cpus()/put_online_cpus() for avoiding text_mutex deadlock. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 13:34:07 +00:00
depends on !PREEMPT
config KPROBES_ON_FTRACE
def_bool y
depends on KPROBES && HAVE_KPROBES_ON_FTRACE
depends on DYNAMIC_FTRACE_WITH_REGS
help
If function tracer is enabled and the arch supports full
passing of pt_regs to function tracing, then kprobes can
optimize on top of function tracing.
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 09:26:42 +00:00
config UPROBES
def_bool n
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 09:26:42 +00:00
help
Uprobes is the user-space counterpart to kprobes: they
enable instrumentation applications (such as 'perf probe')
to establish unintrusive probes in user-space binaries and
libraries, by executing handler functions when the probes
are hit by user-space applications.
( These probes come in the form of single-byte breakpoints,
managed by the kernel and kept transparent to the probed
application. )
uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Also-written-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Roland McGrath <roland@hack.frob.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-mm <linux-mm@kvack.org> Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-09 09:26:42 +00:00
config HAVE_64BIT_ALIGNED_ACCESS
def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
help
Some architectures require 64 bit accesses to be 64 bit
aligned, which also requires structs containing 64 bit values
to be 64 bit aligned too. This includes some 32 bit
architectures which can do 64 bit accesses, as well as 64 bit
architectures without unaligned access.
This symbol should be selected by an architecture if 64 bit
accesses are required to be 64 bit aligned in this way even
though it is not a 64 bit architecture.
See Documentation/unaligned-memory-access.txt for more
information on the topic of unaligned memory accesses.
config HAVE_EFFICIENT_UNALIGNED_ACCESS
bool
help
Some architectures are unable to perform unaligned accesses
without the use of get_unaligned/put_unaligned. Others are
unable to perform such accesses efficiently (e.g. trap on
unaligned access and require fixing it up in the exception
handler.)
This symbol should be selected by an architecture if it can
perform unaligned accesses efficiently to allow different
code paths to be selected for these cases. Some network
drivers, for example, could opt to not fix up alignment
problems with received packets if doing so would not help
much.
See Documentation/unaligned-memory-access.txt for more
information on the topic of unaligned memory accesses.
config ARCH_USE_BUILTIN_BSWAP
bool
help
Modern versions of GCC (since 4.4) have builtin functions
for handling byte-swapping. Using these, instead of the old
inline assembler that the architecture code provides in the
__arch_bswapXX() macros, allows the compiler to see what's
happening and offers more opportunity for optimisation. In
particular, the compiler will be able to combine the byteswap
with a nearby load or store and use load-and-swap or
store-and-swap instructions if the architecture has them. It
should almost *never* result in code which is worse than the
hand-coded assembler in <asm/swab.h>. But just in case it
does, the use of the builtins is optional.
Any architecture with load-and-swap or store-and-swap
instructions should set this. And it shouldn't hurt to set it
on architectures that don't have such instructions.
config KRETPROBES
def_bool y
depends on KPROBES && HAVE_KRETPROBES
config USER_RETURN_NOTIFIER
bool
depends on HAVE_USER_RETURN_NOTIFIER
help
Provide a kernel-internal notification when a cpu is about to
switch to user mode.
config HAVE_IOREMAP_PROT
bool
config HAVE_KPROBES
bool
config HAVE_KRETPROBES
bool
kprobes: Introduce kprobes jump optimization Introduce kprobes jump optimization arch-independent parts. Kprobes uses breakpoint instruction for interrupting execution flow, on some architectures, it can be replaced by a jump instruction and interruption emulation code. This gains kprobs' performance drastically. To enable this feature, set CONFIG_OPTPROBES=y (default y if the arch supports OPTPROBE). Changes in v9: - Fix a bug to optimize probe when enabling. - Check nearby probes can be optimize/unoptimize when disarming/arming kprobes, instead of registering/unregistering. This will help kprobe-tracer because most of probes on it are usually disabled. Changes in v6: - Cleanup coding style for readability. - Add comments around get/put_online_cpus(). Changes in v5: - Use get_online_cpus()/put_online_cpus() for avoiding text_mutex deadlock. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 13:34:07 +00:00
config HAVE_OPTPROBES
bool
config HAVE_KPROBES_ON_FTRACE
bool
printk/nmi: generic solution for safe printk in NMI printk() takes some locks and could not be used a safe way in NMI context. The chance of a deadlock is real especially when printing stacks from all CPUs. This particular problem has been addressed on x86 by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). The patchset brings two big advantages. First, it makes the NMI backtraces safe on all architectures for free. Second, it makes all NMI messages almost safe on all architectures (the temporary buffer is limited. We still should keep the number of messages in NMI context at minimum). Note that there already are several messages printed in NMI context: WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE handlers. These are not easy to avoid. This patch reuses most of the code and makes it generic. It is useful for all messages and architectures that support NMI. The alternative printk_func is set when entering and is reseted when leaving NMI context. It queues IRQ work to copy the messages into the main ring buffer in a safe context. __printk_nmi_flush() copies all available messages and reset the buffer. Then we could use a simple cmpxchg operations to get synchronized with writers. There is also used a spinlock to get synchronized with other flushers. We do not longer use seq_buf because it depends on external lock. It would be hard to make all supported operations safe for a lockless use. It would be confusing and error prone to make only some operations safe. The code is put into separate printk/nmi.c as suggested by Steven Rostedt. It needs a per-CPU buffer and is compiled only on architectures that call nmi_enter(). This is achieved by the new HAVE_NMI Kconfig flag. The are MN10300 and Xtensa architectures. We need to clean up NMI handling there first. Let's do it separately. The patch is heavily based on the draft from Peter Zijlstra, see https://lkml.org/lkml/2015/6/10/327 [arnd@arndb.de: printk-nmi: use %zu format string for size_t] [akpm@linux-foundation.org: min_t->min - all types are size_t here] Signed-off-by: Petr Mladek <pmladek@suse.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part] Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 00:00:33 +00:00
config HAVE_NMI
bool
config HAVE_NMI_WATCHDOG
printk/nmi: generic solution for safe printk in NMI printk() takes some locks and could not be used a safe way in NMI context. The chance of a deadlock is real especially when printing stacks from all CPUs. This particular problem has been addressed on x86 by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). The patchset brings two big advantages. First, it makes the NMI backtraces safe on all architectures for free. Second, it makes all NMI messages almost safe on all architectures (the temporary buffer is limited. We still should keep the number of messages in NMI context at minimum). Note that there already are several messages printed in NMI context: WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE handlers. These are not easy to avoid. This patch reuses most of the code and makes it generic. It is useful for all messages and architectures that support NMI. The alternative printk_func is set when entering and is reseted when leaving NMI context. It queues IRQ work to copy the messages into the main ring buffer in a safe context. __printk_nmi_flush() copies all available messages and reset the buffer. Then we could use a simple cmpxchg operations to get synchronized with writers. There is also used a spinlock to get synchronized with other flushers. We do not longer use seq_buf because it depends on external lock. It would be hard to make all supported operations safe for a lockless use. It would be confusing and error prone to make only some operations safe. The code is put into separate printk/nmi.c as suggested by Steven Rostedt. It needs a per-CPU buffer and is compiled only on architectures that call nmi_enter(). This is achieved by the new HAVE_NMI Kconfig flag. The are MN10300 and Xtensa architectures. We need to clean up NMI handling there first. Let's do it separately. The patch is heavily based on the draft from Peter Zijlstra, see https://lkml.org/lkml/2015/6/10/327 [arnd@arndb.de: printk-nmi: use %zu format string for size_t] [akpm@linux-foundation.org: min_t->min - all types are size_t here] Signed-off-by: Petr Mladek <pmladek@suse.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part] Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 00:00:33 +00:00
depends on HAVE_NMI
bool
#
# An arch should select this if it provides all these things:
#
# task_pt_regs() in asm/processor.h or asm/ptrace.h
# arch_has_single_step() if there is hardware single-step support
# arch_has_block_step() if there is hardware block-step support
# asm/syscall.h supplying asm-generic/syscall.h interface
# linux/regset.h user_regset interfaces
# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
# TIF_NOTIFY_RESUME calls tracehook_notify_resume()
# signal delivery calls tracehook_signal_handler()
#
config HAVE_ARCH_TRACEHOOK
bool
config HAVE_DMA_CONTIGUOUS
bool
smp: Provide generic idle thread allocation All SMP architectures have magic to fork the idle task and to store it for reusage when cpu hotplug is enabled. Provide a generic infrastructure for it. Create/reinit the idle thread for the cpu which is brought up in the generic code and hand the thread pointer to the architecture code via __cpu_up(). Note, that fork_idle() is called via a workqueue, because this guarantees that the idle thread does not get a reference to a user space VM. This can happen when the boot process did not bring up all possible cpus and a later cpu_up() is initiated via the sysfs interface. In that case fork_idle() would be called in the context of the user space task and take a reference on the user space VM. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: David S. Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Richard Weinberger <richard@nod.at> Cc: x86@kernel.org Acked-by: Venkatesh Pallipadi <venki@google.com> Link: http://lkml.kernel.org/r/20120420124557.102478630@linutronix.de
2012-04-20 13:05:45 +00:00
config GENERIC_SMP_IDLE_THREAD
bool
config GENERIC_IDLE_POLL_SETUP
bool
# Select if arch init_task initializer is different to init/init_task.c
config ARCH_INIT_TASK
2012-05-03 09:02:48 +00:00
bool
# Select if arch has its private alloc_task_struct() function
config ARCH_TASK_STRUCT_ALLOCATOR
bool
Clarify naming of thread info/stack allocators We've had the thread info allocated together with the thread stack for most architectures for a long time (since the thread_info was split off from the task struct), but that is about to change. But the patches that move the thread info to be off-stack (and a part of the task struct instead) made it clear how confused the allocator and freeing functions are. Because the common case was that we share an allocation with the thread stack and the thread_info, the two pointers were identical. That identity then meant that we would have things like ti = alloc_thread_info_node(tsk, node); ... tsk->stack = ti; which certainly _worked_ (since stack and thread_info have the same value), but is rather confusing: why are we assigning a thread_info to the stack? And if we move the thread_info away, the "confusing" code just gets to be entirely bogus. So remove all this confusion, and make it clear that we are doing the stack allocation by renaming and clarifying the function names to be about the stack. The fact that the thread_info then shares the allocation is an implementation detail, and not really about the allocation itself. This is a pure renaming and type fix: we pass in the same pointer, it's just that we clarify what the pointer means. The ia64 code that actually only has one single allocation (for all of task_struct, thread_info and kernel thread stack) now looks a bit odd, but since "tsk->stack" is actually not even used there, that oddity doesn't matter. It would be a separate thing to clean that up, I intentionally left the ia64 changes as a pure brute-force renaming and type change. Acked-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24 22:09:37 +00:00
# Select if arch has its private alloc_thread_stack() function
config ARCH_THREAD_STACK_ALLOCATOR
bool
# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
config ARCH_WANTS_DYNAMIC_TASK_STRUCT
bool
config HAVE_REGS_AND_STACK_ACCESS_API
bool
help
This symbol should be selected by an architecure if it supports
the API needed to access registers and stack entries from pt_regs,
declared in asm/ptrace.h
For example the kprobes-based event tracer needs this API.
