[mirror_ubuntu-bionic-kernel.git] / arch / x86 / kernel / signal_32.c

/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/suspend.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
#include <linux/binfmts.h>
#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#include <asm/vdso.h>
#include "sigframe_32.h"

#define DEBUG_SIG 0

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
asmlinkage int
sys_sigsuspend(int history0, int history1, old_sigset_t mask)
{
	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	current->saved_sigmask = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	current->state = TASK_INTERRUPTIBLE;
	schedule();
	set_thread_flag(TIF_RESTORE_SIGMASK);
	return -ERESTARTNOHAND;
}

asmlinkage int 
sys_sigaction(int sig, const struct old_sigaction __user *act,
	      struct old_sigaction __user *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(unsigned long ebx)
{
	/* This is needed to make gcc realize it doesn't own the "struct pt_regs" */
	struct pt_regs *regs = (struct pt_regs *)&ebx;
	const stack_t __user *uss = (const stack_t __user *)ebx;
	stack_t __user *uoss = (stack_t __user *)regs->ecx;

	return do_sigaltstack(uss, uoss, regs->esp);
}


/*
 * Do a signal return; undo the signal stack.
 */

static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *peax)
{
	unsigned int err = 0;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

#define COPY(x)		err |= __get_user(regs->x, &sc->x)

#define COPY_SEG(seg)							\
	{ unsigned short tmp;						\
	  err |= __get_user(tmp, &sc->seg);				\
	  regs->x##seg = tmp; }

#define COPY_SEG_STRICT(seg)						\
	{ unsigned short tmp;						\
	  err |= __get_user(tmp, &sc->seg);				\
	  regs->x##seg = tmp|3; }

#define GET_SEG(seg)							\
	{ unsigned short tmp;						\
	  err |= __get_user(tmp, &sc->seg);				\
	  loadsegment(seg,tmp); }

#define	FIX_EFLAGS	(X86_EFLAGS_AC | X86_EFLAGS_RF |		 \
			 X86_EFLAGS_OF | X86_EFLAGS_DF |		 \
			 X86_EFLAGS_TF | X86_EFLAGS_SF | X86_EFLAGS_ZF | \
			 X86_EFLAGS_AF | X86_EFLAGS_PF | X86_EFLAGS_CF)

	GET_SEG(gs);
	COPY_SEG(fs);
	COPY_SEG(es);
	COPY_SEG(ds);
	COPY(edi);
	COPY(esi);
	COPY(ebp);
	COPY(esp);
	COPY(ebx);
	COPY(edx);
	COPY(ecx);
	COPY(eip);
	COPY_SEG_STRICT(cs);
	COPY_SEG_STRICT(ss);
	
	{
		unsigned int tmpflags;
		err |= __get_user(tmpflags, &sc->eflags);
		regs->eflags = (regs->eflags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
		regs->orig_eax = -1;		/* disable syscall checks */
	}

	{
		struct _fpstate __user * buf;
		err |= __get_user(buf, &sc->fpstate);
		if (buf) {
			if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
				goto badframe;
			err |= restore_i387(buf);
		} else {
			struct task_struct *me = current;
			if (used_math()) {
				clear_fpu(me);
				clear_used_math();
			}
		}
	}

	err |= __get_user(*peax, &sc->eax);
	return err;

badframe:
	return 1;
}

asmlinkage int sys_sigreturn(unsigned long __unused)
{
	struct pt_regs *regs = (struct pt_regs *) &__unused;
	struct sigframe __user *frame = (struct sigframe __user *)(regs->esp - 8);
	sigset_t set;
	int eax;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__get_user(set.sig[0], &frame->sc.oldmask)
	    || (_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, &eax))
		goto badframe;
	return eax;

badframe:
	if (show_unhandled_signals && printk_ratelimit())
		printk("%s%s[%d] bad frame in sigreturn frame:%p eip:%lx"
		       " esp:%lx oeax:%lx\n",
		    task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
		    current->comm, task_pid_nr(current), frame, regs->eip,
		    regs->esp, regs->orig_eax);

	force_sig(SIGSEGV, current);
	return 0;
}	

asmlinkage int sys_rt_sigreturn(unsigned long __unused)
{
	struct pt_regs *regs = (struct pt_regs *) &__unused;
	struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(regs->esp - 4);
	sigset_t set;
	int eax;

	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 (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
		goto badframe;

