[deliverable/linux.git] / arch / x86 / kernel / signal_64.c

/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
 *  2000-2002   x86-64 support by Andi Kleen
 */

#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/ptrace.h>
#include <linux/tracehook.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/compiler.h>
#include <linux/uaccess.h>

#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/i387.h>
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#include <asm/mce.h>
#include <asm/syscall.h>
#include <asm/syscalls.h>
#include "sigframe.h"

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

#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)

#ifdef CONFIG_X86_32
# define FIX_EFLAGS	(__FIX_EFLAGS | X86_EFLAGS_RF)
#else
# define FIX_EFLAGS	__FIX_EFLAGS
#endif

asmlinkage long
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
		struct pt_regs *regs)
{
	return do_sigaltstack(uss, uoss, regs->sp);
}

/*
 * Do a signal return; undo the signal stack.
 */
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
		   unsigned long *pax)
{
	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))

	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
	COPY(dx); COPY(cx); COPY(ip);
	COPY(r8);
	COPY(r9);
	COPY(r10);
	COPY(r11);
	COPY(r12);
	COPY(r13);
	COPY(r14);
	COPY(r15);

	/* Kernel saves and restores only the CS segment register on signals,
	 * which is the bare minimum needed to allow mixed 32/64-bit code.
	 * App's signal handler can save/restore other segments if needed. */
	{
		unsigned cs;
		err |= __get_user(cs, &sc->cs);
		regs->cs = cs | 3;	/* Force into user mode */
	}

	{
		unsigned int tmpflags;
		err |= __get_user(tmpflags, &sc->flags);
		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
		regs->orig_ax = -1;		/* disable syscall checks */
	}

	{
		struct _fpstate __user *buf;
		err |= __get_user(buf, &sc->fpstate);
		err |= restore_i387_xstate(buf);
	}

	err |= __get_user(*pax, &sc->ax);
	return err;
}

asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	sigset_t set;
	unsigned long ax;

	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
	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, &ax))
		goto badframe;

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

	return ax;

badframe:
	signal_fault(regs, frame, "sigreturn");
	return 0;
}

/*
 * Set up a signal frame.
 */

static inline int
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
		unsigned long mask, struct task_struct *me)
{
	int err = 0;

	err |= __put_user(regs->cs, &sc->cs);
	err |= __put_user(0, &sc->gs);
	err |= __put_user(0, &sc->fs);

	err |= __put_user(regs->di, &sc->di);
	err |= __put_user(regs->si, &sc->si);
	err |= __put_user(regs->bp, &sc->bp);
	err |= __put_user(regs->sp, &sc->sp);
	err |= __put_user(regs->bx, &sc->bx);
	err |= __put_user(regs->dx, &sc->dx);
	err |= __put_user(regs->cx, &sc->cx);
	err |= __put_user(regs->ax, &sc->ax);
	err |= __put_user(regs->r8, &sc->r8);
	err |= __put_user(regs->r9, &sc->r9);
	err |= __put_user(regs->r10, &sc->r10);
	err |= __put_user(regs->r11, &sc->r11);
	err |= __put_user(regs->r12, &sc->r12);
	err |= __put_user(regs->r13, &sc->r13);
	err |= __put_user(regs->r14, &sc->r14);
	err |= __put_user(regs->r15, &sc->r15);
	err |= __put_user(me->thread.trap_no, &sc->trapno);
	err |= __put_user(me->thread.error_code, &sc->err);
	err |= __put_user(regs->ip, &sc->ip);
	err |= __put_user(regs->flags, &sc->flags);
	err |= __put_user(mask, &sc->oldmask);
	err |= __put_user(me->thread.cr2, &sc->cr2);

	return err;
}

/*
 * Determine which stack to use..
 */

static void __user *
get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
{
	unsigned long sp;

	/* Default to using normal stack - redzone*/
	sp = regs->sp - 128;

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

	return (void __user *)round_down(sp - size, 64);
}

static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	void __user *fp = NULL;
	int err = 0;
	struct task_struct *me = current;

	if (used_math()) {
		fp = get_stack(ka, regs, sig_xstate_size);
		frame = (void __user *)round_down(
			(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;

		if (save_i387_xstate(fp) < 0)
			err |= -1;
	} else
		frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;

