[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 <asm/vdso.h>
#include <arch/interrupts.h>

#define DEBUG_SIG 0

/*
 * 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_DEFINE0(rt_sigreturn)
{
	struct pt_regs *regs = current_pt_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 (restore_altstack(&frame->uc.uc_stack))
		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(struct ksignal *ksig, sigset_t *set,
			  struct pt_regs *regs)
{
	unsigned long restorer;
	struct rt_sigframe __user *frame;
	int err = 0, sig = ksig->sig;
	int usig;

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));

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

	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 (ksig->ka.sa.sa_flags & SA_SIGINFO) {
		/* At sigreturn time, restore the callee-save registers too. */
		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
		regs->flags |= PT_FLAGS_RESTORE_REGS;
	} else {
		err |= __put_user(ksig->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 |= __save_altstack(&frame->uc.uc_stack, regs->sp);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto err;

	restorer = VDSO_SYM(&__vdso_rt_sigreturn);
	if (ksig->ka.sa.sa_flags & SA_RESTORER)
		restorer = (unsigned long) ksig->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) ksig->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;

err:
	trace_unhandled_signal("bad sigreturn frame", regs,
			      (unsigned long)frame, SIGSEGV);
	return -EFAULT;
}

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

static void handle_signal(struct ksignal *ksig, 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 (!(ksig->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(ksig, oldset, regs);
	else
#endif
		ret = setup_rt_frame(ksig, oldset, regs);

	signal_setup_done(ret, ksig, 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)
{
	struct ksignal ksig;

	/*
	 * 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)".
	 */

	if (get_signal(&ksig)) {
		/* Whee! Actually deliver the signal.  */
		handle_signal(&ksig, 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)
{
	const char *word;

	if (*str == '\0')
		show_unhandled_signals = 2;
	else if (*str != '=' || kstrtoint(++str, 0, &show_unhandled_signals) != 0)
		return 0;

