linux/arch/mips/kernel/signal.c

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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1994 - 2000 Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2014, Imagination Technologies Ltd.
*/
#include <linux/cache.h>
#include <linux/context_tracking.h>
#include <linux/irqflags.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/personality.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/uprobes.h>
#include <linux/compiler.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <asm/abi.h>
#include <asm/asm.h>
#include <linux/bitops.h>
#include <asm/cacheflush.h>
#include <asm/fpu.h>
#include <asm/sim.h>
#include <asm/ucontext.h>
#include <asm/cpu-features.h>
#include <asm/war.h>
#include <asm/dsp.h>
#include <asm/inst.h>
#include <asm/msa.h>
#include "signal-common.h"
static int (*save_fp_context)(void __user *sc);
static int (*restore_fp_context)(void __user *sc);
struct sigframe {
u32 sf_ass[4]; /* argument save space for o32 */
u32 sf_pad[2]; /* Was: signal trampoline */
MIPS: Add definitions for extended context The context introduced by MSA needs to be saved around signals. However, we can't increase the size of struct sigcontext because that will change the offset of the signal mask in struct sigframe or struct ucontext. This patch instead places the new context immediately after the struct sigframe for traditional signals, or similarly after struct ucontext for RT signals. The layout of struct sigframe & struct ucontext is identical from their sigcontext fields onwards, so the offset from the sigcontext to the extended context will always be the same regardless of the type of signal. Userland will be able to search through the extended context by using the magic values to detect which types of context are present. Any unrecognised context can be skipped over using the size field of struct extcontext. Once the magic value END_EXTCONTEXT_MAGIC is seen it is known that there are no further extended context structures to examine. This approach is somewhat similar to that taken by ARM to save VFP & other context at the end of struct ucontext. Userland can determine whether extended context is present by checking for the USED_EXTCONTEXT bit in the sc_used_math field of struct sigcontext. Whilst this could potentially change the historic semantics of sc_used_math if further extended context which does not imply FP context were to be introduced in the future, I have been unable to find any userland code making use of sc_used_math at all. Using one of the fields described as unused in struct sigcontext was considered, but the kernel does not already write to those fields so there would be no guarantee of the field being clear on older kernels. Other alternatives would be to have userland check the kernel version, or to have a HWCAP bit indicating presence of extended context. However there is a desire to have the context & information required to decode it be self contained such that, for example, debuggers could decode the saved context easily. [ralf@linux-mips.org: Fixed conflict.] Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Guenter Roeck <linux@roeck-us.net> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger <richard@nod.at> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Maciej W. Rozycki <macro@codesourcery.com> Patchwork: https://patchwork.linux-mips.org/patch/10795/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-27 19:58:21 +00:00
/* Matches struct ucontext from its uc_mcontext field onwards */
struct sigcontext sf_sc;
sigset_t sf_mask;
MIPS: Add definitions for extended context The context introduced by MSA needs to be saved around signals. However, we can't increase the size of struct sigcontext because that will change the offset of the signal mask in struct sigframe or struct ucontext. This patch instead places the new context immediately after the struct sigframe for traditional signals, or similarly after struct ucontext for RT signals. The layout of struct sigframe & struct ucontext is identical from their sigcontext fields onwards, so the offset from the sigcontext to the extended context will always be the same regardless of the type of signal. Userland will be able to search through the extended context by using the magic values to detect which types of context are present. Any unrecognised context can be skipped over using the size field of struct extcontext. Once the magic value END_EXTCONTEXT_MAGIC is seen it is known that there are no further extended context structures to examine. This approach is somewhat similar to that taken by ARM to save VFP & other context at the end of struct ucontext. Userland can determine whether extended context is present by checking for the USED_EXTCONTEXT bit in the sc_used_math field of struct sigcontext. Whilst this could potentially change the historic semantics of sc_used_math if further extended context which does not imply FP context were to be introduced in the future, I have been unable to find any userland code making use of sc_used_math at all. Using one of the fields described as unused in struct sigcontext was considered, but the kernel does not already write to those fields so there would be no guarantee of the field being clear on older kernels. Other alternatives would be to have userland check the kernel version, or to have a HWCAP bit indicating presence of extended context. However there is a desire to have the context & information required to decode it be self contained such that, for example, debuggers could decode the saved context easily. [ralf@linux-mips.org: Fixed conflict.] Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Guenter Roeck <linux@roeck-us.net> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger <richard@nod.at> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Maciej W. Rozycki <macro@codesourcery.com> Patchwork: https://patchwork.linux-mips.org/patch/10795/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-27 19:58:21 +00:00
unsigned long long sf_extcontext[0];
};
struct rt_sigframe {
u32 rs_ass[4]; /* argument save space for o32 */
u32 rs_pad[2]; /* Was: signal trampoline */
struct siginfo rs_info;
struct ucontext rs_uc;
};
/*
* Thread saved context copy to/from a signal context presumed to be on the
* user stack, and therefore accessed with appropriate macros from uaccess.h.
*/
static int copy_fp_to_sigcontext(void __user *sc)
{
struct mips_abi *abi = current->thread.abi;
uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
int i;
int err = 0;
int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
for (i = 0; i < NUM_FPU_REGS; i += inc) {
err |=
__put_user(get_fpr64(&current->thread.fpu.fpr[i], 0),
&fpregs[i]);
}
err |= __put_user(current->thread.fpu.fcr31, csr);
return err;
}
static int copy_fp_from_sigcontext(void __user *sc)
{
struct mips_abi *abi = current->thread.abi;
uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
int i;
int err = 0;
int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
u64 fpr_val;
for (i = 0; i < NUM_FPU_REGS; i += inc) {
err |= __get_user(fpr_val, &fpregs[i]);
set_fpr64(&current->thread.fpu.fpr[i], 0, fpr_val);
}
err |= __get_user(current->thread.fpu.fcr31, csr);
return err;
}
/*
* Wrappers for the assembly _{save,restore}_fp_context functions.
*/
static int save_hw_fp_context(void __user *sc)
{
struct mips_abi *abi = current->thread.abi;
uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
return _save_fp_context(fpregs, csr);
}
static int restore_hw_fp_context(void __user *sc)
{
struct mips_abi *abi = current->thread.abi;
uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
return _restore_fp_context(fpregs, csr);
}
/*
* Extended context handling.