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

	if (ka->sa.sa_flags & SA_SIGINFO) {
		err |= copy_siginfo_to_user(&frame->info, info);
		if (err)
			goto give_sigsegv;
	}

	/* Create the ucontext.  */
	if (cpu_has_xsave)
		err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
	else
		err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->sp),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
	err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
	if (sizeof(*set) == 16) {
		__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
		__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
	} else
		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	/* x86-64 should always use SA_RESTORER. */
	if (ka->sa.sa_flags & SA_RESTORER) {
		err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
	} else {
		/* could use a vstub here */
		goto give_sigsegv;
	}

	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->di = sig;
	/* In case the signal handler was declared without prototypes */
	regs->ax = 0;

	/* This also works for non SA_SIGINFO handlers because they expect the
	   next argument after the signal number on the stack. */
	regs->si = (unsigned long)&frame->info;
	regs->dx = (unsigned long)&frame->uc;
	regs->ip = (unsigned long) ka->sa.sa_handler;

	regs->sp = (unsigned long)frame;

	/* Set up the CS register to run signal handlers in 64-bit mode,
	   even if the handler happens to be interrupting 32-bit code. */
	regs->cs = __USER_CS;

	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 (syscall_get_nr(current, regs) >= 0) {
		/* If so, check system call restarting.. */
		switch (syscall_get_error(current, regs)) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->ax = -EINTR;
			break;

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

	/*
	 * 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->flags & X86_EFLAGS_TF) &&
	    likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
		regs->flags &= ~X86_EFLAGS_TF;

#ifdef CONFIG_IA32_EMULATION
	if (test_thread_flag(TIF_IA32)) {
		if (ka->sa.sa_flags & SA_SIGINFO)
			ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
		else
			ret = ia32_setup_frame(sig, ka, oldset, regs);
	} else
#endif
	ret = setup_rt_frame(sig, ka, info, oldset, regs);

	if (ret == 0) {
		/*
		 * This has nothing to do with segment registers,
		 * despite the name.  This magic affects uaccess.h
		 * macros' behavior.  Reset it to the normal setting.
		 */
		set_fs(USER_DS);

		/*
		 * Clear the direction flag as per the ABI for function entry.
		 */
		regs->flags &= ~X86_EFLAGS_DF;

		/*
		 * 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->flags &= ~X86_EFLAGS_TF;

		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);

		tracehook_signal_handler(sig, info, ka, regs,
					 test_thread_flag(TIF_SINGLESTEP));
	}

	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 do_signal(struct pt_regs *regs)
{
	struct k_sigaction ka;
	siginfo_t info;
	int signr;
	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.
	 * X86_32: vm86 regs switched out by assembly code before reaching
	 * here, so testing against kernel CS suffices.
	 */
	if (!user_mode(regs))
		return;

	if (current_thread_info()->status & TS_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 (current->thread.debugreg7)
			set_debugreg(current->thread.debugreg7, 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 TS_RESTORE_SIGMASK flag.
			 */
			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
		}
		return;
	}

	/* Did we come from a system call? */
	if (syscall_get_nr(current, regs) >= 0) {
		/* Restart the system call - no handlers present */
		switch (syscall_get_error(current, regs)) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;
		case -ERESTART_RESTARTBLOCK:
			regs->ax = test_thread_flag(TIF_IA32) ?
					__NR_ia32_restart_syscall :
					__NR_restart_syscall;
			regs->ip -= 2;
			break;
		}
	}

	/*
	 * If there's no signal to deliver, we just put the saved sigmask
	 * back.
	 */
	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}
}

void do_notify_resume(struct pt_regs *regs, void *unused,
		      __u32 thread_info_flags)
{
#ifdef CONFIG_X86_MCE
	/* notify userspace of pending MCEs */
	if (thread_info_flags & _TIF_MCE_NOTIFY)
		mce_notify_user();
#endif /* CONFIG_X86_MCE */

