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

	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;
	}

	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) {
		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.
 */
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.  vm86 regs switched out by assembly code
 	 * before reaching here, so testing against kernel
 	 * CS suffices.
	 */
	if (!user_mode(regs))
		return 1;

	if (try_to_freeze())
		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;
4d37e7e3	281	savesegment(gs, tmp);
1da177e4	282	err \|= __put_user(tmp, (unsigned int __user *)&sc->gs);
4d37e7e3	283	savesegment(fs, tmp);
1da177e4 LT	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
d347f372 MO	341	esp -= frame_size;
	342	/* Align the stack pointer according to the i386 ABI,
	343	* i.e. so that on function entry ((sp + 4) & 15) == 0. */
	344	esp = ((esp + 4) & -16ul) - 4;
	345	return (void __user *) esp;
1da177e4 LT	346	}
	347
	348	/* These symbols are defined with the addresses in the vsyscall page.
	349	See vsyscall-sigreturn.S. */
	350	extern void __user __kernel_sigreturn;
	351	extern void __user __kernel_rt_sigreturn;
	352
7c1def16 RM	353	static int setup_frame(int sig, struct k_sigaction *ka,
7c1def16 RM	354	sigset_t set, struct pt_regs regs)
1da177e4 LT	355	{
	356	void __user *restorer;
	357	struct sigframe __user *frame;
	358	int err = 0;
	359	int usig;
	360
	361	frame = get_sigframe(ka, regs, sizeof(*frame));
	362
	363	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	364	goto give_sigsegv;
	365
	366	usig = current_thread_info()->exec_domain
	367	&& current_thread_info()->exec_domain->signal_invmap
	368	&& sig < 32
	369	? current_thread_info()->exec_domain->signal_invmap[sig]
	370	: sig;
	371
	372	err = __put_user(usig, &frame->sig);
	373	if (err)
	374	goto give_sigsegv;
	375
	376	err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
	377	if (err)
	378	goto give_sigsegv;
	379
	380	if (_NSIG_WORDS > 1) {
	381	err = __copy_to_user(&frame->extramask, &set->sig[1],
	382	sizeof(frame->extramask));
	383	if (err)
	384	goto give_sigsegv;
	385	}
	386
	387	restorer = &__kernel_sigreturn;
	388	if (ka->sa.sa_flags & SA_RESTORER)
	389	restorer = ka->sa.sa_restorer;
	390
	391	/* Set up to return from userspace. */
	392	err \|= __put_user(restorer, &frame->pretcode);
	393
	394	/*
	395	* This is popl %eax ; movl $,%eax ; int $0x80
	396	*
	397	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	398	* reasons and because gdb uses it as a signature to notice
	399	* signal handler stack frames.
	400	*/
	401	err \|= __put_user(0xb858, (short __user *)(frame->retcode+0));
	402	err \|= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
	403	err \|= __put_user(0x80cd, (short __user *)(frame->retcode+6));
	404
	405	if (err)
	406	goto give_sigsegv;
	407
	408	/* Set up registers for signal handler */
	409	regs->esp = (unsigned long) frame;
	410	regs->eip = (unsigned long) ka->sa.sa_handler;
	411	regs->eax = (unsigned long) sig;
	412	regs->edx = (unsigned long) 0;
	413	regs->ecx = (unsigned long) 0;
	414
	415	set_fs(USER_DS);
	416	regs->xds = __USER_DS;
	417	regs->xes = __USER_DS;
	418	regs->xss = __USER_DS;
419	regs->xcs = __USER_CS;
420
421	/*
422	* Clear TF when entering the signal handler, but
423	* notify any tracer that was single-stepping it.
424	* The tracer may want to single-step inside the
425	* handler too.
