Consistently use the SYM* family of macros instead of the
deprecated ENTRY(), ENDPROC(), etc. family of macros.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
To allow calling of DAT-off code from kernel the stack needs
to be switched to nodat_stack (or other stack mapped as 1:1).
Before call_nodat() macro was introduced that was necessary
to provide the very same memory address for STNSM and STOSM
instructions. If the kernel would stay on a random stack
(e.g. a virtually mapped one) then a virtual address provided
for STNSM instruction could differ from the physical address
needed for the corresponding STOSM instruction.
After call_nodat() macro is introduced the kernel stack does
not need to be mapped 1:1 anymore, since the macro stores the
physical memory address of return PSW in a register before
entering DAT-off mode. This way the return LPSWE instruction
is able to pick the correct memory location and restore the
DAT-on mode. That however might fail in case the 16-byte return
PSW happened to cross page boundary: PSW mask and PSW address
could end up in two separate non-contiguous physical pages.
Align the return PSW on 16-byte boundary so it always fits
into a single physical page. As result any stack (including
the virtually mapped one) could be used for calling DAT-off
code and prior switching to nodat_stack becomes unnecessary.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Calling kdump kernel is a two-step process that involves
invocation of the purgatory code: first time - to verify
the new kernel checksum and second time - to call the new
kernel itself.
The purgatory code operates on real addresses and does not
expect any memory protection. Therefore, before the purgatory
code is entered the DAT mode is always turned off. However,
it is only restored upon return from the new kernel checksum
verification. In case the purgatory was called to start the
new kernel and failed the control is returned to the old
kernel, but the DAT mode continues staying off.
The new kernel start failure is unlikely and leads to the
disabled wait state anyway. Still that poses a risk, since
the kernel code in general is not DAT-off safe and even
calling the disabled_wait() function might crash.
Introduce call_nodat() macro that allows entering DAT-off
mode, calling an arbitrary function and restoring DAT mode
back on. Switch all invocations of DAT-off code to that
macro and avoid the above described scenario altogether.
Name the call_nodat() macro in small letters after the
already existing call_on_stack() and put it to the same
header file.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
[hca@linux.ibm.com: some small modifications to call_nodat() macro]
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Avoid unnecessary run-time and compile-time type
conversions of do_start_kdump() function return
value and parameter.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The kernel code is not guaranteed DAT-off mode safe.
Turn the DAT mode off immediately before entering the
purgatory.
Further, to avoid subtle side effects reset the system
immediately before turning DAT mode off while making
all necessary preparations in advance.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Remove function validate_ctr_auth() and replace this very small
function by its body.
No functional change.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Function validate_ctr_version() first parameter is a pointer to
a large structure, but only member hw_perf_event::config is used.
Supply this structure member value in the function invocation.
No functional change.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The CPU measurement facility counter information instruction qctri()
retrieves information about the available counter sets.
The information varies between machine generations, but is constant
when running on a particular machine.
For example the CPU measurement facility counter first and second
version numbers determine the amount of counters in a counter
set. This information never changes.
The counter sets are identical for all CPUs in the system. It does
not matter which CPU performs the instruction.
Authorization control of the CPU Measurement facility can only
be changed in the activation profile while the LPAR is not running.
Retrieve the CPU measurement counter information at device driver
initialization time and use its constant values.
Function validate_ctr_version() verifies if a user provided
CPU Measurement counter facility counter is valid and defined.
It now uses the newly introduced static CPU counter facility
information.
To avoid repeated recalculation of the counter set sizes (numbers of
counters per set), which never changes on a running machine,
calculate the counter set size once at device driver initialization
and store the result in an array. Functions cpum_cf_make_setsize()
and cpum_cf_read_setsize() are introduced.
Finally remove cpu_cf_events::info member and use the static CPU
counter facility information instead.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Simplify pr_err() statement into one line and omit return statement.
No functional change.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Struct s390_ctrset_read userdata is filled by ioctl_read operation
using put_user/copy_to_user. However, the ctrset->data value access
is not performed anywhere during the ioctl_read operation.
Remove unnecessary copy_from_user() call.
No functional change.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Suggested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
When function cfset_all_copy() fails, also log the bad return code
in the debug statement (when turned on).
