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

/*
 * Copyright (C) 1991, 1992  Linus Torvalds
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#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/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/suspend.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/sigframe.h>
#include <asm/syscalls.h>
#include <arch/interrupts.h>

#define DEBUG_SIG 0

SYSCALL_DEFINE3(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.
 */

int restore_sigcontext(struct pt_regs *regs,
		       struct sigcontext __user *sc)
{
	int err = 0;
	int i;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	/*
	 * Enforce that sigcontext is like pt_regs, and doesn't mess
	 * up our stack alignment rules.
	 */
	BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
	BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);

	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
		err |= __get_user(regs->regs[i], &sc->gregs[i]);

	/* Ensure that the PL is always set to USER_PL. */
	regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));

	regs->faultnum = INT_SWINT_1_SIGRETURN;

	return err;
}

void signal_fault(const char *type, struct pt_regs *regs,
		  void __user *frame, int sig)
{
	trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
	force_sigsegv(sig, current);
}

/* The assembly shim for this function arranges to ignore the return value. */
SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs)
{
	struct rt_sigframe __user *frame =
		(struct rt_sigframe __user *)(regs->sp);
	sigset_t set;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
		goto badframe;

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

	return 0;

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

/*
 * Set up a signal frame.
 */

int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
{
	int i, err = 0;

	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
		err |= __put_user(regs->regs[i], &sc->gregs[i]);

	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 sp;

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

	/*
	 * If we are on the alternate signal stack and would overflow
	 * it, don't.  Return an always-bogus address instead so we
	 * will die with SIGSEGV.
	 */
	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
		return (void __user __force *)-1UL;

	/* 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;
	}

	sp -= frame_size;
	/*
	 * Align the stack pointer according to the TILE ABI,
	 * i.e. so that on function entry (sp & 15) == 0.
	 */
	sp &= -16UL;
	return (void __user *) sp;
}

static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs *regs)
{
	unsigned long 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;

	/* Always write at least the signal number for the stack backtracer. */
	if (ka->sa.sa_flags & SA_SIGINFO) {
		/* At sigreturn time, restore the callee-save registers too. */
		err |= copy_siginfo_to_user(&frame->info, info);
		regs->flags |= PT_FLAGS_RESTORE_REGS;
	} else {
		err |= __put_user(info->si_signo, &frame->info.si_signo);
	}

	/* Create the ucontext.  */
	err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(NULL, &frame->uc.uc_link);
	err |= __put_user((void __user *)(current->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(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto give_sigsegv;

	restorer = VDSO_BASE;
	if (ka->sa.sa_flags & SA_RESTORER)
		restorer = (unsigned long) ka->sa.sa_restorer;

	/*
	 * Set up registers for signal handler.
	 * Registers that we don't modify keep the value they had from
	 * user-space at the time we took the signal.
	 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
	 * since some things rely on this (e.g. glibc's debug/segfault.c).
	 */
	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
	regs->sp = (unsigned long) frame;
	regs->lr = restorer;
	regs->regs[0] = (unsigned long) usig;
	regs->regs[1] = (unsigned long) &frame->info;
	regs->regs[2] = (unsigned long) &frame->uc;
	regs->flags |= PT_FLAGS_CALLER_SAVES;
	return 0;

give_sigsegv:
	signal_fault("bad setup frame", regs, frame, sig);
	return -EFAULT;
}

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

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

	/* Are we from a system call? */
	if (regs->faultnum == INT_SWINT_1) {
		/* If so, check system call restarting.. */
		switch (regs->regs[0]) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->regs[0] = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ka->sa.sa_flags & SA_RESTART)) {
				regs->regs[0] = -EINTR;
				break;
			}
			/* fallthrough */
		case -ERESTARTNOINTR:
			/* Reload caller-saves to restore r0..r5 and r10. */
			regs->flags |= PT_FLAGS_CALLER_SAVES;
			regs->regs[0] = regs->orig_r0;
			regs->pc -= 8;
		}
	}