426	*/
427	regs->eflags &= ~TF_MASK;
428	if (test_thread_flag(TIF_SINGLESTEP))
429	ptrace_notify(SIGTRAP);
430
431	#if DEBUG_SIG
432	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
433	current->comm, current->pid, frame, regs->eip, frame->pretcode);
434	#endif
435
7c1def16	436	return 1;
1da177e4 LT	437
	438	give_sigsegv:
	439	force_sigsegv(sig, current);
7c1def16	440	return 0;
1da177e4 LT	441	}
1da177e4 LT	442
7c1def16	443	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
1da177e4 LT	444	sigset_t set, struct pt_regs regs)
	445	{
	446	void __user *restorer;
	447	struct rt_sigframe __user *frame;
	448	int err = 0;
	449	int usig;
	450
	451	frame = get_sigframe(ka, regs, sizeof(*frame));
	452
	453	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	454	goto give_sigsegv;
	455
	456	usig = current_thread_info()->exec_domain
	457	&& current_thread_info()->exec_domain->signal_invmap
	458	&& sig < 32
	459	? current_thread_info()->exec_domain->signal_invmap[sig]
	460	: sig;
	461
	462	err \|= __put_user(usig, &frame->sig);
	463	err \|= __put_user(&frame->info, &frame->pinfo);
	464	err \|= __put_user(&frame->uc, &frame->puc);
	465	err \|= copy_siginfo_to_user(&frame->info, info);
	466	if (err)
	467	goto give_sigsegv;
	468
	469	/* Create the ucontext. */
	470	err \|= __put_user(0, &frame->uc.uc_flags);
	471	err \|= __put_user(0, &frame->uc.uc_link);
	472	err \|= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	473	err \|= __put_user(sas_ss_flags(regs->esp),
	474	&frame->uc.uc_stack.ss_flags);
	475	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	476	err \|= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
	477	regs, set->sig[0]);
	478	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	479	if (err)
	480	goto give_sigsegv;
	481
	482	/* Set up to return from userspace. */
	483	restorer = &__kernel_rt_sigreturn;
	484	if (ka->sa.sa_flags & SA_RESTORER)
	485	restorer = ka->sa.sa_restorer;
	486	err \|= __put_user(restorer, &frame->pretcode);
	487
	488	/*
	489	* This is movl $,%eax ; int $0x80
	490	*
	491	* WE DO NOT USE IT ANY MORE! It's only left here for historical
	492	* reasons and because gdb uses it as a signature to notice
	493	* signal handler stack frames.
	494	*/
	495	err \|= __put_user(0xb8, (char __user *)(frame->retcode+0));
	496	err \|= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
	497	err \|= __put_user(0x80cd, (short __user *)(frame->retcode+5));
	498
	499	if (err)
	500	goto give_sigsegv;
	501
	502	/* Set up registers for signal handler */
	503	regs->esp = (unsigned long) frame;
	504	regs->eip = (unsigned long) ka->sa.sa_handler;
	505	regs->eax = (unsigned long) usig;
	506	regs->edx = (unsigned long) &frame->info;
	507	regs->ecx = (unsigned long) &frame->uc;
508
509	set_fs(USER_DS);
510	regs->xds = __USER_DS;
511	regs->xes = __USER_DS;
512	regs->xss = __USER_DS;
513	regs->xcs = __USER_CS;
514
515	/*
516	* Clear TF when entering the signal handler, but
517	* notify any tracer that was single-stepping it.
518	* The tracer may want to single-step inside the
519	* handler too.
520	*/
521	regs->eflags &= ~TF_MASK;
522	if (test_thread_flag(TIF_SINGLESTEP))
523	ptrace_notify(SIGTRAP);
524
525	#if DEBUG_SIG
526	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
527	current->comm, current->pid, frame, regs->eip, frame->pretcode);
528	#endif
529
7c1def16	530	return 1;
1da177e4 LT	531
	532	give_sigsegv:
	533	force_sigsegv(sig, current);
7c1def16	534	return 0;
1da177e4 LT	535	}
	536
	537	/*
	538	* OK, we're invoking a handler
	539	*/
	540
7c1def16	541	static int
1da177e4 LT	542	handle_signal(unsigned long sig, siginfo_t info, struct k_sigaction ka,
	543	sigset_t oldset, struct pt_regs regs)
	544	{
7c1def16 RM	545	int ret;
7c1def16 RM	546
1da177e4 LT	547	/* Are we from a system call? */
	548	if (regs->orig_eax >= 0) {
	549	/* If so, check system call restarting.. */
	550	switch (regs->eax) {
	551	case -ERESTART_RESTARTBLOCK:
	552	case -ERESTARTNOHAND:
	553	regs->eax = -EINTR;
	554	break;
	555
	556	case -ERESTARTSYS:
	557	if (!(ka->sa.sa_flags & SA_RESTART)) {
	558	regs->eax = -EINTR;
	559	break;
	560	}
	561	/* fallthrough */
	562	case -ERESTARTNOINTR:
	563	regs->eax = regs->orig_eax;
	564	regs->eip -= 2;
	565	}
	566	}
	567
	568	/*
	569	* If TF is set due to a debugger (PT_DTRACE), clear the TF flag so
	570	* that register information in the sigcontext is correct.