No functional change
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This is the s390 variant of commit 7dfac3c5f4 ("arm64: module: create
module allocations without exec permissions"):
"The core code manages the executable permissions of code regions of
modules explicitly. It is no longer necessary to create the module vmalloc
regions with RWX permissions. So create them with RW- permissions instead,
which is preferred from a security perspective."
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The ftrace code assumes at two places that module_alloc() returns
executable memory. While this is currently true, this will be changed
with a subsequent patch to follow other architectures which implement
ARCH_HAS_STRICT_MODULE_RWX.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Given that set_memory_rox() and set_memory_rwnx() exist, it is possible
to get rid of all open coded __set_memory() usages and replace them with
proper helper calls everywhere.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diag 308 subcodes expect a physical address as their parameter.
This currently is not a bug, but in the future physical and virtual
addresses might differ.
Fix the confusion by doing a virtual-to-physical conversion in the
exported diag308() and leave the assembly wrapper __diag308() alone.
Note that several callers pass NULL as addr, so check for the case when
NULL is passed and pass 0 to hardware since virt_to_phys(0) might be
nonzero.
Suggested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Randomize the load address of modules in the kernel to make KASLR effective
for modules.
This is the s390 variant of commit e2b32e6785 ("x86, kaslr: randomize
module base load address").
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Just like other architectures provide a kaslr_enabled() function, instead
of directly accessing a global variable.
Also pass the renamed __kaslr_enabled variable from the decompressor to the
kernel, so that kalsr_enabled() is available there too. This will be used
by a subsequent patch which randomizes the module base load address.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Add support for the stackleak feature. Whenever the kernel returns to user
space the kernel stack is filled with a poison value.
Enabling this feature is quite expensive: e.g. after instrumenting the
getpid() system call function to have a 4kb stack the result is an
increased runtime of the system call by a factor of 3.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Allocate early async stack like other early stacks and get rid of
arch_early_irq_init(). This way the async stack is allocated earlier,
and handled like all other stacks.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
s390 is the only architecture which switches from the initial stack to a
later on allocated different stack for the first process.
This is (at least) problematic for the stackleak feature, which instruments
functions to save the current stackpointer within the task structure of the
running process.
The stackleak code compares stack pointers of the current process - and
doesn't expect that the kernel stack of a task can change. Even though the
stackleak feature itself will not cause any harm, the assumption about
kernel stacks being consistent is there, and only s390 doesn't follow that.
Therefore switch back to use init_thread_union, just like all other
architectures.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Make sure the lowcore kernel stack pointer reflects the kernel stack of the
current task as early as possible, instead of having a NULL pointer there.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Make STACK_INIT_OFFSET also available for assembler code, and
use it everywhere instead of open-coding it at several places.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The pattern for all in_<type>_stack() functions is the same; especially
also the size of all stacks is the same. Simplify the code by passing only
the stack address to the generic in_stack() helper, which then can assume a
THREAD_SIZE sized stack.
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Currently, exception tables are marked as ro_after_init. However,
since they are sorted during compile time using scripts/sorttable,
they can be moved to RO_DATA using the RO_EXCEPTION_TABLE_ALIGN macro,
which is specifically designed for this purpose.
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Since commit 4efd417f29 ("s390: raise minimum supported machine
generation to z10"), the long-displacement facility is assumed and
required for the kernel. Clean up a couple of places in the entry code,
where long-displacement could be used directly instead of using a base
register.
However, there are still a few other places where a base register has
to be used to extend short-displacement for the second lowcore page
access. Notably, boot/head.S still has to be built for z900, and in
mcck_int_handler, spt and lbear, which don't have long-displacements,
but need to access save areas at the second lowcore page.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This flag is used to process only fully populated sampling buffers
when an sampling event is stopped on a CPU. By default the last sampling
buffer is also scanned for samples even if the sampling block full
indicator is not set in the trailer entry of a sampling buffer page.
This flag can be set via perf_event_attr::config1 field. It was never
used and never documented. It is useless now.
With PERF_CPUM_SF_FULL_BLOCKS:
When a process is scheduled off the CPU, the sampling is stopped and
the samples are copied to the perf ring buffer and marked invalid.
When stopped at the last full sample buffer page (which is
achieved with the PERF_CPUM_SF_FULL_BLOCKS options), the hardware
sampling will resume at the first free sample entry in the current,
partially filled sample buffer.
