[GitHub/mt8127/android_kernel_alcatel_ttab.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/freezer.h>
#include <linux/tracehook.h>

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

asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
			       struct pt_regs *regs)
{
	return do_sigaltstack(uss, uoss, regs->sp);
}

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_thread_info()->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 (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
		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 k_sigaction *ka, struct pt_regs *regs, int framesize)
{
	unsigned long sp = regs->sp;

	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
		sp = current->sas_ss_sp + current->sas_ss_size;

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

static int
setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
	       sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	int err = 0;

	frame = get_sigframe(ka, 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, info);

	/* Set up the ucontext */
	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 out;

	regs->r12 = sig;
	regs->r11 = (unsigned long) &frame->info;
	regs->r10 = (unsigned long) &frame->uc;
	regs->sp = (unsigned long) frame;
	if (ka->sa.sa_flags & SA_RESTORER)
		regs->lr = (unsigned long)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, sig, regs->sp,
		 regs->pc, ka->sa.sa_handler, regs->lr);

	regs->pc = (unsigned long) 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(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
	      struct pt_regs *regs, int syscall)
{
	int ret;

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

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

	/*
	 * Block the signal if we were successful.
	 */
	if (ret != 0)
		force_sigsegv(sig, current);
	else
		signal_delivered(sig, info, ka, regs, 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)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;

	/*
	 * 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;

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

	if (signr == 0) {
		/* No signal to deliver -- put the saved sigmask back */
		restore_saved_sigmask();
		return;
	}