	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->esp) == -EFAULT)
		goto badframe;

	return eax;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}	

/*
 * Set up a signal frame.
 */

static int
setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
		 struct pt_regs *regs, unsigned long mask)
{
	int tmp, err = 0;

	err |= __put_user(regs->xfs, (unsigned int __user *)&sc->fs);
	savesegment(gs, tmp);
	err |= __put_user(tmp, (unsigned int __user *)&sc->gs);

	err |= __put_user(regs->xes, (unsigned int __user *)&sc->es);
	err |= __put_user(regs->xds, (unsigned int __user *)&sc->ds);
	err |= __put_user(regs->edi, &sc->edi);
	err |= __put_user(regs->esi, &sc->esi);
	err |= __put_user(regs->ebp, &sc->ebp);
	err |= __put_user(regs->esp, &sc->esp);
	err |= __put_user(regs->ebx, &sc->ebx);
	err |= __put_user(regs->edx, &sc->edx);
	err |= __put_user(regs->ecx, &sc->ecx);
	err |= __put_user(regs->eax, &sc->eax);
	err |= __put_user(current->thread.trap_no, &sc->trapno);
	err |= __put_user(current->thread.error_code, &sc->err);
	err |= __put_user(regs->eip, &sc->eip);
	err |= __put_user(regs->xcs, (unsigned int __user *)&sc->cs);
	err |= __put_user(regs->eflags, &sc->eflags);
	err |= __put_user(regs->esp, &sc->esp_at_signal);
	err |= __put_user(regs->xss, (unsigned int __user *)&sc->ss);

	tmp = save_i387(fpstate);
	if (tmp < 0)
	  err = 1;
	else
	  err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);

	/* non-iBCS2 extensions.. */
	err |= __put_user(mask, &sc->oldmask);
	err |= __put_user(current->thread.cr2, &sc->cr2);

	return err;
}

/*
 * Determine which stack to use..
 */
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
{
	unsigned long esp;

	/* Default to using normal stack */
	esp = regs->esp;

	/*
	 * If we are on the alternate signal stack and would overflow it, don't.
	 * Return an always-bogus address instead so we will die with SIGSEGV.
	 */
	if (on_sig_stack(esp) && !likely(on_sig_stack(esp - frame_size)))
		return (void __user *) -1L;

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (sas_ss_flags(esp) == 0)
			esp = current->sas_ss_sp + current->sas_ss_size;
	}

	/* This is the legacy signal stack switching. */
	else if ((regs->xss & 0xffff) != __USER_DS &&
		 !(ka->sa.sa_flags & SA_RESTORER) &&
		 ka->sa.sa_restorer) {
		esp = (unsigned long) ka->sa.sa_restorer;
	}

	esp -= frame_size;
	/* Align the stack pointer according to the i386 ABI,
	 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
	esp = ((esp + 4) & -16ul) - 4;
	return (void __user *) esp;
}

/* These symbols are defined with the addresses in the vsyscall page.
   See vsyscall-sigreturn.S.  */
extern void __user __kernel_sigreturn;
extern void __user __kernel_rt_sigreturn;

static int setup_frame(int sig, struct k_sigaction *ka,
		       sigset_t *set, struct pt_regs * regs)
{
	void __user *restorer;
	struct sigframe __user *frame;
	int err = 0;
	int usig;

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	usig = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err = __put_user(usig, &frame->sig);
	if (err)
		goto give_sigsegv;

	err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
	if (err)
		goto give_sigsegv;

	if (_NSIG_WORDS > 1) {
		err = __copy_to_user(&frame->extramask, &set->sig[1],
				      sizeof(frame->extramask));
		if (err)
			goto give_sigsegv;
	}

	if (current->binfmt->hasvdso)
		restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
	else
		restorer = (void *)&frame->retcode;
	if (ka->sa.sa_flags & SA_RESTORER)
		restorer = ka->sa.sa_restorer;

	/* Set up to return from userspace.  */
	err |= __put_user(restorer, &frame->pretcode);
	 
	/*
	 * This is popl %eax ; movl $,%eax ; int $0x80
	 *
	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
	 * reasons and because gdb uses it as a signature to notice
	 * signal handler stack frames.
	 */
	err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
	err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
	err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));

	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->esp = (unsigned long) frame;
	regs->eip = (unsigned long) ka->sa.sa_handler;
	regs->eax = (unsigned long) sig;
	regs->edx = (unsigned long) 0;
	regs->ecx = (unsigned long) 0;

	regs->xds = __USER_DS;
	regs->xes = __USER_DS;
	regs->xss = __USER_DS;
	regs->xcs = __USER_CS;

	/*
	 * Clear TF when entering the signal handler, but
	 * notify any tracer that was single-stepping it.
	 * The tracer may want to single-step inside the
	 * handler too.
	 */
	regs->eflags &= ~TF_MASK;
	if (test_thread_flag(TIF_SINGLESTEP))
		ptrace_notify(SIGTRAP);

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
		current->comm, current->pid, frame, regs->eip, frame->pretcode);
#endif

	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs * regs)
{
	void __user *restorer;
	struct rt_sigframe __user *frame;
	int err = 0;
	int usig;

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	usig = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= __put_user(usig, &frame->sig);
	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	err |= copy_siginfo_to_user(&frame->info, info);
	if (err)
		goto give_sigsegv;

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->esp),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
			        regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  */
	restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
	if (ka->sa.sa_flags & SA_RESTORER)
		restorer = ka->sa.sa_restorer;
	err |= __put_user(restorer, &frame->pretcode);
	 