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

	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
		clear_thread_flag(TIF_NOTIFY_RESUME);
		tracehook_notify_resume(regs);
	}
}

void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
{
	struct task_struct *me = current;
	if (show_unhandled_signals && printk_ratelimit()) {
		printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
	       me->comm, me->pid, where, frame, regs->ip,
		   regs->sp, regs->orig_ax);
		print_vma_addr(" in ", regs->ip);
		printk("\n");
	}

	force_sig(SIGSEGV, me);
}
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* Copyright (C) 1991, 1992 Linus Torvalds
	3	* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
	4	*
	5	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	6	* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
	7	* 2000-2002 x86-64 support by Andi Kleen
1da177e4 LT	8	*/
	9
	10	#include <linux/sched.h>
	11	#include <linux/mm.h>
	12	#include <linux/smp.h>
1da177e4 LT	13	#include <linux/kernel.h>
	14	#include <linux/signal.h>
	15	#include <linux/errno.h>
	16	#include <linux/wait.h>
	17	#include <linux/ptrace.h>
36a03308	18	#include <linux/tracehook.h>
1da177e4 LT	19	#include <linux/unistd.h>
	20	#include <linux/stddef.h>
	21	#include <linux/personality.h>
	22	#include <linux/compiler.h>
caa007dd GP	23	#include <linux/uaccess.h>
caa007dd GP	24
1a176803	25	#include <asm/processor.h>
1da177e4	26	#include <asm/ucontext.h>
1da177e4 LT	27	#include <asm/i387.h>
1da177e4 LT	28	#include <asm/proto.h>
c5924b7d	29	#include <asm/ia32_unistd.h>
e02e68d3	30	#include <asm/mce.h>
4dfcbb99	31	#include <asm/syscall.h>
bbc1f698	32	#include <asm/syscalls.h>
123a6347	33	#include "sigframe.h"
1da177e4	34
1da177e4 LT	35	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
1da177e4 LT	36
1a176803 HH	37	#define __FIX_EFLAGS (X86_EFLAGS_AC \| X86_EFLAGS_OF \| \
	38	X86_EFLAGS_DF \| X86_EFLAGS_TF \| X86_EFLAGS_SF \| \
	39	X86_EFLAGS_ZF \| X86_EFLAGS_AF \| X86_EFLAGS_PF \| \
	40	X86_EFLAGS_CF)
	41
	42	#ifdef CONFIG_X86_32
	43	# define FIX_EFLAGS (__FIX_EFLAGS \| X86_EFLAGS_RF)
	44	#else
	45	# define FIX_EFLAGS __FIX_EFLAGS
	46	#endif
	47
1da177e4 LT	48	asmlinkage long
	49	sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	50	struct pt_regs *regs)
	51	{
65ea5b03	52	return do_sigaltstack(uss, uoss, regs->sp);
1da177e4 LT	53	}
1da177e4 LT	54
1da177e4 LT	55	/*
	56	* Do a signal return; undo the signal stack.
	57	*/
1da177e4	58	static int
866bc13f HH	59	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc,
866bc13f HH	60	unsigned long *pax)
1da177e4 LT	61	{
	62	unsigned int err = 0;
	63
	64	/* Always make any pending restarted system calls return -EINTR */
	65	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	66
caa007dd	67	#define COPY(x) (err \|= __get_user(regs->x, &sc->x))
1da177e4	68
742fa54a PA	69	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
742fa54a PA	70	COPY(dx); COPY(cx); COPY(ip);
1da177e4 LT	71	COPY(r8);
	72	COPY(r9);
	73	COPY(r10);
	74	COPY(r11);
	75	COPY(r12);
	76	COPY(r13);
	77	COPY(r14);
	78	COPY(r15);
	79
e4e5d324 BF	80	/* Kernel saves and restores only the CS segment register on signals,
	81	* which is the bare minimum needed to allow mixed 32/64-bit code.
	82	* App's signal handler can save/restore other segments if needed. */
	83	{
	84	unsigned cs;
	85	err \|= __get_user(cs, &sc->cs);
	86	regs->cs = cs \| 3; /* Force into user mode */
	87	}
	88
1da177e4 LT	89	{
