[mirror_ubuntu-artful-kernel.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/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/compiler.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#include <asm/mce.h>

/* #define DEBUG_SIG 1 */

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

int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
               sigset_t *set, struct pt_regs * regs); 
int ia32_setup_frame(int sig, struct k_sigaction *ka,
            sigset_t *set, struct pt_regs * regs); 

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.
 */

struct rt_sigframe
{
	char __user *pretcode;
	struct ucontext uc;
	struct siginfo info;
};

static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax)
{
	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 & ~0x40DD5) | (tmpflags & 0x40DD5);
		regs->orig_ax = -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(*prax, &sc->ax);
	return err;

badframe:
	return 1;
}

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 - 8);
	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;

#ifdef DEBUG_SIG
	printk("%d sigreturn ip:%lx sp:%lx frame:%p ax:%lx\n",current->pid,regs->ip,regs->sp,frame,ax);
#endif

	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, 16);
}

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;
	struct _fpstate __user *fp = NULL; 
	int err = 0;
	struct task_struct *me = current;

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

		if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
			goto give_sigsegv;

		if (save_i387(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.  */
	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;

#ifdef DEBUG_SIG
	printk("%d old ip %lx old sp %lx old ax %lx\n", current->pid,regs->ip,regs->sp,regs->ax);
#endif

	/* 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;

	/* This, by contrast, has nothing to do with segment registers -
	   see include/asm-x86_64/uaccess.h for details. */
	set_fs(USER_DS);

	regs->flags &= ~X86_EFLAGS_TF;
	if (test_thread_flag(TIF_SINGLESTEP))
		ptrace_notify(SIGTRAP);
#ifdef DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
		current->comm, current->pid, frame, regs->ip, frame->pretcode);
#endif

	return 0;

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

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

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

#ifdef DEBUG_SIG
	printk("handle_signal pid:%d sig:%lu ip:%lx sp:%lx regs=%p\n",
		current->pid, sig,
		regs->ip, regs->sp, regs);
#endif

	/* Are we from a system call? */
	if ((long)regs->orig_ax >= 0) {
		/* If so, check system call restarting.. */
		switch (regs->ax) {
		        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) {
		spin_lock_irq(&current->sighand->siglock);
		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
		if (!(ka->sa.sa_flags & SA_NODEFER))
			sigaddset(&current->blocked,sig);
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
	}

	return ret;
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 */
static void 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.
	 */
	if (!user_mode(regs))
		return;

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

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		/* Re-enable any watchpoints before delivering the
		 * signal to user space. The processor register will
		 * have been cleared if the watchpoint triggered
		 * inside the kernel.
		 */
		if (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 TIF_RESTORE_SIGMASK flag */
			clear_thread_flag(TIF_RESTORE_SIGMASK);
		}
		return;
	}

	/* Did we come from a system call? */
	if ((long)regs->orig_ax >= 0) {
		/* Restart the system call - no handlers present */
		long res = regs->ax;
		switch (res) {
		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 (test_thread_flag(TIF_RESTORE_SIGMASK)) {
		clear_thread_flag(TIF_RESTORE_SIGMASK);
		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}
}

void
do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
{
#ifdef DEBUG_SIG
	printk("do_notify_resume flags:%x ip:%lx sp:%lx caller:%p pending:%x\n",
	       thread_info_flags, regs->ip, regs->sp, __builtin_return_address(0),signal_pending(current));
#endif
	       
	/* Pending single-step? */
	if (thread_info_flags & _TIF_SINGLESTEP) {
		regs->flags |= X86_EFLAGS_TF;
		clear_thread_flag(TIF_SINGLESTEP);
	}