*/
static inline void __user *sc_to_extcontext(void __user *sc)
{
struct ucontext __user *uc;
/*
* We can just pretend the sigcontext is always embedded in a struct
* ucontext here, because the offset from sigcontext to extended
* context is the same in the struct sigframe case.
*/
uc = container_of(sc, struct ucontext, uc_mcontext);
return &uc->uc_extcontext;
}
static int save_msa_extcontext(void __user *buf)
{
struct msa_extcontext __user *msa = buf;
uint64_t val;
int i, err;
if (!thread_msa_context_live())
return 0;
/*
* Ensure that we can't lose the live MSA context between checking
* for it & writing it to memory.
*/
preempt_disable();
if (is_msa_enabled()) {
/*
* There are no EVA versions of the vector register load/store
* instructions, so MSA context has to be saved to kernel memory
* and then copied to user memory. The save to kernel memory
* should already have been done when handling scalar FP
* context.
*/
tree-wide: replace config_enabled() with IS_ENABLED() The use of config_enabled() against config options is ambiguous. In practical terms, config_enabled() is equivalent to IS_BUILTIN(), but the author might have used it for the meaning of IS_ENABLED(). Using IS_ENABLED(), IS_BUILTIN(), IS_MODULE() etc. makes the intention clearer. This commit replaces config_enabled() with IS_ENABLED() where possible. This commit is only touching bool config options. I noticed two cases where config_enabled() is used against a tristate option: - config_enabled(CONFIG_HWMON) [ drivers/net/wireless/ath/ath10k/thermal.c ] - config_enabled(CONFIG_BACKLIGHT_CLASS_DEVICE) [ drivers/gpu/drm/gma500/opregion.c ] I did not touch them because they should be converted to IS_BUILTIN() in order to keep the logic, but I was not sure it was the authors' intention. Link: http://lkml.kernel.org/r/1465215656-20569-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Stas Sergeev <stsp@list.ru> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: "Dmitry V. Levin" <ldv@altlinux.org> Cc: yu-cheng yu <yu-cheng.yu@intel.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Will Drewry <wad@chromium.org> Cc: Nikolay Martynov <mar.kolya@gmail.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: Rafal Milecki <zajec5@gmail.com> Cc: James Cowgill <James.Cowgill@imgtec.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Qais Yousef <qais.yousef@imgtec.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Mikko Rapeli <mikko.rapeli@iki.fi> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Kalle Valo <kvalo@qca.qualcomm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Tony Wu <tung7970@gmail.com> Cc: Huaitong Han <huaitong.han@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Juergen Gross <jgross@suse.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Gelmini <andrea.gelmini@gelma.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Rabin Vincent <rabin@rab.in> Cc: "Maciej W. Rozycki" <macro@imgtec.com> Cc: David Daney <david.daney@cavium.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-03 20:45:50 +00:00
BUG_ON(IS_ENABLED(CONFIG_EVA));
err = __put_user(read_msa_csr(), &msa->csr);
err |= _save_msa_all_upper(&msa->wr);
preempt_enable();
} else {
preempt_enable();
err = __put_user(current->thread.fpu.msacsr, &msa->csr);
for (i = 0; i < NUM_FPU_REGS; i++) {
val = get_fpr64(&current->thread.fpu.fpr[i], 1);
err |= __put_user(val, &msa->wr[i]);
}
}
err |= __put_user(MSA_EXTCONTEXT_MAGIC, &msa->ext.magic);
err |= __put_user(sizeof(*msa), &msa->ext.size);
return err ? -EFAULT : sizeof(*msa);
}
static int restore_msa_extcontext(void __user *buf, unsigned int size)
{
struct msa_extcontext __user *msa = buf;
unsigned long long val;
unsigned int csr;
int i, err;
tree-wide: replace config_enabled() with IS_ENABLED() The use of config_enabled() against config options is ambiguous. In practical terms, config_enabled() is equivalent to IS_BUILTIN(), but the author might have used it for the meaning of IS_ENABLED(). Using IS_ENABLED(), IS_BUILTIN(), IS_MODULE() etc. makes the intention clearer. This commit replaces config_enabled() with IS_ENABLED() where possible. This commit is only touching bool config options. I noticed two cases where config_enabled() is used against a tristate option: - config_enabled(CONFIG_HWMON) [ drivers/net/wireless/ath/ath10k/thermal.c ] - config_enabled(CONFIG_BACKLIGHT_CLASS_DEVICE) [ drivers/gpu/drm/gma500/opregion.c ] I did not touch them because they should be converted to IS_BUILTIN() in order to keep the logic, but I was not sure it was the authors' intention. Link: http://lkml.kernel.org/r/1465215656-20569-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Stas Sergeev <stsp@list.ru> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: "Dmitry V. Levin" <ldv@altlinux.org> Cc: yu-cheng yu <yu-cheng.yu@intel.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Will Drewry <wad@chromium.org> Cc: Nikolay Martynov <mar.kolya@gmail.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: Rafal Milecki <zajec5@gmail.com> Cc: James Cowgill <James.Cowgill@imgtec.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Qais Yousef <qais.yousef@imgtec.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Mikko Rapeli <mikko.rapeli@iki.fi> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Kalle Valo <kvalo@qca.qualcomm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Tony Wu <tung7970@gmail.com> Cc: Huaitong Han <huaitong.han@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Juergen Gross <jgross@suse.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Gelmini <andrea.gelmini@gelma.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Rabin Vincent <rabin@rab.in> Cc: "Maciej W. Rozycki" <macro@imgtec.com> Cc: David Daney <david.daney@cavium.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-03 20:45:50 +00:00
if (!IS_ENABLED(CONFIG_CPU_HAS_MSA))
MIPS: Prevent "restoration" of MSA context in non-MSA kernels If a kernel doesn't support MSA context (ie. CONFIG_CPU_HAS_MSA=n) then it will only keep 64 bits per FP register in thread context, and the calls to set_fpr64 in restore_msa_extcontext will overrun the end of the FP register context into the FCSR & MSACSR values. GCC 6.x has become smart enough to detect this & complain like so: arch/mips/kernel/signal.c: In function 'protected_restore_fp_context': ./arch/mips/include/asm/processor.h:114:17: error: array subscript is above array bounds [-Werror=array-bounds] fpr->val##width[FPR_IDX(width, idx)] = val; \ ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~ ./arch/mips/include/asm/processor.h:118:1: note: in expansion of macro 'BUILD_FPR_ACCESS' BUILD_FPR_ACCESS(64) The only way to trigger this code to run would be for a program to set up an artificial extended MSA context structure following a sigframe & execute sigreturn. Whilst this doesn't allow a program to write to any state that it couldn't already, it makes little sense to allow this "restoration" of MSA context in a system that doesn't support MSA. Fix this by killing a program with SIGSYS if it tries something as crazy as "restoring" fake MSA context in this way, also fixing the build error & allowing for most of restore_msa_extcontext to be optimised out of kernels without support for MSA. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reported-by: Michal Toman <michal.toman@imgtec.com> Fixes: bf82cb30c7e5 ("MIPS: Save MSA extended context around signals") Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi> Cc: James Hogan <james.hogan@imgtec.com> Cc: Michal Toman <michal.toman@imgtec.com> Cc: linux-mips@linux-mips.org Cc: stable <stable@vger.kernel.org> # v4.3+ Patchwork: https://patchwork.linux-mips.org/patch/13164/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-04-21 17:04:53 +00:00
return SIGSYS;
if (size != sizeof(*msa))
return -EINVAL;
err = get_user(csr, &msa->csr);
if (err)
return err;
preempt_disable();
if (is_msa_enabled()) {
/*
* There are no EVA versions of the vector register load/store
* instructions, so MSA context has to be copied to kernel
* memory and later loaded to registers. The same is true of
* scalar FP context, so FPU & MSA should have already been
* disabled whilst handling scalar FP context.