	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>
4a556f4f	36	#include <asm/vdso.h>
867e359b CM	37	#include <arch/interrupts.h>
	38
	39	#define DEBUG_SIG 0
	40
867e359b CM	41	/*
	42	* Do a signal return; undo the signal stack.
	43	*/
	44
	45	int restore_sigcontext(struct pt_regs *regs,
81711cee	46	struct sigcontext __user *sc)
867e359b CM	47	{
	48	int err = 0;
	49	int i;
	50
	51	/* Always make any pending restarted system calls return -EINTR */
	52	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	53
74fca9da CM	54	/*
	55	* Enforce that sigcontext is like pt_regs, and doesn't mess
	56	* up our stack alignment rules.
	57	*/
	58	BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
	59	BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
	60
867e359b	61	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
74fca9da	62	err \|= __get_user(regs->regs[i], &sc->gregs[i]);
867e359b	63
1deb9c5d CM	64	/* Ensure that the PL is always set to USER_PL. */
	65	regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
	66
867e359b CM	67	regs->faultnum = INT_SWINT_1_SIGRETURN;
867e359b CM	68
867e359b CM	69	return err;
	70	}
	71
571d76ac CM	72	void signal_fault(const char type, struct pt_regs regs,
	73	void __user *frame, int sig)
	74	{
	75	trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
	76	force_sigsegv(sig, current);
	77	}
	78
81711cee	79	/* The assembly shim for this function arranges to ignore the return value. */
6b14e419	80	SYSCALL_DEFINE0(rt_sigreturn)
867e359b	81	{
6b14e419	82	struct pt_regs *regs = current_pt_regs();
867e359b CM	83	struct rt_sigframe __user *frame =
	84	(struct rt_sigframe __user *)(regs->sp);
	85	sigset_t set;
867e359b CM	86
	87	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	88	goto badframe;
	89	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	90	goto badframe;
	91
ad092338	92	set_current_blocked(&set);
867e359b	93
81711cee	94	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
867e359b CM	95	goto badframe;
867e359b CM	96
47669ab0	97	if (restore_altstack(&frame->uc.uc_stack))
867e359b CM	98	goto badframe;
867e359b CM	99
81711cee	100	return 0;
867e359b CM	101
867e359b CM	102	badframe:
571d76ac	103	signal_fault("bad sigreturn frame", regs, frame, 0);
867e359b CM	104	return 0;
	105	}
	106
	107	/*
	108	* Set up a signal frame.
	109	*/
	110
	111	int setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	112	{
	113	int i, err = 0;
	114
	115	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
74fca9da	116	err \|= __put_user(regs->regs[i], &sc->gregs[i]);
867e359b CM	117
	118	return err;
	119	}
	120
	121	/*
	122	* Determine which stack to use..
	123	*/
	124	static inline void __user get_sigframe(struct k_sigaction ka,
	125	struct pt_regs *regs,
	126	size_t frame_size)
	127	{
	128	unsigned long sp;
	129
	130	/* Default to using normal stack */
	131	sp = regs->sp;
	132
	133	/*
	134	* If we are on the alternate signal stack and would overflow
	135	* it, don't. Return an always-bogus address instead so we
	136	* will die with SIGSEGV.
	137	*/
	138	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
0707ad30	139	return (void __user __force *)-1UL;
867e359b CM	140
	141	/* This is the X/Open sanctioned signal stack switching. */
	142	if (ka->sa.sa_flags & SA_ONSTACK) {
	143	if (sas_ss_flags(sp) == 0)
	144	sp = current->sas_ss_sp + current->sas_ss_size;
	145	}
	146
	147	sp -= frame_size;
	148	/*
	149	* Align the stack pointer according to the TILE ABI,
	150	* i.e. so that on function entry (sp & 15) == 0.
	151	*/
	152	sp &= -16UL;
	153	return (void __user *) sp;
	154	}
	155
b3707c7e RW	156	static int setup_rt_frame(struct ksignal ksig, sigset_t set,
b3707c7e RW	157	struct pt_regs *regs)
867e359b CM	158	{
	159	unsigned long restorer;
	160	struct rt_sigframe __user *frame;
b3707c7e	161	int err = 0, sig = ksig->sig;
867e359b CM	162	int usig;
867e359b CM	163
b3707c7e	164	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
867e359b CM	165
867e359b CM	166	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
b3707c7e	167	goto err;
867e359b CM	168
	169	usig = current_thread_info()->exec_domain