#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|_TIF_RESTORE_SIGMASK))
		do_signal(regs);

	if (thread_info_flags & _TIF_HRTICK_RESCHED)
		hrtick_resched();
}

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>
	18	#include <linux/unistd.h>
	19	#include <linux/stddef.h>
	20	#include <linux/personality.h>
	21	#include <linux/compiler.h>
	22	#include <asm/ucontext.h>
	23	#include <asm/uaccess.h>
	24	#include <asm/i387.h>
	25	#include <asm/proto.h>
c5924b7d	26	#include <asm/ia32_unistd.h>
e02e68d3	27	#include <asm/mce.h>
1da177e4 LT	28
	29	/* #define DEBUG_SIG 1 */
	30
	31	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	32
0928d6ef	33	int ia32_setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
1da177e4	34	sigset_t set, struct pt_regs regs);
0928d6ef	35	int ia32_setup_frame(int sig, struct k_sigaction *ka,
1da177e4 LT	36	sigset_t set, struct pt_regs regs);
1da177e4 LT	37
1da177e4 LT	38	asmlinkage long
	39	sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	40	struct pt_regs *regs)
	41	{
65ea5b03	42	return do_sigaltstack(uss, uoss, regs->sp);
1da177e4 LT	43	}
	44
	45
	46	/*
	47	* Do a signal return; undo the signal stack.
	48	*/
	49
	50	struct rt_sigframe
	51	{
993fb38b	52	char __user *pretcode;
1da177e4 LT	53	struct ucontext uc;
	54	struct siginfo info;
	55	};
	56
	57	static int
	58	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc, unsigned long *prax)
	59	{
	60	unsigned int err = 0;
	61
	62	/* Always make any pending restarted system calls return -EINTR */
	63	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	64
	65	#define COPY(x) err \|= __get_user(regs->x, &sc->x)
	66
742fa54a PA	67	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
742fa54a PA	68	COPY(dx); COPY(cx); COPY(ip);
1da177e4 LT	69	COPY(r8);
	70	COPY(r9);
	71	COPY(r10);
	72	COPY(r11);
	73	COPY(r12);
	74	COPY(r13);
	75	COPY(r14);
	76	COPY(r15);
	77
e4e5d324 BF	78	/* Kernel saves and restores only the CS segment register on signals,
	79	* which is the bare minimum needed to allow mixed 32/64-bit code.
	80	* App's signal handler can save/restore other segments if needed. */
	81	{
	82	unsigned cs;
	83	err \|= __get_user(cs, &sc->cs);
	84	regs->cs = cs \| 3; /* Force into user mode */
	85	}
	86
1da177e4 LT	87	{
1da177e4 LT	88	unsigned int tmpflags;
742fa54a	89	err \|= __get_user(tmpflags, &sc->flags);
65ea5b03 PA	90	regs->flags = (regs->flags & ~0x40DD5) \| (tmpflags & 0x40DD5);
65ea5b03 PA	91	regs->orig_ax = -1; /* disable syscall checks */
1da177e4 LT	92	}
	93
	94	{
	95	struct _fpstate __user * buf;
	96	err \|= __get_user(buf, &sc->fpstate);
	97
	98	if (buf) {
	99	if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
	100	goto badframe;
	101	err \|= restore_i387(buf);
	102	} else {
	103	struct task_struct *me = current;
	104	if (used_math()) {
	105	clear_fpu(me);
	106	clear_used_math();
	107	}
	108	}
	109	}
	110
742fa54a	111	err \|= __get_user(*prax, &sc->ax);
1da177e4 LT	112	return err;
	113
	114	badframe:
	115	return 1;
	116	}
	117
	118	asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
	119	{
	120	struct rt_sigframe __user *frame;
	121	sigset_t set;
65ea5b03	122	unsigned long ax;
1da177e4	123
65ea5b03	124	frame = (struct rt_sigframe __user *)(regs->sp - 8);