config HAVE_CLK
bool
help
The <linux/clk.h> calls support software clock gating and
thus are a key power management tool on many systems.
config HAVE_DMA_API_DEBUG
bool
config HAVE_HW_BREAKPOINT
bool
hw-breakpoints: Fix hardware breakpoints -> perf events dependency The kbuild's select command doesn't propagate through the config dependencies. Hence the current rules of hardware breakpoint's config can't ensure perf can never be disabled under us. We have: config X86 selects HAVE_HW_BREAKPOINTS config HAVE_HW_BREAKPOINTS select PERF_EVENTS config PERF_EVENTS [...] x86 will select the breakpoints but that won't propagate to perf events. The user can still disable the latter, but it is necessary for the breakpoints. What we need is: - x86 selects HAVE_HW_BREAKPOINTS and PERF_EVENTS - HAVE_HW_BREAKPOINTS depends on PERF_EVENTS so that we ensure PERF_EVENTS is enabled and frozen for x86. This fixes the following kind of build errors: In file included from arch/x86/kernel/hw_breakpoint.c:31: include/linux/hw_breakpoint.h: In function 'hw_breakpoint_addr': include/linux/hw_breakpoint.h:39: error: 'struct perf_event' has no member named 'attr' v2: Select also ANON_INODES from x86, required for perf Reported-by: Cyrill Gorcunov <gorcunov@gmail.com> Reported-by: Michal Marek <mmarek@suse.cz> Reported-by: Andrew Randrianasulu <randrik_a@yahoo.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> LKML-Reference: <1261010034-7786-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-17 00:33:54 +00:00
depends on PERF_EVENTS
config HAVE_MIXED_BREAKPOINTS_REGS
bool
depends on HAVE_HW_BREAKPOINT
help
Depending on the arch implementation of hardware breakpoints,
some of them have separate registers for data and instruction
breakpoints addresses, others have mixed registers to store
them but define the access type in a control register.
Select this option if your arch implements breakpoints under the
latter fashion.
config HAVE_USER_RETURN_NOTIFIER
bool
config HAVE_PERF_EVENTS_NMI
bool
help
System hardware can generate an NMI using the perf event
subsystem. Also has support for calculating CPU cycle events
to determine how many clock cycles in a given period.
perf: Unified API to record selective sets of arch registers This brings a new API to help the selective dump of registers on event sampling, and its implementation for x86 arch. Added HAVE_PERF_REGS config option to determine if the architecture provides perf registers ABI. The information about desired registers will be passed in u64 mask. It's up to the architecture to map the registers into the mask bits. For the x86 arch implementation, both 32 and 64 bit registers bits are defined within single enum to ensure 64 bit system can provide register dump for compat task if needed in the future. Original-patch-by: Frederic Weisbecker <fweisbec@gmail.com> [ Added missing linux/errno.h include ] Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: "Frank Ch. Eigler" <fche@redhat.com> Cc: Arun Sharma <asharma@fb.com> Cc: Benjamin Redelings <benjamin.redelings@nescent.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Ulrich Drepper <drepper@gmail.com> Link: http://lkml.kernel.org/r/1344345647-11536-2-git-send-email-jolsa@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-07 13:20:36 +00:00
config HAVE_PERF_REGS
bool
help
Support selective register dumps for perf events. This includes
bit-mapping of each registers and a unique architecture id.
2012-08-07 13:20:40 +00:00
config HAVE_PERF_USER_STACK_DUMP
bool
help
Support user stack dumps for perf event samples. This needs
access to the user stack pointer which is not unified across
architectures.
config HAVE_ARCH_JUMP_LABEL
bool
config HAVE_RCU_TABLE_FREE
bool
Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG cmpxchg() is widely used by lockless code, including NMI-safe lockless code. But on some architectures, the cmpxchg() implementation is not NMI-safe, on these architectures the lockless code may need a spin_trylock_irqsave() based implementation. This patch adds a Kconfig option: ARCH_HAVE_NMI_SAFE_CMPXCHG, so that NMI-safe lockless code can depend on it or provide different implementation according to it. On many architectures, cmpxchg is only NMI-safe for several specific operand sizes. So, ARCH_HAVE_NMI_SAFE_CMPXCHG define in this patch only guarantees cmpxchg is NMI-safe for sizeof(unsigned long). Signed-off-by: Huang Ying <ying.huang@intel.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Richard Henderson <rth@twiddle.net> CC: Mikael Starvik <starvik@axis.com> Acked-by: David Howells <dhowells@redhat.com> CC: Yoshinori Sato <ysato@users.sourceforge.jp> CC: Tony Luck <tony.luck@intel.com> CC: Hirokazu Takata <takata@linux-m32r.org> CC: Geert Uytterhoeven <geert@linux-m68k.org> CC: Michal Simek <monstr@monstr.eu> Acked-by: Ralf Baechle <ralf@linux-mips.org> CC: Kyle McMartin <kyle@mcmartin.ca> CC: Martin Schwidefsky <schwidefsky@de.ibm.com> CC: Chen Liqin <liqin.chen@sunplusct.com> CC: "David S. Miller" <davem@davemloft.net> CC: Ingo Molnar <mingo@redhat.com> CC: Chris Zankel <chris@zankel.net> Signed-off-by: Len Brown <len.brown@intel.com>
2011-07-13 05:14:22 +00:00
config ARCH_HAVE_NMI_SAFE_CMPXCHG
bool
config HAVE_ALIGNED_STRUCT_PAGE
bool
help
This makes sure that struct pages are double word aligned and that
e.g. the SLUB allocator can perform double word atomic operations
on a struct page for better performance. However selecting this
might increase the size of a struct page by a word.
config HAVE_CMPXCHG_LOCAL
bool
config HAVE_CMPXCHG_DOUBLE
bool
config ARCH_WANT_IPC_PARSE_VERSION
bool
config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
bool
2012-03-15 17:13:38 +00:00
config ARCH_WANT_OLD_COMPAT_IPC
select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
2012-03-15 17:13:38 +00:00
bool
seccomp: add system call filtering using BPF [This patch depends on luto@mit.edu's no_new_privs patch: https://lkml.org/lkml/2012/1/30/264 The whole series including Andrew's patches can be found here: https://github.com/redpig/linux/tree/seccomp Complete diff here: https://github.com/redpig/linux/compare/1dc65fed...seccomp ] This patch adds support for seccomp mode 2. Mode 2 introduces the ability for unprivileged processes to install system call filtering policy expressed in terms of a Berkeley Packet Filter (BPF) program. This program will be evaluated in the kernel for each system call the task makes and computes a result based on data in the format of struct seccomp_data. A filter program may be installed by calling: struct sock_fprog fprog = { ... }; ... prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &fprog); The return value of the filter program determines if the system call is allowed to proceed or denied. If the first filter program installed allows prctl(2) calls, then the above call may be made repeatedly by a task to further reduce its access to the kernel. All attached programs must be evaluated before a system call will be allowed to proceed. Filter programs will be inherited across fork/clone and execve. However, if the task attaching the filter is unprivileged (!CAP_SYS_ADMIN) the no_new_privs bit will be set on the task. This ensures that unprivileged tasks cannot attach filters that affect privileged tasks (e.g., setuid binary). There are a number of benefits to this approach. A few of which are as follows: - BPF has been exposed to userland for a long time - BPF optimization (and JIT'ing) are well understood - Userland already knows its ABI: system call numbers and desired arguments - No time-of-check-time-of-use vulnerable data accesses are possible. - system call arguments are loaded on access only to minimize copying required for system call policy decisions. Mode 2 support is restricted to architectures that enable HAVE_ARCH_SECCOMP_FILTER. In this patch, the primary dependency is on syscall_get_arguments(). The full desired scope of this feature will add a few minor additional requirements expressed later in this series. Based on discussion, SECCOMP_RET_ERRNO and SECCOMP_RET_TRACE seem to be the desired additional functionality. No architectures are enabled in this patch. Signed-off-by: Will Drewry <wad@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reviewed-by: Indan Zupancic <indan@nul.nu> Acked-by: Eric Paris <eparis@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> v18: - rebase to v3.4-rc2 - s/chk/check/ (akpm@linux-foundation.org,jmorris@namei.org) - allocate with GFP_KERNEL|__GFP_NOWARN (indan@nul.nu) - add a comment for get_u32 regarding endianness (akpm@) - fix other typos, style mistakes (akpm@) - added acked-by v17: - properly guard seccomp filter needed headers (leann@ubuntu.com) - tighten return mask to 0x7fff0000 v16: - no change v15: - add a 4 instr penalty when counting a path to account for seccomp_filter size (indan@nul.nu) - drop the max insns to 256KB (indan@nul.nu) - return ENOMEM if the max insns limit has been hit (indan@nul.nu) - move IP checks after args (indan@nul.nu) - drop !user_filter check (indan@nul.nu) - only allow explicit bpf codes (indan@nul.nu) - exit_code -> exit_sig v14: - put/get_seccomp_filter takes struct task_struct (indan@nul.nu,keescook@chromium.org) - adds seccomp_chk_filter and drops general bpf_run/chk_filter user - add seccomp_bpf_load for use by net/core/filter.c - lower max per-process/per-hierarchy: 1MB - moved nnp/capability check prior to allocation (all of the above: indan@nul.nu) v13: - rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc v12: - added a maximum instruction count per path (indan@nul.nu,oleg@redhat.com) - removed copy_seccomp (keescook@chromium.org,indan@nul.nu) - reworded the prctl_set_seccomp comment (indan@nul.nu) v11: - reorder struct seccomp_data to allow future args expansion (hpa@zytor.com) - style clean up, @compat dropped, compat_sock_fprog32 (indan@nul.nu) - do_exit(SIGSYS) (keescook@chromium.org, luto@mit.edu) - pare down Kconfig doc reference. - extra comment clean up v10: - seccomp_data has changed again to be more aesthetically pleasing (hpa@zytor.com) - calling convention is noted in a new u32 field using syscall_get_arch. This allows for cross-calling convention tasks to use seccomp filters. (hpa@zytor.com) - lots of clean up (thanks, Indan!) v9: - n/a v8: - use bpf_chk_filter, bpf_run_filter. update load_fns - Lots of fixes courtesy of indan@nul.nu: -- fix up load behavior, compat fixups, and merge alloc code, -- renamed pc and dropped __packed, use bool compat. -- Added a hidden CONFIG_SECCOMP_FILTER to synthesize non-arch dependencies v7: (massive overhaul thanks to Indan, others) - added CONFIG_HAVE_ARCH_SECCOMP_FILTER - merged into seccomp.c - minimal seccomp_filter.h - no config option (part of seccomp) - no new prctl - doesn't break seccomp on systems without asm/syscall.h (works but arg access always fails) - dropped seccomp_init_task, extra free functions, ... - dropped the no-asm/syscall.h code paths - merges with network sk_run_filter and sk_chk_filter v6: - fix memory leak on attach compat check failure - require no_new_privs || CAP_SYS_ADMIN prior to filter installation. (luto@mit.edu) - s/seccomp_struct_/seccomp_/ for macros/functions (amwang@redhat.com) - cleaned up Kconfig (amwang@redhat.com) - on block, note if the call was compat (so the # means something) v5: - uses syscall_get_arguments (indan@nul.nu,oleg@redhat.com, mcgrathr@chromium.org) - uses union-based arg storage with hi/lo struct to handle endianness. Compromises between the two alternate proposals to minimize extra arg shuffling and account for endianness assuming userspace uses offsetof(). (mcgrathr@chromium.org, indan@nul.nu) - update Kconfig description - add include/seccomp_filter.h and add its installation - (naive) on-demand syscall argument loading - drop seccomp_t (eparis@redhat.com) v4: - adjusted prctl to make room for PR_[SG]ET_NO_NEW_PRIVS - now uses current->no_new_privs (luto@mit.edu,torvalds@linux-foundation.com) - assign names to seccomp modes (rdunlap@xenotime.net) - fix style issues (rdunlap@xenotime.net) - reworded Kconfig entry (rdunlap@xenotime.net) v3: - macros to inline (oleg@redhat.com) - init_task behavior fixed (oleg@redhat.com) - drop creator entry and extra NULL check (oleg@redhat.com) - alloc returns -EINVAL on bad sizing (serge.hallyn@canonical.com) - adds tentative use of "always_unprivileged" as per torvalds@linux-foundation.org and luto@mit.edu v2: - (patch 2 only) Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-12 21:47:57 +00:00