1da177e4 LT	90	unsigned int tmpflags;
742fa54a	91	err \|= __get_user(tmpflags, &sc->flags);
1a176803	92	regs->flags = (regs->flags & ~FIX_EFLAGS) \| (tmpflags & FIX_EFLAGS);
65ea5b03	93	regs->orig_ax = -1; /* disable syscall checks */
1da177e4 LT	94	}
	95
	96	{
caa007dd	97	struct _fpstate __user *buf;
1da177e4	98	err \|= __get_user(buf, &sc->fpstate);
ab513701	99	err \|= restore_i387_xstate(buf);
1da177e4 LT	100	}
1da177e4 LT	101
866bc13f	102	err \|= __get_user(*pax, &sc->ax);
1da177e4	103	return err;
1da177e4 LT	104	}
	105
	106	asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
	107	{
	108	struct rt_sigframe __user *frame;
	109	sigset_t set;
65ea5b03	110	unsigned long ax;
1da177e4	111
2d19c458 HH	112	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
2d19c458 HH	113	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
1da177e4	114	goto badframe;
2d19c458	115	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
1da177e4	116	goto badframe;
1da177e4 LT	117
	118	sigdelsetmask(&set, ~_BLOCKABLE);
	119	spin_lock_irq(&current->sighand->siglock);
	120	current->blocked = set;
	121	recalc_sigpending();
	122	spin_unlock_irq(&current->sighand->siglock);
caa007dd	123
65ea5b03	124	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
1da177e4 LT	125	goto badframe;
1da177e4 LT	126
65ea5b03	127	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
1da177e4 LT	128	goto badframe;
1da177e4 LT	129
65ea5b03	130	return ax;
1da177e4 LT	131
1da177e4 LT	132	badframe:
caa007dd	133	signal_fault(regs, frame, "sigreturn");
1da177e4	134	return 0;
caa007dd	135	}
1da177e4 LT	136
	137	/*
	138	* Set up a signal frame.
	139	*/
	140
	141	static inline int
caa007dd GP	142	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs,
caa007dd GP	143	unsigned long mask, struct task_struct *me)
1da177e4 LT	144	{
1da177e4 LT	145	int err = 0;
1da177e4	146
e4e5d324	147	err \|= __put_user(regs->cs, &sc->cs);
1da177e4 LT	148	err \|= __put_user(0, &sc->gs);
	149	err \|= __put_user(0, &sc->fs);
	150
742fa54a PA	151	err \|= __put_user(regs->di, &sc->di);
	152	err \|= __put_user(regs->si, &sc->si);
	153	err \|= __put_user(regs->bp, &sc->bp);
	154	err \|= __put_user(regs->sp, &sc->sp);
	155	err \|= __put_user(regs->bx, &sc->bx);
	156	err \|= __put_user(regs->dx, &sc->dx);
	157	err \|= __put_user(regs->cx, &sc->cx);
	158	err \|= __put_user(regs->ax, &sc->ax);
1da177e4 LT	159	err \|= __put_user(regs->r8, &sc->r8);
	160	err \|= __put_user(regs->r9, &sc->r9);
	161	err \|= __put_user(regs->r10, &sc->r10);
	162	err \|= __put_user(regs->r11, &sc->r11);
	163	err \|= __put_user(regs->r12, &sc->r12);
	164	err \|= __put_user(regs->r13, &sc->r13);
	165	err \|= __put_user(regs->r14, &sc->r14);
	166	err \|= __put_user(regs->r15, &sc->r15);
	167	err \|= __put_user(me->thread.trap_no, &sc->trapno);
	168	err \|= __put_user(me->thread.error_code, &sc->err);
742fa54a PA	169	err \|= __put_user(regs->ip, &sc->ip);
742fa54a PA	170	err \|= __put_user(regs->flags, &sc->flags);
1da177e4 LT	171	err \|= __put_user(mask, &sc->oldmask);
	172	err \|= __put_user(me->thread.cr2, &sc->cr2);
	173
	174	return err;
	175	}
	176
	177	/*
	178	* Determine which stack to use..
	179	*/
	180
	181	static void __user *
	182	get_stack(struct k_sigaction ka, struct pt_regs regs, unsigned long size)
	183	{
65ea5b03	184	unsigned long sp;
1da177e4 LT	185
1da177e4 LT	186	/* Default to using normal stack - redzone*/
65ea5b03	187	sp = regs->sp - 128;
1da177e4 LT	188