	/* Set up the stack frame */
#ifdef CONFIG_COMPAT
	if (is_compat_task())
		ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
	else
#endif
		ret = setup_rt_frame(sig, ka, info, oldset, regs);
	if (ret)
		return;
	signal_delivered(sig, info, ka, regs,
			test_thread_flag(TIF_SINGLESTEP));
}

/*
 * 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.
 */
void do_signal(struct pt_regs *regs)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;

	/*
	 * i386 will check if we're coming from kernel mode and bail out
	 * here.  In my experience this just turns weird crashes into
	 * weird spin-hangs.  But if we find a case where this seems
	 * helpful, we can reinstate the check on "!user_mode(regs)".
	 */

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		/* Whee! Actually deliver the signal.  */
		handle_signal(signr, &info, &ka, regs);
		goto done;
	}

	/* Did we come from a system call? */
	if (regs->faultnum == INT_SWINT_1) {
		/* Restart the system call - no handlers present */
		switch (regs->regs[0]) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->flags |= PT_FLAGS_CALLER_SAVES;
			regs->regs[0] = regs->orig_r0;
			regs->pc -= 8;
			break;

		case -ERESTART_RESTARTBLOCK:
			regs->flags |= PT_FLAGS_CALLER_SAVES;
			regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
			regs->pc -= 8;
			break;
		}
	}

	/* If there's no signal to deliver, just put the saved sigmask back. */
	restore_saved_sigmask();

done:
	/* Avoid double syscall restart if there are nested signals. */
	regs->faultnum = INT_SWINT_1_SIGRETURN;
}

int show_unhandled_signals = 1;

static int __init crashinfo(char *str)
{
	unsigned long val;
	const char *word;

	if (*str == '\0')
		val = 2;
	else if (*str != '=' || strict_strtoul(++str, 0, &val) != 0)
		return 0;
	show_unhandled_signals = val;
	switch (show_unhandled_signals) {
	case 0:
		word = "No";
		break;
	case 1:
		word = "One-line";
		break;
	default:
		word = "Detailed";
		break;
	}
	pr_info("%s crash reports will be generated on the console\n", word);
	return 1;
}
__setup("crashinfo", crashinfo);

static void dump_mem(void __user *address)
{
	void __user *addr;
	enum { region_size = 256, bytes_per_line = 16 };
	int i, j, k;
	int found_readable_mem = 0;

	pr_err("\n");
	if (!access_ok(VERIFY_READ, address, 1)) {
		pr_err("Not dumping at address 0x%lx (kernel address)\n",
		       (unsigned long)address);
		return;
	}

	addr = (void __user *)
		(((unsigned long)address & -bytes_per_line) - region_size/2);
	if (addr > address)
		addr = NULL;
	for (i = 0; i < region_size;
	     addr += bytes_per_line, i += bytes_per_line) {
		unsigned char buf[bytes_per_line];
		char line[100];
		if (copy_from_user(buf, addr, bytes_per_line))
			continue;
		if (!found_readable_mem) {
			pr_err("Dumping memory around address 0x%lx:\n",
			       (unsigned long)address);
			found_readable_mem = 1;
		}
		j = sprintf(line, REGFMT":", (unsigned long)addr);
		for (k = 0; k < bytes_per_line; ++k)
			j += sprintf(&line[j], " %02x", buf[k]);
		pr_err("%s\n", line);
	}
	if (!found_readable_mem)
		pr_err("No readable memory around address 0x%lx\n",
		       (unsigned long)address);
}

void trace_unhandled_signal(const char *type, struct pt_regs *regs,
			    unsigned long address, int sig)
{
	struct task_struct *tsk = current;

	if (show_unhandled_signals == 0)
		return;

	/* If the signal is handled, don't show it here. */
	if (!is_global_init(tsk)) {
		void __user *handler =
			tsk->sighand->action[sig-1].sa.sa_handler;
		if (handler != SIG_IGN && handler != SIG_DFL)
			return;
	}