1da177e4 LT	125	if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) {
	126	goto badframe;
	127	}
	128	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) {
	129	goto badframe;
	130	}
	131
	132	sigdelsetmask(&set, ~_BLOCKABLE);
	133	spin_lock_irq(&current->sighand->siglock);
	134	current->blocked = set;
	135	recalc_sigpending();
	136	spin_unlock_irq(&current->sighand->siglock);
	137
65ea5b03	138	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
1da177e4 LT	139	goto badframe;
	140
	141	#ifdef DEBUG_SIG
65ea5b03	142	printk("%d sigreturn ip:%lx sp:%lx frame:%p ax:%lx\n",current->pid,regs->ip,regs->sp,frame,ax);
1da177e4 LT	143	#endif
1da177e4 LT	144
65ea5b03	145	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
1da177e4 LT	146	goto badframe;
1da177e4 LT	147
65ea5b03	148	return ax;
1da177e4 LT	149
	150	badframe:
	151	signal_fault(regs,frame,"sigreturn");
	152	return 0;
	153	}
	154
	155	/*
	156	* Set up a signal frame.
	157	*/
	158
	159	static inline int
	160	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs, unsigned long mask, struct task_struct *me)
	161	{
	162	int err = 0;
1da177e4	163
e4e5d324	164	err \|= __put_user(regs->cs, &sc->cs);
1da177e4 LT	165	err \|= __put_user(0, &sc->gs);
	166	err \|= __put_user(0, &sc->fs);
	167
742fa54a PA	168	err \|= __put_user(regs->di, &sc->di);
	169	err \|= __put_user(regs->si, &sc->si);
	170	err \|= __put_user(regs->bp, &sc->bp);
	171	err \|= __put_user(regs->sp, &sc->sp);
	172	err \|= __put_user(regs->bx, &sc->bx);
	173	err \|= __put_user(regs->dx, &sc->dx);
	174	err \|= __put_user(regs->cx, &sc->cx);
	175	err \|= __put_user(regs->ax, &sc->ax);
1da177e4 LT	176	err \|= __put_user(regs->r8, &sc->r8);
	177	err \|= __put_user(regs->r9, &sc->r9);
	178	err \|= __put_user(regs->r10, &sc->r10);
	179	err \|= __put_user(regs->r11, &sc->r11);
	180	err \|= __put_user(regs->r12, &sc->r12);
	181	err \|= __put_user(regs->r13, &sc->r13);
	182	err \|= __put_user(regs->r14, &sc->r14);
	183	err \|= __put_user(regs->r15, &sc->r15);
	184	err \|= __put_user(me->thread.trap_no, &sc->trapno);
	185	err \|= __put_user(me->thread.error_code, &sc->err);
742fa54a PA	186	err \|= __put_user(regs->ip, &sc->ip);
742fa54a PA	187	err \|= __put_user(regs->flags, &sc->flags);
1da177e4 LT	188	err \|= __put_user(mask, &sc->oldmask);
	189	err \|= __put_user(me->thread.cr2, &sc->cr2);
	190
	191	return err;
	192	}
	193
	194	/*
	195	* Determine which stack to use..
	196	*/
	197
	198	static void __user *
	199	get_stack(struct k_sigaction ka, struct pt_regs regs, unsigned long size)
	200	{
65ea5b03	201	unsigned long sp;
1da177e4 LT	202
1da177e4 LT	203	/* Default to using normal stack - redzone*/
65ea5b03	204	sp = regs->sp - 128;
1da177e4 LT	205
1da177e4 LT	206	/* This is the X/Open sanctioned signal stack switching. */
1da177e4	207	if (ka->sa.sa_flags & SA_ONSTACK) {
65ea5b03 PA	208	if (sas_ss_flags(sp) == 0)
65ea5b03 PA	209	sp = current->sas_ss_sp + current->sas_ss_size;
1da177e4 LT	210	}
1da177e4 LT	211
65ea5b03	212	return (void __user *)round_down(sp - size, 16);
1da177e4 LT	213	}
1da177e4 LT	214
0928d6ef	215	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
1da177e4 LT	216	sigset_t set, struct pt_regs regs)
	217	{
	218	struct rt_sigframe __user *frame;
	219	struct _fpstate __user *fp = NULL;