	/*
	 * This is movl $,%eax ; int $0x80
	 *
	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
	 * reasons and because gdb uses it as a signature to notice
	 * signal handler stack frames.
	 */
	err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
	err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
	err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));

	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->esp = (unsigned long) frame;
	regs->eip = (unsigned long) ka->sa.sa_handler;
	regs->eax = (unsigned long) usig;
	regs->edx = (unsigned long) &frame->info;
	regs->ecx = (unsigned long) &frame->uc;

	regs->xds = __USER_DS;
	regs->xes = __USER_DS;
	regs->xss = __USER_DS;
	regs->xcs = __USER_CS;

	/*
	 * Clear TF when entering the signal handler, but
	 * notify any tracer that was single-stepping it.
	 * The tracer may want to single-step inside the
	 * handler too.
	 */
	regs->eflags &= ~TF_MASK;
	if (test_thread_flag(TIF_SINGLESTEP))
		ptrace_notify(SIGTRAP);

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
		current->comm, current->pid, frame, regs->eip, frame->pretcode);
#endif

	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

/*
 * OK, we're invoking a handler
 */	

static int
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
	      sigset_t *oldset,	struct pt_regs * regs)
{
	int ret;

	/* Are we from a system call? */
	if (regs->orig_eax >= 0) {
		/* If so, check system call restarting.. */
		switch (regs->eax) {
		        case -ERESTART_RESTARTBLOCK:
			case -ERESTARTNOHAND:
				regs->eax = -EINTR;
				break;

			case -ERESTARTSYS:
				if (!(ka->sa.sa_flags & SA_RESTART)) {
					regs->eax = -EINTR;
					break;
				}
			/* fallthrough */
			case -ERESTARTNOINTR:
				regs->eax = regs->orig_eax;
				regs->eip -= 2;
		}
	}

	/*
	 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
	 * flag so that register information in the sigcontext is correct.
	 */
	if (unlikely(regs->eflags & X86_EFLAGS_TF) &&
	    likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
		regs->eflags &= ~X86_EFLAGS_TF;

	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		ret = setup_rt_frame(sig, ka, info, oldset, regs);
	else
		ret = setup_frame(sig, ka, oldset, regs);

	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))
			sigaddset(&current->blocked,sig);
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
	}

	return ret;
}

/*
 * 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.
 */
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
	 * is why we may in certain cases get here from
	 * kernel mode. Just return without doing anything
 	 * if so.  vm86 regs switched out by assembly code
 	 * before reaching here, so testing against kernel
 	 * CS suffices.
	 */
	if (!user_mode(regs))
		return;

	if (test_thread_flag(TIF_RESTORE_SIGMASK))
		oldset = &current->saved_sigmask;
	else
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		/* Re-enable any watchpoints before delivering the
		 * signal to user space. The processor register will
		 * have been cleared if the watchpoint triggered
		 * inside the kernel.
		 */
		if (unlikely(current->thread.debugreg[7]))
			set_debugreg(current->thread.debugreg[7], 7);

		/* Whee!  Actually deliver the signal.  */
		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;
	}

	/* Did we come from a system call? */
	if (regs->orig_eax >= 0) {
		/* Restart the system call - no handlers present */
		switch (regs->eax) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->eax = regs->orig_eax;
			regs->eip -= 2;
			break;

		case -ERESTART_RESTARTBLOCK:
			regs->eax = __NR_restart_syscall;
			regs->eip -= 2;
			break;
		}
	}

	/* 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 the TIF_WORK_MASK flags
 */
__attribute__((regparm(3)))
void do_notify_resume(struct pt_regs *regs, void *_unused,
		      __u32 thread_info_flags)
{
	/* Pending single-step? */
	if (thread_info_flags & _TIF_SINGLESTEP) {
		regs->eflags |= TF_MASK;
		clear_thread_flag(TIF_SINGLESTEP);
	}

	/* deal with pending signal delivery */
	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
		do_signal(regs);

	if (thread_info_flags & _TIF_HRTICK_RESCHED)
		hrtick_resched();
	