*/
tree-wide: replace config_enabled() with IS_ENABLED() The use of config_enabled() against config options is ambiguous. In practical terms, config_enabled() is equivalent to IS_BUILTIN(), but the author might have used it for the meaning of IS_ENABLED(). Using IS_ENABLED(), IS_BUILTIN(), IS_MODULE() etc. makes the intention clearer. This commit replaces config_enabled() with IS_ENABLED() where possible. This commit is only touching bool config options. I noticed two cases where config_enabled() is used against a tristate option: - config_enabled(CONFIG_HWMON) [ drivers/net/wireless/ath/ath10k/thermal.c ] - config_enabled(CONFIG_BACKLIGHT_CLASS_DEVICE) [ drivers/gpu/drm/gma500/opregion.c ] I did not touch them because they should be converted to IS_BUILTIN() in order to keep the logic, but I was not sure it was the authors' intention. Link: http://lkml.kernel.org/r/1465215656-20569-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Stas Sergeev <stsp@list.ru> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: "Dmitry V. Levin" <ldv@altlinux.org> Cc: yu-cheng yu <yu-cheng.yu@intel.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Will Drewry <wad@chromium.org> Cc: Nikolay Martynov <mar.kolya@gmail.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: Rafal Milecki <zajec5@gmail.com> Cc: James Cowgill <James.Cowgill@imgtec.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Qais Yousef <qais.yousef@imgtec.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Mikko Rapeli <mikko.rapeli@iki.fi> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Kalle Valo <kvalo@qca.qualcomm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Tony Wu <tung7970@gmail.com> Cc: Huaitong Han <huaitong.han@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Juergen Gross <jgross@suse.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Gelmini <andrea.gelmini@gelma.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Rabin Vincent <rabin@rab.in> Cc: "Maciej W. Rozycki" <macro@imgtec.com> Cc: David Daney <david.daney@cavium.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-03 20:45:50 +00:00
BUG_ON(IS_ENABLED(CONFIG_EVA));
write_msa_csr(csr);
err |= _restore_msa_all_upper(&msa->wr);
preempt_enable();
} else {
preempt_enable();
current->thread.fpu.msacsr = csr;
for (i = 0; i < NUM_FPU_REGS; i++) {
err |= __get_user(val, &msa->wr[i]);
set_fpr64(&current->thread.fpu.fpr[i], 1, val);
}
}
return err;
}
static int save_extcontext(void __user *buf)
{
int sz;
sz = save_msa_extcontext(buf);
if (sz < 0)
return sz;
buf += sz;
/* If no context was saved then trivially return */
if (!sz)
return 0;
/* Write the end marker */
if (__put_user(END_EXTCONTEXT_MAGIC, (u32 *)buf))
return -EFAULT;
sz += sizeof(((struct extcontext *)NULL)->magic);
return sz;
}
static int restore_extcontext(void __user *buf)
{
struct extcontext ext;
int err;
while (1) {
err = __get_user(ext.magic, (unsigned int *)buf);
if (err)
return err;
if (ext.magic == END_EXTCONTEXT_MAGIC)
return 0;
err = __get_user(ext.size, (unsigned int *)(buf
+ offsetof(struct extcontext, size)));
if (err)
return err;
switch (ext.magic) {
case MSA_EXTCONTEXT_MAGIC:
err = restore_msa_extcontext(buf, ext.size);
break;
default:
err = -EINVAL;
break;
}
if (err)
return err;
buf += ext.size;
}
}
/*
* Helper routines
*/
int protected_save_fp_context(void __user *sc)
{
struct mips_abi *abi = current->thread.abi;
uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
uint32_t __user *used_math = sc + abi->off_sc_used_math;
unsigned int used, ext_sz;
int err;
MIPS: Indicate FP mode in sigcontext sc_used_math The sc_used_math field of struct sigcontext & its variants has traditionally been used as a boolean value indicating only whether or not floating point context is saved within the sigcontext. With various supported FP modes & the ability to switch between them this information will no longer be enough to decode the meaning of the data stored in the sc_fpregs fields of struct sigcontext. To make that possible 3 bits are defined within sc_used_math: - Bit 0 (USED_FP) represents whether FP was used, essentially providing the boolean flag which sc_used_math as a whole provided previously. - Bit 1 (USED_FR1) provides the value of the Status.FR bit at the time the FP context was saved. - Bit 2 (USED_HYBRID_FPRS) indicates whether the FP context was saved under the hybrid FPR scheme. Essentially, when set the odd singles are located in bits 63:32 of the preceding even indexed sc_fpregs element. Any userland that tests whether the sc_used_math field is zero or non-zero will continue to function as expected. Having said that, I could not find any userland which uses the sc_used_math field at all. [ralf@linux-mips.org: Fixed rejects.] Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Guenter Roeck <linux@roeck-us.net> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger <richard@nod.at> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Maciej W. Rozycki <macro@codesourcery.com> Patchwork: https://patchwork.linux-mips.org/patch/10794/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-27 19:58:20 +00:00
used = used_math() ? USED_FP : 0;
if (!used)
goto fp_done;
MIPS: Indicate FP mode in sigcontext sc_used_math The sc_used_math field of struct sigcontext & its variants has traditionally been used as a boolean value indicating only whether or not floating point context is saved within the sigcontext. With various supported FP modes & the ability to switch between them this information will no longer be enough to decode the meaning of the data stored in the sc_fpregs fields of struct sigcontext. To make that possible 3 bits are defined within sc_used_math: - Bit 0 (USED_FP) represents whether FP was used, essentially providing the boolean flag which sc_used_math as a whole provided previously. - Bit 1 (USED_FR1) provides the value of the Status.FR bit at the time the FP context was saved. - Bit 2 (USED_HYBRID_FPRS) indicates whether the FP context was saved under the hybrid FPR scheme. Essentially, when set the odd singles are located in bits 63:32 of the preceding even indexed sc_fpregs element. Any userland that tests whether the sc_used_math field is zero or non-zero will continue to function as expected. Having said that, I could not find any userland which uses the sc_used_math field at all. [ralf@linux-mips.org: Fixed rejects.] Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Guenter Roeck <linux@roeck-us.net> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger <richard@nod.at> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Maciej W. Rozycki <macro@codesourcery.com> Patchwork: https://patchwork.linux-mips.org/patch/10794/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-27 19:58:20 +00:00
if (!test_thread_flag(TIF_32BIT_FPREGS))
used |= USED_FR1;
if (test_thread_flag(TIF_HYBRID_FPREGS))
used |= USED_HYBRID_FPRS;
/*
* EVA does not have userland equivalents of ldc1 or sdc1, so
* save to the kernel FP context & copy that to userland below.
