[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/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->rsp);
}


/*
 * 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(rdi); COPY(rsi); COPY(rbp); COPY(rsp); COPY(rbx);
	COPY(rdx); COPY(rcx); COPY(rip);
	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->eflags);
		regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
		regs->orig_rax = -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->rax);
	return err;

badframe:
	return 1;
}

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

	frame = (struct rt_sigframe __user *)(regs->rsp - 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, &eax))
		goto badframe;

#ifdef DEBUG_SIG
	printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs->rip,regs->rsp,frame,eax);
#endif

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

	return eax;

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->rdi, &sc->rdi);
	err |= __put_user(regs->rsi, &sc->rsi);
	err |= __put_user(regs->rbp, &sc->rbp);
	err |= __put_user(regs->rsp, &sc->rsp);
	err |= __put_user(regs->rbx, &sc->rbx);
	err |= __put_user(regs->rdx, &sc->rdx);
	err |= __put_user(regs->rcx, &sc->rcx);
	err |= __put_user(regs->rax, &sc->rax);
	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->rip, &sc->rip);
	err |= __put_user(regs->eflags, &sc->eflags);
	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 rsp;

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

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

	return (void __user *)round_down(rsp - 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->rsp),
			  &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 rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax);
#endif

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

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

	regs->rsp = (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->eflags &= ~TF_MASK;
	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->rip, 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 rip:%lx rsp:%lx regs=%p\n",
		current->pid, sig,
		regs->rip, regs->rsp, regs);
#endif

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

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

	/*
	 * 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)) {
		if (likely(current->ptrace & PT_DTRACE)) {
			current->ptrace &= ~PT_DTRACE;
			regs->eflags &= ~TF_MASK;
		}
	}

#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) {
		/* 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 (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_rax >= 0) {
		/* Restart the system call - no handlers present */
		long res = regs->rax;
		switch (res) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->rax = regs->orig_rax;
			regs->rip -= 2;
			break;
		case -ERESTART_RESTARTBLOCK:
			regs->rax = test_thread_flag(TIF_IA32) ?
					__NR_ia32_restart_syscall :
					__NR_restart_syscall;
			regs->rip -= 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 rip:%lx rsp:%lx caller:%p pending:%x\n",
	       thread_info_flags, regs->rip, regs->rsp, __builtin_return_address(0),signal_pending(current)); 
#endif
	       
	/* Pending single-step? */
	if (thread_info_flags & _TIF_SINGLESTEP) {
		regs->eflags |= TF_MASK;
		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);
}

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 rip:%lx rsp:%lx orax:%lx\n",
	       me->comm,me->pid,where,frame,regs->rip,regs->rsp,regs->orig_rax); 

