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linux-hardened/arch/m68knommu/kernel/signal.c
Wilson Callan 2d7f16d6d1 m68knommu: fix signal handling return path 
The return from software signal handling pushes code on the stack
that system calls to the kernels cleanup code. This is borrowed
directly from the m68k linux signal handler.

The rt signal case is not quite right for the restricted instruction
set of the ColdFire parts. And neither the normal signal case or rt
signal case properly flushes/pushes the appropriate cache lines.

Rework the return path to just call back through some code fragments
in the kernel proper (with no MMU in the way we can do this). No
cache problems, and less code overall.

Original patch submitted by Wilson Callan <wcallan@savantav.com>

Greg fixed the rt signal return path to use the proper system call

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01 08:08:35 -07:00

774 lines
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/*
* linux/arch/m68knommu/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 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.
*/
/*
* Linux/m68k support by Hamish Macdonald
*
* 68060 fixes by Jesper Skov
*
* 1997-12-01 Modified for POSIX.1b signals by Andreas Schwab
*
* mathemu support by Roman Zippel
* (Note: fpstate in the signal context is completely ignored for the emulator
* and the internal floating point format is put on stack)
*/
/*
* ++roman (07/09/96): implemented signal stacks (specially for tosemu on
* Atari :-) Current limitation: Only one sigstack can be active at one time.
* If a second signal with SA_ONSTACK set arrives while working on a sigstack,
* SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
* signal handlers!
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/highuid.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/ucontext.h>
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
void ret_from_user_signal(void);
void ret_from_user_rt_signal(void);
asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs);
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int do_sigsuspend(struct pt_regs *regs)
{
old_sigset_t mask = regs->d3;
sigset_t saveset;
mask &= _BLOCKABLE;
spin_lock_irq(&current->sighand->siglock);
saveset = current->blocked;
siginitset(&current->blocked, mask);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
regs->d0 = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&saveset, regs))
return -EINTR;
}
}
asmlinkage int
do_rt_sigsuspend(struct pt_regs *regs)
{
sigset_t *unewset = (sigset_t *)regs->d1;
size_t sigsetsize = (size_t)regs->d2;
sigset_t saveset, newset;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&newset, unewset, sizeof(newset)))
return -EFAULT;
sigdelsetmask(&newset, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
saveset = current->blocked;
current->blocked = newset;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
regs->d0 = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&saveset, regs))
return -EINTR;
}
}
asmlinkage int
sys_sigaction(int sig, const struct old_sigaction *act,
struct old_sigaction *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))
return -EFAULT;
__get_user(new_ka.sa.sa_flags, &act->sa_flags);
__get_user(mask, &act->sa_mask);
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))
return -EFAULT;
__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
}
return ret;
}
asmlinkage int
sys_sigaltstack(const stack_t *uss, stack_t *uoss)
{
return do_sigaltstack(uss, uoss, rdusp());
}
/*
* Do a signal return; undo the signal stack.
*
* Keep the return code on the stack quadword aligned!
* That makes the cache flush below easier.
*/
struct sigframe
{
char *pretcode;
int sig;
int code;
struct sigcontext *psc;
char retcode[8];
unsigned long extramask[_NSIG_WORDS-1];
struct sigcontext sc;
};
struct rt_sigframe
{
char *pretcode;
int sig;
struct siginfo *pinfo;
void *puc;
char retcode[8];
struct siginfo info;
struct ucontext uc;
};
#ifdef CONFIG_FPU
static unsigned char fpu_version = 0; /* version number of fpu, set by setup_frame */
static inline int restore_fpu_state(struct sigcontext *sc)
{
int err = 1;
if (FPU_IS_EMU) {
/* restore registers */
memcpy(current->thread.fpcntl, sc->sc_fpcntl, 12);
memcpy(current->thread.fp, sc->sc_fpregs, 24);
return 0;
}
if (sc->sc_fpstate[0]) {
/* Verify the frame format. */
if (sc->sc_fpstate[0] != fpu_version)
goto out;
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %0,%/fp0-%/fp1\n\t"
"fmoveml %1,%/fpcr/%/fpsr/%/fpiar\n\t"
".chip 68k"
: /* no outputs */
: "m" (*sc->sc_fpregs), "m" (*sc->sc_fpcntl));