Without PERF_CPUM_SF_FULL_BLOCKS (default behavior):
The partially filled last sample buffer is scanned and valid samples
are saved to the perf ring buffer. The valid samples are marked invalid.
The sampling is resumed when the process is scheduled on this CPU.
Again the hardware sampling will resume at the first free sample entry in
the current, partially filled sample buffer.
Now the next interrupt handler invocation scans the
full sample block and saves the valid samples to the ring buffer.
It omits the invalid samples at the top of the buffer.
The default behavior is fully sufficient, therefore remove this feature.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Use __ALIGN instead of open coded .align statement to make sure that
vdso code follows global kernel function alignment rules.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Move the ftrace hotpatch trampolines to mcount.S. This allows to make
use of the standard SYM_CODE macros which again makes sure that the
hotpatch trampolines follow the function alignment rules of the rest
of the kernel.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Vasily Gorbik says:
===================
Combine and generalize all methods for finding unused memory in
decompressor, while decreasing complexity, add memory holes support,
while improving error handling (especially in low-memory conditions)
and debug-ability.
===================
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Since regular paging structs are initialized in decompressor already
move KASAN shadow mapping to decompressor as well. This helps to avoid
allocating KASAN required memory in 1 large chunk, de-duplicate paging
structs creation code and start the uncompressed kernel with KASAN
instrumentation right away. This also allows to avoid all pitfalls
accidentally calling KASAN instrumented code during KASAN initialization.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Currently several approaches for finding unused memory in decompressor
are utilized. While "safe_addr" grows towards higher addresses, vmem
code allocates paging structures top down. The former requires careful
ordering. In addition to that ipl report handling code verifies potential
intersections with secure boot certificates on its own. Neither of two
approaches are memory holes aware and consistent with each other in low
memory conditions.
To solve that, existing approaches are generalized and combined
together, as well as online memory ranges are now taken into
consideration.
physmem_info has been extended to contain reserved memory ranges. New
set of functions allow to handle reserves and find unused memory.
All reserves and memory allocations are "typed". In case of out of
memory condition decompressor fails with detailed info on current
reserved ranges and usable online memory.
Linux version 6.2.0 ...
Kernel command line: ... mem=100M
Our of memory allocating 100000 bytes 100000 aligned in range 0:5800000
Reserved memory ranges:
0000000000000000 0000000003e33000 DECOMPRESSOR
0000000003f00000 00000000057648a3 INITRD
00000000063e0000 00000000063e8000 VMEM
00000000063eb000 00000000063f4000 VMEM
00000000063f7800 0000000006400000 VMEM
0000000005800000 0000000006300000 KASAN
Usable online memory ranges (info source: sclp read info [3]):
0000000000000000 0000000006400000
Usable online memory total: 6400000 Reserved: 61b10a3 Free: 24ef5d
Call Trace:
(sp:000000000002bd58 [<0000000000012a70>] physmem_alloc_top_down+0x60/0x14c)
sp:000000000002bdc8 [<0000000000013756>] _pa+0x56/0x6a
sp:000000000002bdf0 [<0000000000013bcc>] pgtable_populate+0x45c/0x65e
sp:000000000002be90 [<00000000000140aa>] setup_vmem+0x2da/0x424
sp:000000000002bec8 [<0000000000011c20>] startup_kernel+0x428/0x8b4
sp:000000000002bf60 [<00000000000100f4>] startup_normal+0xd4/0xd4
physmem_alloc_range allows to find free memory in specified range. It
should be used for one time allocations only like finding position for
amode31 and vmlinux.
physmem_alloc_top_down can be used just like physmem_alloc_range, but
it also allows multiple allocations per type and tries to merge sequential
allocations together. Which is useful for paging structures allocations.
If sequential allocations cannot be merged together they are "chained",
allowing easy per type reserved ranges enumeration and migration to
memblock later. Extra "struct reserved_range" allocated for chaining are
not tracked or reserved but rely on the fact that both
physmem_alloc_range and physmem_alloc_top_down search for free memory
only below current top down allocator position. All reserved ranges
should be transferred to memblock before memblock allocations are
enabled.
The startup code has been reordered to delay any memory allocations until
online memory ranges are detected and occupied memory ranges are marked as
reserved to be excluded from follow-up allocations.
Ipl report certificates are a special case, ipl report certificates list
is checked together with other memory reserves until certificates are
saved elsewhere.