config HAVE_ARCH_SECCOMP_FILTER
bool
help
ptrace,seccomp: Add PTRACE_SECCOMP support This change adds support for a new ptrace option, PTRACE_O_TRACESECCOMP, and a new return value for seccomp BPF programs, SECCOMP_RET_TRACE. When a tracer specifies the PTRACE_O_TRACESECCOMP ptrace option, the tracer will be notified, via PTRACE_EVENT_SECCOMP, for any syscall that results in a BPF program returning SECCOMP_RET_TRACE. The 16-bit SECCOMP_RET_DATA mask of the BPF program return value will be passed as the ptrace_message and may be retrieved using PTRACE_GETEVENTMSG. If the subordinate process is not using seccomp filter, then no system call notifications will occur even if the option is specified. If there is no tracer with PTRACE_O_TRACESECCOMP when SECCOMP_RET_TRACE is returned, the system call will not be executed and an -ENOSYS errno will be returned to userspace. This change adds a dependency on the system call slow path. Any future efforts to use the system call fast path for seccomp filter will need to address this restriction. Signed-off-by: Will Drewry <wad@chromium.org> Acked-by: Eric Paris <eparis@redhat.com> v18: - rebase - comment fatal_signal check - acked-by - drop secure_computing_int comment v17: - ... v16: - update PT_TRACE_MASK to 0xbf4 so that STOP isn't clear on SETOPTIONS call (indan@nul.nu) [note PT_TRACE_MASK disappears in linux-next] v15: - add audit support for non-zero return codes - clean up style (indan@nul.nu) v14: - rebase/nochanges v13: - rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc (Brings back a change to ptrace.c and the masks.) v12: - rebase to linux-next - use ptrace_event and update arch/Kconfig to mention slow-path dependency - drop all tracehook changes and inclusion (oleg@redhat.com) v11: - invert the logic to just make it a PTRACE_SYSCALL accelerator (indan@nul.nu) v10: - moved to PTRACE_O_SECCOMP / PT_TRACE_SECCOMP v9: - n/a v8: - guarded PTRACE_SECCOMP use with an ifdef v7: - introduced Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-12 21:48:02 +00:00
An arch should select this symbol if it provides all of these things:
- syscall_get_arch()
- syscall_get_arguments()
- syscall_rollback()
- syscall_set_return_value()
ptrace,seccomp: Add PTRACE_SECCOMP support This change adds support for a new ptrace option, PTRACE_O_TRACESECCOMP, and a new return value for seccomp BPF programs, SECCOMP_RET_TRACE. When a tracer specifies the PTRACE_O_TRACESECCOMP ptrace option, the tracer will be notified, via PTRACE_EVENT_SECCOMP, for any syscall that results in a BPF program returning SECCOMP_RET_TRACE. The 16-bit SECCOMP_RET_DATA mask of the BPF program return value will be passed as the ptrace_message and may be retrieved using PTRACE_GETEVENTMSG. If the subordinate process is not using seccomp filter, then no system call notifications will occur even if the option is specified. If there is no tracer with PTRACE_O_TRACESECCOMP when SECCOMP_RET_TRACE is returned, the system call will not be executed and an -ENOSYS errno will be returned to userspace. This change adds a dependency on the system call slow path. Any future efforts to use the system call fast path for seccomp filter will need to address this restriction. Signed-off-by: Will Drewry <wad@chromium.org> Acked-by: Eric Paris <eparis@redhat.com> v18: - rebase - comment fatal_signal check - acked-by - drop secure_computing_int comment v17: - ... v16: - update PT_TRACE_MASK to 0xbf4 so that STOP isn't clear on SETOPTIONS call (indan@nul.nu) [note PT_TRACE_MASK disappears in linux-next] v15: - add audit support for non-zero return codes - clean up style (indan@nul.nu) v14: - rebase/nochanges v13: - rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc (Brings back a change to ptrace.c and the masks.) v12: - rebase to linux-next - use ptrace_event and update arch/Kconfig to mention slow-path dependency - drop all tracehook changes and inclusion (oleg@redhat.com) v11: - invert the logic to just make it a PTRACE_SYSCALL accelerator (indan@nul.nu) v10: - moved to PTRACE_O_SECCOMP / PT_TRACE_SECCOMP v9: - n/a v8: - guarded PTRACE_SECCOMP use with an ifdef v7: - introduced Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-12 21:48:02 +00:00
- SIGSYS siginfo_t support
- secure_computing is called from a ptrace_event()-safe context
- secure_computing return value is checked and a return value of -1
results in the system call being skipped immediately.
- seccomp syscall wired up
seccomp: add system call filtering using BPF [This patch depends on luto@mit.edu's no_new_privs patch: https://lkml.org/lkml/2012/1/30/264 The whole series including Andrew's patches can be found here: https://github.com/redpig/linux/tree/seccomp Complete diff here: https://github.com/redpig/linux/compare/1dc65fed...seccomp ] This patch adds support for seccomp mode 2. Mode 2 introduces the ability for unprivileged processes to install system call filtering policy expressed in terms of a Berkeley Packet Filter (BPF) program. This program will be evaluated in the kernel for each system call the task makes and computes a result based on data in the format of struct seccomp_data. A filter program may be installed by calling: struct sock_fprog fprog = { ... }; ... prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &fprog); The return value of the filter program determines if the system call is allowed to proceed or denied. If the first filter program installed allows prctl(2) calls, then the above call may be made repeatedly by a task to further reduce its access to the kernel. All attached programs must be evaluated before a system call will be allowed to proceed. Filter programs will be inherited across fork/clone and execve. However, if the task attaching the filter is unprivileged (!CAP_SYS_ADMIN) the no_new_privs bit will be set on the task. This ensures that unprivileged tasks cannot attach filters that affect privileged tasks (e.g., setuid binary). There are a number of benefits to this approach. A few of which are as follows: - BPF has been exposed to userland for a long time - BPF optimization (and JIT'ing) are well understood - Userland already knows its ABI: system call numbers and desired arguments - No time-of-check-time-of-use vulnerable data accesses are possible. - system call arguments are loaded on access only to minimize copying required for system call policy decisions. Mode 2 support is restricted to architectures that enable HAVE_ARCH_SECCOMP_FILTER. In this patch, the primary dependency is on syscall_get_arguments(). The full desired scope of this feature will add a few minor additional requirements expressed later in this series. Based on discussion, SECCOMP_RET_ERRNO and SECCOMP_RET_TRACE seem to be the desired additional functionality. No architectures are enabled in this patch. Signed-off-by: Will Drewry <wad@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reviewed-by: Indan Zupancic <indan@nul.nu> Acked-by: Eric Paris <eparis@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> v18: - rebase to v3.4-rc2 - s/chk/check/ (akpm@linux-foundation.org,jmorris@namei.org) - allocate with GFP_KERNEL|__GFP_NOWARN (indan@nul.nu) - add a comment for get_u32 regarding endianness (akpm@) - fix other typos, style mistakes (akpm@) - added acked-by v17: - properly guard seccomp filter needed headers (leann@ubuntu.com) - tighten return mask to 0x7fff0000 v16: - no change v15: - add a 4 instr penalty when counting a path to account for seccomp_filter size (indan@nul.nu) - drop the max insns to 256KB (indan@nul.nu) - return ENOMEM if the max insns limit has been hit (indan@nul.nu) - move IP checks after args (indan@nul.nu) - drop !user_filter check (indan@nul.nu) - only allow explicit bpf codes (indan@nul.nu) - exit_code -> exit_sig v14: - put/get_seccomp_filter takes struct task_struct (indan@nul.nu,keescook@chromium.org) - adds seccomp_chk_filter and drops general bpf_run/chk_filter user - add seccomp_bpf_load for use by net/core/filter.c - lower max per-process/per-hierarchy: 1MB - moved nnp/capability check prior to allocation (all of the above: indan@nul.nu) v13: - rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc v12: - added a maximum instruction count per path (indan@nul.nu,oleg@redhat.com) - removed copy_seccomp (keescook@chromium.org,indan@nul.nu) - reworded the prctl_set_seccomp comment (indan@nul.nu) v11: - reorder struct seccomp_data to allow future args expansion (hpa@zytor.com) - style clean up, @compat dropped, compat_sock_fprog32 (indan@nul.nu) - do_exit(SIGSYS) (keescook@chromium.org, luto@mit.edu) - pare down Kconfig doc reference. - extra comment clean up v10: - seccomp_data has changed again to be more aesthetically pleasing (hpa@zytor.com) - calling convention is noted in a new u32 field using syscall_get_arch. This allows for cross-calling convention tasks to use seccomp filters. (hpa@zytor.com) - lots of clean up (thanks, Indan!) v9: - n/a v8: - use bpf_chk_filter, bpf_run_filter. update load_fns - Lots of fixes courtesy of indan@nul.nu: -- fix up load behavior, compat fixups, and merge alloc code, -- renamed pc and dropped __packed, use bool compat. -- Added a hidden CONFIG_SECCOMP_FILTER to synthesize non-arch dependencies v7: (massive overhaul thanks to Indan, others) - added CONFIG_HAVE_ARCH_SECCOMP_FILTER - merged into seccomp.c - minimal seccomp_filter.h - no config option (part of seccomp) - no new prctl - doesn't break seccomp on systems without asm/syscall.h (works but arg access always fails) - dropped seccomp_init_task, extra free functions, ... - dropped the no-asm/syscall.h code paths - merges with network sk_run_filter and sk_chk_filter v6: - fix memory leak on attach compat check failure - require no_new_privs || CAP_SYS_ADMIN prior to filter installation. (luto@mit.edu) - s/seccomp_struct_/seccomp_/ for macros/functions (amwang@redhat.com) - cleaned up Kconfig (amwang@redhat.com) - on block, note if the call was compat (so the # means something) v5: - uses syscall_get_arguments (indan@nul.nu,oleg@redhat.com, mcgrathr@chromium.org) - uses union-based arg storage with hi/lo struct to handle endianness. Compromises between the two alternate proposals to minimize extra arg shuffling and account for endianness assuming userspace uses offsetof(). (mcgrathr@chromium.org, indan@nul.nu) - update Kconfig description - add include/seccomp_filter.h and add its installation - (naive) on-demand syscall argument loading - drop seccomp_t (eparis@redhat.com) v4: - adjusted prctl to make room for PR_[SG]ET_NO_NEW_PRIVS - now uses current->no_new_privs (luto@mit.edu,torvalds@linux-foundation.com) - assign names to seccomp modes (rdunlap@xenotime.net) - fix style issues (rdunlap@xenotime.net) - reworded Kconfig entry (rdunlap@xenotime.net) v3: - macros to inline (oleg@redhat.com) - init_task behavior fixed (oleg@redhat.com) - drop creator entry and extra NULL check (oleg@redhat.com) - alloc returns -EINVAL on bad sizing (serge.hallyn@canonical.com) - adds tentative use of "always_unprivileged" as per torvalds@linux-foundation.org and luto@mit.edu v2: - (patch 2 only) Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-12 21:47:57 +00:00
config SECCOMP_FILTER
def_bool y
depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
help
Enable tasks to build secure computing environments defined
in terms of Berkeley Packet Filter programs which implement
task-defined system call filtering polices.