}
__asm__ volatile (".chip 68k/68881\n\t"
"frestore %0\n\t"
".chip 68k" : : "m" (*sc->sc_fpstate));
err = 0;
out:
return err;
}
#define FPCONTEXT_SIZE 216
#define uc_fpstate uc_filler[0]
#define uc_formatvec uc_filler[FPCONTEXT_SIZE/4]
#define uc_extra uc_filler[FPCONTEXT_SIZE/4+1]
static inline int rt_restore_fpu_state(struct ucontext *uc)
{
unsigned char fpstate[FPCONTEXT_SIZE];
int context_size = 0;
fpregset_t fpregs;
int err = 1;
if (FPU_IS_EMU) {
/* restore fpu control register */
if (__copy_from_user(current->thread.fpcntl,
&uc->uc_mcontext.fpregs.f_pcr, 12))
goto out;
/* restore all other fpu register */
if (__copy_from_user(current->thread.fp,
uc->uc_mcontext.fpregs.f_fpregs, 96))
goto out;
return 0;
}
if (__get_user(*(long *)fpstate, (long *)&uc->uc_fpstate))
goto out;
if (fpstate[0]) {
context_size = fpstate[1];
/* Verify the frame format. */
if (fpstate[0] != fpu_version)
goto out;
if (__copy_from_user(&fpregs, &uc->uc_mcontext.fpregs,
sizeof(fpregs)))
goto out;
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %0,%/fp0-%/fp7\n\t"
"fmoveml %1,%/fpcr/%/fpsr/%/fpiar\n\t"
".chip 68k"
: /* no outputs */
: "m" (*fpregs.f_fpregs),
"m" (fpregs.f_pcr));
}
if (context_size &&
__copy_from_user(fpstate + 4, (long *)&uc->uc_fpstate + 1,
context_size))
goto out;
__asm__ volatile (".chip 68k/68881\n\t"
"frestore %0\n\t"
".chip 68k" : : "m" (*fpstate));
err = 0;
out:
return err;
}
#endif
static inline int
restore_sigcontext(struct pt_regs *regs, struct sigcontext *usc, void *fp,
int *pd0)
{
int formatvec;
struct sigcontext context;
int err = 0;
/* get previous context */
if (copy_from_user(&context, usc, sizeof(context)))
goto badframe;
/* restore passed registers */
regs->d1 = context.sc_d1;
regs->a0 = context.sc_a0;
regs->a1 = context.sc_a1;
((struct switch_stack *)regs - 1)->a5 = context.sc_a5;
regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
regs->pc = context.sc_pc;
regs->orig_d0 = -1; /* disable syscall checks */
wrusp(context.sc_usp);
formatvec = context.sc_formatvec;
regs->format = formatvec >> 12;
regs->vector = formatvec & 0xfff;
#ifdef CONFIG_FPU
err = restore_fpu_state(&context);
#endif
*pd0 = context.sc_d0;
return err;
badframe:
return 1;
}
static inline int
rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
struct ucontext *uc, int *pd0)
{
int temp;
greg_t *gregs = uc->uc_mcontext.gregs;
unsigned long usp;
int err;
err = __get_user(temp, &uc->uc_mcontext.version);
if (temp != MCONTEXT_VERSION)
goto badframe;
/* restore passed registers */
err |= __get_user(regs->d0, &gregs[0]);
err |= __get_user(regs->d1, &gregs[1]);
err |= __get_user(regs->d2, &gregs[2]);
err |= __get_user(regs->d3, &gregs[3]);
err |= __get_user(regs->d4, &gregs[4]);
err |= __get_user(regs->d5, &gregs[5]);
err |= __get_user(sw->d6, &gregs[6]);
err |= __get_user(sw->d7, &gregs[7]);
err |= __get_user(regs->a0, &gregs[8]);
err |= __get_user(regs->a1, &gregs[9]);
err |= __get_user(regs->a2, &gregs[10]);
err |= __get_user(sw->a3, &gregs[11]);
err |= __get_user(sw->a4, &gregs[12]);
err |= __get_user(sw->a5, &gregs[13]);
err |= __get_user(sw->a6, &gregs[14]);
err |= __get_user(usp, &gregs[15]);
wrusp(usp);
err |= __get_user(regs->pc, &gregs[16]);
err |= __get_user(temp, &gregs[17]);
regs->sr = (regs->sr & 0xff00) | (temp & 0xff);
regs->orig_d0 = -1; /* disable syscall checks */
regs->format = temp >> 12;
regs->vector = temp & 0xfff;
if (do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT)
goto badframe;
*pd0 = regs->d0;
return err;
badframe:
return 1;
}
asmlinkage int do_sigreturn(unsigned long __unused)
{
struct switch_stack *sw = (struct switch_stack *) &__unused;
struct pt_regs *regs = (struct pt_regs *) (sw + 1);
unsigned long usp = rdusp();
struct sigframe *frame = (struct sigframe *)(usp - 4);
sigset_t set;
int d0;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
(_NSIG_WORDS > 1 &&
__copy_from_user(&set.sig[1], &frame->extramask,
sizeof(frame->extramask))))
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (restore_sigcontext(regs, &frame->sc, frame + 1, &d0))
goto badframe;
return d0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int do_rt_sigreturn(unsigned long __unused)
{
struct switch_stack *sw = (struct switch_stack *) &__unused;
struct pt_regs *regs = (struct pt_regs *) (sw + 1);
unsigned long usp = rdusp();
struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
sigset_t set;
int d0;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (rt_restore_ucontext(regs, sw, &frame->uc, &d0))
goto badframe;
return d0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
#ifdef CONFIG_FPU
/*
* Set up a signal frame.