KASAN required memory for shadow memory allocation and mapping is reserved
as 1 large chunk which is later passed to KASAN early initialization code.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
In preparation to extending mem_detect with additional information like
reserved ranges rename it to more generic physmem_info. This new naming
also help to avoid confusion by using more exact terms like "physmem
online ranges", etc.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
check_image_bootable() has been introduced with commit 627c9b6205
("s390/boot: block uncompressed vmlinux booting attempts") to make sure
that users don't try to boot uncompressed vmlinux ELF image in qemu. It
used to be possible quite some time ago. That commit prevented confusion
with uncompressed vmlinux image starting to boot and even printing
kernel messages until it crashed. Users might have tried to report the
problem without realizing they are doing something which was not intended.
Since commit f1d3c53237 ("s390/boot: move sclp early buffer from fixed
address in asm to C") check_image_bootable() doesn't function properly
anymore, as well as booting uncompressed vmlinux image in qemu doesn't
really produce any output and crashes. Moving forward it doesn't make
sense to fix check_image_bootable() anymore, so simply remove it.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
report_user_fault() currently does not show which library last_break
points to. Call print_vma_addr() to find out; the output now looks
like this:
Last Breaking-Event-Address:
[<000003ffaa2a56e4>] libc.so.6[3ffaa180000+251000]
For kernel it's unchanged:
Last Breaking-Event-Address:
[<000000000030fd06>] trace_hardirqs_on+0x56/0xc8
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
There is no need to declare an extra tables to just create directory,
this can be easily be done with a prefix path with register_sysctl().
Simplify this registration.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230310234525.3986352-3-mcgrof@kernel.org
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
There is no need to declare an extra tables to just create directory,
this can be easily be done with a prefix path with register_sysctl().
Simplify this registration.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230310234525.3986352-2-mcgrof@kernel.org
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Setting and ->psw.addr in childregs of kernel thread is a rudiment of
the old kernel_thread()/kernel_execve() implementation. Mainline hadn't
been using them since 2012.
And clarify the assignments to frame->sf.gprs - the array stores
grp6..gpr15 values to be set by __switch_to(), so frame->sf.gprs[5]
actually affects grp11, etc.
Better spell that as frame->sf.gprs[11 - 6]...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/ZAU6BYFisE8evmYf@ZenIV
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
There is no point in changing branch prediction state of a cpu shortly
before it enters stop state. Therefore remove __bpon().
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
TIF_ISOLATE_BP is unused since it was introduced with commit 6b73044b2b
("s390: run user space and KVM guests with modified branch prediction").
Given that there is no use case remove it again.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
When leaving interpretive execution because of a program check BPENTER
should be called like it is done on interrupt exit as well.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
- Add empty command line parameter handling stubs to kernel for all command
line parameters which are handled in the decompressor. This avoids
invalid "Unknown kernel command line parameters" messages from the
kernel, and also avoids that these will be incorrectly passed to user
space. This caused already confusion, therefore add the empty stubs
- Add missing phys_to_virt() handling to machine check handler
- Introduce and use a union to be used for zcrypt inline assemblies. This
makes sure that only a register wide member of the union is passed as
input and output parameter to inline assemblies, while usual C code uses
other members of the union to access bit fields of it
- Add and use a READ_ONCE_ALIGNED_128() macro, which can be used to
atomically read a 128-bit value from memory. This replaces the (mis-)use
of the 128-bit cmpxchg operation to do the same in cpum_sf code.
Currently gcc does not generate the used lpq instruction if __READ_ONCE()
is used for aligned 128-bit accesses, therefore use this s390 specific
helper
- Simplify machine check handler code if a task needs to be killed because
of e.g. register corruption due to a machine malfunction
- Perform CPU reset to clear pending interrupts and TLB entries on an
already stopped target CPU before delegating work to it
- Generate arch/s390/boot/vmlinux.map link map for the decompressor, when
CONFIG_VMLINUX_MAP is enabled for debugging purposes
- Fix segment type handling for dcssblk devices. It incorrectly always
returned type "READ/WRITE" even for read-only segements, which can result
in a kernel panic if somebody tries to write to a read-only device
- Sort config S390 select list again
- Fix two kprobe reenter bugs revealed by a recently added kprobe kunit
test
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Merge tag 's390-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Heiko Carstens:
- Add empty command line parameter handling stubs to kernel for all
command line parameters which are handled in the decompressor. This
avoids invalid "Unknown kernel command line parameters" messages from
the kernel, and also avoids that these will be incorrectly passed to
user space. This caused already confusion, therefore add the empty
stubs
- Add missing phys_to_virt() handling to machine check handler
- Introduce and use a union to be used for zcrypt inline assemblies.
