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/*
* Common signal handling code for both 32 and 64 bits
*
* Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
* Extracted from signal_32.c and signal_64.c
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file README.legal in the main directory of
* this archive for more details.
*/
#include <linux/tracehook.h>
#include <linux/signal.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "signal.h"
/* Log an error when sending an unhandled signal to a process. Controlled
* through debug.exception-trace sysctl.
*/
int show_unhandled_signals = 0;
/*
* Allocate space for the signal frame
*/
void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
size_t frame_size, int is_32)
{
unsigned long oldsp, newsp;
/* Default to using normal stack */
oldsp = get_clean_sp(regs, is_32);
/* Check for alt stack */
if ((ka->sa.sa_flags & SA_ONSTACK) &&
current->sas_ss_size && !on_sig_stack(oldsp))
oldsp = (current->sas_ss_sp + current->sas_ss_size);
/* Get aligned frame */
newsp = (oldsp - frame_size) & ~0xFUL;
/* Check access */
if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp))
return NULL;
return (void __user *)newsp;
}
/*
* Restore the user process's signal mask
*/
void restore_sigmask(sigset_t *set)
{
sigdelsetmask(set, ~_BLOCKABLE);
spin_lock_irq(¤t->sighand->siglock);
current->blocked = *set;
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
}
static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
int has_handler)
{
unsigned long ret = regs->gpr[3];
int restart = 1;
/* syscall ? */
if (TRAP(regs) != 0x0C00)
return;
/* error signalled ? */
if (!(regs->ccr & 0x10000000))
return;
switch (ret) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
/* ERESTARTNOHAND means that the syscall should only be
* restarted if there was no handler for the signal, and since
* we only get here if there is a handler, we dont restart.
*/
restart = !has_handler;
break;
case ERESTARTSYS:
/* ERESTARTSYS means to restart the syscall if there is no
* handler or the handler was registered with SA_RESTART
*/
restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
break;
case ERESTARTNOINTR:
/* ERESTARTNOINTR means that the syscall should be
* called again after the signal handler returns.
*/
break;
default:
return;
}
if (restart) {
if (ret == ERESTART_RESTARTBLOCK)
regs->gpr[0] = __NR_restart_syscall;
else
regs->gpr[3] = regs->orig_gpr3;
regs->nip -= 4;
regs->result = 0;
} else {
regs->result = -EINTR;
regs->gpr[3] = EINTR;
regs->ccr |= 0x10000000;
}
}
static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
{
siginfo_t info;
int signr;
struct k_sigaction ka;
int ret;
int is32 = is_32bit_task();
if (current_thread_info()->local_flags & _TLF_RESTORE_SIGMASK)
oldset = ¤t->saved_sigmask;
else if (!oldset)
oldset = ¤t->blocked;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
/* Is there any syscall restart business here ? */
check_syscall_restart(regs, &ka, signr > 0);
if (signr <= 0) {
struct thread_info *ti = current_thread_info();
/* No signal to deliver -- put the saved sigmask back */
if (ti->local_flags & _TLF_RESTORE_SIGMASK) {
ti->local_flags &= ~_TLF_RESTORE_SIGMASK;
sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
}
return 0; /* no signals delivered */
}
/*
* Reenable the DABR before delivering the signal to
* user space. The DABR will have been cleared if it
* triggered inside the kernel.
*/
if (current->thread.dabr) {
set_dabr(current->thread.dabr);
#if defined(CONFIG_BOOKE)
mtspr(SPRN_DBCR0, current->thread.dbcr0);
#endif
}
if (is32) {
if (ka.sa.sa_flags & SA_SIGINFO)
ret = handle_rt_signal32(signr, &ka, &info, oldset,
regs);
else
ret = handle_signal32(signr, &ka, &info, oldset,
regs);
} else {
ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
}
if (ret) {
spin_lock_irq(¤t->sighand->siglock);
sigorsets(¤t->blocked, ¤t->blocked,
&ka.sa.sa_mask);
if (!(ka.sa.sa_flags & SA_NODEFER))
sigaddset(¤t->blocked, signr);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
/*
* A signal was successfully delivered; the saved sigmask is in
* its frame, and we can clear the TLF_RESTORE_SIGMASK flag.
*/
current_thread_info()->local_flags &= ~_TLF_RESTORE_SIGMASK;
/*
* Let tracing know that we've done the handler setup.
*/
tracehook_signal_handler(signr, &info, &ka, regs,
test_thread_flag(TIF_SINGLESTEP));
}
return ret;
}
void do_signal(struct pt_regs *regs, unsigned long thread_info_flags)
{
if (thread_info_flags & _TIF_SIGPENDING)
do_signal_pending(NULL, regs);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
unsigned long r5, unsigned long r6, unsigned long r7,
unsigned long r8, struct pt_regs *regs)
{
return do_sigaltstack(uss, uoss, regs->gpr[1]);
}
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