[mirror_ubuntu-bionic-kernel.git] / arch / avr32 / kernel / signal.c

/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * Based on linux/arch/sh/kernel/signal.c
 *  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/tracehook.h>

#include <linux/uaccess.h>
#include <asm/ucontext.h>
#include <asm/syscalls.h>

struct rt_sigframe
{
	struct siginfo info;
	struct ucontext uc;
	unsigned long retcode;
};

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

#define COPY(x)		err |= __get_user(regs->x, &sc->x)
	COPY(sr);
	COPY(pc);
	COPY(lr);
	COPY(sp);
	COPY(r12);
	COPY(r11);
	COPY(r10);
	COPY(r9);
	COPY(r8);
	COPY(r7);
	COPY(r6);
	COPY(r5);
	COPY(r4);
	COPY(r3);
	COPY(r2);
	COPY(r1);
	COPY(r0);
#undef	COPY

	/*
	 * Don't allow anyone to pretend they're running in supervisor
	 * mode or something...
	 */
	err |= !valid_user_regs(regs);

	return err;
}


asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	sigset_t set;

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

	frame = (struct rt_sigframe __user *)regs->sp;
	pr_debug("SIG return: frame = %p\n", frame);

	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;

	pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
		 regs->pc, regs->lr, regs->sp);

	return regs->r12;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

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

#define COPY(x)		err |= __put_user(regs->x, &sc->x)
	COPY(sr);
	COPY(pc);
	COPY(lr);
	COPY(sp);
	COPY(r12);
	COPY(r11);
	COPY(r10);
	COPY(r9);
	COPY(r8);
	COPY(r7);
	COPY(r6);
	COPY(r5);
	COPY(r4);
	COPY(r3);
	COPY(r2);
	COPY(r1);
	COPY(r0);
#undef	COPY

	return err;
}

static inline void __user *
get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
{
	unsigned long sp = sigsp(regs->sp, ksig);

	return (void __user *)((sp - framesize) & ~3);
}

static int
setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	int err = 0;

	frame = get_sigframe(ksig, regs, sizeof(*frame));
	err = -EFAULT;
	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
		goto out;

	/*
	 * Set up the return code:
	 *
	 *	mov	r8, __NR_rt_sigreturn
	 *	scall
	 *
	 * Note: This will blow up since we're using a non-executable
	 * stack. Better use SA_RESTORER.
	 */
#if __NR_rt_sigreturn > 127
# error __NR_rt_sigreturn must be < 127 to fit in a short mov
#endif
	err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20),
			 &frame->retcode);

	err |= copy_siginfo_to_user(&frame->info, &ksig->info);

	/* Set up the ucontext */
	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 out;

	regs->r12 = ksig->sig;
	regs->r11 = (unsigned long) &frame->info;
	regs->r10 = (unsigned long) &frame->uc;
	regs->sp = (unsigned long) frame;
	if (ksig->ka.sa.sa_flags & SA_RESTORER)
		regs->lr = (unsigned long)ksig->ka.sa.sa_restorer;
	else {
		printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
		       current->comm, current->pid);
		regs->lr = (unsigned long) &frame->retcode;
	}

	pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
		 current->comm, current->pid, ksig->sig, regs->sp,
		 regs->pc, ksig->ka.sa.sa_handler, regs->lr);

	regs->pc = (unsigned long)ksig->ka.sa.sa_handler;

out:
	return err;
}

static inline void setup_syscall_restart(struct pt_regs *regs)
{
	if (regs->r12 == -ERESTART_RESTARTBLOCK)
		regs->r8 = __NR_restart_syscall;
	else
		regs->r12 = regs->r12_orig;
	regs->pc -= 2;
}

static inline void
handle_signal(struct ksignal *ksig, struct pt_regs *regs, int syscall)
{
	int ret;

	/*
	 * Set up the stack frame
	 */
	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);

	/*
	 * Check that the resulting registers are sane
	 */
	ret |= !valid_user_regs(regs);

	/*
	 * Block the signal if we were successful.
	 */
	signal_setup_done(ret, ksig, 0);
}

/*
 * 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, int syscall)
{
	struct ksignal ksig;

	/*
	 * 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;

	get_signal(&ksig);
	if (syscall) {
		switch (regs->r12) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			if (ksig.sig > 0) {
				regs->r12 = -EINTR;
				break;
			}
			/* fall through */
		case -ERESTARTSYS:
			if (ksig.sig > 0 && !(ksig.ka.sa.sa_flags & SA_RESTART)) {
				regs->r12 = -EINTR;
				break;
			}
			/* fall through */
		case -ERESTARTNOINTR:
			setup_syscall_restart(regs);
		}
	}

	if (!ksig.sig) {
		/* No signal to deliver -- put the saved sigmask back */
		restore_saved_sigmask();
		return;
	}

	handle_signal(&ksig, regs, syscall);
}

asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
{
	int syscall = 0;

	if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
		syscall = 1;

	if (ti->flags & _TIF_SIGPENDING)
		do_signal(regs, syscall);