	220	int err = 0;
	221	struct task_struct *me = current;
	222
	223	if (used_math()) {
	224	fp = get_stack(ka, regs, sizeof(struct _fpstate));
	225	frame = (void __user *)round_down(
	226	(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
	227
	228	if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
	229	goto give_sigsegv;
	230
	231	if (save_i387(fp) < 0)
	232	err \|= -1;
	233	} else
	234	frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
	235
	236	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	237	goto give_sigsegv;
	238
	239	if (ka->sa.sa_flags & SA_SIGINFO) {
	240	err \|= copy_siginfo_to_user(&frame->info, info);
	241	if (err)
	242	goto give_sigsegv;
	243	}
	244
	245	/* Create the ucontext. */
	246	err \|= __put_user(0, &frame->uc.uc_flags);
	247	err \|= __put_user(0, &frame->uc.uc_link);
	248	err \|= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
65ea5b03	249	err \|= __put_user(sas_ss_flags(regs->sp),
1da177e4 LT	250	&frame->uc.uc_stack.ss_flags);
	251	err \|= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
	252	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
	253	err \|= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
	254	if (sizeof(*set) == 16) {
	255	__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
	256	__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
	257	} else
	258	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	259
	260	/* Set up to return from userspace. If provided, use a stub
	261	already in userspace. */
	262	/* x86-64 should always use SA_RESTORER. */
	263	if (ka->sa.sa_flags & SA_RESTORER) {
	264	err \|= __put_user(ka->sa.sa_restorer, &frame->pretcode);
	265	} else {
	266	/* could use a vstub here */
	267	goto give_sigsegv;
	268	}
	269
	270	if (err)
	271	goto give_sigsegv;
	272
	273	#ifdef DEBUG_SIG
65ea5b03	274	printk("%d old ip %lx old sp %lx old ax %lx\n", current->pid,regs->ip,regs->sp,regs->ax);
1da177e4 LT	275	#endif
	276
	277	/* Set up registers for signal handler */
65ea5b03	278	regs->di = sig;
1da177e4	279	/* In case the signal handler was declared without prototypes */
65ea5b03	280	regs->ax = 0;
1da177e4 LT	281
	282	/* This also works for non SA_SIGINFO handlers because they expect the
	283	next argument after the signal number on the stack. */
65ea5b03 PA	284	regs->si = (unsigned long)&frame->info;
	285	regs->dx = (unsigned long)&frame->uc;
	286	regs->ip = (unsigned long) ka->sa.sa_handler;
1da177e4	287
65ea5b03	288	regs->sp = (unsigned long)frame;
1da177e4	289
e4e5d324 BF	290	/* Set up the CS register to run signal handlers in 64-bit mode,
	291	even if the handler happens to be interrupting 32-bit code. */
	292	regs->cs = __USER_CS;
	293
	294	/* This, by contrast, has nothing to do with segment registers -
	295	see include/asm-x86_64/uaccess.h for details. */
1da177e4	296	set_fs(USER_DS);
e4e5d324	297
053de044	298	regs->flags &= ~X86_EFLAGS_TF;
be61bff7 AK	299	if (test_thread_flag(TIF_SINGLESTEP))
be61bff7 AK	300	ptrace_notify(SIGTRAP);
1da177e4	301	#ifdef DEBUG_SIG
1c3d99c1	302	printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
65ea5b03	303	current->comm, current->pid, frame, regs->ip, frame->pretcode);
1da177e4 LT	304	#endif
1da177e4 LT	305
1d001df1	306	return 0;