*/
tree-wide: replace config_enabled() with IS_ENABLED() The use of config_enabled() against config options is ambiguous. In practical terms, config_enabled() is equivalent to IS_BUILTIN(), but the author might have used it for the meaning of IS_ENABLED(). Using IS_ENABLED(), IS_BUILTIN(), IS_MODULE() etc. makes the intention clearer. This commit replaces config_enabled() with IS_ENABLED() where possible. This commit is only touching bool config options. I noticed two cases where config_enabled() is used against a tristate option: - config_enabled(CONFIG_HWMON) [ drivers/net/wireless/ath/ath10k/thermal.c ] - config_enabled(CONFIG_BACKLIGHT_CLASS_DEVICE) [ drivers/gpu/drm/gma500/opregion.c ] I did not touch them because they should be converted to IS_BUILTIN() in order to keep the logic, but I was not sure it was the authors' intention. Link: http://lkml.kernel.org/r/1465215656-20569-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Stas Sergeev <stsp@list.ru> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: "Dmitry V. Levin" <ldv@altlinux.org> Cc: yu-cheng yu <yu-cheng.yu@intel.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Will Drewry <wad@chromium.org> Cc: Nikolay Martynov <mar.kolya@gmail.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: Rafal Milecki <zajec5@gmail.com> Cc: James Cowgill <James.Cowgill@imgtec.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Qais Yousef <qais.yousef@imgtec.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Mikko Rapeli <mikko.rapeli@iki.fi> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Kalle Valo <kvalo@qca.qualcomm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Tony Wu <tung7970@gmail.com> Cc: Huaitong Han <huaitong.han@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Juergen Gross <jgross@suse.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Gelmini <andrea.gelmini@gelma.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Rabin Vincent <rabin@rab.in> Cc: "Maciej W. Rozycki" <macro@imgtec.com> Cc: David Daney <david.daney@cavium.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-03 20:45:50 +00:00
if (IS_ENABLED(CONFIG_EVA))
lose_fpu(1);
while (1) {
lock_fpu_owner();
if (is_fpu_owner()) {
err = save_fp_context(sc);
unlock_fpu_owner();
} else {
unlock_fpu_owner();
err = copy_fp_to_sigcontext(sc);
}
if (likely(!err))
break;
/* touch the sigcontext and try again */
err = __put_user(0, &fpregs[0]) |
__put_user(0, &fpregs[31]) |
__put_user(0, csr);
if (err)
return err; /* really bad sigcontext */
}
fp_done:
ext_sz = err = save_extcontext(sc_to_extcontext(sc));
if (err < 0)
return err;
used |= ext_sz ? USED_EXTCONTEXT : 0;
return __put_user(used, used_math);
}
int protected_restore_fp_context(void __user *sc)
{
struct mips_abi *abi = current->thread.abi;
uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
uint32_t __user *used_math = sc + abi->off_sc_used_math;
unsigned int used;
int err, sig = 0, tmp __maybe_unused;
err = __get_user(used, used_math);
MIPS: Indicate FP mode in sigcontext sc_used_math The sc_used_math field of struct sigcontext & its variants has traditionally been used as a boolean value indicating only whether or not floating point context is saved within the sigcontext. With various supported FP modes & the ability to switch between them this information will no longer be enough to decode the meaning of the data stored in the sc_fpregs fields of struct sigcontext. To make that possible 3 bits are defined within sc_used_math: - Bit 0 (USED_FP) represents whether FP was used, essentially providing the boolean flag which sc_used_math as a whole provided previously. - Bit 1 (USED_FR1) provides the value of the Status.FR bit at the time the FP context was saved. - Bit 2 (USED_HYBRID_FPRS) indicates whether the FP context was saved under the hybrid FPR scheme. Essentially, when set the odd singles are located in bits 63:32 of the preceding even indexed sc_fpregs element. Any userland that tests whether the sc_used_math field is zero or non-zero will continue to function as expected. Having said that, I could not find any userland which uses the sc_used_math field at all. [ralf@linux-mips.org: Fixed rejects.] Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Guenter Roeck <linux@roeck-us.net> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger <richard@nod.at> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Maciej W. Rozycki <macro@codesourcery.com> Patchwork: https://patchwork.linux-mips.org/patch/10794/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-27 19:58:20 +00:00
conditional_used_math(used & USED_FP);
/*
* The signal handler may have used FPU; give it up if the program
* doesn't want it following sigreturn.