	handle_signal(signr, &ka, &info, 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>
7dfb7103	18	#include <linux/freezer.h>
733e5e4b	19	#include <linux/tracehook.h>
5f97f7f9 HS	20
	21	#include <asm/uaccess.h>
	22	#include <asm/ucontext.h>
c80ce2d5	23	#include <asm/syscalls.h>
5f97f7f9	24
5f97f7f9 HS	25	asmlinkage int sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	26	struct pt_regs *regs)
	27	{
	28	return do_sigaltstack(uss, uoss, regs->sp);
	29	}
	30
	31	struct rt_sigframe
	32	{
	33	struct siginfo info;
	34	struct ucontext uc;
	35	unsigned long retcode;
	36	};
	37
	38	static int
	39	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc)
	40	{
	41	int err = 0;
	42
	43	#define COPY(x) err \|= __get_user(regs->x, &sc->x)
	44	COPY(sr);
	45	COPY(pc);
	46	COPY(lr);
	47	COPY(sp);
	48	COPY(r12);
	49	COPY(r11);
	50	COPY(r10);
	51	COPY(r9);
	52	COPY(r8);
	53	COPY(r7);
	54	COPY(r6);
	55	COPY(r5);
	56	COPY(r4);
	57	COPY(r3);
	58	COPY(r2);
	59	COPY(r1);
	60	COPY(r0);
	61	#undef COPY
	62
	63	/*
	64	* Don't allow anyone to pretend they're running in supervisor
	65	* mode or something...
	66	*/
	67	err \|= !valid_user_regs(regs);
	68
	69	return err;
	70	}
	71
	72
	73	asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
	74	{
	75	struct rt_sigframe __user *frame;
	76	sigset_t set;
	77
446cdd13 AV	78	/* Always make any pending restarted system calls return -EINTR */
	79	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	80
5f97f7f9 HS	81	frame = (struct rt_sigframe __user *)regs->sp;
	82	pr_debug("SIG return: frame = %p\n", frame);
	83
	84	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	85	goto badframe;
	86
	87	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	88	goto badframe;
	89
49209590	90	set_current_blocked(&set);
5f97f7f9 HS	91
	92	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	93	goto badframe;
	94
7c1b90a1 MK	95	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
	96	goto badframe;
	97
5f97f7f9 HS	98	pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
	99	regs->pc, regs->lr, regs->sp);
	100
	101	return regs->r12;
	102
	103	badframe:
	104	force_sig(SIGSEGV, current);
	105	return 0;
	106	}
	107
	108	static int
	109	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	110	{
	111	int err = 0;
	112
	113	#define COPY(x) err \|= __put_user(regs->x, &sc->x)
	114	COPY(sr);
	115	COPY(pc);
	116	COPY(lr);
	117	COPY(sp);
	118	COPY(r12);
	119	COPY(r11);
	120	COPY(r10);
	121	COPY(r9);
	122	COPY(r8);
	123	COPY(r7);
	124	COPY(r6);
	125	COPY(r5);
	126	COPY(r4);
	127	COPY(r3);
	128	COPY(r2);
	129	COPY(r1);
	130	COPY(r0);
	131	#undef COPY
	132
	133	return err;
	134	}
	135
	136	static inline void __user *
	137	get_sigframe(struct k_sigaction ka, struct pt_regs regs, int framesize)
	138	{
	139	unsigned long sp = regs->sp;
	140
	141	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
	142	sp = current->sas_ss_sp + current->sas_ss_size;
	143
	144	return (void __user *)((sp - framesize) & ~3);
	145	}
	146
	147	static int
	148	setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	149	sigset_t set, struct pt_regs regs)
	150	{
	151	struct rt_sigframe __user *frame;
	152	int err = 0;
	153
	154	frame = get_sigframe(ka, regs, sizeof(*frame));
	155	err = -EFAULT;
	156	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
	157	goto out;
	158
	159	/*
	160	* Set up the return code:
	161	*
162	* mov r8, __NR_rt_sigreturn
163	* scall
164	*
165	* Note: This will blow up since we're using a non-executable
166	* stack. Better use SA_RESTORER.
167	*/
168	#if __NR_rt_sigreturn > 127
169	# error __NR_rt_sigreturn must be < 127 to fit in a short mov
170	#endif
171	err = __put_user(0x3008d733 \| (__NR_rt_sigreturn << 20),
172	&frame->retcode);
173
174	err \|= copy_siginfo_to_user(&frame->info, info);
175
176	/* Set up the ucontext */
177	err \|= __put_user(0, &frame->uc.uc_flags);
178	err \|= __put_user(NULL, &frame->uc.uc_link);
179	err \|= __put_user((void __user *)current->sas_ss_sp,
180	&frame->uc.uc_stack.ss_sp);
181	err \|= __put_user(sas_ss_flags(regs->sp),
182	&frame->uc.uc_stack.ss_flags);
183	err \|= __put_user(current->sas_ss_size,
184	&frame->uc.uc_stack.ss_size);
185	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
186	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
187
188	if (err)
189	goto out;
190
191	regs->r12 = sig;
192	regs->r11 = (unsigned long) &frame->info;
193	regs->r10 = (unsigned long) &frame->uc;
194	regs->sp = (unsigned long) frame;
195	if (ka->sa.sa_flags & SA_RESTORER)
196	regs->lr = (unsigned long)ka->sa.sa_restorer;
197	else {
198	printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
199	current->comm, current->pid);
200	regs->lr = (unsigned long) &frame->retcode;
201	}
202
203	pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
204	current->comm, current->pid, sig, regs->sp,
205	regs->pc, ka->sa.sa_handler, regs->lr);
206
207	regs->pc = (unsigned long) ka->sa.sa_handler;
208
209	out:
210	return err;
211	}
212
288ddad5	213	static inline void setup_syscall_restart(struct pt_regs *regs)
5f97f7f9 HS	214	{
	215	if (regs->r12 == -ERESTART_RESTARTBLOCK)
	216	regs->r8 = __NR_restart_syscall;
	217	else
	218	regs->r12 = regs->r12_orig;
	219	regs->pc -= 2;
	220	}
	221
	222	static inline void
	223	handle_signal(unsigned long sig, struct k_sigaction ka, siginfo_t info,
b7f9a11a	224	struct pt_regs *regs, int syscall)
5f97f7f9 HS	225	{
	226	int ret;
	227
	228	/*
	229	* Set up the stack frame
	230	*/
b7f9a11a	231	ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
5f97f7f9 HS	232
	233	/*
	234	* Check that the resulting registers are sane
	235	*/
	236	ret \|= !valid_user_regs(regs);
	237
	238	/*
e1b1fd79	239	* Block the signal if we were successful.
5f97f7f9	240	*/
a610d6e6 AV	241	if (ret != 0)
	242	force_sigsegv(sig, current);
	243	else
efee984c	244	signal_delivered(sig, info, ka, regs, 0);
5f97f7f9 HS	245	}
	246
	247	/*
	248	* Note that 'init' is a special process: it doesn't get signals it
	249	* doesn't want to handle. Thus you cannot kill init even with a
	250	* SIGKILL even by mistake.
	251	*/
b7f9a11a	252	static void do_signal(struct pt_regs *regs, int syscall)
5f97f7f9 HS	253	{
	254	siginfo_t info;
	255	int signr;
	256	struct k_sigaction ka;
	257
	258	/*
	259	* We want the common case to go fast, which is why we may in
	260	* certain cases get here from kernel mode. Just return
	261	* without doing anything if so.
	262	*/
	263	if (!user_mode(regs))
b7f9a11a	264	return;
5f97f7f9 HS	265
5f97f7f9 HS	266	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
5f97f7f9 HS	267	if (syscall) {
	268	switch (regs->r12) {
	269	case -ERESTART_RESTARTBLOCK:
	270	case -ERESTARTNOHAND:
	271	if (signr > 0) {
	272	regs->r12 = -EINTR;
	273	break;
	274	}
	275	/* fall through */
	276	case -ERESTARTSYS:
	277	if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) {
	278	regs->r12 = -EINTR;
	279	break;
	280	}
	281	/* fall through */
	282	case -ERESTARTNOINTR:
288ddad5	283	setup_syscall_restart(regs);
5f97f7f9 HS	284	}
	285	}
	286
	287	if (signr == 0) {
	288	/* No signal to deliver -- put the saved sigmask back */
51a7b448	289	restore_saved_sigmask();
b7f9a11a	290	return;
5f97f7f9 HS	291	}
5f97f7f9 HS	292
b7f9a11a	293	handle_signal(signr, &ka, &info, regs, syscall);
5f97f7f9 HS	294	}
	295
	296	asmlinkage void do_notify_resume(struct pt_regs regs, struct thread_info ti)
	297	{
	298	int syscall = 0;
	299
	300	if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
	301	syscall = 1;
	302
6fd84c08	303	if (ti->flags & _TIF_SIGPENDING))
b7f9a11a	304	do_signal(regs, syscall);
d0420c83 DH	305
	306	if (ti->flags & _TIF_NOTIFY_RESUME) {
	307	clear_thread_flag(TIF_NOTIFY_RESUME);
	308	tracehook_notify_resume(regs);
	309	}
5f97f7f9	310	}