	/* Rate-limit the one-line output, not the detailed output. */
	if (show_unhandled_signals <= 1 && !printk_ratelimit())
		return;

	printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
	       task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
	       tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);

	print_vma_addr(KERN_CONT " in ", regs->pc);

	printk(KERN_CONT "\n");

	if (show_unhandled_signals > 1) {
		switch (sig) {
		case SIGILL:
		case SIGFPE:
		case SIGSEGV:
		case SIGBUS:
			pr_err("User crash: signal %d,"
			       " trap %ld, address 0x%lx\n",
			       sig, regs->faultnum, address);
			show_regs(regs);
			dump_mem((void __user *)address);
			break;
		default:
			pr_err("User crash: signal %d, trap %ld\n",
			       sig, regs->faultnum);
			break;
		}
	}
}
Commit	Line	Data
867e359b CM	1	/*
	2	* Copyright (C) 1991, 1992 Linus Torvalds
	3	* Copyright 2010 Tilera Corporation. All Rights Reserved.
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation, version 2.
	8	*
	9	* This program is distributed in the hope that it will be useful, but
	10	* WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	12	* NON INFRINGEMENT. See the GNU General Public License for
	13	* more details.
	14	*/
	15
	16	#include <linux/sched.h>
	17	#include <linux/mm.h>
	18	#include <linux/smp.h>
867e359b CM	19	#include <linux/kernel.h>
	20	#include <linux/signal.h>
	21	#include <linux/errno.h>
	22	#include <linux/wait.h>
	23	#include <linux/unistd.h>
	24	#include <linux/stddef.h>
	25	#include <linux/personality.h>
	26	#include <linux/suspend.h>
	27	#include <linux/ptrace.h>
	28	#include <linux/elf.h>
	29	#include <linux/compat.h>
	30	#include <linux/syscalls.h>
	31	#include <linux/uaccess.h>
	32	#include <asm/processor.h>
	33	#include <asm/ucontext.h>
	34	#include <asm/sigframe.h>
0707ad30	35	#include <asm/syscalls.h>
867e359b CM	36	#include <arch/interrupts.h>
	37
	38	#define DEBUG_SIG 0
	39
d929b6ae CM	40	SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss,
d929b6ae CM	41	stack_t __user , uoss, struct pt_regs , regs)
867e359b CM	42	{
	43	return do_sigaltstack(uss, uoss, regs->sp);
	44	}
	45
	46
	47	/*
	48	* Do a signal return; undo the signal stack.
	49	*/
	50
	51	int restore_sigcontext(struct pt_regs *regs,
81711cee	52	struct sigcontext __user *sc)
867e359b CM	53	{
	54	int err = 0;
	55	int i;
	56
	57	/* Always make any pending restarted system calls return -EINTR */
	58	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	59
74fca9da CM	60	/*
	61	* Enforce that sigcontext is like pt_regs, and doesn't mess
	62	* up our stack alignment rules.
	63	*/
	64	BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
	65	BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
	66
867e359b	67	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
74fca9da	68	err \|= __get_user(regs->regs[i], &sc->gregs[i]);
867e359b	69
1deb9c5d CM	70	/* Ensure that the PL is always set to USER_PL. */
	71	regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
	72
867e359b CM	73	regs->faultnum = INT_SWINT_1_SIGRETURN;
867e359b CM	74
867e359b CM	75	return err;
	76	}
	77
571d76ac CM	78	void signal_fault(const char type, struct pt_regs regs,
	79	void __user *frame, int sig)
	80	{
	81	trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
	82	force_sigsegv(sig, current);
	83	}
	84
81711cee	85	/* The assembly shim for this function arranges to ignore the return value. */
d929b6ae	86	SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs)
867e359b CM	87	{
	88	struct rt_sigframe __user *frame =