	if (ti->flags & _TIF_NOTIFY_RESUME) {
		clear_thread_flag(TIF_NOTIFY_RESUME);
		tracehook_notify_resume(regs);
	}
}
Commit	Line	Data
5f97f7f9 HS	1	/*
	2	* Copyright (C) 2004-2006 Atmel Corporation
	3	*
	4	* Based on linux/arch/sh/kernel/signal.c
	5	* Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
	6	* Copyright (C) 1991, 1992 Linus Torvalds
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/sched.h>
	14	#include <linux/mm.h>
	15	#include <linux/errno.h>
	16	#include <linux/ptrace.h>
	17	#include <linux/unistd.h>
733e5e4b	18	#include <linux/tracehook.h>
5f97f7f9	19
7c0f6ba6	20	#include <linux/uaccess.h>
5f97f7f9	21	#include <asm/ucontext.h>
c80ce2d5	22	#include <asm/syscalls.h>
5f97f7f9	23
5f97f7f9 HS	24	struct rt_sigframe
	25	{
	26	struct siginfo info;
	27	struct ucontext uc;
	28	unsigned long retcode;
	29	};
	30
	31	static int
	32	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc)
	33	{
	34	int err = 0;
	35
	36	#define COPY(x) err \|= __get_user(regs->x, &sc->x)
	37	COPY(sr);
	38	COPY(pc);
	39	COPY(lr);
	40	COPY(sp);
	41	COPY(r12);
	42	COPY(r11);
	43	COPY(r10);
	44	COPY(r9);
	45	COPY(r8);
	46	COPY(r7);
	47	COPY(r6);
	48	COPY(r5);
	49	COPY(r4);
	50	COPY(r3);
	51	COPY(r2);
	52	COPY(r1);
	53	COPY(r0);
	54	#undef COPY
	55
	56	/*
	57	* Don't allow anyone to pretend they're running in supervisor
	58	* mode or something...
	59	*/
	60	err \|= !valid_user_regs(regs);
	61
	62	return err;
	63	}
	64
	65
	66	asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
	67	{
	68	struct rt_sigframe __user *frame;
	69	sigset_t set;
	70
446cdd13	71	/* Always make any pending restarted system calls return -EINTR */
f56141e3	72	current->restart_block.fn = do_no_restart_syscall;
446cdd13	73
5f97f7f9 HS	74	frame = (struct rt_sigframe __user *)regs->sp;
	75	pr_debug("SIG return: frame = %p\n", frame);
	76
	77	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	78	goto badframe;
	79
	80	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	81	goto badframe;
	82
49209590	83	set_current_blocked(&set);
5f97f7f9 HS	84
	85	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	86	goto badframe;
	87
47880695	88	if (restore_altstack(&frame->uc.uc_stack))
7c1b90a1 MK	89	goto badframe;
7c1b90a1 MK	90
5f97f7f9 HS	91	pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
	92	regs->pc, regs->lr, regs->sp);
	93
	94	return regs->r12;
	95
	96	badframe:
	97	force_sig(SIGSEGV, current);
	98	return 0;
	99	}
	100
	101	static int
	102	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	103	{
	104	int err = 0;
	105
	106	#define COPY(x) err \|= __put_user(regs->x, &sc->x)
	107	COPY(sr);
	108	COPY(pc);
	109	COPY(lr);
	110	COPY(sp);
	111	COPY(r12);
	112	COPY(r11);
	113	COPY(r10);
	114	COPY(r9);
	115	COPY(r8);
	116	COPY(r7);
	117	COPY(r6);
	118	COPY(r5);
	119	COPY(r4);
	120	COPY(r3);
	121	COPY(r2);
	122	COPY(r1);
	123	COPY(r0);
	124	#undef COPY
	125
	126	return err;
	127	}
	128
	129	static inline void __user *
065f31bd	130	get_sigframe(struct ksignal ksig, struct pt_regs regs, int framesize)
5f97f7f9	131	{
065f31bd	132	unsigned long sp = sigsp(regs->sp, ksig);
5f97f7f9 HS	133
	134	return (void __user *)((sp - framesize) & ~3);
	135	}
	136
	137	static int
d809709a	138	setup_rt_frame(struct ksignal ksig, sigset_t set, struct pt_regs *regs)
5f97f7f9 HS	139	{
	140	struct rt_sigframe __user *frame;
	141	int err = 0;
	142
065f31bd	143	frame = get_sigframe(ksig, regs, sizeof(*frame));
5f97f7f9 HS	144	err = -EFAULT;
	145	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
	146	goto out;
	147
	148	/*
	149	* Set up the return code:
	150	*
	151	* mov r8, __NR_rt_sigreturn
	152	* scall
	153	*
	154	* Note: This will blow up since we're using a non-executable
	155	* stack. Better use SA_RESTORER.
	156	*/
	157	#if __NR_rt_sigreturn > 127
	158	# error __NR_rt_sigreturn must be < 127 to fit in a short mov
	159	#endif
	160	err = __put_user(0x3008d733 \| (__NR_rt_sigreturn << 20),