	170	&& current_thread_info()->exec_domain->signal_invmap
	171	&& sig < 32
	172	? current_thread_info()->exec_domain->signal_invmap[sig]
	173	: sig;
	174
	175	/* Always write at least the signal number for the stack backtracer. */
b3707c7e	176	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
867e359b	177	/* At sigreturn time, restore the callee-save registers too. */
b3707c7e	178	err \|= copy_siginfo_to_user(&frame->info, &ksig->info);
867e359b CM	179	regs->flags \|= PT_FLAGS_RESTORE_REGS;
867e359b CM	180	} else {
b3707c7e	181	err \|= __put_user(ksig->info.si_signo, &frame->info.si_signo);
867e359b CM	182	}
	183
	184	/* Create the ucontext. */
	185	err \|= __clear_user(&frame->save_area, sizeof(frame->save_area));
	186	err \|= __put_user(0, &frame->uc.uc_flags);
0707ad30	187	err \|= __put_user(NULL, &frame->uc.uc_link);
47669ab0	188	err \|= __save_altstack(&frame->uc.uc_stack, regs->sp);
867e359b CM	189	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
	190	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	191	if (err)
b3707c7e	192	goto err;
867e359b	193
4a556f4f	194	restorer = VDSO_SYM(&__vdso_rt_sigreturn);
b3707c7e RW	195	if (ksig->ka.sa.sa_flags & SA_RESTORER)
b3707c7e RW	196	restorer = (unsigned long) ksig->ka.sa.sa_restorer;
867e359b CM	197
	198	/*
	199	* Set up registers for signal handler.
	200	* Registers that we don't modify keep the value they had from
	201	* user-space at the time we took the signal.
74fca9da CM	202	* We always pass siginfo and mcontext, regardless of SA_SIGINFO,
74fca9da CM	203	* since some things rely on this (e.g. glibc's debug/segfault.c).
867e359b	204	*/
b3707c7e	205	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
867e359b CM	206	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
	207	regs->sp = (unsigned long) frame;
	208	regs->lr = restorer;
	209	regs->regs[0] = (unsigned long) usig;
74fca9da CM	210	regs->regs[1] = (unsigned long) &frame->info;
	211	regs->regs[2] = (unsigned long) &frame->uc;
	212	regs->flags \|= PT_FLAGS_CALLER_SAVES;
867e359b CM	213	return 0;
867e359b CM	214
b3707c7e RW	215	err:
	216	trace_unhandled_signal("bad sigreturn frame", regs,
	217	(unsigned long)frame, SIGSEGV);
867e359b CM	218	return -EFAULT;
	219	}
	220
	221	/*
	222	* OK, we're invoking a handler
	223	*/
	224
b3707c7e	225	static void handle_signal(struct ksignal ksig, struct pt_regs regs)
867e359b	226	{
b7f9a11a	227	sigset_t *oldset = sigmask_to_save();
867e359b CM	228	int ret;
867e359b CM	229
867e359b CM	230	/* Are we from a system call? */
	231	if (regs->faultnum == INT_SWINT_1) {
	232	/* If so, check system call restarting.. */
	233	switch (regs->regs[0]) {
	234	case -ERESTART_RESTARTBLOCK:
	235	case -ERESTARTNOHAND:
	236	regs->regs[0] = -EINTR;
	237	break;
	238
	239	case -ERESTARTSYS:
b3707c7e	240	if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
867e359b CM	241	regs->regs[0] = -EINTR;
	242	break;
	243	}
	244	/* fallthrough */
	245	case -ERESTARTNOINTR:
	246	/* Reload caller-saves to restore r0..r5 and r10. */
	247	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	248	regs->regs[0] = regs->orig_r0;
	249	regs->pc -= 8;
	250	}
	251	}
	252
	253	/* Set up the stack frame */
	254	#ifdef CONFIG_COMPAT
	255	if (is_compat_task())
b3707c7e	256	ret = compat_setup_rt_frame(ksig, oldset, regs);
867e359b CM	257	else
867e359b CM	258	#endif
b3707c7e RW	259	ret = setup_rt_frame(ksig, oldset, regs);
	260
	261	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
867e359b CM	262	}
	263
	264	/*
	265	* Note that 'init' is a special process: it doesn't get signals it doesn't
	266	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	267	* mistake.
	268	*/
	269	void do_signal(struct pt_regs *regs)
	270	{
b3707c7e	271	struct ksignal ksig;
867e359b CM	272
	273	/*
	274	* i386 will check if we're coming from kernel mode and bail out
	275	* here. In my experience this just turns weird crashes into
	276	* weird spin-hangs. But if we find a case where this seems
	277	* helpful, we can reinstate the check on "!user_mode(regs)".
	278	*/
	279
b3707c7e	280	if (get_signal(&ksig)) {
867e359b	281	/* Whee! Actually deliver the signal. */