	clear_thread_flag(TIF_IRET);
}
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* Copyright (C) 1991, 1992 Linus Torvalds
	3	*
	4	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	5	* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
	6	*/
	7
	8	#include <linux/sched.h>
	9	#include <linux/mm.h>
	10	#include <linux/smp.h>
1da177e4 LT	11	#include <linux/kernel.h>
	12	#include <linux/signal.h>
	13	#include <linux/errno.h>
	14	#include <linux/wait.h>
	15	#include <linux/unistd.h>
	16	#include <linux/stddef.h>
	17	#include <linux/personality.h>
	18	#include <linux/suspend.h>
	19	#include <linux/ptrace.h>
	20	#include <linux/elf.h>
9fbbd4dd	21	#include <linux/binfmts.h>
1da177e4 LT	22	#include <asm/processor.h>
	23	#include <asm/ucontext.h>
	24	#include <asm/uaccess.h>
	25	#include <asm/i387.h>
6c3652ef	26	#include <asm/vdso.h>
56cc623c	27	#include "sigframe_32.h"
1da177e4 LT	28
	29	#define DEBUG_SIG 0
	30
	31	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	32
	33	/*
	34	* Atomically swap in the new signal mask, and wait for a signal.
	35	*/
	36	asmlinkage int
	37	sys_sigsuspend(int history0, int history1, old_sigset_t mask)
	38	{
1da177e4 LT	39	mask &= _BLOCKABLE;
1da177e4 LT	40	spin_lock_irq(&current->sighand->siglock);
283828f3	41	current->saved_sigmask = current->blocked;
1da177e4 LT	42	siginitset(&current->blocked, mask);
	43	recalc_sigpending();
	44	spin_unlock_irq(&current->sighand->siglock);
	45
283828f3 DH	46	current->state = TASK_INTERRUPTIBLE;
	47	schedule();
	48	set_thread_flag(TIF_RESTORE_SIGMASK);
	49	return -ERESTARTNOHAND;
1da177e4 LT	50	}
	51
	52	asmlinkage int
	53	sys_sigaction(int sig, const struct old_sigaction __user *act,
	54	struct old_sigaction __user *oact)
	55	{
	56	struct k_sigaction new_ka, old_ka;
	57	int ret;
	58
	59	if (act) {
	60	old_sigset_t mask;
	61	if (!access_ok(VERIFY_READ, act, sizeof(*act)) \|\|
	62	__get_user(new_ka.sa.sa_handler, &act->sa_handler) \|\|
	63	__get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
	64	return -EFAULT;
	65	__get_user(new_ka.sa.sa_flags, &act->sa_flags);
	66	__get_user(mask, &act->sa_mask);
	67	siginitset(&new_ka.sa.sa_mask, mask);
	68	}
	69
	70	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
	71
	72	if (!ret && oact) {
	73	if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) \|\|
	74	__put_user(old_ka.sa.sa_handler, &oact->sa_handler) \|\|
	75	__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
	76	return -EFAULT;
	77	__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
	78	__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	79	}
	80
	81	return ret;
	82	}
	83
	84	asmlinkage int
	85	sys_sigaltstack(unsigned long ebx)
	86	{
	87	/* This is needed to make gcc realize it doesn't own the "struct pt_regs" */
	88	struct pt_regs regs = (struct pt_regs )&ebx;
	89	const stack_t __user uss = (const stack_t __user )ebx;
	90	stack_t __user uoss = (stack_t __user )regs->ecx;
	91
	92	return do_sigaltstack(uss, uoss, regs->esp);
	93	}
	94
	95
	96	/*
	97	* Do a signal return; undo the signal stack.
	98	*/
	99
	100	static int
	101	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc, int *peax)
	102	{
	103	unsigned int err = 0;
	104
	105	/* Always make any pending restarted system calls return -EINTR */
	106	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	107
	108	#define COPY(x) err \|= __get_user(regs->x, &sc->x)
	109
	110	#define COPY_SEG(seg) \
	111	{ unsigned short tmp; \
	112	err \|= __get_user(tmp, &sc->seg); \
	113	regs->x##seg = tmp; }
114
115	#define COPY_SEG_STRICT(seg) \
116	{ unsigned short tmp; \
117	err \|= __get_user(tmp, &sc->seg); \
118	regs->x##seg = tmp\|3; }
119
120	#define GET_SEG(seg) \
121	{ unsigned short tmp; \
122	err \|= __get_user(tmp, &sc->seg); \
123	loadsegment(seg,tmp); }
124
8bed51cd CE	125	#define FIX_EFLAGS (X86_EFLAGS_AC \| X86_EFLAGS_RF \| \
8bed51cd CE	126	X86_EFLAGS_OF \| X86_EFLAGS_DF \| \
1da177e4 LT	127	X86_EFLAGS_TF \| X86_EFLAGS_SF \| X86_EFLAGS_ZF \| \
	128	X86_EFLAGS_AF \| X86_EFLAGS_PF \| X86_EFLAGS_CF)
	129
464d1a78 JF	130	GET_SEG(gs);
464d1a78 JF	131	COPY_SEG(fs);
1da177e4 LT	132	COPY_SEG(es);
	133	COPY_SEG(ds);
	134	COPY(edi);
	135	COPY(esi);
	136	COPY(ebp);
	137	COPY(esp);
	138	COPY(ebx);
	139	COPY(edx);
	140	COPY(ecx);
	141	COPY(eip);
	142	COPY_SEG_STRICT(cs);
