[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/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>
733e5e4b	18	#include <linux/tracehook.h>
5f97f7f9 HS	19
	20	#include <asm/uaccess.h>
	21	#include <asm/ucontext.h>
c80ce2d5	22	#include <asm/syscalls.h>
5f97f7f9	23
5f97f7f9 HS	24	asmlinkage int sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	25	struct pt_regs *regs)
	26	{
	27	return do_sigaltstack(uss, uoss, regs->sp);
	28	}
	29
	30	struct rt_sigframe
	31	{
	32	struct siginfo info;
	33	struct ucontext uc;
	34	unsigned long retcode;
	35	};
	36
	37	static int
	38	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc)
	39	{
	40	int err = 0;
	41
	42	#define COPY(x) err \|= __get_user(regs->x, &sc->x)
	43	COPY(sr);
	44	COPY(pc);
	45	COPY(lr);
	46	COPY(sp);
	47	COPY(r12);
	48	COPY(r11);
	49	COPY(r10);
	50	COPY(r9);
	51	COPY(r8);
	52	COPY(r7);
	53	COPY(r6);
	54	COPY(r5);
	55	COPY(r4);
	56	COPY(r3);
	57	COPY(r2);
	58	COPY(r1);
	59	COPY(r0);
	60	#undef COPY
	61
	62	/*
	63	* Don't allow anyone to pretend they're running in supervisor
	64	* mode or something...
	65	*/
	66	err \|= !valid_user_regs(regs);
	67
	68	return err;
	69	}
	70
	71
	72	asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
	73	{
	74	struct rt_sigframe __user *frame;
	75	sigset_t set;
	76
446cdd13 AV	77	/* Always make any pending restarted system calls return -EINTR */
	78	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	79
5f97f7f9 HS	80	frame = (struct rt_sigframe __user *)regs->sp;
	81	pr_debug("SIG return: frame = %p\n", frame);
	82
	83	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	84	goto badframe;
	85
	86	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	87	goto badframe;
	88
49209590	89	set_current_blocked(&set);
5f97f7f9 HS	90
	91	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	92	goto badframe;
	93
7c1b90a1 MK	94	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
	95	goto badframe;
	96
5f97f7f9 HS	97	pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
	98	regs->pc, regs->lr, regs->sp);
	99
	100	return regs->r12;
	101
	102	badframe:
	103	force_sig(SIGSEGV, current);
	104	return 0;
	105	}
	106
	107	static int
	108	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	109	{
	110	int err = 0;
	111
	112	#define COPY(x) err \|= __put_user(regs->x, &sc->x)
	113	COPY(sr);
	114	COPY(pc);
	115	COPY(lr);
	116	COPY(sp);
	117	COPY(r12);
	118	COPY(r11);
	119	COPY(r10);
	120	COPY(r9);
	121	COPY(r8);
	122	COPY(r7);
	123	COPY(r6);
	124	COPY(r5);
	125	COPY(r4);
	126	COPY(r3);
	127	COPY(r2);
	128	COPY(r1);
	129	COPY(r0);
	130	#undef COPY
	131
	132	return err;
	133	}
	134
	135	static inline void __user *
	136	get_sigframe(struct k_sigaction ka, struct pt_regs regs, int framesize)
	137	{
	138	unsigned long sp = regs->sp;
	139
	140	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
	141	sp = current->sas_ss_sp + current->sas_ss_size;
	142
	143	return (void __user *)((sp - framesize) & ~3);
	144	}
	145
	146	static int
	147	setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	148	sigset_t set, struct pt_regs regs)
	149	{
	150	struct rt_sigframe __user *frame;
	151	int err = 0;
	152
	153	frame = get_sigframe(ka, regs, sizeof(*frame));
	154	err = -EFAULT;
	155	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
	156	goto out;
	157
	158	/*
	159	* Set up the return code:
	160	*
161	* mov r8, __NR_rt_sigreturn
162	* scall
163	*
164	* Note: This will blow up since we're using a non-executable
165	* stack. Better use SA_RESTORER.