	571	*/
	572	if (unlikely(regs->eflags & TF_MASK)
	573	&& likely(current->ptrace & PT_DTRACE)) {
	574	current->ptrace &= ~PT_DTRACE;
	575	regs->eflags &= ~TF_MASK;
	576	}
	577
	578	/* Set up the stack frame */
	579	if (ka->sa.sa_flags & SA_SIGINFO)
7c1def16	580	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	581	else
7c1def16	582	ret = setup_frame(sig, ka, oldset, regs);
1da177e4	583
69be8f18	584	if (ret) {
1da177e4 LT	585	spin_lock_irq(&current->sighand->siglock);
1da177e4 LT	586	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
69be8f18 SR	587	if (!(ka->sa.sa_flags & SA_NODEFER))
69be8f18 SR	588	sigaddset(&current->blocked,sig);
1da177e4 LT	589	recalc_sigpending();
	590	spin_unlock_irq(&current->sighand->siglock);
	591	}
7c1def16 RM	592
7c1def16 RM	593	return ret;
1da177e4 LT	594	}
	595
	596	/*
	597	* Note that 'init' is a special process: it doesn't get signals it doesn't
	598	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	599	* mistake.
	600	*/
	601	int fastcall do_signal(struct pt_regs regs, sigset_t oldset)
	602	{
	603	siginfo_t info;
	604	int signr;
	605	struct k_sigaction ka;
	606
	607	/*
	608	* We want the common case to go fast, which
	609	* is why we may in certain cases get here from
	610	* kernel mode. Just return without doing anything
0998e422 ZA	611	* if so. vm86 regs switched out by assembly code
	612	* before reaching here, so testing against kernel
	613	* CS suffices.
1da177e4	614	*/
717b594a	615	if (!user_mode(regs))
1da177e4 LT	616	return 1;
1da177e4 LT	617
6f0dcb72	618	if (try_to_freeze())
1da177e4	619	goto no_signal;
1da177e4 LT	620
	621	if (!oldset)
	622	oldset = &current->blocked;
	623
	624	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	625	if (signr > 0) {
	626	/* Reenable any watchpoints before delivering the
	627	* signal to user space. The processor register will
	628	* have been cleared if the watchpoint triggered
	629	* inside the kernel.
	630	*/
	631	if (unlikely(current->thread.debugreg[7])) {
1cc6f12e	632	set_debugreg(current->thread.debugreg[7], 7);
1da177e4 LT	633	}
	634
	635	/* Whee! Actually deliver the signal. */
7c1def16	636	return handle_signal(signr, &info, &ka, oldset, regs);
1da177e4 LT	637	}
	638
	639	no_signal:
	640	/* Did we come from a system call? */
	641	if (regs->orig_eax >= 0) {
	642	/* Restart the system call - no handlers present */
	643	if (regs->eax == -ERESTARTNOHAND \|\|
	644	regs->eax == -ERESTARTSYS \|\|
	645	regs->eax == -ERESTARTNOINTR) {
	646	regs->eax = regs->orig_eax;
	647	regs->eip -= 2;
	648	}
	649	if (regs->eax == -ERESTART_RESTARTBLOCK){
	650	regs->eax = __NR_restart_syscall;
	651	regs->eip -= 2;
	652	}
	653	}
	654	return 0;
	655	}
	656
	657	/*
	658	* notification of userspace execution resumption
	659	* - triggered by current->work.notify_resume
	660	*/
	661	__attribute__((regparm(3)))
	662	void do_notify_resume(struct pt_regs regs, sigset_t oldset,
	663	__u32 thread_info_flags)
	664	{
	665	/* Pending single-step? */
	666	if (thread_info_flags & _TIF_SINGLESTEP) {
	667	regs->eflags \|= TF_MASK;
	668	clear_thread_flag(TIF_SINGLESTEP);
	669	}
	670	/* deal with pending signal delivery */
	671	if (thread_info_flags & _TIF_SIGPENDING)
	672	do_signal(regs,oldset);
	673
	674	clear_thread_flag(TIF_IRET);
	675	}