*/
if (err || !(used & USED_FP))
lose_fpu(0);
if (err)
return err;
if (!(used & USED_FP))
goto fp_done;
err = sig = fpcsr_pending(csr);
if (err < 0)
return err;
/*
* EVA does not have userland equivalents of ldc1 or sdc1, so we
* disable the FPU here such that the code below simply copies to
* the kernel FP context.
*/
tree-wide: replace config_enabled() with IS_ENABLED() The use of config_enabled() against config options is ambiguous. In practical terms, config_enabled() is equivalent to IS_BUILTIN(), but the author might have used it for the meaning of IS_ENABLED(). Using IS_ENABLED(), IS_BUILTIN(), IS_MODULE() etc. makes the intention clearer. This commit replaces config_enabled() with IS_ENABLED() where possible. This commit is only touching bool config options. I noticed two cases where config_enabled() is used against a tristate option: - config_enabled(CONFIG_HWMON) [ drivers/net/wireless/ath/ath10k/thermal.c ] - config_enabled(CONFIG_BACKLIGHT_CLASS_DEVICE) [ drivers/gpu/drm/gma500/opregion.c ] I did not touch them because they should be converted to IS_BUILTIN() in order to keep the logic, but I was not sure it was the authors' intention. Link: http://lkml.kernel.org/r/1465215656-20569-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Stas Sergeev <stsp@list.ru> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: "Dmitry V. Levin" <ldv@altlinux.org> Cc: yu-cheng yu <yu-cheng.yu@intel.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Will Drewry <wad@chromium.org> Cc: Nikolay Martynov <mar.kolya@gmail.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Cc: Rafal Milecki <zajec5@gmail.com> Cc: James Cowgill <James.Cowgill@imgtec.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Alex Smith <alex.smith@imgtec.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Qais Yousef <qais.yousef@imgtec.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Mikko Rapeli <mikko.rapeli@iki.fi> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Kalle Valo <kvalo@qca.qualcomm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Tony Wu <tung7970@gmail.com> Cc: Huaitong Han <huaitong.han@intel.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Juergen Gross <jgross@suse.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Gelmini <andrea.gelmini@gelma.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Rabin Vincent <rabin@rab.in> Cc: "Maciej W. Rozycki" <macro@imgtec.com> Cc: David Daney <david.daney@cavium.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-03 20:45:50 +00:00
if (IS_ENABLED(CONFIG_EVA))
lose_fpu(0);
while (1) {
lock_fpu_owner();
if (is_fpu_owner()) {
err = restore_fp_context(sc);
unlock_fpu_owner();
} else {
unlock_fpu_owner();
err = copy_fp_from_sigcontext(sc);
}
if (likely(!err))
break;
/* touch the sigcontext and try again */
err = __get_user(tmp, &fpregs[0]) |
__get_user(tmp, &fpregs[31]) |
__get_user(tmp, csr);
if (err)
break; /* really bad sigcontext */
}
fp_done:
MIPS: Prevent "restoration" of MSA context in non-MSA kernels If a kernel doesn't support MSA context (ie. CONFIG_CPU_HAS_MSA=n) then it will only keep 64 bits per FP register in thread context, and the calls to set_fpr64 in restore_msa_extcontext will overrun the end of the FP register context into the FCSR & MSACSR values. GCC 6.x has become smart enough to detect this & complain like so: arch/mips/kernel/signal.c: In function 'protected_restore_fp_context': ./arch/mips/include/asm/processor.h:114:17: error: array subscript is above array bounds [-Werror=array-bounds] fpr->val##width[FPR_IDX(width, idx)] = val; \ ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~ ./arch/mips/include/asm/processor.h:118:1: note: in expansion of macro 'BUILD_FPR_ACCESS' BUILD_FPR_ACCESS(64) The only way to trigger this code to run would be for a program to set up an artificial extended MSA context structure following a sigframe & execute sigreturn. Whilst this doesn't allow a program to write to any state that it couldn't already, it makes little sense to allow this "restoration" of MSA context in a system that doesn't support MSA. Fix this by killing a program with SIGSYS if it tries something as crazy as "restoring" fake MSA context in this way, also fixing the build error & allowing for most of restore_msa_extcontext to be optimised out of kernels without support for MSA. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reported-by: Michal Toman <michal.toman@imgtec.com> Fixes: bf82cb30c7e5 ("MIPS: Save MSA extended context around signals") Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi> Cc: James Hogan <james.hogan@imgtec.com> Cc: Michal Toman <michal.toman@imgtec.com> Cc: linux-mips@linux-mips.org Cc: stable <stable@vger.kernel.org> # v4.3+ Patchwork: https://patchwork.linux-mips.org/patch/13164/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-04-21 17:04:53 +00:00
if (!err && (used & USED_EXTCONTEXT))
err = restore_extcontext(sc_to_extcontext(sc));
return err ?: sig;
}
int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
int err = 0;
int i;
err |= __put_user(regs->cp0_epc, &sc->sc_pc);
err |= __put_user(0, &sc->sc_regs[0]);
for (i = 1; i < 32; i++)
err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
#ifdef CONFIG_CPU_HAS_SMARTMIPS
err |= __put_user(regs->acx, &sc->sc_acx);
#endif
err |= __put_user(regs->hi, &sc->sc_mdhi);
err |= __put_user(regs->lo, &sc->sc_mdlo);
if (cpu_has_dsp) {
err |= __put_user(mfhi1(), &sc->sc_hi1);
err |= __put_user(mflo1(), &sc->sc_lo1);
err |= __put_user(mfhi2(), &sc->sc_hi2);
err |= __put_user(mflo2(), &sc->sc_lo2);
err |= __put_user(mfhi3(), &sc->sc_hi3);
err |= __put_user(mflo3(), &sc->sc_lo3);
err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
}
/*
* Save FPU state to signal context. Signal handler
* will "inherit" current FPU state.
*/
err |= protected_save_fp_context(sc);
return err;
}
static size_t extcontext_max_size(void)
{
size_t sz = 0;
/*
* The assumption here is that between this point & the point at which
* the extended context is saved the size of the context should only
* ever be able to shrink (if the task is preempted), but never grow.
* That is, what this function returns is an upper bound on the size of
* the extended context for the current task at the current time.
