[deliverable/linux.git] / arch / i386 / kernel / signal.c

/*
 *  linux/arch/i386/kernel/signal.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/smp_lock.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 <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#include "sigframe.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)
{
	struct pt_regs * regs = (struct pt_regs *) &history0;
	sigset_t saveset;

	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	saveset = 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;
	}
}

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_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);
	GET_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:
	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;

	tmp = 0;
	__asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp));
	err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
	__asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp));
	err |= __put_user(tmp, (unsigned int __user *)&sc->fs);

	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;

	/* 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;
	}

	return (void __user *)((esp - frame_size) & -8ul);
}

/* 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;
	}

	restorer = &__kernel_sigreturn;
	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;

	set_fs(USER_DS);
	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 1;

give_sigsegv:
	force_sigsegv(sig, current);
	return 0;
}

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 = &__kernel_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;

	set_fs(USER_DS);
	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 1;

give_sigsegv:
	force_sigsegv(sig, current);
	return 0;
}

/*
 * 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 (PT_DTRACE), clear the TF flag so
	 * that register information in the sigcontext is correct.
	 */
	if (unlikely(regs->eflags & TF_MASK)
	    && likely(current->ptrace & PT_DTRACE)) {
		current->ptrace &= ~PT_DTRACE;
		regs->eflags &= ~TF_MASK;
	}

	/* 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 && !(ka->sa.sa_flags & SA_NODEFER)) {
		spin_lock_irq(&current->sighand->siglock);
		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
		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.
 */
int fastcall do_signal(struct pt_regs *regs, sigset_t *oldset)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;

	/*
	 * 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.
	 */
	if ((regs->xcs & 3) != 3)
		return 1;

	if (current->flags & PF_FREEZE) {
		refrigerator(0);
		goto no_signal;
	}

	if (!oldset)
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		/* Reenable 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.  */
		return handle_signal(signr, &info, &ka, oldset, regs);
	}

 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) {
			regs->eax = regs->orig_eax;
			regs->eip -= 2;
		}
		if (regs->eax == -ERESTART_RESTARTBLOCK){
			regs->eax = __NR_restart_syscall;
			regs->eip -= 2;
		}
	}
	return 0;
}

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