1da177e4 LT	189	/* This is the X/Open sanctioned signal stack switching. */
1da177e4	190	if (ka->sa.sa_flags & SA_ONSTACK) {
65ea5b03 PA	191	if (sas_ss_flags(sp) == 0)
65ea5b03 PA	192	sp = current->sas_ss_sp + current->sas_ss_size;
1da177e4 LT	193	}
1da177e4 LT	194
c37b5efe	195	return (void __user *)round_down(sp - size, 64);
1da177e4 LT	196	}
1da177e4 LT	197
0928d6ef	198	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
caa007dd	199	sigset_t set, struct pt_regs regs)
1da177e4 LT	200	{
1da177e4 LT	201	struct rt_sigframe __user *frame;
ab513701	202	void __user *fp = NULL;
1da177e4 LT	203	int err = 0;
	204	struct task_struct *me = current;
	205
	206	if (used_math()) {
3c1c7f10	207	fp = get_stack(ka, regs, sig_xstate_size);
1da177e4 LT	208	frame = (void __user *)round_down(
	209	(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
	210
ab513701	211	if (save_i387_xstate(fp) < 0)
caa007dd	212	err \|= -1;
1da177e4 LT	213	} else
	214	frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
	215
	216	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	217	goto give_sigsegv;
	218
caa007dd	219	if (ka->sa.sa_flags & SA_SIGINFO) {
1da177e4 LT	220	err \|= copy_siginfo_to_user(&frame->info, info);
	221	if (err)
	222	goto give_sigsegv;
	223	}
caa007dd	224
1da177e4	225	/* Create the ucontext. */
c37b5efe SS	226	if (cpu_has_xsave)
	227	err \|= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
	228	else
	229	err \|= __put_user(0, &frame->uc.uc_flags);
1da177e4 LT	230	err \|= __put_user(0, &frame->uc.uc_link);
1da177e4 LT	231	err \|= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
65ea5b03	232	err \|= __put_user(sas_ss_flags(regs->sp),
1da177e4 LT	233	&frame->uc.uc_stack.ss_flags);
	234	err \|= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
	235	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
	236	err \|= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
caa007dd	237	if (sizeof(*set) == 16) {
1da177e4	238	__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
caa007dd	239	__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
1da177e4 LT	240	} else
	241	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	242
	243	/* Set up to return from userspace. If provided, use a stub
	244	already in userspace. */
	245	/* x86-64 should always use SA_RESTORER. */
	246	if (ka->sa.sa_flags & SA_RESTORER) {
	247	err \|= __put_user(ka->sa.sa_restorer, &frame->pretcode);
	248	} else {
	249	/* could use a vstub here */
caa007dd	250	goto give_sigsegv;
1da177e4 LT	251	}
	252
	253	if (err)
	254	goto give_sigsegv;
	255
1da177e4	256	/* Set up registers for signal handler */
65ea5b03	257	regs->di = sig;
caa007dd	258	/* In case the signal handler was declared without prototypes */
65ea5b03	259	regs->ax = 0;
1da177e4 LT	260
	261	/* This also works for non SA_SIGINFO handlers because they expect the
	262	next argument after the signal number on the stack. */
65ea5b03 PA	263	regs->si = (unsigned long)&frame->info;
	264	regs->dx = (unsigned long)&frame->uc;
	265	regs->ip = (unsigned long) ka->sa.sa_handler;
1da177e4	266
65ea5b03	267	regs->sp = (unsigned long)frame;
1da177e4	268
e4e5d324 BF	269	/* Set up the CS register to run signal handlers in 64-bit mode,
	270	even if the handler happens to be interrupting 32-bit code. */
	271	regs->cs = __USER_CS;
	272
1d001df1	273	return 0;
1da177e4 LT	274
	275	give_sigsegv:
	276	force_sigsegv(sig, current);
1d001df1	277	return -EFAULT;
1da177e4 LT	278	}
	279
	280	/*
	281	* OK, we're invoking a handler
