[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

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

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;

	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))
		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;

	/*
	 * Notify any tracer that was single-stepping it.
	 * The tracer may want to single-step inside the
	 * handler too.
	 */
	if (test_thread_flag(TIF_SINGLESTEP))
		ptrace_notify(SIGTRAP);

	return 0;

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

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

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

	/* Are we from a system call? */
	if (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 == 0) {
		/* This code is only called from system calls or from
		 * the work_pending path in the return-to-user code, and
		 * either way we can re-enable interrupts unconditionally.
		 */
		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.
 */
void do_signal(struct pt_regs *regs)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	sigset_t *oldset;

	/*
	 * 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 (current_thread_info()->status & TS_RESTORE_SIGMASK)
		oldset = &current->saved_sigmask;
	else
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		/* Whee! Actually deliver the signal.  */
		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
			/*
			 * A signal was successfully delivered; the saved
			 * sigmask will have been stored in the signal frame,
			 * and will be restored by sigreturn, so we can simply
			 * clear the TS_RESTORE_SIGMASK flag.
			 */
			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
		}

		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. */
	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}

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
	40	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	41
d929b6ae CM	42	SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss,
d929b6ae CM	43	stack_t __user , uoss, struct pt_regs , regs)
867e359b CM	44	{
	45	return do_sigaltstack(uss, uoss, regs->sp);
	46	}
	47
	48
	49	/*
	50	* Do a signal return; undo the signal stack.
	51	*/
	52
	53	int restore_sigcontext(struct pt_regs *regs,
81711cee	54	struct sigcontext __user *sc)
867e359b CM	55	{
	56	int err = 0;
	57	int i;
	58
	59	/* Always make any pending restarted system calls return -EINTR */
	60	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	61
74fca9da CM	62	/*
	63	* Enforce that sigcontext is like pt_regs, and doesn't mess
	64	* up our stack alignment rules.
	65	*/
	66	BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
	67	BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
	68
867e359b	69	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
74fca9da	70	err \|= __get_user(regs->regs[i], &sc->gregs[i]);
867e359b	71
1deb9c5d CM	72	/* Ensure that the PL is always set to USER_PL. */
	73	regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
	74
867e359b CM	75	regs->faultnum = INT_SWINT_1_SIGRETURN;
867e359b CM	76
867e359b CM	77	return err;
	78	}
	79
571d76ac CM	80	void signal_fault(const char type, struct pt_regs regs,
	81	void __user *frame, int sig)
	82	{
	83	trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
	84	force_sigsegv(sig, current);
	85	}
	86
81711cee	87	/* The assembly shim for this function arranges to ignore the return value. */
d929b6ae	88	SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs)
867e359b CM	89	{
	90	struct rt_sigframe __user *frame =
	91	(struct rt_sigframe __user *)(regs->sp);
	92	sigset_t set;
867e359b CM	93
	94	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	95	goto badframe;
	96	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	97	goto badframe;
	98
	99	sigdelsetmask(&set, ~_BLOCKABLE);
	100	spin_lock_irq(&current->sighand->siglock);