See Documentation/prctl/seccomp_filter.txt for details.
GCC plugin infrastructure This patch allows to build the whole kernel with GCC plugins. It was ported from grsecurity/PaX. The infrastructure supports building out-of-tree modules and building in a separate directory. Cross-compilation is supported too. Currently the x86, arm, arm64 and uml architectures enable plugins. The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory there. The plugins compile with these options: * -fno-rtti: gcc is compiled with this option so the plugins must use it too * -fno-exceptions: this is inherited from gcc too * -fasynchronous-unwind-tables: this is inherited from gcc too * -ggdb: it is useful for debugging a plugin (better backtrace on internal errors) * -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h) * -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version variable, plugin-version.h) The infrastructure introduces a new Makefile target called gcc-plugins. It supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++). This script also checks the availability of the included headers in scripts/gcc-plugins/gcc-common.h. The gcc-common.h header contains frequently included headers for GCC plugins and it has a compatibility layer for the supported gcc versions. The gcc-generate-*-pass.h headers automatically generate the registration structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes. Note that 'make clean' keeps the *.so files (only the distclean or mrproper targets clean all) because they are needed for out-of-tree modules. Based on work created by the PaX Team. Signed-off-by: Emese Revfy <re.emese@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-05-23 22:09:38 +00:00
config HAVE_GCC_PLUGINS
bool
help
An arch should select this symbol if it supports building with
GCC plugins.
menuconfig GCC_PLUGINS
bool "GCC plugins"
depends on HAVE_GCC_PLUGINS
depends on !COMPILE_TEST
GCC plugin infrastructure This patch allows to build the whole kernel with GCC plugins. It was ported from grsecurity/PaX. The infrastructure supports building out-of-tree modules and building in a separate directory. Cross-compilation is supported too. Currently the x86, arm, arm64 and uml architectures enable plugins. The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory there. The plugins compile with these options: * -fno-rtti: gcc is compiled with this option so the plugins must use it too * -fno-exceptions: this is inherited from gcc too * -fasynchronous-unwind-tables: this is inherited from gcc too * -ggdb: it is useful for debugging a plugin (better backtrace on internal errors) * -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h) * -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version variable, plugin-version.h) The infrastructure introduces a new Makefile target called gcc-plugins. It supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++). This script also checks the availability of the included headers in scripts/gcc-plugins/gcc-common.h. The gcc-common.h header contains frequently included headers for GCC plugins and it has a compatibility layer for the supported gcc versions. The gcc-generate-*-pass.h headers automatically generate the registration structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes. Note that 'make clean' keeps the *.so files (only the distclean or mrproper targets clean all) because they are needed for out-of-tree modules. Based on work created by the PaX Team. Signed-off-by: Emese Revfy <re.emese@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-05-23 22:09:38 +00:00
help
GCC plugins are loadable modules that provide extra features to the
compiler. They are useful for runtime instrumentation and static analysis.
See Documentation/gcc-plugins.txt for details.
config GCC_PLUGIN_CYC_COMPLEXITY
bool "Compute the cyclomatic complexity of a function"
depends on GCC_PLUGINS
help
The complexity M of a function's control flow graph is defined as:
M = E - N + 2P
where
E = the number of edges
N = the number of nodes
P = the number of connected components (exit nodes).
config GCC_PLUGIN_SANCOV
bool
depends on GCC_PLUGINS
help
This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
basic blocks. It supports all gcc versions with plugin support (from
gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
by Dmitry Vyukov <dvyukov@google.com>.
gcc-plugins: Add latent_entropy plugin This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals. The need for very-early boot entropy tends to be very architecture or system design specific, so this plugin is more suited for those sorts of special cases. The existing kernel RNG already attempts to extract entropy from reliable runtime variation, but this plugin takes the idea to a logical extreme by permuting a global variable based on any variation in code execution (e.g. a different value (and permutation function) is used to permute the global based on loop count, case statement, if/then/else branching, etc). To do this, the plugin starts by inserting a local variable in every marked function. The plugin then adds logic so that the value of this variable is modified by randomly chosen operations (add, xor and rol) and random values (gcc generates separate static values for each location at compile time and also injects the stack pointer at runtime). The resulting value depends on the control flow path (e.g., loops and branches taken). Before the function returns, the plugin mixes this local variable into the latent_entropy global variable. The value of this global variable is added to the kernel entropy pool in do_one_initcall() and _do_fork(), though it does not credit any bytes of entropy to the pool; the contents of the global are just used to mix the pool. Additionally, the plugin can pre-initialize arrays with build-time random contents, so that two different kernel builds running on identical hardware will not have the same starting values. Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: expanded commit message and code comments] Signed-off-by: Kees Cook <keescook@chromium.org>
2016-06-20 18:41:19 +00:00
config GCC_PLUGIN_LATENT_ENTROPY
bool "Generate some entropy during boot and runtime"
depends on GCC_PLUGINS
help
By saying Y here the kernel will instrument some kernel code to
extract some entropy from both original and artificially created
program state. This will help especially embedded systems where
there is little 'natural' source of entropy normally. The cost
is some slowdown of the boot process (about 0.5%) and fork and
irq processing.
Note that entropy extracted this way is not cryptographically
secure!
This plugin was ported from grsecurity/PaX. More information at:
* https://grsecurity.net/
* https://pax.grsecurity.net/
config HAVE_CC_STACKPROTECTOR
bool
help
An arch should select this symbol if:
- its compiler supports the -fstack-protector option
- it has implemented a stack canary (e.g. __stack_chk_guard)
config CC_STACKPROTECTOR
stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG This changes the stack protector config option into a choice of "None", "Regular", and "Strong": CONFIG_CC_STACKPROTECTOR_NONE CONFIG_CC_STACKPROTECTOR_REGULAR CONFIG_CC_STACKPROTECTOR_STRONG "Regular" means the old CONFIG_CC_STACKPROTECTOR=y option. "Strong" is a new mode introduced by this patch. With "Strong" the kernel is built with -fstack-protector-strong (available in gcc 4.9 and later). This option increases the coverage of the stack protector without the heavy performance hit of -fstack-protector-all. For reference, the stack protector options available in gcc are: -fstack-protector-all: Adds the stack-canary saving prefix and stack-canary checking suffix to _all_ function entry and exit. Results in substantial use of stack space for saving the canary for deep stack users (e.g. historically xfs), and measurable (though shockingly still low) performance hit due to all the saving/checking. Really not suitable for sane systems, and was entirely removed as an option from the kernel many years ago. -fstack-protector: Adds the canary save/check to functions that define an 8 (--param=ssp-buffer-size=N, N=8 by default) or more byte local char array. Traditionally, stack overflows happened with string-based manipulations, so this was a way to find those functions. Very few total functions actually get the canary; no measurable performance or size overhead. -fstack-protector-strong Adds the canary for a wider set of functions, since it's not just those with strings that have ultimately been vulnerable to stack-busting. With this superset, more functions end up with a canary, but it still remains small compared to all functions with only a small change in performance. Based on the original design document, a function gets the canary when it contains any of: - local variable's address used as part of the right hand side of an assignment or function argument - local variable is an array (or union containing an array), regardless of array type or length - uses register local variables https://docs.google.com/a/google.com/document/d/1xXBH6rRZue4f296vGt9YQcuLVQHeE516stHwt8M9xyU Find below a comparison of "size" and "objdump" output when built with gcc-4.9 in three configurations: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) With -strong, ARM's compressed boot code now triggers stack protection, so a static guard was added. Since this is only used during decompression and was never used before, the exposure here is very small. Once it switches to the full kernel, the stack guard is back to normal. Chrome OS has been using -fstack-protector-strong for its kernel builds for the last 8 months with no problems. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1387481759-14535-3-git-send-email-keescook@chromium.org [ Improved the changelog and descriptions some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-19 19:35:59 +00:00
def_bool n
help
Set when a stack-protector mode is enabled, so that the build
can enable kernel-side support for the GCC feature.