*/
static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
{
if (FPU_IS_EMU) {
/* save registers */
memcpy(sc->sc_fpcntl, current->thread.fpcntl, 12);
memcpy(sc->sc_fpregs, current->thread.fp, 24);
return;
}
__asm__ volatile (".chip 68k/68881\n\t"
"fsave %0\n\t"
".chip 68k"
: : "m" (*sc->sc_fpstate) : "memory");
if (sc->sc_fpstate[0]) {
fpu_version = sc->sc_fpstate[0];
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %/fp0-%/fp1,%0\n\t"
"fmoveml %/fpcr/%/fpsr/%/fpiar,%1\n\t"
".chip 68k"
: /* no outputs */
: "m" (*sc->sc_fpregs),
"m" (*sc->sc_fpcntl)
: "memory");
}
}
static inline int rt_save_fpu_state(struct ucontext *uc, struct pt_regs *regs)
{
unsigned char fpstate[FPCONTEXT_SIZE];
int context_size = 0;
int err = 0;
if (FPU_IS_EMU) {
/* save fpu control register */
err |= copy_to_user(&uc->uc_mcontext.fpregs.f_pcr,
current->thread.fpcntl, 12);
/* save all other fpu register */
err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpregs,
current->thread.fp, 96);
return err;
}
__asm__ volatile (".chip 68k/68881\n\t"
"fsave %0\n\t"
".chip 68k"
: : "m" (*fpstate) : "memory");
err |= __put_user(*(long *)fpstate, (long *)&uc->uc_fpstate);
if (fpstate[0]) {
fpregset_t fpregs;
context_size = fpstate[1];
fpu_version = fpstate[0];
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %/fp0-%/fp7,%0\n\t"
"fmoveml %/fpcr/%/fpsr/%/fpiar,%1\n\t"
".chip 68k"
: /* no outputs */
: "m" (*fpregs.f_fpregs),
"m" (fpregs.f_pcr)
: "memory");
err |= copy_to_user(&uc->uc_mcontext.fpregs, &fpregs,
sizeof(fpregs));
}
if (context_size)
err |= copy_to_user((long *)&uc->uc_fpstate + 1, fpstate + 4,
context_size);
return err;
}
#endif
static void setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
unsigned long mask)
{
sc->sc_mask = mask;
sc->sc_usp = rdusp();
sc->sc_d0 = regs->d0;
sc->sc_d1 = regs->d1;
sc->sc_a0 = regs->a0;
sc->sc_a1 = regs->a1;
sc->sc_a5 = ((struct switch_stack *)regs - 1)->a5;
sc->sc_sr = regs->sr;
sc->sc_pc = regs->pc;
sc->sc_formatvec = regs->format << 12 | regs->vector;
#ifdef CONFIG_FPU
save_fpu_state(sc, regs);
#endif
}
static inline int rt_setup_ucontext(struct ucontext *uc, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *)regs - 1;
greg_t *gregs = uc->uc_mcontext.gregs;
int err = 0;
err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
err |= __put_user(regs->d0, &gregs[0]);
err |= __put_user(regs->d1, &gregs[1]);
err |= __put_user(regs->d2, &gregs[2]);
err |= __put_user(regs->d3, &gregs[3]);
err |= __put_user(regs->d4, &gregs[4]);
err |= __put_user(regs->d5, &gregs[5]);
err |= __put_user(sw->d6, &gregs[6]);
err |= __put_user(sw->d7, &gregs[7]);
err |= __put_user(regs->a0, &gregs[8]);
err |= __put_user(regs->a1, &gregs[9]);
err |= __put_user(regs->a2, &gregs[10]);
err |= __put_user(sw->a3, &gregs[11]);
err |= __put_user(sw->a4, &gregs[12]);
err |= __put_user(sw->a5, &gregs[13]);
err |= __put_user(sw->a6, &gregs[14]);
err |= __put_user(rdusp(), &gregs[15]);
err |= __put_user(regs->pc, &gregs[16]);
err |= __put_user(regs->sr, &gregs[17]);
#ifdef CONFIG_FPU
err |= rt_save_fpu_state(uc, regs);
#endif
return err;
}
static inline void *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
{
unsigned long usp;
/* Default to using normal stack. */
usp = rdusp();
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (!sas_ss_flags(usp))
usp = current->sas_ss_sp + current->sas_ss_size;
}
return (void *)((usp - frame_size) & -8UL);
}
static void setup_frame (int sig, struct k_sigaction *ka,
sigset_t *set, struct pt_regs *regs)
{
struct sigframe *frame;
struct sigcontext context;
int err = 0;
frame = get_sigframe(ka, regs, sizeof(*frame));
err |= __put_user((current_thread_info()->exec_domain
&& current_thread_info()->exec_domain->signal_invmap
&& sig < 32
? current_thread_info()->exec_domain->signal_invmap[sig]
: sig),
&frame->sig);
err |= __put_user(regs->vector, &frame->code);
err |= __put_user(&frame->sc, &frame->psc);
if (_NSIG_WORDS > 1)
err |= copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask));
setup_sigcontext(&context, regs, set->sig[0]);
err |= copy_to_user (&frame->sc, &context, sizeof(context));
