linux/arch/arm/kernel/signal.c
Will Deacon 433e2f307b ARM: 7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK"
This reverts commit 6b5c8045ec.

Conflicts:

	arch/arm/kernel/ptrace.c

The new syscall restarting code can lead to problems if we take an
interrupt in userspace just before restarting the svc instruction. If
a signal is delivered when returning from the interrupt, the
TIF_SYSCALL_RESTARTSYS will remain set and cause any syscalls executed
from the signal handler to be treated as a restart of the previously
interrupted system call. This includes the final sigreturn call, meaning
that we may fail to exit from the signal context. Furthermore, if a
system call made from the signal handler requires a restart via the
restart_block, it is possible to clear the thread flag and fail to
restart the originally interrupted system call.

The right solution to this problem is to perform the restarting in the
kernel, avoiding the possibility of handling a further signal before the
restart is complete. Since we're almost at -rc6, let's revert the new
method for now and aim for in-kernel restarting at a later date.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-05 09:50:56 +01:00

687 lines
19 KiB
C

/*
* linux/arch/arm/kernel/signal.c
*
* Copyright (C) 1995-2009 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/personality.h>
#include <linux/freezer.h>
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <asm/elf.h>
#include <asm/cacheflush.h>
#include <asm/ucontext.h>
#include <asm/unistd.h>
#include <asm/vfp.h>
#include "signal.h"
/*
* For ARM syscalls, we encode the syscall number into the instruction.
*/
#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
/*
* With EABI, the syscall number has to be loaded into r7.
*/
#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
/*
* For Thumb syscalls, we pass the syscall number via r7. We therefore
* need two 16-bit instructions.
*/
#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
const unsigned long sigreturn_codes[7] = {
MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
};
/*
* Either we support OABI only, or we have EABI with the OABI
* compat layer enabled. In the later case we don't know if
* user space is EABI or not, and if not we must not clobber r7.
* Always using the OABI syscall solves that issue and works for
* all those cases.
*/
const unsigned long syscall_restart_code[2] = {
SWI_SYS_RESTART, /* swi __NR_restart_syscall */
0xe49df004, /* ldr pc, [sp], #4 */
};
/*
* atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
{
sigset_t blocked;
siginitset(&blocked, mask);
return sigsuspend(&blocked);
}
asmlinkage int
sys_sigaction(int sig, const struct old_sigaction __user *act,
struct old_sigaction __user *oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
if (act) {
old_sigset_t mask;
if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
__get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
__get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
__get_user(mask, &act->sa_mask))
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)) ||
__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
__put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
return -EFAULT;
}
return ret;
}
#ifdef CONFIG_CRUNCH
static int preserve_crunch_context(struct crunch_sigframe __user *frame)
{
char kbuf[sizeof(*frame) + 8];
struct crunch_sigframe *kframe;
/* the crunch context must be 64 bit aligned */
kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
kframe->magic = CRUNCH_MAGIC;
kframe->size = CRUNCH_STORAGE_SIZE;
crunch_task_copy(current_thread_info(), &kframe->storage);
return __copy_to_user(frame, kframe, sizeof(*frame));
}
static int restore_crunch_context(struct crunch_sigframe __user *frame)
{
char kbuf[sizeof(*frame) + 8];
struct crunch_sigframe *kframe;
/* the crunch context must be 64 bit aligned */
kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
if (__copy_from_user(kframe, frame, sizeof(*frame)))
return -1;
if (kframe->magic != CRUNCH_MAGIC ||
kframe->size != CRUNCH_STORAGE_SIZE)
return -1;
crunch_task_restore(current_thread_info(), &kframe->storage);
return 0;
}
#endif
#ifdef CONFIG_IWMMXT
static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
{
char kbuf[sizeof(*frame) + 8];
struct iwmmxt_sigframe *kframe;
/* the iWMMXt context must be 64 bit aligned */
kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
kframe->magic = IWMMXT_MAGIC;
kframe->size = IWMMXT_STORAGE_SIZE;
iwmmxt_task_copy(current_thread_info(), &kframe->storage);
return __copy_to_user(frame, kframe, sizeof(*frame));
}
static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
{
char kbuf[sizeof(*frame) + 8];
struct iwmmxt_sigframe *kframe;
/* the iWMMXt context must be 64 bit aligned */
kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
if (__copy_from_user(kframe, frame, sizeof(*frame)))
return -1;
if (kframe->magic != IWMMXT_MAGIC ||
kframe->size != IWMMXT_STORAGE_SIZE)
return -1;
iwmmxt_task_restore(current_thread_info(), &kframe->storage);
return 0;
}
#endif
#ifdef CONFIG_VFP
static int preserve_vfp_context(struct vfp_sigframe __user *frame)
{
const unsigned long magic = VFP_MAGIC;
const unsigned long size = VFP_STORAGE_SIZE;
int err = 0;
__put_user_error(magic, &frame->magic, err);
__put_user_error(size, &frame->size, err);
if (err)
return -EFAULT;
return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
}
static int restore_vfp_context(struct vfp_sigframe __user *frame)
{
unsigned long magic;
unsigned long size;
int err = 0;