	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	{
	42	return do_sigaltstack(uss, uoss, regs->rsp);
	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
	67	COPY(rdi); COPY(rsi); COPY(rbp); COPY(rsp); COPY(rbx);
	68	COPY(rdx); COPY(rcx); COPY(rip);
	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	{
	88	unsigned int tmpflags;
	89	err \|= __get_user(tmpflags, &sc->eflags);
	90	regs->eflags = (regs->eflags & ~0x40DD5) \| (tmpflags & 0x40DD5);
	91	regs->orig_rax = -1; /* disable syscall checks */
	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
	111	err \|= __get_user(*prax, &sc->rax);
	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;
	122	unsigned long eax;
	123
	124	frame = (struct rt_sigframe __user *)(regs->rsp - 8);
	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
	138	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
	139	goto badframe;
	140
	141	#ifdef DEBUG_SIG
1c3d99c1	142	printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs->rip,regs->rsp,frame,eax);
1da177e4 LT	143	#endif
	144
	145	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->rsp) == -EFAULT)
	146	goto badframe;
	147
	148	return eax;
	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
	168	err \|= __put_user(regs->rdi, &sc->rdi);
	169	err \|= __put_user(regs->rsi, &sc->rsi);
	170	err \|= __put_user(regs->rbp, &sc->rbp);
	171	err \|= __put_user(regs->rsp, &sc->rsp);
	172	err \|= __put_user(regs->rbx, &sc->rbx);
	173	err \|= __put_user(regs->rdx, &sc->rdx);
	174	err \|= __put_user(regs->rcx, &sc->rcx);
	175	err \|= __put_user(regs->rax, &sc->rax);
	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);
	186	err \|= __put_user(regs->rip, &sc->rip);
be61bff7	187	err \|= __put_user(regs->eflags, &sc->eflags);
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	{
	201	unsigned long rsp;
	202
	203	/* Default to using normal stack - redzone*/
	204	rsp = regs->rsp - 128;
	205
	206	/* This is the X/Open sanctioned signal stack switching. */
1da177e4 LT	207	if (ka->sa.sa_flags & SA_ONSTACK) {
	208	if (sas_ss_flags(rsp) == 0)
	209	rsp = current->sas_ss_sp + current->sas_ss_size;
	210	}
	211
	212	return (void __user *)round_down(rsp - size, 16);
	213	}
	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);
	249	err \|= __put_user(sas_ss_flags(regs->rsp),
	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
	274	printk("%d old rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax);
	275	#endif
	276
	277	/* Set up registers for signal handler */
1da177e4 LT	278	regs->rdi = sig;
	279	/* In case the signal handler was declared without prototypes */
	280	regs->rax = 0;
	281
	282	/* This also works for non SA_SIGINFO handlers because they expect the
	283	next argument after the signal number on the stack. */
	284	regs->rsi = (unsigned long)&frame->info;
	285	regs->rdx = (unsigned long)&frame->uc;
	286	regs->rip = (unsigned long) ka->sa.sa_handler;
	287
	288	regs->rsp = (unsigned long)frame;
	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
be61bff7 AK	298	regs->eflags &= ~TF_MASK;
	299	if (test_thread_flag(TIF_SINGLESTEP))
	300	ptrace_notify(SIGTRAP);
1da177e4	301	#ifdef DEBUG_SIG
1c3d99c1	302	printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
1da177e4 LT	303	current->comm, current->pid, frame, regs->rip, frame->pretcode);
	304	#endif
	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 LT	323	#ifdef DEBUG_SIG
	324	printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n",
	325	current->pid, sig,
	326	regs->rip, regs->rsp, regs);
	327	#endif
	328
	329	/* Are we from a system call? */
	330	if ((long)regs->orig_rax >= 0) {
	331	/* If so, check system call restarting.. */
	332	switch (regs->rax) {
	333	case -ERESTART_RESTARTBLOCK:
	334	case -ERESTARTNOHAND:
	335	regs->rax = -EINTR;
	336	break;
	337
	338	case -ERESTARTSYS:
	339	if (!(ka->sa.sa_flags & SA_RESTART)) {
	340	regs->rax = -EINTR;
	341	break;
	342	}
	343	/* fallthrough */
	344	case -ERESTARTNOINTR:
	345	regs->rax = regs->orig_rax;
	346	regs->rip -= 2;
	347	break;
	348	}
	349	}
	350
d61915da AK	351	/*
	352	* If TF is set due to a debugger (PT_DTRACE), clear the TF
	353	* flag so that register information in the sigcontext is
	354	* correct.
	355	*/
	356	if (unlikely(regs->eflags & TF_MASK)) {
	357	if (likely(current->ptrace & PT_DTRACE)) {
	358	current->ptrace &= ~PT_DTRACE;
	359	regs->eflags &= ~TF_MASK;
	360	}
	361	}
	362
1da177e4 LT	363	#ifdef CONFIG_IA32_EMULATION
	364	if (test_thread_flag(TIF_IA32)) {
	365	if (ka->sa.sa_flags & SA_SIGINFO)