*/
if (thread_msa_context_live())
sz += sizeof(struct msa_extcontext);
/* If any context is saved then we'll append the end marker */
if (sz)
sz += sizeof(((struct extcontext *)NULL)->magic);
return sz;
}
int fpcsr_pending(unsigned int __user *fpcsr)
{
int err, sig = 0;
unsigned int csr, enabled;
err = __get_user(csr, fpcsr);
enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
/*
* If the signal handler set some FPU exceptions, clear it and
* send SIGFPE.
*/
if (csr & enabled) {
csr &= ~enabled;
err |= __put_user(csr, fpcsr);
sig = SIGFPE;
}
return err ?: sig;
}
int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
unsigned long treg;
int err = 0;
int i;
/* Always make any pending restarted system calls return -EINTR */
all arches, signal: move restart_block to struct task_struct If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12 23:01:14 +00:00
current->restart_block.fn = do_no_restart_syscall;
err |= __get_user(regs->cp0_epc, &sc->sc_pc);
#ifdef CONFIG_CPU_HAS_SMARTMIPS
err |= __get_user(regs->acx, &sc->sc_acx);
#endif
err |= __get_user(regs->hi, &sc->sc_mdhi);
err |= __get_user(regs->lo, &sc->sc_mdlo);
if (cpu_has_dsp) {
err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
}
for (i = 1; i < 32; i++)
err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
return err ?: protected_restore_fp_context(sc);
}
void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
size_t frame_size)
{
unsigned long sp;
/* Leave space for potential extended context */
frame_size += extcontext_max_size();
/* Default to using normal stack */
sp = regs->regs[29];
/*
* FPU emulator may have it's own trampoline active just
* above the user stack, 16-bytes before the next lowest
* 16 byte boundary. Try to avoid trashing it.
*/
sp -= 32;
sp = sigsp(sp, ksig);
return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
}
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
#ifdef CONFIG_TRAD_SIGNALS
SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset)
{
return sys_rt_sigsuspend(uset, sizeof(sigset_t));
}
#endif
#ifdef CONFIG_TRAD_SIGNALS
SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
struct sigaction __user *, oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
int err = 0;
if (act) {
old_sigset_t mask;
if (!access_ok(VERIFY_READ, act, sizeof(*act)))
return -EFAULT;
err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
err |= __get_user(mask, &act->sa_mask.sig[0]);
if (err)
return -EFAULT;
siginitset(&new_ka.sa.sa_mask, mask);
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
return -EFAULT;
err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
err |= __put_user(0, &oact->sa_mask.sig[1]);
err |= __put_user(0, &oact->sa_mask.sig[2]);
err |= __put_user(0, &oact->sa_mask.sig[3]);
if (err)
return -EFAULT;
}
return ret;
}
#endif
#ifdef CONFIG_TRAD_SIGNALS
asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
{
struct sigframe __user *frame;
sigset_t blocked;
int sig;
frame = (struct sigframe __user *) regs.regs[29];
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
goto badframe;
set_current_blocked(&blocked);
sig = restore_sigcontext(&regs, &frame->sf_sc);
if (sig < 0)
goto badframe;
else if (sig)
force_sig(sig, current);
/*
* Don't let your children do this ...
*/
__asm__ __volatile__(
"move\t$29, %0\n\t"
"j\tsyscall_exit"
:/* no outputs */
:"r" (&regs));
/* Unreached */
badframe:
force_sig(SIGSEGV, current);
}
#endif /* CONFIG_TRAD_SIGNALS */
asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
{
struct rt_sigframe __user *frame;
sigset_t set;
int sig;
frame = (struct rt_sigframe __user *) regs.regs[29];
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
if (sig < 0)
goto badframe;
else if (sig)
force_sig(sig, current);
if (restore_altstack(&frame->rs_uc.uc_stack))
goto badframe;
/*
* Don't let your children do this ...
*/
__asm__ __volatile__(
"move\t$29, %0\n\t"
"j\tsyscall_exit"
:/* no outputs */
:"r" (&regs));
/* Unreached */
badframe:
force_sig(SIGSEGV, current);
}
#ifdef CONFIG_TRAD_SIGNALS
static int setup_frame(void *sig_return, struct ksignal *ksig,
struct pt_regs *regs, sigset_t *set)
{
struct sigframe __user *frame;
int err = 0;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
return -EFAULT;
err |= setup_sigcontext(regs, &frame->sf_sc);
err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
if (err)
return -EFAULT;
/*
* Arguments to signal handler:
*
* a0 = signal number
* a1 = 0 (should be cause)
* a2 = pointer to struct sigcontext
*
* $25 and c0_epc point to the signal handler, $29 points to the
* struct sigframe.
*/
regs->regs[ 4] = ksig->sig;
regs->regs[ 5] = 0;
regs->regs[ 6] = (unsigned long) &frame->sf_sc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) sig_return;
regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
current->comm, current->pid,
frame, regs->cp0_epc, regs->regs[31]);
return 0;
}
#endif
static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
struct pt_regs *regs, sigset_t *set)
{
struct rt_sigframe __user *frame;
int err = 0;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
return -EFAULT;
/* Create siginfo. */
err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
/* Create the ucontext. */
err |= __put_user(0, &frame->rs_uc.uc_flags);
err |= __put_user(NULL, &frame->rs_uc.uc_link);
err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
if (err)
return -EFAULT;
/*
* Arguments to signal handler:
*
* a0 = signal number
* a1 = 0 (should be cause)
* a2 = pointer to ucontext
*
* $25 and c0_epc point to the signal handler, $29 points to
* the struct rt_sigframe.