1da177e4 LT	307
	308	give_sigsegv:
	309	force_sigsegv(sig, current);
1d001df1	310	return -EFAULT;
1da177e4 LT	311	}
	312
	313	/*
	314	* OK, we're invoking a handler
	315	*/
	316
0928d6ef	317	static int
1da177e4 LT	318	handle_signal(unsigned long sig, siginfo_t info, struct k_sigaction ka,
	319	sigset_t oldset, struct pt_regs regs)
	320	{
0928d6ef RM	321	int ret;
0928d6ef RM	322
1da177e4	323	#ifdef DEBUG_SIG
65ea5b03	324	printk("handle_signal pid:%d sig:%lu ip:%lx sp:%lx regs=%p\n",
1da177e4	325	current->pid, sig,
65ea5b03	326	regs->ip, regs->sp, regs);
1da177e4 LT	327	#endif
	328
	329	/* Are we from a system call? */
65ea5b03	330	if ((long)regs->orig_ax >= 0) {
1da177e4	331	/* If so, check system call restarting.. */
65ea5b03	332	switch (regs->ax) {
1da177e4 LT	333	case -ERESTART_RESTARTBLOCK:
1da177e4 LT	334	case -ERESTARTNOHAND:
65ea5b03	335	regs->ax = -EINTR;
1da177e4 LT	336	break;
	337
	338	case -ERESTARTSYS:
	339	if (!(ka->sa.sa_flags & SA_RESTART)) {
65ea5b03	340	regs->ax = -EINTR;
1da177e4 LT	341	break;
	342	}
	343	/* fallthrough */
	344	case -ERESTARTNOINTR:
65ea5b03 PA	345	regs->ax = regs->orig_ax;
65ea5b03 PA	346	regs->ip -= 2;
1da177e4 LT	347	break;
	348	}
	349	}
	350
d61915da	351	/*
e1f28773 RM	352	* If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
e1f28773 RM	353	* flag so that register information in the sigcontext is correct.
d61915da	354	*/
65ea5b03	355	if (unlikely(regs->flags & X86_EFLAGS_TF) &&
e1f28773	356	likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
65ea5b03	357	regs->flags &= ~X86_EFLAGS_TF;
d61915da	358
1da177e4 LT	359	#ifdef CONFIG_IA32_EMULATION
	360	if (test_thread_flag(TIF_IA32)) {
	361	if (ka->sa.sa_flags & SA_SIGINFO)
0928d6ef	362	ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	363	else
0928d6ef	364	ret = ia32_setup_frame(sig, ka, oldset, regs);
1da177e4 LT	365	} else
1da177e4 LT	366	#endif
0928d6ef	367	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	368
1d001df1	369	if (ret == 0) {
1da177e4 LT	370	spin_lock_irq(&current->sighand->siglock);
1da177e4 LT	371	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
69be8f18 SR	372	if (!(ka->sa.sa_flags & SA_NODEFER))
69be8f18 SR	373	sigaddset(&current->blocked,sig);
1da177e4 LT	374	recalc_sigpending();
	375	spin_unlock_irq(&current->sighand->siglock);
	376	}
0928d6ef RM	377
0928d6ef RM	378	return ret;
1da177e4 LT	379	}
	380
	381	/*
	382	* Note that 'init' is a special process: it doesn't get signals it doesn't
	383	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	384	* mistake.
	385	*/
1d001df1	386	static void do_signal(struct pt_regs *regs)
1da177e4 LT	387	{
	388	struct k_sigaction ka;
	389	siginfo_t info;
	390	int signr;
1d001df1	391	sigset_t *oldset;
1da177e4 LT	392
	393	/*
	394	* We want the common case to go fast, which
	395	* is why we may in certain cases get here from
	396	* kernel mode. Just return without doing anything
	397	* if so.
	398	*/
76381fee	399	if (!user_mode(regs))
1d001df1	400	return;
1da177e4	401
1d001df1 AK	402	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	403	oldset = &current->saved_sigmask;
	404	else
1da177e4 LT	405	oldset = &current->blocked;
	406
	407	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	408	if (signr > 0) {