choice
prompt "Stack Protector buffer overflow detection"
depends on HAVE_CC_STACKPROTECTOR
stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG This changes the stack protector config option into a choice of "None", "Regular", and "Strong": CONFIG_CC_STACKPROTECTOR_NONE CONFIG_CC_STACKPROTECTOR_REGULAR CONFIG_CC_STACKPROTECTOR_STRONG "Regular" means the old CONFIG_CC_STACKPROTECTOR=y option. "Strong" is a new mode introduced by this patch. With "Strong" the kernel is built with -fstack-protector-strong (available in gcc 4.9 and later). This option increases the coverage of the stack protector without the heavy performance hit of -fstack-protector-all. For reference, the stack protector options available in gcc are: -fstack-protector-all: Adds the stack-canary saving prefix and stack-canary checking suffix to _all_ function entry and exit. Results in substantial use of stack space for saving the canary for deep stack users (e.g. historically xfs), and measurable (though shockingly still low) performance hit due to all the saving/checking. Really not suitable for sane systems, and was entirely removed as an option from the kernel many years ago. -fstack-protector: Adds the canary save/check to functions that define an 8 (--param=ssp-buffer-size=N, N=8 by default) or more byte local char array. Traditionally, stack overflows happened with string-based manipulations, so this was a way to find those functions. Very few total functions actually get the canary; no measurable performance or size overhead. -fstack-protector-strong Adds the canary for a wider set of functions, since it's not just those with strings that have ultimately been vulnerable to stack-busting. With this superset, more functions end up with a canary, but it still remains small compared to all functions with only a small change in performance. Based on the original design document, a function gets the canary when it contains any of: - local variable's address used as part of the right hand side of an assignment or function argument - local variable is an array (or union containing an array), regardless of array type or length - uses register local variables https://docs.google.com/a/google.com/document/d/1xXBH6rRZue4f296vGt9YQcuLVQHeE516stHwt8M9xyU Find below a comparison of "size" and "objdump" output when built with gcc-4.9 in three configurations: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) With -strong, ARM's compressed boot code now triggers stack protection, so a static guard was added. Since this is only used during decompression and was never used before, the exposure here is very small. Once it switches to the full kernel, the stack guard is back to normal. Chrome OS has been using -fstack-protector-strong for its kernel builds for the last 8 months with no problems. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1387481759-14535-3-git-send-email-keescook@chromium.org [ Improved the changelog and descriptions some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-19 19:35:59 +00:00
default CC_STACKPROTECTOR_NONE
help
stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG This changes the stack protector config option into a choice of "None", "Regular", and "Strong": CONFIG_CC_STACKPROTECTOR_NONE CONFIG_CC_STACKPROTECTOR_REGULAR CONFIG_CC_STACKPROTECTOR_STRONG "Regular" means the old CONFIG_CC_STACKPROTECTOR=y option. "Strong" is a new mode introduced by this patch. With "Strong" the kernel is built with -fstack-protector-strong (available in gcc 4.9 and later). This option increases the coverage of the stack protector without the heavy performance hit of -fstack-protector-all. For reference, the stack protector options available in gcc are: -fstack-protector-all: Adds the stack-canary saving prefix and stack-canary checking suffix to _all_ function entry and exit. Results in substantial use of stack space for saving the canary for deep stack users (e.g. historically xfs), and measurable (though shockingly still low) performance hit due to all the saving/checking. Really not suitable for sane systems, and was entirely removed as an option from the kernel many years ago. -fstack-protector: Adds the canary save/check to functions that define an 8 (--param=ssp-buffer-size=N, N=8 by default) or more byte local char array. Traditionally, stack overflows happened with string-based manipulations, so this was a way to find those functions. Very few total functions actually get the canary; no measurable performance or size overhead. -fstack-protector-strong Adds the canary for a wider set of functions, since it's not just those with strings that have ultimately been vulnerable to stack-busting. With this superset, more functions end up with a canary, but it still remains small compared to all functions with only a small change in performance. Based on the original design document, a function gets the canary when it contains any of: - local variable's address used as part of the right hand side of an assignment or function argument - local variable is an array (or union containing an array), regardless of array type or length - uses register local variables https://docs.google.com/a/google.com/document/d/1xXBH6rRZue4f296vGt9YQcuLVQHeE516stHwt8M9xyU Find below a comparison of "size" and "objdump" output when built with gcc-4.9 in three configurations: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) With -strong, ARM's compressed boot code now triggers stack protection, so a static guard was added. Since this is only used during decompression and was never used before, the exposure here is very small. Once it switches to the full kernel, the stack guard is back to normal. Chrome OS has been using -fstack-protector-strong for its kernel builds for the last 8 months with no problems. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1387481759-14535-3-git-send-email-keescook@chromium.org [ Improved the changelog and descriptions some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-19 19:35:59 +00:00
This option turns on the "stack-protector" GCC feature. This
feature puts, at the beginning of functions, a canary value on
the stack just before the return address, and validates
the value just before actually returning. Stack based buffer
overflows (that need to overwrite this return address) now also
overwrite the canary, which gets detected and the attack is then
neutralized via a kernel panic.
stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG This changes the stack protector config option into a choice of "None", "Regular", and "Strong": CONFIG_CC_STACKPROTECTOR_NONE CONFIG_CC_STACKPROTECTOR_REGULAR CONFIG_CC_STACKPROTECTOR_STRONG "Regular" means the old CONFIG_CC_STACKPROTECTOR=y option. "Strong" is a new mode introduced by this patch. With "Strong" the kernel is built with -fstack-protector-strong (available in gcc 4.9 and later). This option increases the coverage of the stack protector without the heavy performance hit of -fstack-protector-all. For reference, the stack protector options available in gcc are: -fstack-protector-all: Adds the stack-canary saving prefix and stack-canary checking suffix to _all_ function entry and exit. Results in substantial use of stack space for saving the canary for deep stack users (e.g. historically xfs), and measurable (though shockingly still low) performance hit due to all the saving/checking. Really not suitable for sane systems, and was entirely removed as an option from the kernel many years ago. -fstack-protector: Adds the canary save/check to functions that define an 8 (--param=ssp-buffer-size=N, N=8 by default) or more byte local char array. Traditionally, stack overflows happened with string-based manipulations, so this was a way to find those functions. Very few total functions actually get the canary; no measurable performance or size overhead. -fstack-protector-strong Adds the canary for a wider set of functions, since it's not just those with strings that have ultimately been vulnerable to stack-busting. With this superset, more functions end up with a canary, but it still remains small compared to all functions with only a small change in performance. Based on the original design document, a function gets the canary when it contains any of: - local variable's address used as part of the right hand side of an assignment or function argument - local variable is an array (or union containing an array), regardless of array type or length - uses register local variables https://docs.google.com/a/google.com/document/d/1xXBH6rRZue4f296vGt9YQcuLVQHeE516stHwt8M9xyU Find below a comparison of "size" and "objdump" output when built with gcc-4.9 in three configurations: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) With -strong, ARM's compressed boot code now triggers stack protection, so a static guard was added. Since this is only used during decompression and was never used before, the exposure here is very small. Once it switches to the full kernel, the stack guard is back to normal. Chrome OS has been using -fstack-protector-strong for its kernel builds for the last 8 months with no problems. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1387481759-14535-3-git-send-email-keescook@chromium.org [ Improved the changelog and descriptions some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-19 19:35:59 +00:00
config CC_STACKPROTECTOR_NONE
bool "None"
help
Disable "stack-protector" GCC feature.
config CC_STACKPROTECTOR_REGULAR
bool "Regular"
select CC_STACKPROTECTOR
help
Functions will have the stack-protector canary logic added if they
have an 8-byte or larger character array on the stack.
This feature requires gcc version 4.2 or above, or a distribution
stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG This changes the stack protector config option into a choice of "None", "Regular", and "Strong": CONFIG_CC_STACKPROTECTOR_NONE CONFIG_CC_STACKPROTECTOR_REGULAR CONFIG_CC_STACKPROTECTOR_STRONG "Regular" means the old CONFIG_CC_STACKPROTECTOR=y option. "Strong" is a new mode introduced by this patch. With "Strong" the kernel is built with -fstack-protector-strong (available in gcc 4.9 and later). This option increases the coverage of the stack protector without the heavy performance hit of -fstack-protector-all. For reference, the stack protector options available in gcc are: -fstack-protector-all: Adds the stack-canary saving prefix and stack-canary checking suffix to _all_ function entry and exit. Results in substantial use of stack space for saving the canary for deep stack users (e.g. historically xfs), and measurable (though shockingly still low) performance hit due to all the saving/checking. Really not suitable for sane systems, and was entirely removed as an option from the kernel many years ago. -fstack-protector: Adds the canary save/check to functions that define an 8 (--param=ssp-buffer-size=N, N=8 by default) or more byte local char array. Traditionally, stack overflows happened with string-based manipulations, so this was a way to find those functions. Very few total functions actually get the canary; no measurable performance or size overhead. -fstack-protector-strong Adds the canary for a wider set of functions, since it's not just those with strings that have ultimately been vulnerable to stack-busting. With this superset, more functions end up with a canary, but it still remains small compared to all functions with only a small change in performance. Based on the original design document, a function gets the canary when it contains any of: - local variable's address used as part of the right hand side of an assignment or function argument - local variable is an array (or union containing an array), regardless of array type or length - uses register local variables https://docs.google.com/a/google.com/document/d/1xXBH6rRZue4f296vGt9YQcuLVQHeE516stHwt8M9xyU Find below a comparison of "size" and "objdump" output when built with gcc-4.9 in three configurations: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) With -strong, ARM's compressed boot code now triggers stack protection, so a static guard was added. Since this is only used during decompression and was never used before, the exposure here is very small. Once it switches to the full kernel, the stack guard is back to normal. Chrome OS has been using -fstack-protector-strong for its kernel builds for the last 8 months with no problems. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@linux-mips.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1387481759-14535-3-git-send-email-keescook@chromium.org [ Improved the changelog and descriptions some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-19 19:35:59 +00:00
gcc with the feature backported ("-fstack-protector").
On an x86 "defconfig" build, this feature adds canary checks to
about 3% of all kernel functions, which increases kernel code size
by about 0.3%.
config CC_STACKPROTECTOR_STRONG
bool "Strong"
select CC_STACKPROTECTOR
help
Functions will have the stack-protector canary logic added in any
of the following conditions:
- local variable's address used as part of the right hand side of an
assignment or function argument
- local variable is an array (or union containing an array),
regardless of array type or length
- uses register local variables
This feature requires gcc version 4.9 or above, or a distribution
gcc with the feature backported ("-fstack-protector-strong").