	89	(struct rt_sigframe __user *)(regs->sp);
	90	sigset_t set;
867e359b CM	91
	92	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	93	goto badframe;
	94	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	95	goto badframe;
	96
ad092338	97	set_current_blocked(&set);
867e359b	98
81711cee	99	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
867e359b CM	100	goto badframe;
	101
	102	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
	103	goto badframe;
	104
81711cee	105	return 0;
867e359b CM	106
867e359b CM	107	badframe:
571d76ac	108	signal_fault("bad sigreturn frame", regs, frame, 0);
867e359b CM	109	return 0;
	110	}
	111
	112	/*
	113	* Set up a signal frame.
	114	*/
	115
	116	int setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	117	{
	118	int i, err = 0;
	119
	120	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
74fca9da	121	err \|= __put_user(regs->regs[i], &sc->gregs[i]);
867e359b CM	122
	123	return err;
	124	}
	125
	126	/*
	127	* Determine which stack to use..
	128	*/
	129	static inline void __user get_sigframe(struct k_sigaction ka,
	130	struct pt_regs *regs,
	131	size_t frame_size)
	132	{
	133	unsigned long sp;
	134
	135	/* Default to using normal stack */
	136	sp = regs->sp;
	137
	138	/*
	139	* If we are on the alternate signal stack and would overflow
	140	* it, don't. Return an always-bogus address instead so we
	141	* will die with SIGSEGV.
	142	*/
	143	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
0707ad30	144	return (void __user __force *)-1UL;
867e359b CM	145
	146	/* This is the X/Open sanctioned signal stack switching. */
	147	if (ka->sa.sa_flags & SA_ONSTACK) {
	148	if (sas_ss_flags(sp) == 0)
	149	sp = current->sas_ss_sp + current->sas_ss_size;
	150	}
	151
	152	sp -= frame_size;
	153	/*
	154	* Align the stack pointer according to the TILE ABI,
	155	* i.e. so that on function entry (sp & 15) == 0.
	156	*/
	157	sp &= -16UL;
	158	return (void __user *) sp;
	159	}
	160
	161	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	162	sigset_t set, struct pt_regs regs)
	163	{
	164	unsigned long restorer;
	165	struct rt_sigframe __user *frame;
	166	int err = 0;
	167	int usig;
	168
	169	frame = get_sigframe(ka, regs, sizeof(*frame));
	170
	171	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	172	goto give_sigsegv;
	173
	174	usig = current_thread_info()->exec_domain
	175	&& current_thread_info()->exec_domain->signal_invmap
	176	&& sig < 32
	177	? current_thread_info()->exec_domain->signal_invmap[sig]
	178	: sig;
	179
	180	/* Always write at least the signal number for the stack backtracer. */
	181	if (ka->sa.sa_flags & SA_SIGINFO) {
	182	/* At sigreturn time, restore the callee-save registers too. */
	183	err \|= copy_siginfo_to_user(&frame->info, info);
	184	regs->flags \|= PT_FLAGS_RESTORE_REGS;
	185	} else {
	186	err \|= __put_user(info->si_signo, &frame->info.si_signo);
	187	}
	188
	189	/* Create the ucontext. */
	190	err \|= __clear_user(&frame->save_area, sizeof(frame->save_area));
	191	err \|= __put_user(0, &frame->uc.uc_flags);
0707ad30 CM	192	err \|= __put_user(NULL, &frame->uc.uc_link);
0707ad30 CM	193	err \|= __put_user((void __user *)(current->sas_ss_sp),
867e359b CM	194	&frame->uc.uc_stack.ss_sp);
	195	err \|= __put_user(sas_ss_flags(regs->sp),
	196	&frame->uc.uc_stack.ss_flags);
	197	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	198	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
	199	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	200	if (err)
	201	goto give_sigsegv;
	202
	203	restorer = VDSO_BASE;