676b1855	409	/* Re-enable any watchpoints before delivering the
1da177e4 LT	410	* signal to user space. The processor register will
	411	* have been cleared if the watchpoint triggered
	412	* inside the kernel.
	413	*/
	414	if (current->thread.debugreg7)
e9129e56	415	set_debugreg(current->thread.debugreg7, 7);
1da177e4 LT	416
1da177e4 LT	417	/* Whee! Actually deliver the signal. */
1d001df1 AK	418	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
	419	/* a signal was successfully delivered; the saved
	420	* sigmask will have been stored in the signal frame,
	421	* and will be restored by sigreturn, so we can simply
	422	* clear the TIF_RESTORE_SIGMASK flag */
	423	clear_thread_flag(TIF_RESTORE_SIGMASK);
	424	}
	425	return;
1da177e4 LT	426	}
1da177e4 LT	427
1da177e4	428	/* Did we come from a system call? */
65ea5b03	429	if ((long)regs->orig_ax >= 0) {
1da177e4	430	/* Restart the system call - no handlers present */
65ea5b03	431	long res = regs->ax;
1d001df1 AK	432	switch (res) {
	433	case -ERESTARTNOHAND:
	434	case -ERESTARTSYS:
	435	case -ERESTARTNOINTR:
65ea5b03 PA	436	regs->ax = regs->orig_ax;
65ea5b03 PA	437	regs->ip -= 2;
1d001df1 AK	438	break;
1d001df1 AK	439	case -ERESTART_RESTARTBLOCK:
65ea5b03	440	regs->ax = test_thread_flag(TIF_IA32) ?
607a1685 AK	441	__NR_ia32_restart_syscall :
607a1685 AK	442	__NR_restart_syscall;
65ea5b03	443	regs->ip -= 2;
1d001df1	444	break;
1da177e4 LT	445	}
1da177e4 LT	446	}
1d001df1 AK	447
	448	/* if there's no signal to deliver, we just put the saved sigmask
	449	back. */
	450	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	451	clear_thread_flag(TIF_RESTORE_SIGMASK);
	452	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	453	}
1da177e4 LT	454	}
1da177e4 LT	455
1d001df1 AK	456	void
1d001df1 AK	457	do_notify_resume(struct pt_regs regs, void unused, __u32 thread_info_flags)
1da177e4 LT	458	{
1da177e4 LT	459	#ifdef DEBUG_SIG
65ea5b03 PA	460	printk("do_notify_resume flags:%x ip:%lx sp:%lx caller:%p pending:%x\n",
65ea5b03 PA	461	thread_info_flags, regs->ip, regs->sp, __builtin_return_address(0),signal_pending(current));
1da177e4 LT	462	#endif
	463
	464	/* Pending single-step? */
	465	if (thread_info_flags & _TIF_SINGLESTEP) {
053de044	466	regs->flags \|= X86_EFLAGS_TF;
1da177e4 LT	467	clear_thread_flag(TIF_SINGLESTEP);
	468	}
	469
e02e68d3 TH	470	#ifdef CONFIG_X86_MCE
	471	/* notify userspace of pending MCEs */
	472	if (thread_info_flags & _TIF_MCE_NOTIFY)
	473	mce_notify_user();
	474	#endif /* CONFIG_X86_MCE */
	475
1da177e4	476	/* deal with pending signal delivery */
1d001df1 AK	477	if (thread_info_flags & (_TIF_SIGPENDING\|_TIF_RESTORE_SIGMASK))
1d001df1 AK	478	do_signal(regs);
8f4d37ec PZ	479
	480	if (thread_info_flags & _TIF_HRTICK_RESCHED)
	481	hrtick_resched();
1da177e4 LT	482	}
	483
	484	void signal_fault(struct pt_regs regs, void __user frame, char *where)
	485	{
	486	struct task_struct *me = current;
03252919 AK	487	if (show_unhandled_signals && printk_ratelimit()) {
03252919 AK	488	printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
65ea5b03	489	me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
03252919 AK	490	print_vma_addr(" in ", regs->ip);
	491	printk("\n");
	492	}
1da177e4 LT	493
	494	force_sig(SIGSEGV, me);
	495	}