On an x86 "defconfig" build, this feature adds canary checks to
about 20% of all kernel functions, which increases the kernel code
size by about 2%.
endchoice
kbuild: allow architectures to use thin archives instead of ld -r ld -r is an incremental link used to create built-in.o files in build subdirectories. It produces relocatable object files containing all its input files, and these are are then pulled together and relocated in the final link. Aside from the bloat, this constrains the final link relocations, which has bitten large powerpc builds with unresolvable relocations in the final link. Alan Modra has recommended the kernel use thin archives for linking. This is an alternative and means that the linker has more information available to it when it links the kernel. This patch enables a config option architectures can select, which causes all built-in.o files to be built as thin archives. built-in.o files in subdirectories do not get symbol table or index attached, which improves speed and size. The final link pass creates a built-in.o archive in the root output directory which includes the symbol table and index. The linker then uses takes this file to link. The --whole-archive linker option is required, because the linker now has visibility to every individual object file, and it will otherwise just completely avoid including those without external references (consider a file with EXPORT_SYMBOL or initcall or hardware exceptions as its only entry points). The traditional built works "by luck" as built-in.o files are large enough that they're going to get external references. However this optimisation is unpredictable for the kernel (due to above external references), ineffective at culling unused, and costly because the .o files have to be searched for references. Superior alternatives for link-time culling should be used instead. Build characteristics for inclink vs thinarc, on a small powerpc64le pseries VM with a modest .config: inclink thinarc sizes vmlinux 15 618 680 15 625 028 sum of all built-in.o 56 091 808 1 054 334 sum excluding root built-in.o 151 430 find -name built-in.o | xargs rm ; time make vmlinux real 22.772s 21.143s user 13.280s 13.430s sys 4.310s 2.750s - Final kernel pulled in only about 6K more, which shows how ineffective the object file culling is. - Build performance looks improved due to less pagecache activity. On IO constrained systems it could be a bigger win. - Build size saving is significant. Side note, the toochain understands archives, so there's some tricks, $ ar t built-in.o # list all files you linked with $ size built-in.o # and their sizes $ objdump -d built-in.o # disassembly (unrelocated) with filenames Implementation by sfr, minor tweaks by npiggin. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-08-24 12:29:19 +00:00
config THIN_ARCHIVES
bool
help
Select this if the architecture wants to use thin archives
instead of ld -r to create the built-in.o files.
config LD_DEAD_CODE_DATA_ELIMINATION
bool
help
Select this if the architecture wants to do dead code and
data elimination with the linker by compiling with
-ffunction-sections -fdata-sections and linking with
--gc-sections.
This requires that the arch annotates or otherwise protects
its external entry points from being discarded. Linker scripts
must also merge .text.*, .data.*, and .bss.* correctly into
output sections. Care must be taken not to pull in unrelated
sections (e.g., '.text.init'). Typically '.' in section names
is used to distinguish them from label names / C identifiers.
config HAVE_ARCH_WITHIN_STACK_FRAMES
bool
help
An architecture should select this if it can walk the kernel stack
frames to determine if an object is part of either the arguments
or local variables (i.e. that it excludes saved return addresses,
and similar) by implementing an inline arch_within_stack_frames(),
which is used by CONFIG_HARDENED_USERCOPY.
config HAVE_CONTEXT_TRACKING
bool
help
Provide kernel/user boundaries probes necessary for subsystems
that need it, such as userspace RCU extended quiescent state.
Syscalls need to be wrapped inside user_exit()-user_enter() through
the slow path using TIF_NOHZ flag. Exceptions handlers must be
wrapped as well. Irqs are already protected inside
rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
irq exit still need to be protected.
config HAVE_VIRT_CPU_ACCOUNTING
bool
config HAVE_VIRT_CPU_ACCOUNTING_GEN
bool
default y if 64BIT
help
With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
Before enabling this option, arch code must be audited
to ensure there are no races in concurrent read/write of
cputime_t. For example, reading/writing 64-bit cputime_t on
some 32-bit arches may require multiple accesses, so proper
locking is needed to protect against concurrent accesses.
config HAVE_IRQ_TIME_ACCOUNTING
bool
help
Archs need to ensure they use a high enough resolution clock to
support irq time accounting and then call enable_sched_clock_irqtime().
config HAVE_ARCH_TRANSPARENT_HUGEPAGE
bool
config HAVE_ARCH_HUGE_VMAP
bool
mm: soft-dirty bits for user memory changes tracking The soft-dirty is a bit on a PTE which helps to track which pages a task writes to. In order to do this tracking one should 1. Clear soft-dirty bits from PTEs ("echo 4 > /proc/PID/clear_refs) 2. Wait some time. 3. Read soft-dirty bits (55'th in /proc/PID/pagemap2 entries) To do this tracking, the writable bit is cleared from PTEs when the soft-dirty bit is. Thus, after this, when the task tries to modify a page at some virtual address the #PF occurs and the kernel sets the soft-dirty bit on the respective PTE. Note, that although all the task's address space is marked as r/o after the soft-dirty bits clear, the #PF-s that occur after that are processed fast. This is so, since the pages are still mapped to physical memory, and thus all the kernel does is finds this fact out and puts back writable, dirty and soft-dirty bits on the PTE. Another thing to note, is that when mremap moves PTEs they are marked with soft-dirty as well, since from the user perspective mremap modifies the virtual memory at mremap's new address. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 22:01:20 +00:00
config HAVE_ARCH_SOFT_DIRTY
bool
2012-09-28 05:01:03 +00:00
config HAVE_MOD_ARCH_SPECIFIC
bool
help
The arch uses struct mod_arch_specific to store data. Many arches
just need a simple module loader without arch specific data - those
should not enable this.
config MODULES_USE_ELF_RELA
bool
help
Modules only use ELF RELA relocations. Modules with ELF REL
relocations will give an error.
config MODULES_USE_ELF_REL
bool
help
Modules only use ELF REL relocations. Modules with ELF RELA
relocations will give an error.
config HAVE_UNDERSCORE_SYMBOL_PREFIX
bool
help
Some architectures generate an _ in front of C symbols; things like
module loading and assembly files need to know about this.
irq: Optimize softirq stack selection in irq exit If irq_exit() is called on the arch's specified irq stack, it should be safe to run softirqs inline under that same irq stack as it is near empty by the time we call irq_exit(). For example if we use the same stack for both hard and soft irqs here, the worst case scenario is: hardirq -> softirq -> hardirq. But then the softirq supersedes the first hardirq as the stack user since irq_exit() is called in a mostly empty stack. So the stack merge in this case looks acceptable. Stack overrun still have a chance to happen if hardirqs have more opportunities to nest, but then it's another problem to solve. So lets adapt the irq exit's softirq stack on top of a new Kconfig symbol that can be defined when irq_exit() runs on the irq stack. That way we can spare some stack switch on irq processing and all the cache issues that come along. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@au1.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@au1.ibm.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Andrew Morton <akpm@linux-foundation.org>
2013-09-24 15:17:47 +00:00
config HAVE_IRQ_EXIT_ON_IRQ_STACK
bool
help
Architecture doesn't only execute the irq handler on the irq stack
but also irq_exit(). This way we can process softirqs on this irq
stack instead of switching to a new one when we call __do_softirq()
in the end of an hardirq.
This spares a stack switch and improves cache usage on softirq
processing.
mm: define default PGTABLE_LEVELS to two By this time all architectures which support more than two page table levels should be covered. This patch add default definiton of PGTABLE_LEVELS equal 2. We also add assert to detect inconsistence between CONFIG_PGTABLE_LEVELS and __PAGETABLE_PMD_FOLDED/__PAGETABLE_PUD_FOLDED. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: David Howells <dhowells@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14 22:46:17 +00:00
config PGTABLE_LEVELS
int
default 2
mm: expose arch_mmap_rnd when available When an architecture fully supports randomizing the ELF load location, a per-arch mmap_rnd() function is used to find a randomized mmap base. In preparation for randomizing the location of ET_DYN binaries separately from mmap, this renames and exports these functions as arch_mmap_rnd(). Additionally introduces CONFIG_ARCH_HAS_ELF_RANDOMIZE for describing this feature on architectures that support it (which is a superset of ARCH_BINFMT_ELF_RANDOMIZE_PIE, since s390 already supports a separated ET_DYN ASLR from mmap ASLR without the ARCH_BINFMT_ELF_RANDOMIZE_PIE logic). Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: "David A. Long" <dave.long@linaro.org> Cc: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Arun Chandran <achandran@mvista.com> Cc: Yann Droneaud <ydroneaud@opteya.com> Cc: Min-Hua Chen <orca.chen@gmail.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Vineeth Vijayan <vvijayan@mvista.com> Cc: Jeff Bailey <jeffbailey@google.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Behan Webster <behanw@converseincode.com> Cc: Ismael Ripoll <iripoll@upv.es> Cc: Jan-Simon Mller <dl9pf@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14 22:48:00 +00:00
config ARCH_HAS_ELF_RANDOMIZE
bool
help
An architecture supports choosing randomized locations for
stack, mmap, brk, and ET_DYN. Defined functions:
- arch_mmap_rnd()
mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE The arch_randomize_brk() function is used on several architectures, even those that don't support ET_DYN ASLR. To avoid bulky extern/#define tricks, consolidate the support under CONFIG_ARCH_HAS_ELF_RANDOMIZE for the architectures that support it, while still handling CONFIG_COMPAT_BRK. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: "David A. Long" <dave.long@linaro.org> Cc: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Arun Chandran <achandran@mvista.com> Cc: Yann Droneaud <ydroneaud@opteya.com> Cc: Min-Hua Chen <orca.chen@gmail.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Vineeth Vijayan <vvijayan@mvista.com> Cc: Jeff Bailey <jeffbailey@google.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Behan Webster <behanw@converseincode.com> Cc: Ismael Ripoll <iripoll@upv.es> Cc: Jan-Simon Mller <dl9pf@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14 22:48:12 +00:00
- arch_randomize_brk()
mm: expose arch_mmap_rnd when available When an architecture fully supports randomizing the ELF load location, a per-arch mmap_rnd() function is used to find a randomized mmap base. In preparation for randomizing the location of ET_DYN binaries separately from mmap, this renames and exports these functions as arch_mmap_rnd(). Additionally introduces CONFIG_ARCH_HAS_ELF_RANDOMIZE for describing this feature on architectures that support it (which is a superset of ARCH_BINFMT_ELF_RANDOMIZE_PIE, since s390 already supports a separated ET_DYN ASLR from mmap ASLR without the ARCH_BINFMT_ELF_RANDOMIZE_PIE logic). Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: "David A. Long" <dave.long@linaro.org> Cc: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Arun Chandran <achandran@mvista.com> Cc: Yann Droneaud <ydroneaud@opteya.com> Cc: Min-Hua Chen <orca.chen@gmail.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Vineeth Vijayan <vvijayan@mvista.com> Cc: Jeff Bailey <jeffbailey@google.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Behan Webster <behanw@converseincode.com> Cc: Ismael Ripoll <iripoll@upv.es> Cc: Jan-Simon Mller <dl9pf@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14 22:48:00 +00:00
