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[PATCH] Handle TIF_RESTORE_SIGMASK for i386

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Handle TIF_RESTORE_SIGMASK as added by David Woodhouse's patch entitled:

        [PATCH] 2/3 Add TIF_RESTORE_SIGMASK support for arch/powerpc
        [PATCH] 3/3 Generic sys_rt_sigsuspend

It does the following:

 (1) Declares TIF_RESTORE_SIGMASK for i386.

 (2) Invokes it over to do_signal() when TIF_RESTORE_SIGMASK is set.

 (3) Makes do_signal() support TIF_RESTORE_SIGMASK, using the signal mask saved
     in current->saved_sigmask.

 (4) Discards sys_rt_sigsuspend() from the arch, using the generic one instead.

 (5) Makes sys_sigsuspend() save the signal mask and set TIF_RESTORE_SIGMASK
     rather than attempting to fudge the return registers.

 (6) Makes sys_sigsuspend() return -ERESTARTNOHAND rather than looping
     intrinsically.

 (7) Makes setup_frame(), setup_rt_frame() and handle_signal() return 0 or
     -EFAULT rather than true/false to be consistent with the rest of the
     kernel.

Due to the fact do_signal() is then only called from one place:

 (8) Makes do_signal() no longer have a return value is it was just being
     ignored; force_sig() takes care of this.

 (9) Discards the old sigmask argument to do_signal() as it's no longer
     necessary.

(10) Makes do_signal() static.

(11) Marks the second argument to do_notify_resume() as unused. The unused
     argument should remain in the middle as the arguments are passed in as
     registers, and the ordering is specific in entry.S

Given the way do_signal() is now no longer called from sys_{,rt_}sigsuspend(),
they no longer need access to the exception frame, and so can just take
arguments normally.

This patch depends on sys_rt_sigsuspend patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
David Howells 2006-01-18 17:44:00 -08:00 committed by Linus Torvalds
parent a411aee96e
commit 283828f3c1
4 changed files with 51 additions and 62 deletions
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109
arch/i386/kernel/signal.c
View File

@ -37,51 +37,17 @@
asmlinkage int
sys_sigsuspend(int history0, int history1, old_sigset_t mask)
{
struct pt_regs * regs = (struct pt_regs *) &history0;
sigset_t saveset;
mask &= _BLOCKABLE;
spin_lock_irq(&current->sighand->siglock);
saveset = current->blocked;
current->saved_sigmask = current->blocked;
siginitset(&current->blocked, mask);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
regs->eax = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(regs, &saveset))
return -EINTR;
}
}
asmlinkage int
sys_rt_sigsuspend(struct pt_regs regs)
{
sigset_t saveset, newset;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (regs.ecx != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&newset, (sigset_t __user *)regs.ebx, 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.eax = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&regs, &saveset))
return -EINTR;
}
current->state = TASK_INTERRUPTIBLE;
schedule();
set_thread_flag(TIF_RESTORE_SIGMASK);
return -ERESTARTNOHAND;
}
asmlinkage int
@ -433,11 +399,11 @@ static int setup_frame(int sig, struct k_sigaction *ka,
current->comm, current->pid, frame, regs->eip, frame->pretcode);
#endif
return 1;
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return 0;
return -EFAULT;
}
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
@ -527,11 +493,11 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
current->comm, current->pid, frame, regs->eip, frame->pretcode);
#endif
return 1;
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return 0;
return -EFAULT;
}
/*
@ -581,7 +547,7 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
else
ret = setup_frame(sig, ka, oldset, regs);
if (ret) {
if (ret == 0) {
spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
@ -598,11 +564,12 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*/
int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset)
static void fastcall do_signal(struct pt_regs *regs)
{
siginfo_t info;
int signr;
struct k_sigaction ka;
sigset_t *oldset;
/*
* We want the common case to go fast, which
@ -613,12 +580,14 @@ int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset)
* CS suffices.
*/
if (!user_mode(regs))
return 1;
return;
if (try_to_freeze())
goto no_signal;
if (!oldset)
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = &current->saved_sigmask;
else
oldset = &current->blocked;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
@ -628,38 +597,55 @@ int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset)
* have been cleared if the watchpoint triggered
* inside the kernel.
*/
if (unlikely(current->thread.debugreg[7])) {
if (unlikely(current->thread.debugreg[7]))
set_debugreg(current->thread.debugreg[7], 7);
}
/* Whee! Actually deliver the signal. */
return handle_signal(signr, &info, &ka, oldset, regs);
if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
/* 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);
}
return;
}
no_signal:
no_signal:
/* Did we come from a system call? */
if (regs->orig_eax >= 0) {
/* Restart the system call - no handlers present */
if (regs->eax == -ERESTARTNOHAND ||
regs->eax == -ERESTARTSYS ||
regs->eax == -ERESTARTNOINTR) {
switch (regs->eax) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->eax = regs->orig_eax;
regs->eip -= 2;
}
if (regs->eax == -ERESTART_RESTARTBLOCK){
break;
case -ERESTART_RESTARTBLOCK:
regs->eax = __NR_restart_syscall;
regs->eip -= 2;
break;
}
}
return 0;
/* if there's no signal to deliver, we just put the saved sigmask
* back */
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
}
/*
* notification of userspace execution resumption
* - triggered by current->work.notify_resume
* - triggered by the TIF_WORK_MASK flags
*/
__attribute__((regparm(3)))
void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
void do_notify_resume(struct pt_regs *regs, void *_unused,
__u32 thread_info_flags)
{
/* Pending single-step? */
@ -667,9 +653,10 @@ void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
regs->eflags |= TF_MASK;
clear_thread_flag(TIF_SINGLESTEP);
}
/* deal with pending signal delivery */
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs,oldset);
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
do_signal(regs);
clear_thread_flag(TIF_IRET);
}

1
include/asm-i386/signal.h
View File

@ -218,7 +218,6 @@ static __inline__ int sigfindinword(unsigned long word)
}
struct pt_regs;
extern int FASTCALL(do_signal(struct pt_regs *regs, sigset_t *oldset));
#define ptrace_signal_deliver(regs, cookie) \
do { \

2
include/asm-i386/thread_info.h
View File

@ -140,6 +140,7 @@ register unsigned long current_stack_pointer asm("esp") __attribute_used__;
#define TIF_SYSCALL_EMU 6 /* syscall emulation active */
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 17
@ -152,6 +153,7 @@ register unsigned long current_stack_pointer asm("esp") __attribute_used__;
#define _TIF_SYSCALL_EMU (1<<TIF_SYSCALL_EMU)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
/* work to do on interrupt/exception return */

1
include/asm-i386/unistd.h
View File

@ -430,6 +430,7 @@ __syscall_return(type,__res); \
#define __ARCH_WANT_SYS_SIGPENDING
#define __ARCH_WANT_SYS_SIGPROCMASK
#define __ARCH_WANT_SYS_RT_SIGACTION
#define __ARCH_WANT_SYS_RT_SIGSUSPEND
#endif
#ifdef __KERNEL_SYSCALLS__