This makes sure that only a register wide member of the union is
passed as input and output parameter to inline assemblies, while
usual C code uses other members of the union to access bit fields of
it
- Add and use a READ_ONCE_ALIGNED_128() macro, which can be used to
atomically read a 128-bit value from memory. This replaces the
(mis-)use of the 128-bit cmpxchg operation to do the same in cpum_sf
code. Currently gcc does not generate the used lpq instruction if
__READ_ONCE() is used for aligned 128-bit accesses, therefore use
this s390 specific helper
- Simplify machine check handler code if a task needs to be killed
because of e.g. register corruption due to a machine malfunction
- Perform CPU reset to clear pending interrupts and TLB entries on an
already stopped target CPU before delegating work to it
- Generate arch/s390/boot/vmlinux.map link map for the decompressor,
when CONFIG_VMLINUX_MAP is enabled for debugging purposes
- Fix segment type handling for dcssblk devices. It incorrectly always
returned type "READ/WRITE" even for read-only segements, which can
result in a kernel panic if somebody tries to write to a read-only
device
- Sort config S390 select list again
- Fix two kprobe reenter bugs revealed by a recently added kprobe kunit
test
* tag 's390-6.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/kprobes: fix current_kprobe never cleared after kprobes reenter
s390/kprobes: fix irq mask clobbering on kprobe reenter from post_handler
s390/Kconfig: sort config S390 select list again
s390/extmem: return correct segment type in __segment_load()
s390/decompressor: add link map saving
s390/smp: perform cpu reset before delegating work to target cpu
s390/mcck: cleanup user process termination path
s390/cpum_sf: use READ_ONCE_ALIGNED_128() instead of 128-bit cmpxchg
s390/rwonce: add READ_ONCE_ALIGNED_128() macro
s390/ap,zcrypt,vfio: introduce and use ap_queue_status_reg union
s390/nmi: fix virtual-physical address confusion
s390/setup: do not complain about parameters handled in decompressor
Recent test_kprobe_missed kprobes kunit test uncovers the following
problem. Once kprobe is triggered from another kprobe (kprobe reenter),
all future kprobes on this cpu are considered as kprobe reenter, thus
pre_handler and post_handler are not being called and kprobes are counted
as "missed".
Commit b9599798f9 ("[S390] kprobes: activation and deactivation")
introduced a simpler scheme for kprobes (de)activation and status
tracking by using push_kprobe/pop_kprobe, which supposed to work for
both initial kprobe entry as well as kprobe reentry and helps to avoid
handling those two cases differently. The problem is that a sequence of
calls in case of kprobes reenter:
push_kprobe() <- NULL (current_kprobe)
push_kprobe() <- kprobe1 (current_kprobe)
pop_kprobe() -> kprobe1 (current_kprobe)
pop_kprobe() -> kprobe1 (current_kprobe)
leaves "kprobe1" as "current_kprobe" on this cpu, instead of setting it
to NULL. In fact push_kprobe/pop_kprobe can only store a single state
(there is just one prev_kprobe in kprobe_ctlblk). Which is a hack but
sufficient, there is no need to have another prev_kprobe just to store
NULL. To make a simple and backportable fix simply reset "prev_kprobe"
when kprobe is poped from this "stack". No need to worry about
"kprobe_status" in this case, because its value is only checked when
current_kprobe != NULL.
Cc: stable@vger.kernel.org
Fixes: b9599798f9 ("[S390] kprobes: activation and deactivation")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Recent test_kprobe_missed kprobes kunit test uncovers the following error
(reported when CONFIG_DEBUG_ATOMIC_SLEEP is enabled):
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 662, name: kunit_try_catch
preempt_count: 0, expected: 0
RCU nest depth: 0, expected: 0
no locks held by kunit_try_catch/662.