mm: mmap: add new /proc tunable for mmap_base ASLR Address Space Layout Randomization (ASLR) provides a barrier to exploitation of user-space processes in the presence of security vulnerabilities by making it more difficult to find desired code/data which could help an attack. This is done by adding a random offset to the location of regions in the process address space, with a greater range of potential offset values corresponding to better protection/a larger search-space for brute force, but also to greater potential for fragmentation. The offset added to the mmap_base address, which provides the basis for the majority of the mappings for a process, is set once on process exec in arch_pick_mmap_layout() and is done via hard-coded per-arch values, which reflect, hopefully, the best compromise for all systems. The trade-off between increased entropy in the offset value generation and the corresponding increased variability in address space fragmentation is not absolute, however, and some platforms may tolerate higher amounts of entropy. This patch introduces both new Kconfig values and a sysctl interface which may be used to change the amount of entropy used for offset generation on a system. The direct motivation for this change was in response to the libstagefright vulnerabilities that affected Android, specifically to information provided by Google's project zero at: http://googleprojectzero.blogspot.com/2015/09/stagefrightened.html The attack presented therein, by Google's project zero, specifically targeted the limited randomness used to generate the offset added to the mmap_base address in order to craft a brute-force-based attack. Concretely, the attack was against the mediaserver process, which was limited to respawning every 5 seconds, on an arm device. The hard-coded 8 bits used resulted in an average expected success rate of defeating the mmap ASLR after just over 10 minutes (128 tries at 5 seconds a piece). With this patch, and an accompanying increase in the entropy value to 16 bits, the same attack would take an average expected time of over 45 hours (32768 tries), which makes it both less feasible and more likely to be noticed. The introduced Kconfig and sysctl options are limited by per-arch minimum and maximum values, the minimum of which was chosen to match the current hard-coded value and the maximum of which was chosen so as to give the greatest flexibility without generating an invalid mmap_base address, generally a 3-4 bits less than the number of bits in the user-space accessible virtual address space. When decided whether or not to change the default value, a system developer should consider that mmap_base address could be placed anywhere up to 2^(value) bits away from the non-randomized location, which would introduce variable-sized areas above and below the mmap_base address such that the maximum vm_area_struct size may be reduced, preventing very large allocations. This patch (of 4): ASLR only uses as few as 8 bits to generate the random offset for the mmap base address on 32 bit architectures. This value was chosen to prevent a poorly chosen value from dividing the address space in such a way as to prevent large allocations. This may not be an issue on all platforms. Allow the specification of a minimum number of bits so that platforms desiring greater ASLR protection may determine where to place the trade-off. Signed-off-by: Daniel Cashman <dcashman@google.com> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Don Zickus <dzickus@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Rientjes <rientjes@google.com> Cc: Mark Salyzyn <salyzyn@android.com> Cc: Jeff Vander Stoep <jeffv@google.com> Cc: Nick Kralevich <nnk@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Borislav Petkov <bp@suse.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14 23:19:53 +00:00
config HAVE_ARCH_MMAP_RND_BITS
bool
help
An arch should select this symbol if it supports setting a variable
number of bits for use in establishing the base address for mmap
allocations, has MMU enabled and provides values for both:
- ARCH_MMAP_RND_BITS_MIN
- ARCH_MMAP_RND_BITS_MAX
exit_thread: remove empty bodies Define HAVE_EXIT_THREAD for archs which want to do something in exit_thread. For others, let's define exit_thread as an empty inline. This is a cleanup before we change the prototype of exit_thread to accept a task parameter. [akpm@linux-foundation.org: fix mips] Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Howells <dhowells@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Hogan <james.hogan@imgtec.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonas Bonn <jonas@southpole.se> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mikael Starvik <starvik@axis.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@arm.linux.org.uk> Cc: Steven Miao <realmz6@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 00:00:16 +00:00
config HAVE_EXIT_THREAD
bool
help
An architecture implements exit_thread.
mm: mmap: add new /proc tunable for mmap_base ASLR Address Space Layout Randomization (ASLR) provides a barrier to exploitation of user-space processes in the presence of security vulnerabilities by making it more difficult to find desired code/data which could help an attack. This is done by adding a random offset to the location of regions in the process address space, with a greater range of potential offset values corresponding to better protection/a larger search-space for brute force, but also to greater potential for fragmentation. The offset added to the mmap_base address, which provides the basis for the majority of the mappings for a process, is set once on process exec in arch_pick_mmap_layout() and is done via hard-coded per-arch values, which reflect, hopefully, the best compromise for all systems. The trade-off between increased entropy in the offset value generation and the corresponding increased variability in address space fragmentation is not absolute, however, and some platforms may tolerate higher amounts of entropy. This patch introduces both new Kconfig values and a sysctl interface which may be used to change the amount of entropy used for offset generation on a system. The direct motivation for this change was in response to the libstagefright vulnerabilities that affected Android, specifically to information provided by Google's project zero at: http://googleprojectzero.blogspot.com/2015/09/stagefrightened.html The attack presented therein, by Google's project zero, specifically targeted the limited randomness used to generate the offset added to the mmap_base address in order to craft a brute-force-based attack. Concretely, the attack was against the mediaserver process, which was limited to respawning every 5 seconds, on an arm device. The hard-coded 8 bits used resulted in an average expected success rate of defeating the mmap ASLR after just over 10 minutes (128 tries at 5 seconds a piece). With this patch, and an accompanying increase in the entropy value to 16 bits, the same attack would take an average expected time of over 45 hours (32768 tries), which makes it both less feasible and more likely to be noticed. The introduced Kconfig and sysctl options are limited by per-arch minimum and maximum values, the minimum of which was chosen to match the current hard-coded value and the maximum of which was chosen so as to give the greatest flexibility without generating an invalid mmap_base address, generally a 3-4 bits less than the number of bits in the user-space accessible virtual address space. When decided whether or not to change the default value, a system developer should consider that mmap_base address could be placed anywhere up to 2^(value) bits away from the non-randomized location, which would introduce variable-sized areas above and below the mmap_base address such that the maximum vm_area_struct size may be reduced, preventing very large allocations. This patch (of 4): ASLR only uses as few as 8 bits to generate the random offset for the mmap base address on 32 bit architectures. This value was chosen to prevent a poorly chosen value from dividing the address space in such a way as to prevent large allocations. This may not be an issue on all platforms. Allow the specification of a minimum number of bits so that platforms desiring greater ASLR protection may determine where to place the trade-off. Signed-off-by: Daniel Cashman <dcashman@google.com> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Don Zickus <dzickus@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Rientjes <rientjes@google.com> Cc: Mark Salyzyn <salyzyn@android.com> Cc: Jeff Vander Stoep <jeffv@google.com> Cc: Nick Kralevich <nnk@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Borislav Petkov <bp@suse.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14 23:19:53 +00:00
config ARCH_MMAP_RND_BITS_MIN
int
config ARCH_MMAP_RND_BITS_MAX
int
config ARCH_MMAP_RND_BITS_DEFAULT
int
config ARCH_MMAP_RND_BITS
int "Number of bits to use for ASLR of mmap base address" if EXPERT
range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
default ARCH_MMAP_RND_BITS_MIN
depends on HAVE_ARCH_MMAP_RND_BITS
help
This value can be used to select the number of bits to use to
determine the random offset to the base address of vma regions
resulting from mmap allocations. This value will be bounded
by the architecture's minimum and maximum supported values.
This value can be changed after boot using the
/proc/sys/vm/mmap_rnd_bits tunable
config HAVE_ARCH_MMAP_RND_COMPAT_BITS
bool
help
An arch should select this symbol if it supports running applications
in compatibility mode, supports setting a variable number of bits for
use in establishing the base address for mmap allocations, has MMU
enabled and provides values for both:
- ARCH_MMAP_RND_COMPAT_BITS_MIN
- ARCH_MMAP_RND_COMPAT_BITS_MAX
config ARCH_MMAP_RND_COMPAT_BITS_MIN
int
config ARCH_MMAP_RND_COMPAT_BITS_MAX
int
config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
int
config ARCH_MMAP_RND_COMPAT_BITS
int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
default ARCH_MMAP_RND_COMPAT_BITS_MIN
depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
help
This value can be used to select the number of bits to use to
determine the random offset to the base address of vma regions
resulting from mmap allocations for compatible applications This
value will be bounded by the architecture's minimum and maximum
supported values.
This value can be changed after boot using the
/proc/sys/vm/mmap_rnd_compat_bits tunable
clone: support passing tls argument via C rather than pt_regs magic clone has some of the quirkiest syscall handling in the kernel, with a pile of special cases, historical curiosities, and architecture-specific calling conventions. In particular, clone with CLONE_SETTLS accepts a parameter "tls" that the C entry point completely ignores and some assembly entry points overwrite; instead, the low-level arch-specific code pulls the tls parameter out of the arch-specific register captured as part of pt_regs on entry to the kernel. That's a massive hack, and it makes the arch-specific code only work when called via the specific existing syscall entry points; because of this hack, any new clone-like system call would have to accept an identical tls argument in exactly the same arch-specific position, rather than providing a unified system call entry point across architectures. The first patch allows architectures to handle the tls argument via normal C parameter passing, if they opt in by selecting HAVE_COPY_THREAD_TLS. The second patch makes 32-bit and 64-bit x86 opt into this. These two patches came out of the clone4 series, which isn't ready for this merge window, but these first two cleanup patches were entirely uncontroversial and have acks. I'd like to go ahead and submit these two so that other architectures can begin building on top of this and opting into HAVE_COPY_THREAD_TLS. However, I'm also happy to wait and send these through the next merge window (along with v3 of clone4) if anyone would prefer that. This patch (of 2): clone with CLONE_SETTLS accepts an argument to set the thread-local storage area for the new thread. sys_clone declares an int argument tls_val in the appropriate point in the argument list (based on the various CLONE_BACKWARDS variants), but doesn't actually use or pass along that argument. Instead, sys_clone calls do_fork, which calls copy_process, which calls the arch-specific copy_thread, and copy_thread pulls the corresponding syscall argument out of the pt_regs captured at kernel entry (knowing what argument of clone that architecture passes tls in). Apart from being awful and inscrutable, that also only works because only one code path into copy_thread can pass the CLONE_SETTLS flag, and that code path comes from sys_clone with its architecture-specific argument-passing order. This prevents introducing a new version of the clone system call without propagating the same architecture-specific position of the tls argument. However, there's no reason to pull the argument out of pt_regs when sys_clone could just pass it down via C function call arguments. Introduce a new CONFIG_HAVE_COPY_THREAD_TLS for architectures to opt into, and a new copy_thread_tls that accepts the tls parameter as an additional unsigned long (syscall-argument-sized) argument. Change sys_clone's tls argument to an unsigned long (which does not change the ABI), and pass that down to copy_thread_tls. Architectures that don't opt into copy_thread_tls will continue to ignore the C argument to sys_clone in favor of the pt_regs captured at kernel entry, and thus will be unable to introduce new versions of the clone syscall. Patch co-authored by Josh Triplett and Thiago Macieira. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thiago Macieira <thiago.macieira@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 22:01:19 +00:00
config HAVE_COPY_THREAD_TLS
bool
help
Architecture provides copy_thread_tls to accept tls argument via
normal C parameter passing, rather than extracting the syscall
argument from pt_regs.