	143	COPY_SEG_STRICT(ss);
	144
	145	{
	146	unsigned int tmpflags;
	147	err \|= __get_user(tmpflags, &sc->eflags);
	148	regs->eflags = (regs->eflags & ~FIX_EFLAGS) \| (tmpflags & FIX_EFLAGS);
	149	regs->orig_eax = -1; /* disable syscall checks */
	150	}
	151
	152	{
	153	struct _fpstate __user * buf;
	154	err \|= __get_user(buf, &sc->fpstate);
	155	if (buf) {
	156	if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
	157	goto badframe;
	158	err \|= restore_i387(buf);
	159	} else {
	160	struct task_struct *me = current;
	161	if (used_math()) {
	162	clear_fpu(me);
	163	clear_used_math();
	164	}
	165	}
	166	}
	167
	168	err \|= __get_user(*peax, &sc->eax);
	169	return err;
	170
	171	badframe:
	172	return 1;
	173	}
	174
	175	asmlinkage int sys_sigreturn(unsigned long __unused)
	176	{
	177	struct pt_regs regs = (struct pt_regs ) &__unused;
	178	struct sigframe __user frame = (struct sigframe __user )(regs->esp - 8);
	179	sigset_t set;
	180	int eax;
	181
	182	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	183	goto badframe;
	184	if (__get_user(set.sig[0], &frame->sc.oldmask)
	185	\|\| (_NSIG_WORDS > 1
	186	&& __copy_from_user(&set.sig[1], &frame->extramask,
	187	sizeof(frame->extramask))))
	188	goto badframe;
	189
	190	sigdelsetmask(&set, ~_BLOCKABLE);
	191	spin_lock_irq(&current->sighand->siglock);
	192	current->blocked = set;
	193	recalc_sigpending();
	194	spin_unlock_irq(&current->sighand->siglock);
	195
196	if (restore_sigcontext(regs, &frame->sc, &eax))
197	goto badframe;
198	return eax;
199
200	badframe:
abd4f750 MAS	201	if (show_unhandled_signals && printk_ratelimit())
	202	printk("%s%s[%d] bad frame in sigreturn frame:%p eip:%lx"
	203	" esp:%lx oeax:%lx\n",
19c5870c AD	204	task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
19c5870c AD	205	current->comm, task_pid_nr(current), frame, regs->eip,
abd4f750 MAS	206	regs->esp, regs->orig_eax);
abd4f750 MAS	207
1da177e4 LT	208	force_sig(SIGSEGV, current);
	209	return 0;
	210	}
	211
	212	asmlinkage int sys_rt_sigreturn(unsigned long __unused)
	213	{
	214	struct pt_regs regs = (struct pt_regs ) &__unused;
	215	struct rt_sigframe __user frame = (struct rt_sigframe __user )(regs->esp - 4);
	216	sigset_t set;
	217	int eax;
	218
	219	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	220	goto badframe;
	221	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	222	goto badframe;
	223
	224	sigdelsetmask(&set, ~_BLOCKABLE);
	225	spin_lock_irq(&current->sighand->siglock);
	226	current->blocked = set;
	227	recalc_sigpending();
	228	spin_unlock_irq(&current->sighand->siglock);
	229
	230	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
	231	goto badframe;
	232
	233	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->esp) == -EFAULT)
	234	goto badframe;
	235
	236	return eax;
	237
	238	badframe:
	239	force_sig(SIGSEGV, current);
	240	return 0;
	241	}
	242
	243	/*
	244	* Set up a signal frame.
	245	*/
	246
	247	static int
	248	setup_sigcontext(struct sigcontext __user sc, struct _fpstate __user fpstate,
	249	struct pt_regs *regs, unsigned long mask)
	250	{
	251	int tmp, err = 0;
	252
464d1a78 JF	253	err \|= __put_user(regs->xfs, (unsigned int __user *)&sc->fs);
	254	savesegment(gs, tmp);
	255	err \|= __put_user(tmp, (unsigned int __user *)&sc->gs);
1da177e4 LT	256
	257	err \|= __put_user(regs->xes, (unsigned int __user *)&sc->es);
	258	err \|= __put_user(regs->xds, (unsigned int __user *)&sc->ds);
	259	err \|= __put_user(regs->edi, &sc->edi);
	260	err \|= __put_user(regs->esi, &sc->esi);
	261	err \|= __put_user(regs->ebp, &sc->ebp);
	262	err \|= __put_user(regs->esp, &sc->esp);
	263	err \|= __put_user(regs->ebx, &sc->ebx);
	264	err \|= __put_user(regs->edx, &sc->edx);
	265	err \|= __put_user(regs->ecx, &sc->ecx);
	266	err \|= __put_user(regs->eax, &sc->eax);
	267	err \|= __put_user(current->thread.trap_no, &sc->trapno);
	268	err \|= __put_user(current->thread.error_code, &sc->err);
	269	err \|= __put_user(regs->eip, &sc->eip);
	270	err \|= __put_user(regs->xcs, (unsigned int __user *)&sc->cs);
	271	err \|= __put_user(regs->eflags, &sc->eflags);
	272	err \|= __put_user(regs->esp, &sc->esp_at_signal);
	273	err \|= __put_user(regs->xss, (unsigned int __user *)&sc->ss);
	274
	275	tmp = save_i387(fpstate);
	276	if (tmp < 0)
	277	err = 1;
	278	else