0928d6ef	366	ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	367	else
0928d6ef	368	ret = ia32_setup_frame(sig, ka, oldset, regs);
1da177e4 LT	369	} else
1da177e4 LT	370	#endif
0928d6ef	371	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	372
1d001df1	373	if (ret == 0) {
1da177e4 LT	374	spin_lock_irq(&current->sighand->siglock);
1da177e4 LT	375	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
69be8f18 SR	376	if (!(ka->sa.sa_flags & SA_NODEFER))
69be8f18 SR	377	sigaddset(&current->blocked,sig);
1da177e4 LT	378	recalc_sigpending();
	379	spin_unlock_irq(&current->sighand->siglock);
	380	}
0928d6ef RM	381
0928d6ef RM	382	return ret;
1da177e4 LT	383	}
	384
	385	/*
	386	* Note that 'init' is a special process: it doesn't get signals it doesn't
	387	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	388	* mistake.
	389	*/
1d001df1	390	static void do_signal(struct pt_regs *regs)
1da177e4 LT	391	{
	392	struct k_sigaction ka;
	393	siginfo_t info;
	394	int signr;
1d001df1	395	sigset_t *oldset;
1da177e4 LT	396
	397	/*
	398	* We want the common case to go fast, which
	399	* is why we may in certain cases get here from
	400	* kernel mode. Just return without doing anything
	401	* if so.
	402	*/
76381fee	403	if (!user_mode(regs))
1d001df1	404	return;
1da177e4	405
1d001df1 AK	406	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	407	oldset = &current->saved_sigmask;
	408	else
1da177e4 LT	409	oldset = &current->blocked;
	410
	411	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	412	if (signr > 0) {
	413	/* Reenable any watchpoints before delivering the
	414	* signal to user space. The processor register will
	415	* have been cleared if the watchpoint triggered
	416	* inside the kernel.
	417	*/
	418	if (current->thread.debugreg7)
e9129e56	419	set_debugreg(current->thread.debugreg7, 7);
1da177e4 LT	420
1da177e4 LT	421	/* Whee! Actually deliver the signal. */
1d001df1 AK	422	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
	423	/* a signal was successfully delivered; the saved
	424	* sigmask will have been stored in the signal frame,
	425	* and will be restored by sigreturn, so we can simply
	426	* clear the TIF_RESTORE_SIGMASK flag */
	427	clear_thread_flag(TIF_RESTORE_SIGMASK);
	428	}
	429	return;
1da177e4 LT	430	}
1da177e4 LT	431
1da177e4 LT	432	/* Did we come from a system call? */
	433	if ((long)regs->orig_rax >= 0) {
	434	/* Restart the system call - no handlers present */
	435	long res = regs->rax;
1d001df1 AK	436	switch (res) {
	437	case -ERESTARTNOHAND:
	438	case -ERESTARTSYS:
	439	case -ERESTARTNOINTR:
1da177e4 LT	440	regs->rax = regs->orig_rax;
1da177e4 LT	441	regs->rip -= 2;
1d001df1 AK	442	break;
1d001df1 AK	443	case -ERESTART_RESTARTBLOCK:
607a1685 AK	444	regs->rax = test_thread_flag(TIF_IA32) ?
	445	__NR_ia32_restart_syscall :
	446	__NR_restart_syscall;
1da177e4	447	regs->rip -= 2;
1d001df1	448	break;
1da177e4 LT	449	}
1da177e4 LT	450	}
1d001df1 AK	451
	452	/* if there's no signal to deliver, we just put the saved sigmask
	453	back. */
	454	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	455	clear_thread_flag(TIF_RESTORE_SIGMASK);
	456	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	457	}
1da177e4 LT	458	}
1da177e4 LT	459
1d001df1 AK	460	void
1d001df1 AK	461	do_notify_resume(struct pt_regs regs, void unused, __u32 thread_info_flags)
1da177e4 LT	462	{
1da177e4 LT	463	#ifdef DEBUG_SIG
1c3d99c1	464	printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%p pending:%x\n",
1da177e4 LT	465	thread_info_flags, regs->rip, regs->rsp, __builtin_return_address(0),signal_pending(current));
	466	#endif
	467
	468	/* Pending single-step? */
	469	if (thread_info_flags & _TIF_SINGLESTEP) {
	470	regs->eflags \|= TF_MASK;
	471	clear_thread_flag(TIF_SINGLESTEP);
	472	}
	473
e02e68d3 TH	474	#ifdef CONFIG_X86_MCE
	475	/* notify userspace of pending MCEs */
	476	if (thread_info_flags & _TIF_MCE_NOTIFY)
	477	mce_notify_user();
	478	#endif /* CONFIG_X86_MCE */
	479
1da177e4	480	/* deal with pending signal delivery */
1d001df1 AK	481	if (thread_info_flags & (_TIF_SIGPENDING\|_TIF_RESTORE_SIGMASK))
1d001df1 AK	482	do_signal(regs);
1da177e4 LT	483	}
	484
	485	void signal_fault(struct pt_regs regs, void __user frame, char *where)
	486	{
	487	struct task_struct *me = current;
abd4f750	488	if (show_unhandled_signals && printk_ratelimit())
1da177e4 LT	489	printk("%s[%d] bad frame in %s frame:%p rip:%lx rsp:%lx orax:%lx\n",
	490	me->comm,me->pid,where,frame,regs->rip,regs->rsp,regs->orig_rax);
	491
	492	force_sig(SIGSEGV, me);
	493	}