config HAVE_STACK_VALIDATION
bool
help
Architecture supports the 'objtool check' host tool command, which
performs compile-time stack metadata validation.
config HAVE_ARCH_HASH
bool
default n
help
If this is set, the architecture provides an <asm/hash.h>
file which provides platform-specific implementations of some
functions in <linux/hash.h> or fs/namei.c.
config ISA_BUS_API
def_bool ISA
#
# ABI hall of shame
#
config CLONE_BACKWARDS
bool
help
Architecture has tls passed as the 4th argument of clone(2),
not the 5th one.
config CLONE_BACKWARDS2
bool
help
Architecture has the first two arguments of clone(2) swapped.
config CLONE_BACKWARDS3
bool
help
Architecture has tls passed as the 3rd argument of clone(2),
not the 5th one.
config ODD_RT_SIGACTION
bool
help
Architecture has unusual rt_sigaction(2) arguments
config OLD_SIGSUSPEND
bool
help
Architecture has old sigsuspend(2) syscall, of one-argument variety
config OLD_SIGSUSPEND3
bool
help
Even weirder antique ABI - three-argument sigsuspend(2)
config OLD_SIGACTION
bool
help
Architecture has old sigaction(2) syscall. Nope, not the same
as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
but fairly different variant of sigaction(2), thanks to OSF/1
compatibility...
config COMPAT_OLD_SIGACTION
bool
dma-mapping: make the generic coherent dma mmap implementation optional This series converts all remaining architectures to use dma_map_ops and the generic implementation of the DMA API. This not only simplifies the code a lot, but also prepares for possible future changes like more generic non-iommu dma_ops implementations or generic per-device dma_map_ops. This patch (of 16): We have a couple architectures that do not want to support this code, so add another Kconfig symbol that disables the code similar to what we do for the nommu case. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: David Howells <dhowells@redhat.com> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Helge Deller <deller@gmx.de> Cc: James Hogan <james.hogan@imgtec.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Mark Salter <msalter@redhat.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 23:01:22 +00:00
config ARCH_NO_COHERENT_DMA_MMAP
bool
lib/GCD.c: use binary GCD algorithm instead of Euclidean The binary GCD algorithm is based on the following facts: 1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2) 2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b) 3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b) Even on x86 machines with reasonable division hardware, the binary algorithm runs about 25% faster (80% the execution time) than the division-based Euclidian algorithm. On platforms like Alpha and ARMv6 where division is a function call to emulation code, it's even more significant. There are two variants of the code here, depending on whether a fast __ffs (find least significant set bit) instruction is available. This allows the unpredictable branches in the bit-at-a-time shifting loop to be eliminated. If fast __ffs is not available, the "even/odd" GCD variant is used. I use the following code to benchmark: #include <stdio.h> #include <stdlib.h> #include <stdint.h> #include <string.h> #include <time.h> #include <unistd.h> #define swap(a, b) \ do { \ a ^= b; \ b ^= a; \ a ^= b; \ } while (0) unsigned long gcd0(unsigned long a, unsigned long b) { unsigned long r; if (a < b) { swap(a, b); } if (b == 0) return a; while ((r = a % b) != 0) { a = b; b = r; } return b; } unsigned long gcd1(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); for (;;) { a >>= __builtin_ctzl(a); if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd2(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; for (;;) { while (!(a & r)) a >>= 1; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } unsigned long gcd3(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); if (b == 1) return r & -r; for (;;) { a >>= __builtin_ctzl(a); if (a == 1) return r & -r; if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd4(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; if (b == r) return r; for (;;) { while (!(a & r)) a >>= 1; if (a == r) return r; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = { gcd0, gcd1, gcd2, gcd3, gcd4, }; #define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0])) #if defined(__x86_64__) #define rdtscll(val) do { \ unsigned long __a,__d; \ __asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \ (val) = ((unsigned long long)__a) | (((unsigned long long)__d)<<32); \ } while(0) static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { unsigned long long start, end; unsigned long long ret; unsigned long gcd_res; rdtscll(start); gcd_res = gcd(a, b); rdtscll(end); if (end >= start) ret = end - start; else ret = ~0ULL - start + 1 + end; *res = gcd_res; return ret; } #else static inline struct timespec read_time(void) { struct timespec time; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time); return time; } static inline unsigned long long diff_time(struct timespec start, struct timespec end) { struct timespec temp; if ((end.tv_nsec - start.tv_nsec) < 0) { temp.tv_sec = end.tv_sec - start.tv_sec - 1; temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec; } else { temp.tv_sec = end.tv_sec - start.tv_sec; temp.tv_nsec = end.tv_nsec - start.tv_nsec; } return temp.tv_sec * 1000000000ULL + temp.tv_nsec; } static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { struct timespec start, end; unsigned long gcd_res; start = read_time(); gcd_res = gcd(a, b); end = read_time(); *res = gcd_res; return diff_time(start, end); } #endif static inline unsigned long get_rand() { if (sizeof(long) == 8) return (unsigned long)rand() << 32 | rand(); else return rand(); } int main(int argc, char **argv) { unsigned int seed = time(0); int loops = 100; int repeats = 1000; unsigned long (*res)[TEST_ENTRIES]; unsigned long long elapsed[TEST_ENTRIES]; int i, j, k; for (;;) { int opt = getopt(argc, argv, "n:r:s:"); /* End condition always first */ if (opt == -1) break; switch (opt) { case 'n': loops = atoi(optarg); break; case 'r': repeats = atoi(optarg); break; case 's': seed = strtoul(optarg, NULL, 10); break; default: /* You won't actually get here. */ break; } } res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops); memset(elapsed, 0, sizeof(elapsed)); srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); /* Do we have args? */ unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); unsigned long long min_elapsed[TEST_ENTRIES]; for (k = 0; k < repeats; k++) { for (i = 0; i < TEST_ENTRIES; i++) { unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &res[j][i]); if (k == 0 || min_elapsed[i] > tmp) min_elapsed[i] = tmp; } } for (i = 0; i < TEST_ENTRIES; i++) elapsed[i] += min_elapsed[i]; } for (i = 0; i < TEST_ENTRIES; i++) printf("gcd%d: elapsed %llu\n", i, elapsed[i]); k = 0; srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); for (i = 1; i < TEST_ENTRIES; i++) { if (res[j][i] != res[j][0]) break; } if (i < TEST_ENTRIES) { if (k == 0) { k = 1; fprintf(stderr, "Error:\n"); } fprintf(stderr, "gcd(%lu, %lu): ", a, b); for (i = 0; i < TEST_ENTRIES; i++) fprintf(stderr, "%ld%s", res[j][i], i < TEST_ENTRIES - 1 ? ", " : "\n"); } } if (k == 0) fprintf(stderr, "PASS\n"); free(res); return 0; } Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got: zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 10174 gcd1: elapsed 2120 gcd2: elapsed 2902 gcd3: elapsed 2039 gcd4: elapsed 2812 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9309 gcd1: elapsed 2280 gcd2: elapsed 2822 gcd3: elapsed 2217 gcd4: elapsed 2710 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9589 gcd1: elapsed 2098 gcd2: elapsed 2815 gcd3: elapsed 2030 gcd4: elapsed 2718 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9914 gcd1: elapsed 2309 gcd2: elapsed 2779 gcd3: elapsed 2228 gcd4: elapsed 2709 PASS [akpm@linux-foundation.org: avoid #defining a CONFIG_ variable] Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com> Signed-off-by: George Spelvin <linux@horizon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 00:03:57 +00:00
config CPU_NO_EFFICIENT_FFS
def_bool n
config HAVE_ARCH_VMAP_STACK
def_bool n
help
An arch should select this symbol if it can support kernel stacks
in vmalloc space. This means:
- vmalloc space must be large enough to hold many kernel stacks.
This may rule out many 32-bit architectures.
- Stacks in vmalloc space need to work reliably. For example, if
vmap page tables are created on demand, either this mechanism
needs to work while the stack points to a virtual address with
unpopulated page tables or arch code (switch_to() and switch_mm(),
most likely) needs to ensure that the stack's page table entries
are populated before running on a possibly unpopulated stack.
- If the stack overflows into a guard page, something reasonable
should happen. The definition of "reasonable" is flexible, but
instantly rebooting without logging anything would be unfriendly.
config VMAP_STACK
default y
bool "Use a virtually-mapped stack"
depends on HAVE_ARCH_VMAP_STACK && !KASAN
---help---
Enable this if you want the use virtually-mapped kernel stacks
with guard pages. This causes kernel stack overflows to be
caught immediately rather than causing difficult-to-diagnose
corruption.
This is presently incompatible with KASAN because KASAN expects
the stack to map directly to the KASAN shadow map using a formula
that is incorrect if the stack is in vmalloc space.
gcov: add gcov profiling infrastructure Enable the use of GCC's coverage testing tool gcov [1] with the Linux kernel. gcov may be useful for: * debugging (has this code been reached at all?) * test improvement (how do I change my test to cover these lines?) * minimizing kernel configurations (do I need this option if the associated code is never run?) The profiling patch incorporates the following changes: * change kbuild to include profiling flags * provide functions needed by profiling code * present profiling data as files in debugfs Note that on some architectures, enabling gcc's profiling option "-fprofile-arcs" for the entire kernel may trigger compile/link/ run-time problems, some of which are caused by toolchain bugs and others which require adjustment of architecture code. For this reason profiling the entire kernel is initially restricted to those architectures for which it is known to work without changes. This restriction can be lifted once an architecture has been tested and found compatible with gcc's profiling. Profiling of single files or directories is still available on all platforms (see config help text). [1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-17 23:28:08 +00:00
source "kernel/gcov/Kconfig"