__get_user_error(magic, &frame->magic, err);
__get_user_error(size, &frame->size, err);
if (err)
return -EFAULT;
if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
return -EINVAL;
return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
}
#endif
/*
* Do a signal return; undo the signal stack. These are aligned to 64-bit.
*/
struct sigframe {
struct ucontext uc;
unsigned long retcode[2];
};
struct rt_sigframe {
struct siginfo info;
struct sigframe sig;
};
static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
{
struct aux_sigframe __user *aux;
sigset_t set;
int err;
err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
if (err == 0)
set_current_blocked(&set);
__get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
__get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
__get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
__get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
__get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
__get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
__get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
__get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
__get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
__get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
__get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
__get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
__get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
__get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
__get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
__get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
__get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
err |= !valid_user_regs(regs);
aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
#ifdef CONFIG_CRUNCH
if (err == 0)
err |= restore_crunch_context(&aux->crunch);
#endif
#ifdef CONFIG_IWMMXT
if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
err |= restore_iwmmxt_context(&aux->iwmmxt);
#endif
#ifdef CONFIG_VFP
if (err == 0)
err |= restore_vfp_context(&aux->vfp);
#endif
return err;
}
asmlinkage int sys_sigreturn(struct pt_regs *regs)
{
struct sigframe __user *frame;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
/*
* Since we stacked the signal on a 64-bit boundary,
* then 'sp' should be word aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->ARM_sp & 7)
goto badframe;
frame = (struct sigframe __user *)regs->ARM_sp;
if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
goto badframe;
if (restore_sigframe(regs, frame))
goto badframe;
return regs->ARM_r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
/*
* Since we stacked the signal on a 64-bit boundary,
* then 'sp' should be word aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->ARM_sp & 7)
goto badframe;
frame = (struct rt_sigframe __user *)regs->ARM_sp;
if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
goto badframe;
if (restore_sigframe(regs, &frame->sig))
goto badframe;
if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
goto badframe;
return regs->ARM_r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static int
setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
{
struct aux_sigframe __user *aux;
int err = 0;
__put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
__put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
__put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
__put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
__put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
__put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
__put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
__put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
__put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
__put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
__put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
__put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
__put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
__put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
__put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
__put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
__put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
__put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
__put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
__put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
#ifdef CONFIG_CRUNCH
if (err == 0)
err |= preserve_crunch_context(&aux->crunch);
#endif
#ifdef CONFIG_IWMMXT
if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
err |= preserve_iwmmxt_context(&aux->iwmmxt);
#endif
#ifdef CONFIG_VFP
if (err == 0)
err |= preserve_vfp_context(&aux->vfp);
#endif
__put_user_error(0, &aux->end_magic, err);
return err;
}
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
{
unsigned long sp = regs->ARM_sp;
void __user *frame;
/*
* This is the X/Open sanctioned signal stack switching.
*/
if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
/*
* ATPCS B01 mandates 8-byte alignment
*/
frame = (void __user *)((sp - framesize) & ~7);
/*
* Check that we can actually write to the signal frame.
*/
if (!access_ok(VERIFY_WRITE, frame, framesize))
frame = NULL;
return frame;
}
static int
setup_return(struct pt_regs *regs, struct k_sigaction *ka,
unsigned long __user *rc, void __user *frame, int usig)
{
unsigned long handler = (unsigned long)ka->sa.sa_handler;
unsigned long retcode;
int thumb = 0;
unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
cpsr |= PSR_ENDSTATE;
/*