/* Set up to return from userspace. */
err |= __put_user((void *) ret_from_user_signal, &frame->pretcode);
if (err)
goto give_sigsegv;
/* Set up registers for signal handler */
wrusp ((unsigned long) frame);
regs->pc = (unsigned long) ka->sa.sa_handler;
((struct switch_stack *)regs - 1)->a5 = current->mm->start_data;
regs->format = 0x4; /*set format byte to make stack appear modulo 4
which it will be when doing the rte */
adjust_stack:
/* Prepare to skip over the extra stuff in the exception frame. */
if (regs->stkadj) {
struct pt_regs *tregs =
(struct pt_regs *)((ulong)regs + regs->stkadj);
#if defined(DEBUG)
printk(KERN_DEBUG "Performing stackadjust=%04x\n", regs->stkadj);
#endif
/* This must be copied with decreasing addresses to
handle overlaps. */
tregs->vector = 0;
tregs->format = 0;
tregs->pc = regs->pc;
tregs->sr = regs->sr;
}
return;
give_sigsegv:
force_sigsegv(sig, current);
goto adjust_stack;
}
static void setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe *frame;
int err = 0;
frame = get_sigframe(ka, regs, sizeof(*frame));
err |= __put_user((current_thread_info()->exec_domain
&& current_thread_info()->exec_domain->signal_invmap
&& sig < 32
? current_thread_info()->exec_domain->signal_invmap[sig]
: sig),
&frame->sig);
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user((void *)current->sas_ss_sp,
&frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(rdusp()),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= rt_setup_ucontext(&frame->uc, regs);
err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));
/* Set up to return from userspace. */
err |= __put_user((void *) ret_from_user_rt_signal, &frame->pretcode);
if (err)
goto give_sigsegv;
/* Set up registers for signal handler */
wrusp ((unsigned long) frame);
regs->pc = (unsigned long) ka->sa.sa_handler;
((struct switch_stack *)regs - 1)->a5 = current->mm->start_data;
regs->format = 0x4; /*set format byte to make stack appear modulo 4
which it will be when doing the rte */
adjust_stack:
/* Prepare to skip over the extra stuff in the exception frame. */
if (regs->stkadj) {
struct pt_regs *tregs =
(struct pt_regs *)((ulong)regs + regs->stkadj);
#if defined(DEBUG)
printk(KERN_DEBUG "Performing stackadjust=%04x\n", regs->stkadj);
#endif
/* This must be copied with decreasing addresses to
handle overlaps. */
tregs->vector = 0;
tregs->format = 0;
tregs->pc = regs->pc;
tregs->sr = regs->sr;
}
return;
give_sigsegv:
force_sigsegv(sig, current);
goto adjust_stack;
}
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->d0) {
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->d0 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->d0 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
do_restart:
regs->d0 = regs->orig_d0;
regs->pc -= 2;
break;
}
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *oldset, struct pt_regs *regs)
{
/* are we from a system call? */
if (regs->orig_d0 >= 0)
/* If so, check system call restarting.. */
handle_restart(regs, ka, 1);
/* set up the stack frame */
if (ka->sa.sa_flags & SA_SIGINFO)
setup_rt_frame(sig, ka, info, oldset, regs);
else
setup_frame(sig, ka, oldset, regs);
if (ka->sa.sa_flags & SA_ONESHOT)
ka->sa.sa_handler = SIG_DFL;
spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(&current->blocked,sig);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
}
/*
* 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.
*/
asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs)
{
struct k_sigaction ka;
siginfo_t info;
int signr;
/*
* We want the common case to go fast, which
* is why we may in certain cases get here from
* kernel mode. Just return without doing anything
* if so.
*/
if (!user_mode(regs))
return 1;
if (!oldset)
oldset = &current->blocked;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* Whee! Actually deliver the signal. */
handle_signal(signr, &ka, &info, oldset, regs);
return 1;
}
/* Did we come from a system call? */
if (regs->orig_d0 >= 0) {
/* Restart the system call - no handlers present */
handle_restart(regs, NULL, 0);
}
return 0;
}
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