	101	current->blocked = set;
	102	recalc_sigpending();
	103	spin_unlock_irq(&current->sighand->siglock);
	104
81711cee	105	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
867e359b CM	106	goto badframe;
	107
	108	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
	109	goto badframe;
	110
81711cee	111	return 0;
867e359b CM	112
867e359b CM	113	badframe:
571d76ac	114	signal_fault("bad sigreturn frame", regs, frame, 0);
867e359b CM	115	return 0;
	116	}
	117
	118	/*
	119	* Set up a signal frame.
	120	*/
	121
	122	int setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	123	{
	124	int i, err = 0;
	125
	126	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
74fca9da	127	err \|= __put_user(regs->regs[i], &sc->gregs[i]);
867e359b CM	128
	129	return err;
	130	}
	131
	132	/*
	133	* Determine which stack to use..
	134	*/
	135	static inline void __user get_sigframe(struct k_sigaction ka,
	136	struct pt_regs *regs,
	137	size_t frame_size)
	138	{
	139	unsigned long sp;
	140
	141	/* Default to using normal stack */
	142	sp = regs->sp;
	143
	144	/*
	145	* If we are on the alternate signal stack and would overflow
	146	* it, don't. Return an always-bogus address instead so we
	147	* will die with SIGSEGV.
	148	*/
	149	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
0707ad30	150	return (void __user __force *)-1UL;
867e359b CM	151
	152	/* This is the X/Open sanctioned signal stack switching. */
	153	if (ka->sa.sa_flags & SA_ONSTACK) {
	154	if (sas_ss_flags(sp) == 0)
	155	sp = current->sas_ss_sp + current->sas_ss_size;
	156	}
	157
	158	sp -= frame_size;
	159	/*
	160	* Align the stack pointer according to the TILE ABI,
	161	* i.e. so that on function entry (sp & 15) == 0.
	162	*/
	163	sp &= -16UL;
	164	return (void __user *) sp;
	165	}
	166
	167	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	168	sigset_t set, struct pt_regs regs)
	169	{
	170	unsigned long restorer;
	171	struct rt_sigframe __user *frame;
	172	int err = 0;
	173	int usig;
	174
	175	frame = get_sigframe(ka, regs, sizeof(*frame));
	176
	177	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	178	goto give_sigsegv;
	179
	180	usig = current_thread_info()->exec_domain
	181	&& current_thread_info()->exec_domain->signal_invmap
	182	&& sig < 32
	183	? current_thread_info()->exec_domain->signal_invmap[sig]
	184	: sig;
	185
	186	/* Always write at least the signal number for the stack backtracer. */
	187	if (ka->sa.sa_flags & SA_SIGINFO) {
	188	/* At sigreturn time, restore the callee-save registers too. */
	189	err \|= copy_siginfo_to_user(&frame->info, info);
	190	regs->flags \|= PT_FLAGS_RESTORE_REGS;
	191	} else {
	192	err \|= __put_user(info->si_signo, &frame->info.si_signo);
	193	}
	194
	195	/* Create the ucontext. */
	196	err \|= __clear_user(&frame->save_area, sizeof(frame->save_area));
	197	err \|= __put_user(0, &frame->uc.uc_flags);
0707ad30 CM	198	err \|= __put_user(NULL, &frame->uc.uc_link);
0707ad30 CM	199	err \|= __put_user((void __user *)(current->sas_ss_sp),
867e359b CM	200	&frame->uc.uc_stack.ss_sp);
	201	err \|= __put_user(sas_ss_flags(regs->sp),
	202	&frame->uc.uc_stack.ss_flags);
	203	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	204	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
	205	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	206	if (err)
	207	goto give_sigsegv;
	208
	209	restorer = VDSO_BASE;
	210	if (ka->sa.sa_flags & SA_RESTORER)
	211	restorer = (unsigned long) ka->sa.sa_restorer;
	212
	213	/*
	214	* Set up registers for signal handler.
	215	* Registers that we don't modify keep the value they had from
	216	* user-space at the time we took the signal.
74fca9da CM	217	* We always pass siginfo and mcontext, regardless of SA_SIGINFO,
74fca9da CM	218	* since some things rely on this (e.g. glibc's debug/segfault.c).
867e359b CM	219	*/
	220	regs->pc = (unsigned long) ka->sa.sa_handler;