*/
regs->regs[ 4] = ksig->sig;
regs->regs[ 5] = (unsigned long) &frame->rs_info;
regs->regs[ 6] = (unsigned long) &frame->rs_uc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) sig_return;
regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
current->comm, current->pid,
frame, regs->cp0_epc, regs->regs[31]);
return 0;
}
struct mips_abi mips_abi = {
#ifdef CONFIG_TRAD_SIGNALS
.setup_frame = setup_frame,
#endif
.setup_rt_frame = setup_rt_frame,
.restart = __NR_restart_syscall,
.off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
.off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
.off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
MIPS: Initial implementation of a VDSO Add an initial implementation of a proper (i.e. an ELF shared library) VDSO. With this commit it does not export any symbols, it only replaces the current signal return trampoline page. A later commit will add user implementations of gettimeofday()/clock_gettime(). To support both new toolchains and old ones which don't generate ABI flags section, we define its content manually and then use a tool (genvdso) to patch up the section to have the correct name and type. genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the kernel, and generates a C file containing a "struct mips_vdso_image" containing both the VDSO data and these offsets. This C file is compiled into the kernel. On 64-bit kernels we require a different VDSO for each supported ABI, so we may build up to 3 different VDSOs. The VDSO to use is selected by the mips_abi structure. A kernel/user shared data page is created and mapped below the VDSO image. This is currently empty, but will be used by the user time function implementations which are added later. [markos.chandras@imgtec.com: - Add more comments - Move abi detection in genvdso.h since it's the get_symbol function that needs it. - Add an R6 specific way to calculate the base address of VDSO in order to avoid the branch instruction which affects performance. - Do not patch .gnu.attributes since it's not needed for dynamic linking. - Simplify Makefile a little bit. - checkpatch fixes - Restrict VDSO support for binutils < 2.25 for pre-R6 - Include atomic64.h for O32 variant on MIPS64] Signed-off-by: Alex Smith <alex.smith@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11337/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-10-21 08:54:38 +00:00
.vdso = &vdso_image,
};
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int ret;
struct mips_abi *abi = current->thread.abi;
void *vdso = current->mm->context.vdso;
MIPS: Use per-mm page to execute branch delay slot instructions In some cases the kernel needs to execute an instruction from the delay slot of an emulated branch instruction. These cases include: - Emulated floating point branch instructions (bc1[ft]l?) for systems which don't include an FPU, or upon which the kernel is run with the "nofpu" parameter. - MIPSr6 systems running binaries targeting older revisions of the architecture, which may include branch instructions whose encodings are no longer valid in MIPSr6. Executing instructions from such delay slots is done by writing the instruction to memory followed by a trap, as part of an "emuframe", and executing it. This avoids the requirement of an emulator for the entire MIPS instruction set. Prior to this patch such emuframes are written to the user stack and executed from there. This patch moves FP branch delay emuframes off of the user stack and into a per-mm page. Allocating a page per-mm leaves userland with access to only what it had access to previously, and compared to other solutions is relatively simple. When a thread requires a delay slot emulation, it is allocated a frame. A thread may only have one frame allocated at any one time, since it may only ever be executing one instruction at any one time. In order to ensure that we can free up allocated frame later, its index is recorded in struct thread_struct. In the typical case, after executing the delay slot instruction we'll execute a break instruction with the BRK_MEMU code. This traps back to the kernel & leads to a call to do_dsemulret which frees the allocated frame & moves the user PC back to the instruction that would have executed following the emulated branch. In some cases the delay slot instruction may be invalid, such as a branch, or may trigger an exception. In these cases the BRK_MEMU break instruction will not be hit. In order to ensure that frames are freed this patch introduces dsemul_thread_cleanup() and calls it to free any allocated frame upon thread exit. If the instruction generated an exception & leads to a signal being delivered to the thread, or indeed if a signal simply happens to be delivered to the thread whilst it is executing from the struct emuframe, then we need to take care to exit the frame appropriately. This is done by either rolling back the user PC to the branch or advancing it to the continuation PC prior to signal delivery, using dsemul_thread_rollback(). If this were not done then a sigreturn would return to the struct emuframe, and if that frame had meanwhile been used in response to an emulated branch instruction within the signal handler then we would execute the wrong user code. Whilst a user could theoretically place something like a compact branch to self in a delay slot and cause their thread to become stuck in an infinite loop with the frame never being deallocated, this would: - Only affect the users single process. - Be architecturally invalid since there would be a branch in the delay slot, which is forbidden. - Be extremely unlikely to happen by mistake, and provide a program with no more ability to harm the system than a simple infinite loop would. If a thread requires a delay slot emulation & no frame is available to it (ie. the process has enough other threads that all frames are currently in use) then the thread joins a waitqueue. It will sleep until a frame is freed by another thread in the process. Since we now know whether a thread has an allocated frame due to our tracking of its index, the cookie field of struct emuframe is removed as we can be more certain whether we have a valid frame. Since a thread may only ever have a single frame at any given time, the epc field of struct emuframe is also removed & the PC to continue from is instead stored in struct thread_struct. Together these changes simplify & shrink struct emuframe somewhat, allowing twice as many frames to fit into the page allocated for them. The primary benefit of this patch is that we are now free to mark the user stack non-executable where that is possible. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com> Cc: Maciej Rozycki <maciej.rozycki@imgtec.com> Cc: Faraz Shahbazker <faraz.shahbazker@imgtec.com> Cc: Raghu Gandham <raghu.gandham@imgtec.com> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13764/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-07-08 10:06:19 +00:00
/*
* If we were emulating a delay slot instruction, exit that frame such
* that addresses in the sigframe are as expected for userland and we
* don't have a problem if we reuse the thread's frame for an
* instruction within the signal handler.