	279	err \|= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
	280
	281	/* non-iBCS2 extensions.. */
	282	err \|= __put_user(mask, &sc->oldmask);
	283	err \|= __put_user(current->thread.cr2, &sc->cr2);
	284
	285	return err;
	286	}
	287
	288	/*
	289	* Determine which stack to use..
	290	*/
	291	static inline void __user *
	292	get_sigframe(struct k_sigaction ka, struct pt_regs regs, size_t frame_size)
	293	{
	294	unsigned long esp;
	295
	296	/* Default to using normal stack */
	297	esp = regs->esp;
	298
83bd0102 RM	299	/*
	300	* If we are on the alternate signal stack and would overflow it, don't.
	301	* Return an always-bogus address instead so we will die with SIGSEGV.
	302	*/
	303	if (on_sig_stack(esp) && !likely(on_sig_stack(esp - frame_size)))
	304	return (void __user *) -1L;
	305
1da177e4 LT	306	/* This is the X/Open sanctioned signal stack switching. */
	307	if (ka->sa.sa_flags & SA_ONSTACK) {
	308	if (sas_ss_flags(esp) == 0)
	309	esp = current->sas_ss_sp + current->sas_ss_size;
	310	}
	311
	312	/* This is the legacy signal stack switching. */
	313	else if ((regs->xss & 0xffff) != __USER_DS &&
	314	!(ka->sa.sa_flags & SA_RESTORER) &&
	315	ka->sa.sa_restorer) {
	316	esp = (unsigned long) ka->sa.sa_restorer;
	317	}
	318
d347f372 MO	319	esp -= frame_size;
	320	/* Align the stack pointer according to the i386 ABI,
	321	* i.e. so that on function entry ((sp + 4) & 15) == 0. */
	322	esp = ((esp + 4) & -16ul) - 4;
	323	return (void __user *) esp;
1da177e4 LT	324	}
	325
	326	/* These symbols are defined with the addresses in the vsyscall page.
	327	See vsyscall-sigreturn.S. */
	328	extern void __user __kernel_sigreturn;
	329	extern void __user __kernel_rt_sigreturn;
	330
7c1def16 RM	331	static int setup_frame(int sig, struct k_sigaction *ka,
7c1def16 RM	332	sigset_t set, struct pt_regs regs)
1da177e4 LT	333	{
	334	void __user *restorer;
	335	struct sigframe __user *frame;
	336	int err = 0;
	337	int usig;
	338
	339	frame = get_sigframe(ka, regs, sizeof(*frame));
	340
	341	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	342	goto give_sigsegv;
	343
	344	usig = current_thread_info()->exec_domain
	345	&& current_thread_info()->exec_domain->signal_invmap
	346	&& sig < 32
	347	? current_thread_info()->exec_domain->signal_invmap[sig]
	348	: sig;
	349
	350	err = __put_user(usig, &frame->sig);
	351	if (err)
	352	goto give_sigsegv;
	353
	354	err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
	355	if (err)
	356	goto give_sigsegv;
	357
	358	if (_NSIG_WORDS > 1) {
	359	err = __copy_to_user(&frame->extramask, &set->sig[1],
	360	sizeof(frame->extramask));
	361	if (err)
	362	goto give_sigsegv;
	363	}
	364
9fbbd4dd	365	if (current->binfmt->hasvdso)
6c3652ef	366	restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
9fbbd4dd AK	367	else
9fbbd4dd AK	368	restorer = (void *)&frame->retcode;
1da177e4 LT	369	if (ka->sa.sa_flags & SA_RESTORER)
	370	restorer = ka->sa.sa_restorer;
	371
	372	/* Set up to return from userspace. */
	373	err \|= __put_user(restorer, &frame->pretcode);
	374
	375	/*
	376	* This is popl %eax ; movl $,%eax ; int $0x80
	377	*
	378	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	379	* reasons and because gdb uses it as a signature to notice
	380	* signal handler stack frames.
	381	*/
	382	err \|= __put_user(0xb858, (short __user *)(frame->retcode+0));
	383	err \|= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
	384	err \|= __put_user(0x80cd, (short __user *)(frame->retcode+6));
	385
	386	if (err)
	387	goto give_sigsegv;
	388
	389	/* Set up registers for signal handler */
	390	regs->esp = (unsigned long) frame;
	391	regs->eip = (unsigned long) ka->sa.sa_handler;
	392	regs->eax = (unsigned long) sig;
	393	regs->edx = (unsigned long) 0;
	394	regs->ecx = (unsigned long) 0;
	395
1da177e4 LT	396	regs->xds = __USER_DS;
	397	regs->xes = __USER_DS;
	398	regs->xss = __USER_DS;
	399	regs->xcs = __USER_CS;
	400
	401	/*
	402	* Clear TF when entering the signal handler, but
	403	* notify any tracer that was single-stepping it.
	404	* The tracer may want to single-step inside the
	405	* handler too.
	406	*/
	407	regs->eflags &= ~TF_MASK;
	408	if (test_thread_flag(TIF_SINGLESTEP))
	409	ptrace_notify(SIGTRAP);
	410
	411	#if DEBUG_SIG
	412	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