caa007dd	282	*/
1da177e4	283
0928d6ef	284	static int
1da177e4	285	handle_signal(unsigned long sig, siginfo_t info, struct k_sigaction ka,
ac66f3fd	286	sigset_t oldset, struct pt_regs regs)
1da177e4	287	{
0928d6ef RM	288	int ret;
0928d6ef RM	289
1da177e4	290	/* Are we from a system call? */
4dfcbb99	291	if (syscall_get_nr(current, regs) >= 0) {
1da177e4	292	/* If so, check system call restarting.. */
4dfcbb99	293	switch (syscall_get_error(current, regs)) {
ac66f3fd HH	294	case -ERESTART_RESTARTBLOCK:
	295	case -ERESTARTNOHAND:
	296	regs->ax = -EINTR;
	297	break;
1da177e4	298
ac66f3fd HH	299	case -ERESTARTSYS:
	300	if (!(ka->sa.sa_flags & SA_RESTART)) {
	301	regs->ax = -EINTR;
1da177e4	302	break;
ac66f3fd HH	303	}
	304	/* fallthrough */
	305	case -ERESTARTNOINTR:
	306	regs->ax = regs->orig_ax;
	307	regs->ip -= 2;
	308	break;
1da177e4 LT	309	}
	310	}
	311
d61915da	312	/*
e1f28773 RM	313	* If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
e1f28773 RM	314	* flag so that register information in the sigcontext is correct.
d61915da	315	*/
65ea5b03	316	if (unlikely(regs->flags & X86_EFLAGS_TF) &&
e1f28773	317	likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
65ea5b03	318	regs->flags &= ~X86_EFLAGS_TF;
d61915da	319
1da177e4 LT	320	#ifdef CONFIG_IA32_EMULATION
	321	if (test_thread_flag(TIF_IA32)) {
	322	if (ka->sa.sa_flags & SA_SIGINFO)
0928d6ef	323	ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	324	else
0928d6ef	325	ret = ia32_setup_frame(sig, ka, oldset, regs);
caa007dd	326	} else
1da177e4	327	#endif
0928d6ef	328	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	329
1d001df1	330	if (ret == 0) {
55928e37 RM	331	/*
	332	* This has nothing to do with segment registers,
	333	* despite the name. This magic affects uaccess.h
	334	* macros' behavior. Reset it to the normal setting.
	335	*/
	336	set_fs(USER_DS);
	337
8b9c5ff3 RM	338	/*
	339	* Clear the direction flag as per the ABI for function entry.
	340	*/
	341	regs->flags &= ~X86_EFLAGS_DF;
	342
	343	/*
	344	* Clear TF when entering the signal handler, but
	345	* notify any tracer that was single-stepping it.
	346	* The tracer may want to single-step inside the
	347	* handler too.
	348	*/
	349	regs->flags &= ~X86_EFLAGS_TF;
8b9c5ff3	350
1da177e4	351	spin_lock_irq(&current->sighand->siglock);
caa007dd	352	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
69be8f18	353	if (!(ka->sa.sa_flags & SA_NODEFER))
caa007dd	354	sigaddset(&current->blocked, sig);
1da177e4 LT	355	recalc_sigpending();
1da177e4 LT	356	spin_unlock_irq(&current->sighand->siglock);
36a03308 RM	357
	358	tracehook_signal_handler(sig, info, ka, regs,
	359	test_thread_flag(TIF_SINGLESTEP));
1da177e4	360	}
0928d6ef RM	361
0928d6ef RM	362	return ret;
1da177e4 LT	363	}
	364
	365	/*
	366	* Note that 'init' is a special process: it doesn't get signals it doesn't
	367	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	368	* mistake.
	369	*/
1d001df1	370	static void do_signal(struct pt_regs *regs)
1da177e4 LT	371	{
	372	struct k_sigaction ka;
	373	siginfo_t info;
	374	int signr;
1d001df1	375	sigset_t *oldset;
1da177e4 LT	376
1da177e4 LT	377	/*
ac66f3fd HH	378	* We want the common case to go fast, which is why we may in certain
ac66f3fd HH	379	* cases get here from kernel mode. Just return without doing anything
1da177e4	380	* if so.
ac66f3fd HH	381	* X86_32: vm86 regs switched out by assembly code before reaching
ac66f3fd HH	382	* here, so testing against kernel CS suffices.