*/
dsemul_thread_rollback(regs);
if (regs->regs[0]) {
switch(regs->regs[2]) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
regs->regs[2] = EINTR;
break;
case ERESTARTSYS:
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
regs->regs[2] = EINTR;
break;
}
/* fallthrough */
case ERESTARTNOINTR:
regs->regs[7] = regs->regs[26];
regs->regs[2] = regs->regs[0];
regs->cp0_epc -= 4;
}
regs->regs[0] = 0; /* Don't deal with this again. */
}
if (sig_uses_siginfo(&ksig->ka, abi))
MIPS: Initial implementation of a VDSO Add an initial implementation of a proper (i.e. an ELF shared library) VDSO. With this commit it does not export any symbols, it only replaces the current signal return trampoline page. A later commit will add user implementations of gettimeofday()/clock_gettime(). To support both new toolchains and old ones which don't generate ABI flags section, we define its content manually and then use a tool (genvdso) to patch up the section to have the correct name and type. genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the kernel, and generates a C file containing a "struct mips_vdso_image" containing both the VDSO data and these offsets. This C file is compiled into the kernel. On 64-bit kernels we require a different VDSO for each supported ABI, so we may build up to 3 different VDSOs. The VDSO to use is selected by the mips_abi structure. A kernel/user shared data page is created and mapped below the VDSO image. This is currently empty, but will be used by the user time function implementations which are added later. [markos.chandras@imgtec.com: - Add more comments - Move abi detection in genvdso.h since it's the get_symbol function that needs it. - Add an R6 specific way to calculate the base address of VDSO in order to avoid the branch instruction which affects performance. - Do not patch .gnu.attributes since it's not needed for dynamic linking. - Simplify Makefile a little bit. - checkpatch fixes - Restrict VDSO support for binutils < 2.25 for pre-R6 - Include atomic64.h for O32 variant on MIPS64] Signed-off-by: Alex Smith <alex.smith@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11337/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-10-21 08:54:38 +00:00
ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,
ksig, regs, oldset);
else
MIPS: Initial implementation of a VDSO Add an initial implementation of a proper (i.e. an ELF shared library) VDSO. With this commit it does not export any symbols, it only replaces the current signal return trampoline page. A later commit will add user implementations of gettimeofday()/clock_gettime(). To support both new toolchains and old ones which don't generate ABI flags section, we define its content manually and then use a tool (genvdso) to patch up the section to have the correct name and type. genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the kernel, and generates a C file containing a "struct mips_vdso_image" containing both the VDSO data and these offsets. This C file is compiled into the kernel. On 64-bit kernels we require a different VDSO for each supported ABI, so we may build up to 3 different VDSOs. The VDSO to use is selected by the mips_abi structure. A kernel/user shared data page is created and mapped below the VDSO image. This is currently empty, but will be used by the user time function implementations which are added later. [markos.chandras@imgtec.com: - Add more comments - Move abi detection in genvdso.h since it's the get_symbol function that needs it. - Add an R6 specific way to calculate the base address of VDSO in order to avoid the branch instruction which affects performance. - Do not patch .gnu.attributes since it's not needed for dynamic linking. - Simplify Makefile a little bit. - checkpatch fixes - Restrict VDSO support for binutils < 2.25 for pre-R6 - Include atomic64.h for O32 variant on MIPS64] Signed-off-by: Alex Smith <alex.smith@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11337/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-10-21 08:54:38 +00:00
ret = abi->setup_frame(vdso + abi->vdso->off_sigreturn,
ksig, regs, oldset);
signal_setup_done(ret, ksig, 0);
}
static void do_signal(struct pt_regs *regs)
{
struct ksignal ksig;
if (get_signal(&ksig)) {
/* Whee! Actually deliver the signal. */
handle_signal(&ksig, regs);
return;
}
if (regs->regs[0]) {
switch (regs->regs[2]) {
case ERESTARTNOHAND:
case ERESTARTSYS:
case ERESTARTNOINTR:
regs->regs[2] = regs->regs[0];
regs->regs[7] = regs->regs[26];
regs->cp0_epc -= 4;
break;
case ERESTART_RESTARTBLOCK:
regs->regs[2] = current->thread.abi->restart;
regs->regs[7] = regs->regs[26];
regs->cp0_epc -= 4;
break;
}
regs->regs[0] = 0; /* Don't deal with this again. */
}
/*
* If there's no signal to deliver, we just put the saved sigmask
* back
*/
restore_saved_sigmask();
}
/*
* notification of userspace execution resumption
* - triggered by the TIF_WORK_MASK flags
*/
asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
__u32 thread_info_flags)
{
local_irq_enable();
user_exit();
if (thread_info_flags & _TIF_UPROBE)
uprobe_notify_resume(regs);
/* deal with pending signal delivery */
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
user_enter();
}
#ifdef CONFIG_SMP
static int smp_save_fp_context(void __user *sc)
{
return raw_cpu_has_fpu
? save_hw_fp_context(sc)
: copy_fp_to_sigcontext(sc);
}
static int smp_restore_fp_context(void __user *sc)
{
return raw_cpu_has_fpu
? restore_hw_fp_context(sc)
: copy_fp_from_sigcontext(sc);
}
#endif
static int signal_setup(void)
{
MIPS: Add definitions for extended context The context introduced by MSA needs to be saved around signals. However, we can't increase the size of struct sigcontext because that will change the offset of the signal mask in struct sigframe or struct ucontext. This patch instead places the new context immediately after the struct sigframe for traditional signals, or similarly after struct ucontext for RT signals. The layout of struct sigframe & struct ucontext is identical from their sigcontext fields onwards, so the offset from the sigcontext to the extended context will always be the same regardless of the type of signal. Userland will be able to search through the extended context by using the magic values to detect which types of context are present. Any unrecognised context can be skipped over using the size field of struct extcontext. Once the magic value END_EXTCONTEXT_MAGIC is seen it is known that there are no further extended context structures to examine. This approach is somewhat similar to that taken by ARM to save VFP & other context at the end of struct ucontext. Userland can determine whether extended context is present by checking for the USED_EXTCONTEXT bit in the sc_used_math field of struct sigcontext. Whilst this could potentially change the historic semantics of sc_used_math if further extended context which does not imply FP context were to be introduced in the future, I have been unable to find any userland code making use of sc_used_math at all. Using one of the fields described as unused in struct sigcontext was considered, but the kernel does not already write to those fields so there would be no guarantee of the field being clear on older kernels. Other alternatives would be to have userland check the kernel version, or to have a HWCAP bit indicating presence of extended context. However there is a desire to have the context & information required to decode it be self contained such that, for example, debuggers could decode the saved context easily. [ralf@linux-mips.org: Fixed conflict.] Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Guenter Roeck <linux@roeck-us.net> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger <richard@nod.at> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Maciej W. Rozycki <macro@codesourcery.com> Patchwork: https://patchwork.linux-mips.org/patch/10795/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-07-27 19:58:21 +00:00
/*
* The offset from sigcontext to extended context should be the same
* regardless of the type of signal, such that userland can always know
* where to look if it wishes to find the extended context structures.
*/
BUILD_BUG_ON((offsetof(struct sigframe, sf_extcontext) -
offsetof(struct sigframe, sf_sc)) !=
(offsetof(struct rt_sigframe, rs_uc.uc_extcontext) -
offsetof(struct rt_sigframe, rs_uc.uc_mcontext)));
#ifdef CONFIG_SMP
/* For now just do the cpu_has_fpu check when the functions are invoked */
save_fp_context = smp_save_fp_context;
restore_fp_context = smp_restore_fp_context;
#else
if (cpu_has_fpu) {
save_fp_context = save_hw_fp_context;
restore_fp_context = restore_hw_fp_context;
} else {
save_fp_context = copy_fp_to_sigcontext;
restore_fp_context = copy_fp_from_sigcontext;
}
#endif /* CONFIG_SMP */
return 0;
}
arch_initcall(signal_setup);