kernel_optimize_test/arch/um/kernel/signal.c
Matt Fleming d982d5955e um: use set_current_blocked() and block_sigmask()
As described in commit e6fa16ab9c ("signal: sigprocmask() should do
retarget_shared_pending()") the modification of current->blocked is
incorrect as we need to check whether the signal we're about to block is
pending in the shared queue.

Also, use the new helper function introduced in commit 5e6292c0f2
("signal: add block_sigmask() for adding sigmask to current->blocked")
which centralises the code for updating current->blocked after
successfully delivering a signal and reduces the amount of duplicate
code across architectures.  In the past some architectures got this code
wrong, so using this helper function should stop that from happening
again.

Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 16:58:31 -07:00

170 lines
4.3 KiB
C

/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <asm/siginfo.h>
#include <asm/signal.h>
#include <asm/unistd.h>
#include "frame_kern.h"
#include "kern_util.h"
EXPORT_SYMBOL(block_signals);
EXPORT_SYMBOL(unblock_signals);
#define _S(nr) (1<<((nr)-1))
#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
/*
* OK, we're invoking a handler
*/
static int handle_signal(struct pt_regs *regs, unsigned long signr,
struct k_sigaction *ka, siginfo_t *info,
sigset_t *oldset)
{
unsigned long sp;
int err;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
/* Did we come from a system call? */
if (PT_REGS_SYSCALL_NR(regs) >= 0) {
/* If so, check system call restarting.. */
switch (PT_REGS_SYSCALL_RET(regs)) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
PT_REGS_SYSCALL_RET(regs) = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
PT_REGS_SYSCALL_RET(regs) = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
PT_REGS_RESTART_SYSCALL(regs);
PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
break;
}
}
sp = PT_REGS_SP(regs);
if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
sp = current->sas_ss_sp + current->sas_ss_size;
#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
if (!(ka->sa.sa_flags & SA_SIGINFO))
err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
else
#endif
err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
if (err)
force_sigsegv(signr, current);
else
block_sigmask(ka, signr);
return err;
}
static int kern_do_signal(struct pt_regs *regs)
{
struct k_sigaction ka_copy;
siginfo_t info;
sigset_t *oldset;
int sig, handled_sig = 0;
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = &current->saved_sigmask;
else
oldset = &current->blocked;
while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
handled_sig = 1;
/* Whee! Actually deliver the signal. */
if (!handle_signal(regs, sig, &ka_copy, &info, oldset)) {
/*
* a signal was successfully delivered; the saved
* sigmask will have been stored in the signal frame,
* and will be restored by sigreturn, so we can simply
* clear the TIF_RESTORE_SIGMASK flag
*/
if (test_thread_flag(TIF_RESTORE_SIGMASK))
clear_thread_flag(TIF_RESTORE_SIGMASK);
break;
}
}
/* Did we come from a system call? */
if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
/* Restart the system call - no handlers present */
switch (PT_REGS_SYSCALL_RET(regs)) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
PT_REGS_RESTART_SYSCALL(regs);
break;
case -ERESTART_RESTARTBLOCK:
PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
PT_REGS_RESTART_SYSCALL(regs);
break;
}
}
/*
* This closes a way to execute a system call on the host. If
* you set a breakpoint on a system call instruction and singlestep
* from it, the tracing thread used to PTRACE_SINGLESTEP the process
* rather than PTRACE_SYSCALL it, allowing the system call to execute
* on the host. The tracing thread will check this flag and
* PTRACE_SYSCALL if necessary.
*/
if (current->ptrace & PT_DTRACE)
current->thread.singlestep_syscall =
is_syscall(PT_REGS_IP(&current->thread.regs));
/*
* if there's no signal to deliver, we just put the saved sigmask
* back
*/
if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
return handled_sig;
}
int do_signal(void)
{
return kern_do_signal(&current->thread.regs);
}
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
{
sigset_t blocked;
mask &= _BLOCKABLE;
siginitset(&blocked, mask);
set_current_blocked(&blocked);
current->state = TASK_INTERRUPTIBLE;
schedule();
set_thread_flag(TIF_RESTORE_SIGMASK);
return -ERESTARTNOHAND;
}
long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
return do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs));
}