* Maybe we need to deliver a 32-bit signal to a 26-bit task.
*/
if (ka->sa.sa_flags & SA_THIRTYTWO)
cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
#ifdef CONFIG_ARM_THUMB
if (elf_hwcap & HWCAP_THUMB) {
/*
* The LSB of the handler determines if we're going to
* be using THUMB or ARM mode for this signal handler.
*/
thumb = handler & 1;
if (thumb) {
cpsr |= PSR_T_BIT;
#if __LINUX_ARM_ARCH__ >= 7
/* clear the If-Then Thumb-2 execution state */
cpsr &= ~PSR_IT_MASK;
#endif
} else
cpsr &= ~PSR_T_BIT;
}
#endif
if (ka->sa.sa_flags & SA_RESTORER) {
retcode = (unsigned long)ka->sa.sa_restorer;
} else {
unsigned int idx = thumb << 1;
if (ka->sa.sa_flags & SA_SIGINFO)
idx += 3;
if (__put_user(sigreturn_codes[idx], rc) ||
__put_user(sigreturn_codes[idx+1], rc+1))
return 1;
if (cpsr & MODE32_BIT) {
/*
* 32-bit code can use the new high-page
* signal return code support.
*/
retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
} else {
/*
* Ensure that the instruction cache sees
* the return code written onto the stack.
*/
flush_icache_range((unsigned long)rc,
(unsigned long)(rc + 2));
retcode = ((unsigned long)rc) + thumb;
}
}
regs->ARM_r0 = usig;
regs->ARM_sp = (unsigned long)frame;
regs->ARM_lr = retcode;
regs->ARM_pc = handler;
regs->ARM_cpsr = cpsr;
return 0;
}
static int
setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
{
struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
int err = 0;
if (!frame)
return 1;
/*
* Set uc.uc_flags to a value which sc.trap_no would never have.
*/
__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
err |= setup_sigframe(frame, regs, set);
if (err == 0)
err = setup_return(regs, ka, frame->retcode, frame, usig);
return err;
}
static int
setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
stack_t stack;
int err = 0;
if (!frame)
return 1;
err |= copy_siginfo_to_user(&frame->info, info);
__put_user_error(0, &frame->sig.uc.uc_flags, err);
__put_user_error(NULL, &frame->sig.uc.uc_link, err);
memset(&stack, 0, sizeof(stack));
stack.ss_sp = (void __user *)current->sas_ss_sp;
stack.ss_flags = sas_ss_flags(regs->ARM_sp);
stack.ss_size = current->sas_ss_size;
err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
err |= setup_sigframe(&frame->sig, regs, set);
if (err == 0)
err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
if (err == 0) {
/*
* For realtime signals we must also set the second and third
* arguments for the signal handler.
* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
*/
regs->ARM_r1 = (unsigned long)&frame->info;
regs->ARM_r2 = (unsigned long)&frame->sig.uc;
}
return err;
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, struct pt_regs *regs)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = current;
sigset_t *oldset = sigmask_to_save();
int usig = sig;
int ret;
/*
* translate the signal
*/
if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
usig = thread->exec_domain->signal_invmap[usig];
/*
* Set up the stack frame
*/
if (ka->sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(usig, ka, info, oldset, regs);
else
ret = setup_frame(usig, ka, oldset, regs);
/*
* Check that the resulting registers are actually sane.
*/
ret |= !valid_user_regs(regs);
if (ret != 0) {
force_sigsegv(sig, tsk);
return;
}
signal_delivered(sig, info, ka, regs, 0);
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals that
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
static void do_signal(struct pt_regs *regs, int syscall)
{
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
struct k_sigaction ka;
siginfo_t info;
int signr;
/*
* If we were from a system call, check for system call restarting...
*/
if (syscall) {
continue_addr = regs->ARM_pc;
restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
retval = regs->ARM_r0;
/*
* Prepare for system call restart. We do this here so that a
* debugger will see the already changed PSW.
*/
switch (retval) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->ARM_r0 = regs->ARM_ORIG_r0;
regs->ARM_pc = restart_addr;
break;
case -ERESTART_RESTARTBLOCK:
regs->ARM_r0 = -EINTR;
break;
}
}
/*
* Get the signal to deliver. When running under ptrace, at this
* point the debugger may change all our registers ...
*/
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/*
* Depending on the signal settings we may need to revert the
* decision to restart the system call. But skip this if a
* debugger has chosen to restart at a different PC.
*/
if (regs->ARM_pc == restart_addr) {
if (retval == -ERESTARTNOHAND
|| (retval == -ERESTARTSYS
&& !(ka.sa.sa_flags & SA_RESTART))) {
regs->ARM_r0 = -EINTR;
regs->ARM_pc = continue_addr;
}
}
handle_signal(signr, &ka, &info, regs);
return;
}
if (syscall) {
/*
* Handle restarting a different system call. As above,
* if a debugger has chosen to restart at a different PC,
* ignore the restart.
*/
if (retval == -ERESTART_RESTARTBLOCK
&& regs->ARM_pc == continue_addr) {
if (thumb_mode(regs)) {
regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
regs->ARM_pc -= 2;
} else {
#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
regs->ARM_r7 = __NR_restart_syscall;
regs->ARM_pc -= 4;
#else
u32 __user *usp;
regs->ARM_sp -= 4;
usp = (u32 __user *)regs->ARM_sp;
if (put_user(regs->ARM_pc, usp) == 0) {
regs->ARM_pc = KERN_RESTART_CODE;
} else {
regs->ARM_sp += 4;
force_sigsegv(0, current);
}
#endif
}
}
}
restore_saved_sigmask();
}
asmlinkage void
do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
{
if (thread_flags & _TIF_SIGPENDING)
do_signal(regs, syscall);
if (thread_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}