Commit 283828f3 authored by David Howells's avatar David Howells Committed by Linus Torvalds
Browse files

[PATCH] Handle TIF_RESTORE_SIGMASK for i386 



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: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent a411aee9

arch/i386/kernel/signal.c

+48 −61
Original line number Diff line number Diff line
@@ -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;

	}

	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:

	/* 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);

}

include/asm-i386/signal.h

+0 −1
Original line number Diff line number Diff line
@@ -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 {						\

include/asm-i386/thread_info.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

include/asm-i386/unistd.h

+1 −0
Original line number Diff line number Diff line
@@ -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__

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