	413	current->comm, current->pid, frame, regs->eip, frame->pretcode);
	414	#endif
	415
283828f3	416	return 0;
1da177e4 LT	417
	418	give_sigsegv:
	419	force_sigsegv(sig, current);
283828f3	420	return -EFAULT;
1da177e4 LT	421	}
1da177e4 LT	422
7c1def16	423	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
1da177e4 LT	424	sigset_t set, struct pt_regs regs)
	425	{
	426	void __user *restorer;
	427	struct rt_sigframe __user *frame;
	428	int err = 0;
	429	int usig;
	430
	431	frame = get_sigframe(ka, regs, sizeof(*frame));
	432
	433	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	434	goto give_sigsegv;
	435
	436	usig = current_thread_info()->exec_domain
	437	&& current_thread_info()->exec_domain->signal_invmap
	438	&& sig < 32
	439	? current_thread_info()->exec_domain->signal_invmap[sig]
	440	: sig;
	441
	442	err \|= __put_user(usig, &frame->sig);
	443	err \|= __put_user(&frame->info, &frame->pinfo);
	444	err \|= __put_user(&frame->uc, &frame->puc);
	445	err \|= copy_siginfo_to_user(&frame->info, info);
	446	if (err)
	447	goto give_sigsegv;
	448
	449	/* Create the ucontext. */
	450	err \|= __put_user(0, &frame->uc.uc_flags);
	451	err \|= __put_user(0, &frame->uc.uc_link);
	452	err \|= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	453	err \|= __put_user(sas_ss_flags(regs->esp),
	454	&frame->uc.uc_stack.ss_flags);
	455	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	456	err \|= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
	457	regs, set->sig[0]);
	458	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	459	if (err)
	460	goto give_sigsegv;
	461
	462	/* Set up to return from userspace. */
6c3652ef	463	restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
1da177e4 LT	464	if (ka->sa.sa_flags & SA_RESTORER)
	465	restorer = ka->sa.sa_restorer;
	466	err \|= __put_user(restorer, &frame->pretcode);
	467
	468	/*
	469	* This is movl $,%eax ; int $0x80
	470	*
	471	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	472	* reasons and because gdb uses it as a signature to notice
	473	* signal handler stack frames.
	474	*/
	475	err \|= __put_user(0xb8, (char __user *)(frame->retcode+0));
	476	err \|= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
	477	err \|= __put_user(0x80cd, (short __user *)(frame->retcode+5));
	478
	479	if (err)
	480	goto give_sigsegv;
	481
	482	/* Set up registers for signal handler */
	483	regs->esp = (unsigned long) frame;
	484	regs->eip = (unsigned long) ka->sa.sa_handler;
	485	regs->eax = (unsigned long) usig;
	486	regs->edx = (unsigned long) &frame->info;
	487	regs->ecx = (unsigned long) &frame->uc;
	488
1da177e4 LT	489	regs->xds = __USER_DS;
	490	regs->xes = __USER_DS;
	491	regs->xss = __USER_DS;
	492	regs->xcs = __USER_CS;
	493
	494	/*
	495	* Clear TF when entering the signal handler, but
	496	* notify any tracer that was single-stepping it.
	497	* The tracer may want to single-step inside the
	498	* handler too.
	499	*/
	500	regs->eflags &= ~TF_MASK;
	501	if (test_thread_flag(TIF_SINGLESTEP))
	502	ptrace_notify(SIGTRAP);
	503
	504	#if DEBUG_SIG
	505	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
	506	current->comm, current->pid, frame, regs->eip, frame->pretcode);
	507	#endif
	508
283828f3	509	return 0;
1da177e4 LT	510
	511	give_sigsegv:
	512	force_sigsegv(sig, current);
283828f3	513	return -EFAULT;
1da177e4 LT	514	}
	515
	516	/*
	517	* OK, we're invoking a handler
	518	*/
	519
7c1def16	520	static int
1da177e4 LT	521	handle_signal(unsigned long sig, siginfo_t info, struct k_sigaction ka,
	522	sigset_t oldset, struct pt_regs regs)
	523	{
7c1def16 RM	524	int ret;
7c1def16 RM	525
1da177e4 LT	526	/* Are we from a system call? */
	527	if (regs->orig_eax >= 0) {
	528	/* If so, check system call restarting.. */
	529	switch (regs->eax) {
	530	case -ERESTART_RESTARTBLOCK:
	531	case -ERESTARTNOHAND:
	532	regs->eax = -EINTR;
	533	break;
	534
	535	case -ERESTARTSYS:
	536	if (!(ka->sa.sa_flags & SA_RESTART)) {
	537	regs->eax = -EINTR;
	538	break;
	539	}
	540	/* fallthrough */
	541	case -ERESTARTNOINTR:
	542	regs->eax = regs->orig_eax;
	543	regs->eip -= 2;
	544	}
	545	}
	546
	547	/*
e1f28773 RM	548	* If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
e1f28773 RM	549	* flag so that register information in the sigcontext is correct.
1da177e4	550	*/