	204	if (ka->sa.sa_flags & SA_RESTORER)
	205	restorer = (unsigned long) ka->sa.sa_restorer;
	206
	207	/*
	208	* Set up registers for signal handler.
	209	* Registers that we don't modify keep the value they had from
	210	* user-space at the time we took the signal.
74fca9da CM	211	* We always pass siginfo and mcontext, regardless of SA_SIGINFO,
74fca9da CM	212	* since some things rely on this (e.g. glibc's debug/segfault.c).
867e359b CM	213	*/
	214	regs->pc = (unsigned long) ka->sa.sa_handler;
	215	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
	216	regs->sp = (unsigned long) frame;
	217	regs->lr = restorer;
	218	regs->regs[0] = (unsigned long) usig;
74fca9da CM	219	regs->regs[1] = (unsigned long) &frame->info;
	220	regs->regs[2] = (unsigned long) &frame->uc;
	221	regs->flags \|= PT_FLAGS_CALLER_SAVES;
867e359b CM	222	return 0;
	223
	224	give_sigsegv:
571d76ac	225	signal_fault("bad setup frame", regs, frame, sig);
867e359b CM	226	return -EFAULT;
	227	}
	228
	229	/*
	230	* OK, we're invoking a handler
	231	*/
	232
a610d6e6	233	static void handle_signal(unsigned long sig, siginfo_t *info,
b7f9a11a	234	struct k_sigaction *ka,
867e359b CM	235	struct pt_regs *regs)
867e359b CM	236	{
b7f9a11a	237	sigset_t *oldset = sigmask_to_save();
867e359b CM	238	int ret;
867e359b CM	239
867e359b CM	240	/* Are we from a system call? */
	241	if (regs->faultnum == INT_SWINT_1) {
	242	/* If so, check system call restarting.. */
	243	switch (regs->regs[0]) {
	244	case -ERESTART_RESTARTBLOCK:
	245	case -ERESTARTNOHAND:
	246	regs->regs[0] = -EINTR;
	247	break;
	248
	249	case -ERESTARTSYS:
	250	if (!(ka->sa.sa_flags & SA_RESTART)) {
	251	regs->regs[0] = -EINTR;
	252	break;
	253	}
	254	/* fallthrough */
	255	case -ERESTARTNOINTR:
	256	/* Reload caller-saves to restore r0..r5 and r10. */
	257	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	258	regs->regs[0] = regs->orig_r0;
	259	regs->pc -= 8;
	260	}
	261	}
	262
	263	/* Set up the stack frame */
	264	#ifdef CONFIG_COMPAT
	265	if (is_compat_task())
	266	ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
	267	else
	268	#endif
	269	ret = setup_rt_frame(sig, ka, info, oldset, regs);
a610d6e6 AV	270	if (ret)
a610d6e6 AV	271	return;
a925328d AV	272	signal_delivered(sig, info, ka, regs,
a925328d AV	273	test_thread_flag(TIF_SINGLESTEP));
867e359b CM	274	}
	275
	276	/*
	277	* Note that 'init' is a special process: it doesn't get signals it doesn't
	278	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	279	* mistake.
	280	*/
	281	void do_signal(struct pt_regs *regs)
	282	{
	283	siginfo_t info;
	284	int signr;
	285	struct k_sigaction ka;
867e359b CM	286
	287	/*
	288	* i386 will check if we're coming from kernel mode and bail out
	289	* here. In my experience this just turns weird crashes into
	290	* weird spin-hangs. But if we find a case where this seems
	291	* helpful, we can reinstate the check on "!user_mode(regs)".
	292	*/
	293
867e359b CM	294	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	295	if (signr > 0) {
	296	/* Whee! Actually deliver the signal. */
a610d6e6	297	handle_signal(signr, &info, &ka, regs);
34a89d26	298	goto done;
867e359b CM	299	}
	300
	301	/* Did we come from a system call? */
	302	if (regs->faultnum == INT_SWINT_1) {
	303	/* Restart the system call - no handlers present */
	304	switch (regs->regs[0]) {
	305	case -ERESTARTNOHAND:
	306	case -ERESTARTSYS:
	307	case -ERESTARTNOINTR:
	308	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	309	regs->regs[0] = regs->orig_r0;
	310	regs->pc -= 8;
	311	break;
	312
	313	case -ERESTART_RESTARTBLOCK:
	314	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	315	regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
	316	regs->pc -= 8;
	317	break;
	318	}
	319	}
	320
	321	/* If there's no signal to deliver, just put the saved sigmask back. */
51a7b448	322	restore_saved_sigmask();
34a89d26 CM	323
	324	done:
	325	/* Avoid double syscall restart if there are nested signals. */
	326	regs->faultnum = INT_SWINT_1_SIGRETURN;
867e359b	327	}
571d76ac CM	328
	329	int show_unhandled_signals = 1;
	330
	331	static int __init crashinfo(char *str)
	332	{
	333	unsigned long val;
	334	const char *word;
	335
	336	if (*str == '\0')
	337	val = 2;
	338	else if (*str != '=' \|\| strict_strtoul(++str, 0, &val) != 0)
	339	return 0;
	340	show_unhandled_signals = val;
	341	switch (show_unhandled_signals) {
	342	case 0:
	343	word = "No";
	344	break;
	345	case 1:
	346	word = "One-line";
	347	break;
	348	default:
	349	word = "Detailed";
	350	break;
	351	}
	352	pr_info("%s crash reports will be generated on the console\n", word);
	353	return 1;
	354	}
	355	__setup("crashinfo", crashinfo);
	356
	357	static void dump_mem(void __user *address)
	358	{
	359	void __user *addr;
	360	enum { region_size = 256, bytes_per_line = 16 };
	361	int i, j, k;
	362	int found_readable_mem = 0;
	363
	364	pr_err("\n");
	365	if (!access_ok(VERIFY_READ, address, 1)) {
	366	pr_err("Not dumping at address 0x%lx (kernel address)\n",
	367	(unsigned long)address);
	368	return;
	369	}
	370
	371	addr = (void __user *)
	372	(((unsigned long)address & -bytes_per_line) - region_size/2);
	373	if (addr > address)
	374	addr = NULL;
	375	for (i = 0; i < region_size;
	376	addr += bytes_per_line, i += bytes_per_line) {
	377	unsigned char buf[bytes_per_line];
	378	char line[100];
	379	if (copy_from_user(buf, addr, bytes_per_line))
	380	continue;
	381	if (!found_readable_mem) {
	382	pr_err("Dumping memory around address 0x%lx:\n",
	383	(unsigned long)address);
	384	found_readable_mem = 1;
	385	}
	386	j = sprintf(line, REGFMT":", (unsigned long)addr);
	387	for (k = 0; k < bytes_per_line; ++k)
	388	j += sprintf(&line[j], " %02x", buf[k]);
	389	pr_err("%s\n", line);
	390	}
	391	if (!found_readable_mem)
392	pr_err("No readable memory around address 0x%lx\n",
393	(unsigned long)address);
394	}
395
396	void trace_unhandled_signal(const char type, struct pt_regs regs,
397	unsigned long address, int sig)
398	{
399	struct task_struct *tsk = current;
400
401	if (show_unhandled_signals == 0)
402	return;
403
404	/* If the signal is handled, don't show it here. */
405	if (!is_global_init(tsk)) {
406	void __user *handler =
407	tsk->sighand->action[sig-1].sa.sa_handler;
408	if (handler != SIG_IGN && handler != SIG_DFL)
409	return;
410	}
411
412	/* Rate-limit the one-line output, not the detailed output. */
413	if (show_unhandled_signals <= 1 && !printk_ratelimit())
414	return;
415
416	printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
417	task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
418	tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
419
420	print_vma_addr(KERN_CONT " in ", regs->pc);
421
422	printk(KERN_CONT "\n");
423
424	if (show_unhandled_signals > 1) {
425	switch (sig) {
426	case SIGILL:
427	case SIGFPE:
428	case SIGSEGV:
429	case SIGBUS:
430	pr_err("User crash: signal %d,"
431	" trap %ld, address 0x%lx\n",
432	sig, regs->faultnum, address);
433	show_regs(regs);
434	dump_mem((void __user *)address);
435	break;
436	default:
437	pr_err("User crash: signal %d, trap %ld\n",
438	sig, regs->faultnum);
439	break;
440	}
441	}
442	}