b3707c7e	282	handle_signal(&ksig, regs);
34a89d26	283	goto done;
867e359b CM	284	}
	285
	286	/* Did we come from a system call? */
	287	if (regs->faultnum == INT_SWINT_1) {
	288	/* Restart the system call - no handlers present */
	289	switch (regs->regs[0]) {
	290	case -ERESTARTNOHAND:
	291	case -ERESTARTSYS:
	292	case -ERESTARTNOINTR:
	293	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	294	regs->regs[0] = regs->orig_r0;
	295	regs->pc -= 8;
	296	break;
	297
	298	case -ERESTART_RESTARTBLOCK:
	299	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	300	regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
	301	regs->pc -= 8;
	302	break;
	303	}
	304	}
	305
	306	/* If there's no signal to deliver, just put the saved sigmask back. */
51a7b448	307	restore_saved_sigmask();
34a89d26 CM	308
	309	done:
	310	/* Avoid double syscall restart if there are nested signals. */
	311	regs->faultnum = INT_SWINT_1_SIGRETURN;
867e359b	312	}
571d76ac CM	313
	314	int show_unhandled_signals = 1;
	315
	316	static int __init crashinfo(char *str)
	317	{
571d76ac CM	318	const char *word;
	319
	320	if (*str == '\0')
b2dfa048 DW	321	show_unhandled_signals = 2;
b2dfa048 DW	322	else if (*str != '=' \|\| kstrtoint(++str, 0, &show_unhandled_signals) != 0)
571d76ac	323	return 0;
b2dfa048	324
571d76ac CM	325	switch (show_unhandled_signals) {
	326	case 0:
	327	word = "No";
	328	break;
	329	case 1:
	330	word = "One-line";
	331	break;
	332	default:
	333	word = "Detailed";
	334	break;
	335	}
	336	pr_info("%s crash reports will be generated on the console\n", word);
	337	return 1;
	338	}
	339	__setup("crashinfo", crashinfo);
	340
	341	static void dump_mem(void __user *address)
	342	{
	343	void __user *addr;
	344	enum { region_size = 256, bytes_per_line = 16 };
	345	int i, j, k;
	346	int found_readable_mem = 0;
	347
	348	pr_err("\n");
	349	if (!access_ok(VERIFY_READ, address, 1)) {
	350	pr_err("Not dumping at address 0x%lx (kernel address)\n",
	351	(unsigned long)address);
	352	return;
	353	}
	354
	355	addr = (void __user *)
	356	(((unsigned long)address & -bytes_per_line) - region_size/2);
	357	if (addr > address)
	358	addr = NULL;
	359	for (i = 0; i < region_size;
	360	addr += bytes_per_line, i += bytes_per_line) {
	361	unsigned char buf[bytes_per_line];
	362	char line[100];
	363	if (copy_from_user(buf, addr, bytes_per_line))
	364	continue;
	365	if (!found_readable_mem) {
	366	pr_err("Dumping memory around address 0x%lx:\n",
	367	(unsigned long)address);
	368	found_readable_mem = 1;
	369	}
	370	j = sprintf(line, REGFMT":", (unsigned long)addr);
	371	for (k = 0; k < bytes_per_line; ++k)
	372	j += sprintf(&line[j], " %02x", buf[k]);
	373	pr_err("%s\n", line);
	374	}
	375	if (!found_readable_mem)
	376	pr_err("No readable memory around address 0x%lx\n",
	377	(unsigned long)address);
	378	}
	379
	380	void trace_unhandled_signal(const char type, struct pt_regs regs,
	381	unsigned long address, int sig)
	382	{
	383	struct task_struct *tsk = current;
	384
	385	if (show_unhandled_signals == 0)
	386	return;
	387
	388	/* If the signal is handled, don't show it here. */
389	if (!is_global_init(tsk)) {
390	void __user *handler =
391	tsk->sighand->action[sig-1].sa.sa_handler;
392	if (handler != SIG_IGN && handler != SIG_DFL)
393	return;
394	}
395
396	/* Rate-limit the one-line output, not the detailed output. */
397	if (show_unhandled_signals <= 1 && !printk_ratelimit())
398	return;
399
400	printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
401	task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
402	tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
403
404	print_vma_addr(KERN_CONT " in ", regs->pc);
405
406	printk(KERN_CONT "\n");
407
408	if (show_unhandled_signals > 1) {
409	switch (sig) {
410	case SIGILL:
411	case SIGFPE:
412	case SIGSEGV:
413	case SIGBUS:
414	pr_err("User crash: signal %d,"
415	" trap %ld, address 0x%lx\n",
416	sig, regs->faultnum, address);
417	show_regs(regs);
418	dump_mem((void __user *)address);
419	break;
420	default:
421	pr_err("User crash: signal %d, trap %ld\n",
422	sig, regs->faultnum);
423	break;
424	}
425	}
426	}