e1f28773 RM	551	if (unlikely(regs->eflags & X86_EFLAGS_TF) &&
	552	likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
	553	regs->eflags &= ~X86_EFLAGS_TF;
1da177e4 LT	554
	555	/* Set up the stack frame */
	556	if (ka->sa.sa_flags & SA_SIGINFO)
7c1def16	557	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	558	else
7c1def16	559	ret = setup_frame(sig, ka, oldset, regs);
1da177e4	560
283828f3	561	if (ret == 0) {
1da177e4 LT	562	spin_lock_irq(&current->sighand->siglock);
1da177e4 LT	563	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
69be8f18 SR	564	if (!(ka->sa.sa_flags & SA_NODEFER))
69be8f18 SR	565	sigaddset(&current->blocked,sig);
1da177e4 LT	566	recalc_sigpending();
	567	spin_unlock_irq(&current->sighand->siglock);
	568	}
7c1def16 RM	569
7c1def16 RM	570	return ret;
1da177e4 LT	571	}
	572
	573	/*
	574	* Note that 'init' is a special process: it doesn't get signals it doesn't
	575	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	576	* mistake.
	577	*/
283828f3	578	static void fastcall do_signal(struct pt_regs *regs)
1da177e4 LT	579	{
	580	siginfo_t info;
	581	int signr;
	582	struct k_sigaction ka;
283828f3	583	sigset_t *oldset;
1da177e4 LT	584
	585	/*
	586	* We want the common case to go fast, which
	587	* is why we may in certain cases get here from
	588	* kernel mode. Just return without doing anything
0998e422 ZA	589	* if so. vm86 regs switched out by assembly code
	590	* before reaching here, so testing against kernel
	591	* CS suffices.
1da177e4	592	*/
717b594a	593	if (!user_mode(regs))
283828f3	594	return;
1da177e4	595
283828f3 DH	596	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	597	oldset = &current->saved_sigmask;
	598	else
1da177e4 LT	599	oldset = &current->blocked;
	600
	601	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	602	if (signr > 0) {
27b46d76	603	/* Re-enable any watchpoints before delivering the
1da177e4 LT	604	* signal to user space. The processor register will
	605	* have been cleared if the watchpoint triggered
	606	* inside the kernel.
	607	*/
283828f3	608	if (unlikely(current->thread.debugreg[7]))
1cc6f12e	609	set_debugreg(current->thread.debugreg[7], 7);
1da177e4 LT	610
1da177e4 LT	611	/* Whee! Actually deliver the signal. */
283828f3 DH	612	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
	613	/* a signal was successfully delivered; the saved
	614	* sigmask will have been stored in the signal frame,
	615	* and will be restored by sigreturn, so we can simply
	616	* clear the TIF_RESTORE_SIGMASK flag */
	617	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	618	clear_thread_flag(TIF_RESTORE_SIGMASK);
	619	}
	620
	621	return;
1da177e4 LT	622	}
1da177e4 LT	623
1da177e4 LT	624	/* Did we come from a system call? */
	625	if (regs->orig_eax >= 0) {
	626	/* Restart the system call - no handlers present */
283828f3 DH	627	switch (regs->eax) {
	628	case -ERESTARTNOHAND:
	629	case -ERESTARTSYS:
	630	case -ERESTARTNOINTR:
1da177e4 LT	631	regs->eax = regs->orig_eax;
1da177e4 LT	632	regs->eip -= 2;
283828f3 DH	633	break;
	634
	635	case -ERESTART_RESTARTBLOCK:
1da177e4 LT	636	regs->eax = __NR_restart_syscall;
1da177e4 LT	637	regs->eip -= 2;
283828f3	638	break;
1da177e4 LT	639	}
1da177e4 LT	640	}
283828f3 DH	641
	642	/* if there's no signal to deliver, we just put the saved sigmask
	643	* back */
	644	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	645	clear_thread_flag(TIF_RESTORE_SIGMASK);
	646	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	647	}
1da177e4 LT	648	}
	649
	650	/*
	651	* notification of userspace execution resumption
283828f3	652	* - triggered by the TIF_WORK_MASK flags
1da177e4 LT	653	*/
1da177e4 LT	654	__attribute__((regparm(3)))
283828f3	655	void do_notify_resume(struct pt_regs regs, void _unused,
1da177e4 LT	656	__u32 thread_info_flags)
	657	{
	658	/* Pending single-step? */
	659	if (thread_info_flags & _TIF_SINGLESTEP) {
	660	regs->eflags \|= TF_MASK;
	661	clear_thread_flag(TIF_SINGLESTEP);
	662	}
283828f3	663
1da177e4	664	/* deal with pending signal delivery */
283828f3 DH	665	if (thread_info_flags & (_TIF_SIGPENDING \| _TIF_RESTORE_SIGMASK))
283828f3 DH	666	do_signal(regs);
8f4d37ec PZ	667
	668	if (thread_info_flags & _TIF_HRTICK_RESCHED)
	669	hrtick_resched();
1da177e4 LT	670
	671	clear_thread_flag(TIF_IRET);
	672	}