1da177e4	383	*/
76381fee	384	if (!user_mode(regs))
1d001df1	385	return;
1da177e4	386
5a8da0ea	387	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
1d001df1 AK	388	oldset = &current->saved_sigmask;
1d001df1 AK	389	else
1da177e4 LT	390	oldset = &current->blocked;
	391
	392	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	393	if (signr > 0) {
676b1855	394	/* Re-enable any watchpoints before delivering the
1da177e4 LT	395	* signal to user space. The processor register will
	396	* have been cleared if the watchpoint triggered
	397	* inside the kernel.
	398	*/
	399	if (current->thread.debugreg7)
e9129e56	400	set_debugreg(current->thread.debugreg7, 7);
1da177e4 LT	401
1da177e4 LT	402	/* Whee! Actually deliver the signal. */
1d001df1	403	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
5a8da0ea RM	404	/*
5a8da0ea RM	405	* A signal was successfully delivered; the saved
1d001df1 AK	406	* sigmask will have been stored in the signal frame,
1d001df1 AK	407	* and will be restored by sigreturn, so we can simply
5a8da0ea RM	408	* clear the TS_RESTORE_SIGMASK flag.
	409	*/
	410	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
1d001df1 AK	411	}
1d001df1 AK	412	return;
1da177e4 LT	413	}
1da177e4 LT	414
1da177e4	415	/* Did we come from a system call? */
4dfcbb99	416	if (syscall_get_nr(current, regs) >= 0) {
1da177e4	417	/* Restart the system call - no handlers present */
4dfcbb99	418	switch (syscall_get_error(current, regs)) {
1d001df1 AK	419	case -ERESTARTNOHAND:
	420	case -ERESTARTSYS:
	421	case -ERESTARTNOINTR:
65ea5b03 PA	422	regs->ax = regs->orig_ax;
65ea5b03 PA	423	regs->ip -= 2;
1d001df1 AK	424	break;
1d001df1 AK	425	case -ERESTART_RESTARTBLOCK:
65ea5b03	426	regs->ax = test_thread_flag(TIF_IA32) ?
607a1685 AK	427	__NR_ia32_restart_syscall :
607a1685 AK	428	__NR_restart_syscall;
65ea5b03	429	regs->ip -= 2;
1d001df1	430	break;
1da177e4 LT	431	}
1da177e4 LT	432	}
1d001df1	433
ac66f3fd HH	434	/*
	435	* If there's no signal to deliver, we just put the saved sigmask
	436	* back.
	437	*/
5a8da0ea RM	438	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
5a8da0ea RM	439	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
1d001df1 AK	440	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
1d001df1 AK	441	}
1da177e4 LT	442	}
1da177e4 LT	443
ac66f3fd HH	444	void do_notify_resume(struct pt_regs regs, void unused,
ac66f3fd HH	445	__u32 thread_info_flags)
1da177e4	446	{
e02e68d3 TH	447	#ifdef CONFIG_X86_MCE
	448	/* notify userspace of pending MCEs */
	449	if (thread_info_flags & _TIF_MCE_NOTIFY)
	450	mce_notify_user();
	451	#endif /* CONFIG_X86_MCE */
	452
1da177e4	453	/* deal with pending signal delivery */
5a8da0ea	454	if (thread_info_flags & _TIF_SIGPENDING)
1d001df1	455	do_signal(regs);
59e52130 RM	456
	457	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
	458	clear_thread_flag(TIF_NOTIFY_RESUME);
	459	tracehook_notify_resume(regs);
	460	}
1da177e4 LT	461	}
	462
	463	void signal_fault(struct pt_regs regs, void __user frame, char *where)
caa007dd GP	464	{
caa007dd GP	465	struct task_struct *me = current;
03252919 AK	466	if (show_unhandled_signals && printk_ratelimit()) {
03252919 AK	467	printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
caa007dd GP	468	me->comm, me->pid, where, frame, regs->ip,
caa007dd GP	469	regs->sp, regs->orig_ax);
03252919 AK	470	print_vma_addr(" in ", regs->ip);
	471	printk("\n");
	472	}
1da177e4	473
caa007dd GP	474	force_sig(SIGSEGV, me);
caa007dd GP	475	}