	221	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
	222	regs->sp = (unsigned long) frame;
	223	regs->lr = restorer;
	224	regs->regs[0] = (unsigned long) usig;
74fca9da CM	225	regs->regs[1] = (unsigned long) &frame->info;
	226	regs->regs[2] = (unsigned long) &frame->uc;
	227	regs->flags \|= PT_FLAGS_CALLER_SAVES;
867e359b CM	228
	229	/*
	230	* Notify any tracer that was single-stepping it.
	231	* The tracer may want to single-step inside the
	232	* handler too.
	233	*/
	234	if (test_thread_flag(TIF_SINGLESTEP))
	235	ptrace_notify(SIGTRAP);
	236
	237	return 0;
	238
	239	give_sigsegv:
571d76ac	240	signal_fault("bad setup frame", regs, frame, sig);
867e359b CM	241	return -EFAULT;
	242	}
	243
	244	/*
	245	* OK, we're invoking a handler
	246	*/
	247
	248	static int handle_signal(unsigned long sig, siginfo_t *info,
	249	struct k_sigaction ka, sigset_t oldset,
	250	struct pt_regs *regs)
	251	{
	252	int ret;
	253
867e359b CM	254	/* Are we from a system call? */
	255	if (regs->faultnum == INT_SWINT_1) {
	256	/* If so, check system call restarting.. */
	257	switch (regs->regs[0]) {
	258	case -ERESTART_RESTARTBLOCK:
	259	case -ERESTARTNOHAND:
	260	regs->regs[0] = -EINTR;
	261	break;
	262
	263	case -ERESTARTSYS:
	264	if (!(ka->sa.sa_flags & SA_RESTART)) {
	265	regs->regs[0] = -EINTR;
	266	break;
	267	}
	268	/* fallthrough */
	269	case -ERESTARTNOINTR:
	270	/* Reload caller-saves to restore r0..r5 and r10. */
	271	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	272	regs->regs[0] = regs->orig_r0;
	273	regs->pc -= 8;
	274	}
	275	}
	276
	277	/* Set up the stack frame */
	278	#ifdef CONFIG_COMPAT
	279	if (is_compat_task())
	280	ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
	281	else
	282	#endif
	283	ret = setup_rt_frame(sig, ka, info, oldset, regs);
	284	if (ret == 0) {
	285	/* This code is only called from system calls or from
	286	* the work_pending path in the return-to-user code, and
	287	* either way we can re-enable interrupts unconditionally.
	288	*/
	289	spin_lock_irq(&current->sighand->siglock);
	290	sigorsets(&current->blocked,
	291	&current->blocked, &ka->sa.sa_mask);
	292	if (!(ka->sa.sa_flags & SA_NODEFER))
	293	sigaddset(&current->blocked, sig);
	294	recalc_sigpending();
	295	spin_unlock_irq(&current->sighand->siglock);
	296	}
	297
	298	return ret;
	299	}
	300
	301	/*
	302	* Note that 'init' is a special process: it doesn't get signals it doesn't
	303	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	304	* mistake.
	305	*/
	306	void do_signal(struct pt_regs *regs)
	307	{
	308	siginfo_t info;
	309	int signr;
	310	struct k_sigaction ka;
	311	sigset_t *oldset;
	312
	313	/*
	314	* i386 will check if we're coming from kernel mode and bail out
	315	* here. In my experience this just turns weird crashes into
	316	* weird spin-hangs. But if we find a case where this seems
	317	* helpful, we can reinstate the check on "!user_mode(regs)".
318	*/
319
320	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
321	oldset = &current->saved_sigmask;
322	else
323	oldset = &current->blocked;
324
325	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
326	if (signr > 0) {
327	/* Whee! Actually deliver the signal. */
328	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
329	/*
330	* A signal was successfully delivered; the saved
331	* sigmask will have been stored in the signal frame,
332	* and will be restored by sigreturn, so we can simply
333	* clear the TS_RESTORE_SIGMASK flag.
334	*/
335	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
336	}
337
34a89d26	338	goto done;
867e359b CM	339	}
	340
	341	/* Did we come from a system call? */
	342	if (regs->faultnum == INT_SWINT_1) {
	343	/* Restart the system call - no handlers present */
	344	switch (regs->regs[0]) {
	345	case -ERESTARTNOHAND:
	346	case -ERESTARTSYS:
	347	case -ERESTARTNOINTR:
	348	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	349	regs->regs[0] = regs->orig_r0;
	350	regs->pc -= 8;
	351	break;
	352
	353	case -ERESTART_RESTARTBLOCK:
	354	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	355	regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
	356	regs->pc -= 8;
	357	break;
	358	}
	359	}
	360
	361	/* If there's no signal to deliver, just put the saved sigmask back. */
	362	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
	363	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
	364	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	365	}
34a89d26 CM	366
	367	done:
	368	/* Avoid double syscall restart if there are nested signals. */
	369	regs->faultnum = INT_SWINT_1_SIGRETURN;
867e359b	370	}
571d76ac CM	371
	372	int show_unhandled_signals = 1;
	373
	374	static int __init crashinfo(char *str)
	375	{
	376	unsigned long val;
	377	const char *word;
	378
	379	if (*str == '\0')
	380	val = 2;
	381	else if (*str != '=' \|\| strict_strtoul(++str, 0, &val) != 0)
	382	return 0;
	383	show_unhandled_signals = val;
	384	switch (show_unhandled_signals) {
	385	case 0:
	386	word = "No";
	387	break;
	388	case 1:
	389	word = "One-line";
	390	break;
	391	default:
	392	word = "Detailed";
	393	break;
	394	}
	395	pr_info("%s crash reports will be generated on the console\n", word);
	396	return 1;
	397	}
	398	__setup("crashinfo", crashinfo);
	399
	400	static void dump_mem(void __user *address)
	401	{
	402	void __user *addr;
	403	enum { region_size = 256, bytes_per_line = 16 };
	404	int i, j, k;
	405	int found_readable_mem = 0;
	406
	407	pr_err("\n");
	408	if (!access_ok(VERIFY_READ, address, 1)) {
	409	pr_err("Not dumping at address 0x%lx (kernel address)\n",
	410	(unsigned long)address);
	411	return;
	412	}
	413
	414	addr = (void __user *)
	415	(((unsigned long)address & -bytes_per_line) - region_size/2);
	416	if (addr > address)
	417	addr = NULL;
	418	for (i = 0; i < region_size;
	419	addr += bytes_per_line, i += bytes_per_line) {
	420	unsigned char buf[bytes_per_line];
	421	char line[100];
	422	if (copy_from_user(buf, addr, bytes_per_line))
	423	continue;
	424	if (!found_readable_mem) {
	425	pr_err("Dumping memory around address 0x%lx:\n",
	426	(unsigned long)address);
	427	found_readable_mem = 1;
	428	}
	429	j = sprintf(line, REGFMT":", (unsigned long)addr);
	430	for (k = 0; k < bytes_per_line; ++k)
	431	j += sprintf(&line[j], " %02x", buf[k]);
	432	pr_err("%s\n", line);
	433	}
	434	if (!found_readable_mem)
435	pr_err("No readable memory around address 0x%lx\n",
436	(unsigned long)address);
437	}
438
439	void trace_unhandled_signal(const char type, struct pt_regs regs,
440	unsigned long address, int sig)
441	{
442	struct task_struct *tsk = current;
443
444	if (show_unhandled_signals == 0)
445	return;
446
447	/* If the signal is handled, don't show it here. */
448	if (!is_global_init(tsk)) {
449	void __user *handler =
450	tsk->sighand->action[sig-1].sa.sa_handler;
451	if (handler != SIG_IGN && handler != SIG_DFL)
452	return;
453	}
454
455	/* Rate-limit the one-line output, not the detailed output. */
456	if (show_unhandled_signals <= 1 && !printk_ratelimit())
457	return;
458
459	printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
460	task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
461	tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
462
463	print_vma_addr(KERN_CONT " in ", regs->pc);
464
465	printk(KERN_CONT "\n");
466
467	if (show_unhandled_signals > 1) {
468	switch (sig) {
469	case SIGILL:
470	case SIGFPE:
471	case SIGSEGV:
472	case SIGBUS:
473	pr_err("User crash: signal %d,"
474	" trap %ld, address 0x%lx\n",
475	sig, regs->faultnum, address);
476	show_regs(regs);
477	dump_mem((void __user *)address);
478	break;
479	default:
480	pr_err("User crash: signal %d, trap %ld\n",
481	sig, regs->faultnum);
482	break;
483	}
484	}
485	}