166	*/
167	#if __NR_rt_sigreturn > 127
168	# error __NR_rt_sigreturn must be < 127 to fit in a short mov
169	#endif
170	err = __put_user(0x3008d733 \| (__NR_rt_sigreturn << 20),
171	&frame->retcode);
172
173	err \|= copy_siginfo_to_user(&frame->info, info);
174
175	/* Set up the ucontext */
176	err \|= __put_user(0, &frame->uc.uc_flags);
177	err \|= __put_user(NULL, &frame->uc.uc_link);
178	err \|= __put_user((void __user *)current->sas_ss_sp,
179	&frame->uc.uc_stack.ss_sp);
180	err \|= __put_user(sas_ss_flags(regs->sp),
181	&frame->uc.uc_stack.ss_flags);
182	err \|= __put_user(current->sas_ss_size,
183	&frame->uc.uc_stack.ss_size);
184	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
185	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
186
187	if (err)
188	goto out;
189
190	regs->r12 = sig;
191	regs->r11 = (unsigned long) &frame->info;
192	regs->r10 = (unsigned long) &frame->uc;
193	regs->sp = (unsigned long) frame;
194	if (ka->sa.sa_flags & SA_RESTORER)
195	regs->lr = (unsigned long)ka->sa.sa_restorer;
196	else {
197	printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
198	current->comm, current->pid);
199	regs->lr = (unsigned long) &frame->retcode;
200	}
201
202	pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
203	current->comm, current->pid, sig, regs->sp,
204	regs->pc, ka->sa.sa_handler, regs->lr);
205
206	regs->pc = (unsigned long) ka->sa.sa_handler;
207
208	out:
209	return err;
210	}
211
288ddad5	212	static inline void setup_syscall_restart(struct pt_regs *regs)
5f97f7f9 HS	213	{
	214	if (regs->r12 == -ERESTART_RESTARTBLOCK)
	215	regs->r8 = __NR_restart_syscall;
	216	else
	217	regs->r12 = regs->r12_orig;
	218	regs->pc -= 2;
	219	}
	220
	221	static inline void
	222	handle_signal(unsigned long sig, struct k_sigaction ka, siginfo_t info,
b7f9a11a	223	struct pt_regs *regs, int syscall)
5f97f7f9 HS	224	{
	225	int ret;
	226
	227	/*
	228	* Set up the stack frame
	229	*/
b7f9a11a	230	ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
5f97f7f9 HS	231
	232	/*
	233	* Check that the resulting registers are sane
	234	*/
	235	ret \|= !valid_user_regs(regs);
	236
	237	/*
e1b1fd79	238	* Block the signal if we were successful.
5f97f7f9	239	*/
a610d6e6 AV	240	if (ret != 0)
	241	force_sigsegv(sig, current);
	242	else
efee984c	243	signal_delivered(sig, info, ka, regs, 0);
5f97f7f9 HS	244	}
	245
	246	/*
	247	* Note that 'init' is a special process: it doesn't get signals it
	248	* doesn't want to handle. Thus you cannot kill init even with a
	249	* SIGKILL even by mistake.
	250	*/
b7f9a11a	251	static void do_signal(struct pt_regs *regs, int syscall)
5f97f7f9 HS	252	{
	253	siginfo_t info;
	254	int signr;
	255	struct k_sigaction ka;
	256
	257	/*
	258	* We want the common case to go fast, which is why we may in
	259	* certain cases get here from kernel mode. Just return
	260	* without doing anything if so.
	261	*/
	262	if (!user_mode(regs))
b7f9a11a	263	return;
5f97f7f9 HS	264
5f97f7f9 HS	265	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
5f97f7f9 HS	266	if (syscall) {
	267	switch (regs->r12) {
	268	case -ERESTART_RESTARTBLOCK:
	269	case -ERESTARTNOHAND:
	270	if (signr > 0) {
	271	regs->r12 = -EINTR;
	272	break;
	273	}
	274	/* fall through */
	275	case -ERESTARTSYS:
	276	if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) {
	277	regs->r12 = -EINTR;
	278	break;
	279	}
	280	/* fall through */
	281	case -ERESTARTNOINTR:
288ddad5	282	setup_syscall_restart(regs);
5f97f7f9 HS	283	}
	284	}
	285
	286	if (signr == 0) {
	287	/* No signal to deliver -- put the saved sigmask back */
51a7b448	288	restore_saved_sigmask();
b7f9a11a	289	return;
5f97f7f9 HS	290	}
5f97f7f9 HS	291
b7f9a11a	292	handle_signal(signr, &ka, &info, regs, syscall);
5f97f7f9 HS	293	}
	294
	295	asmlinkage void do_notify_resume(struct pt_regs regs, struct thread_info ti)
	296	{
	297	int syscall = 0;
	298
	299	if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
	300	syscall = 1;
	301
03240b27	302	if (ti->flags & _TIF_SIGPENDING)
b7f9a11a	303	do_signal(regs, syscall);
d0420c83 DH	304
	305	if (ti->flags & _TIF_NOTIFY_RESUME) {
	306	clear_thread_flag(TIF_NOTIFY_RESUME);
	307	tracehook_notify_resume(regs);
	308	}
5f97f7f9	309	}