	161	&frame->retcode);
	162
d809709a	163	err \|= copy_siginfo_to_user(&frame->info, &ksig->info);
5f97f7f9 HS	164
	165	/* Set up the ucontext */
	166	err \|= __put_user(0, &frame->uc.uc_flags);
	167	err \|= __put_user(NULL, &frame->uc.uc_link);
47880695	168	err \|= __save_altstack(&frame->uc.uc_stack, regs->sp);
5f97f7f9 HS	169	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
	170	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	171
	172	if (err)
	173	goto out;
	174
d809709a	175	regs->r12 = ksig->sig;
5f97f7f9 HS	176	regs->r11 = (unsigned long) &frame->info;
	177	regs->r10 = (unsigned long) &frame->uc;
	178	regs->sp = (unsigned long) frame;
d809709a RW	179	if (ksig->ka.sa.sa_flags & SA_RESTORER)
d809709a RW	180	regs->lr = (unsigned long)ksig->ka.sa.sa_restorer;
5f97f7f9 HS	181	else {
	182	printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
	183	current->comm, current->pid);
	184	regs->lr = (unsigned long) &frame->retcode;
	185	}
	186
	187	pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
d809709a RW	188	current->comm, current->pid, ksig->sig, regs->sp,
d809709a RW	189	regs->pc, ksig->ka.sa.sa_handler, regs->lr);
5f97f7f9	190
d809709a	191	regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
5f97f7f9 HS	192
	193	out:
	194	return err;
	195	}
	196
288ddad5	197	static inline void setup_syscall_restart(struct pt_regs *regs)
5f97f7f9 HS	198	{
	199	if (regs->r12 == -ERESTART_RESTARTBLOCK)
	200	regs->r8 = __NR_restart_syscall;
	201	else
	202	regs->r12 = regs->r12_orig;
	203	regs->pc -= 2;
	204	}
	205
	206	static inline void
d809709a	207	handle_signal(struct ksignal ksig, struct pt_regs regs, int syscall)
5f97f7f9 HS	208	{
	209	int ret;
	210
	211	/*
	212	* Set up the stack frame
	213	*/
d809709a	214	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
5f97f7f9 HS	215
	216	/*
	217	* Check that the resulting registers are sane
	218	*/
	219	ret \|= !valid_user_regs(regs);
	220
	221	/*
e1b1fd79	222	* Block the signal if we were successful.
5f97f7f9	223	*/
d809709a	224	signal_setup_done(ret, ksig, 0);
5f97f7f9 HS	225	}
	226
	227	/*
	228	* Note that 'init' is a special process: it doesn't get signals it
	229	* doesn't want to handle. Thus you cannot kill init even with a
	230	* SIGKILL even by mistake.
	231	*/
b7f9a11a	232	static void do_signal(struct pt_regs *regs, int syscall)
5f97f7f9	233	{
d809709a	234	struct ksignal ksig;
5f97f7f9 HS	235
	236	/*
	237	* We want the common case to go fast, which is why we may in
	238	* certain cases get here from kernel mode. Just return
	239	* without doing anything if so.
	240	*/
	241	if (!user_mode(regs))
b7f9a11a	242	return;
5f97f7f9	243
d809709a	244	get_signal(&ksig);
5f97f7f9 HS	245	if (syscall) {
	246	switch (regs->r12) {
	247	case -ERESTART_RESTARTBLOCK:
	248	case -ERESTARTNOHAND:
d809709a	249	if (ksig.sig > 0) {
5f97f7f9 HS	250	regs->r12 = -EINTR;
	251	break;
	252	}
	253	/* fall through */
	254	case -ERESTARTSYS:
d809709a	255	if (ksig.sig > 0 && !(ksig.ka.sa.sa_flags & SA_RESTART)) {
5f97f7f9 HS	256	regs->r12 = -EINTR;
	257	break;
	258	}
	259	/* fall through */
	260	case -ERESTARTNOINTR:
288ddad5	261	setup_syscall_restart(regs);
5f97f7f9 HS	262	}
	263	}
	264
d809709a	265	if (!ksig.sig) {
5f97f7f9	266	/* No signal to deliver -- put the saved sigmask back */
51a7b448	267	restore_saved_sigmask();
b7f9a11a	268	return;
5f97f7f9 HS	269	}
5f97f7f9 HS	270
d809709a	271	handle_signal(&ksig, regs, syscall);
5f97f7f9 HS	272	}
	273
	274	asmlinkage void do_notify_resume(struct pt_regs regs, struct thread_info ti)
	275	{
	276	int syscall = 0;
	277
	278	if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
	279	syscall = 1;
	280
03240b27	281	if (ti->flags & _TIF_SIGPENDING)
b7f9a11a	282	do_signal(regs, syscall);
d0420c83 DH	283
	284	if (ti->flags & _TIF_NOTIFY_RESUME) {
	285	clear_thread_flag(TIF_NOTIFY_RESUME);
	286	tracehook_notify_resume(regs);
	287	}
5f97f7f9	288	}