irq event stamp: 280
hardirqs last enabled at (279): [<00000003e60a3d42>] __do_pgm_check+0x17a/0x1c0
hardirqs last disabled at (280): [<00000003e3bd774a>] kprobe_exceptions_notify+0x27a/0x318
softirqs last enabled at (0): [<00000003e3c5c890>] copy_process+0x14a8/0x4c80
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 46 PID: 662 Comm: kunit_try_catch Tainted: G N 6.2.0-173644-g44c18d77f0c0 #2
Hardware name: IBM 3931 A01 704 (LPAR)
Call Trace:
[<00000003e60a3a00>] dump_stack_lvl+0x120/0x198
[<00000003e3d02e82>] __might_resched+0x60a/0x668
[<00000003e60b9908>] __mutex_lock+0xc0/0x14e0
[<00000003e60bad5a>] mutex_lock_nested+0x32/0x40
[<00000003e3f7b460>] unregister_kprobe+0x30/0xd8
[<00000003e51b2602>] test_kprobe_missed+0xf2/0x268
[<00000003e51b5406>] kunit_try_run_case+0x10e/0x290
[<00000003e51b7dfa>] kunit_generic_run_threadfn_adapter+0x62/0xb8
[<00000003e3ce30f8>] kthread+0x2d0/0x398
[<00000003e3b96afa>] __ret_from_fork+0x8a/0xe8
[<00000003e60ccada>] ret_from_fork+0xa/0x40
The reason for this error report is that kprobes handling code failed
to restore irqs.
The problem is that when kprobe is triggered from another kprobe
post_handler current sequence of enable_singlestep / disable_singlestep
is the following:
enable_singlestep <- original kprobe (saves kprobe_saved_imask)
enable_singlestep <- kprobe triggered from post_handler (clobbers kprobe_saved_imask)
disable_singlestep <- kprobe triggered from post_handler (restores kprobe_saved_imask)
disable_singlestep <- original kprobe (restores wrong clobbered kprobe_saved_imask)
There is just one kprobe_ctlblk per cpu and both calls saves and
loads irq mask to kprobe_saved_imask. To fix the problem simply move
resume_execution (which calls disable_singlestep) before calling
post_handler. This also fixes the problem that post_handler is called
with pt_regs which were not yet adjusted after single-stepping.
Cc: stable@vger.kernel.org
Fixes: 4ba069b802 ("[S390] add kprobes support.")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Clear CPU state (e.g. all TLB entries, prefetched instructions, etc.)
of the target CPU, however without clearing register contents before
starting any work on it.
This puts the target CPU in a more defined state compared to the
current Stop + Restart sigp orders.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
If a machine check interrupt hits while user process is
running __s390_handle_mcck() helper function is called
directly from the interrupt handler and terminates the
current process by calling make_task_dead() routine.
The make_task_dead() is not allowed to be called from
interrupt context which forces the machine check handler
switch to the kernel stack and enable local interrupts
first.
The __s390_handle_mcck() could also be called to service
pending work, but this time from the external interrupts
handler. It is the machine check handler that establishes
the work and schedules the external interrupt, therefore
the machine check interrupt itself should be disabled
while reading out the corresponding variable:
local_mcck_disable();
mcck = *this_cpu_ptr(&cpu_mcck);
memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
local_mcck_enable();
However, local_mcck_disable() does not have effect when
__s390_handle_mcck() is called directly form the machine
check handler, since the machine check interrupt is still
disabled. Therefore, it is not the opening bracket to the
following local_mcck_enable() function.
Simplify the user process termination flow by scheduling
the external interrupt and killing the affected process
from the interrupt context.
Assume a kernel-generated signal is always delivered and
ignore a value returned by do_send_sig_info() funciton.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Use READ_ONCE_ALIGNED_128() to read the previous value in front of a
128-bit cmpxchg loop, instead of (mis-)using a 128-bit cmpxchg operation to
do the same.
This makes the code more readable and is faster.
Link: https://lore.kernel.org/r/20230224100237.3247871-3-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
When a machine check is received while in SIE, it is reinjected into the
guest in some cases. The respective code needs to access the sie_block,
which is taken from the backed up R14.
Since reinjection only occurs while we are in SIE (i.e. between the
labels sie_entry and sie_leave in entry.S and thus if CIF_MCCK_GUEST is
set), the backed up R14 will always contain a physical address in
s390_backup_mcck_info.
This currently works, because virtual and physical addresses are
the same.
Add phys_to_virt() to resolve the virtual-physical confusion.
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/r/20230216121208.4390-2-nrb@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
