[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>

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

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;

	sigdelsetmask(&set, ~_BLOCKABLE);
	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,
	      sigset_t *oldset, struct pt_regs *regs, int syscall)
{
	int ret;

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

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

	if (ret != 0) {
		force_sigsegv(sig, current);
		return;
	}

	/*
	 * Block the signal if we were successful.
	 */
	block_sigmask(ka, sig);
	clear_thread_flag(TIF_RESTORE_SIGMASK);
}

/*
 * 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.
 */
int do_signal(struct pt_regs *regs, sigset_t *oldset, 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 0;

	if (test_thread_flag(TIF_RESTORE_SIGMASK))
		oldset = &current->saved_sigmask;
	else if (!oldset)
		oldset = &current->blocked;

	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 0;
	}

	handle_signal(signr, &ka, &info, oldset, regs, syscall);
	return 1;
}

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 | _TIF_RESTORE_SIGMASK))
		do_signal(regs, &current->blocked, 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 HS	24
	25	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	26
	27	asmlinkage int sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	28	struct pt_regs *regs)
	29	{
	30	return do_sigaltstack(uss, uoss, regs->sp);
	31	}
	32
	33	struct rt_sigframe
	34	{
	35	struct siginfo info;
	36	struct ucontext uc;
	37	unsigned long retcode;
	38	};
	39
	40	static int
	41	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc)
	42	{
	43	int err = 0;
	44
	45	#define COPY(x) err \|= __get_user(regs->x, &sc->x)
	46	COPY(sr);
	47	COPY(pc);
	48	COPY(lr);
	49	COPY(sp);
	50	COPY(r12);
	51	COPY(r11);
	52	COPY(r10);
	53	COPY(r9);
	54	COPY(r8);
	55	COPY(r7);
	56	COPY(r6);
	57	COPY(r5);
	58	COPY(r4);
	59	COPY(r3);
	60	COPY(r2);
	61	COPY(r1);
	62	COPY(r0);
	63	#undef COPY
	64
	65	/*
	66	* Don't allow anyone to pretend they're running in supervisor
	67	* mode or something...
	68	*/
	69	err \|= !valid_user_regs(regs);
	70
	71	return err;
	72	}
	73
	74
	75	asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
	76	{
	77	struct rt_sigframe __user *frame;
	78	sigset_t set;
	79
446cdd13 AV	80	/* Always make any pending restarted system calls return -EINTR */
	81	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	82
5f97f7f9 HS	83	frame = (struct rt_sigframe __user *)regs->sp;
	84	pr_debug("SIG return: frame = %p\n", frame);
	85
	86	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	87	goto badframe;
	88
	89	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	90	goto badframe;
	91
	92	sigdelsetmask(&set, ~_BLOCKABLE);
49209590	93	set_current_blocked(&set);
5f97f7f9 HS	94
	95	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	96	goto badframe;
	97
7c1b90a1 MK	98	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
	99	goto badframe;
	100
5f97f7f9 HS	101	pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
	102	regs->pc, regs->lr, regs->sp);
	103
	104	return regs->r12;
	105
	106	badframe:
	107	force_sig(SIGSEGV, current);
	108	return 0;
	109	}
	110
	111	static int
	112	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	113	{
	114	int err = 0;
	115
	116	#define COPY(x) err \|= __put_user(regs->x, &sc->x)
	117	COPY(sr);
	118	COPY(pc);
	119	COPY(lr);
	120	COPY(sp);
	121	COPY(r12);
	122	COPY(r11);
	123	COPY(r10);
	124	COPY(r9);
	125	COPY(r8);
	126	COPY(r7);
	127	COPY(r6);
	128	COPY(r5);
	129	COPY(r4);
	130	COPY(r3);
	131	COPY(r2);
	132	COPY(r1);
	133	COPY(r0);
	134	#undef COPY
	135
	136	return err;
	137	}
	138
	139	static inline void __user *
	140	get_sigframe(struct k_sigaction ka, struct pt_regs regs, int framesize)
	141	{
	142	unsigned long sp = regs->sp;
	143
	144	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
	145	sp = current->sas_ss_sp + current->sas_ss_size;
	146
	147	return (void __user *)((sp - framesize) & ~3);
	148	}
	149
	150	static int
	151	setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	152	sigset_t set, struct pt_regs regs)
	153	{
	154	struct rt_sigframe __user *frame;
	155	int err = 0;
	156
	157	frame = get_sigframe(ka, regs, sizeof(*frame));
	158	err = -EFAULT;
	159	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
	160	goto out;
	161
	162	/*
	163	* Set up the return code:
	164	*
165	* mov r8, __NR_rt_sigreturn
166	* scall
167	*
168	* Note: This will blow up since we're using a non-executable
169	* stack. Better use SA_RESTORER.
170	*/
171	#if __NR_rt_sigreturn > 127
172	# error __NR_rt_sigreturn must be < 127 to fit in a short mov
173	#endif
174	err = __put_user(0x3008d733 \| (__NR_rt_sigreturn << 20),
175	&frame->retcode);
176
177	err \|= copy_siginfo_to_user(&frame->info, info);
178
179	/* Set up the ucontext */
180	err \|= __put_user(0, &frame->uc.uc_flags);
181	err \|= __put_user(NULL, &frame->uc.uc_link);
182	err \|= __put_user((void __user *)current->sas_ss_sp,
183	&frame->uc.uc_stack.ss_sp);
184	err \|= __put_user(sas_ss_flags(regs->sp),
185	&frame->uc.uc_stack.ss_flags);
186	err \|= __put_user(current->sas_ss_size,
187	&frame->uc.uc_stack.ss_size);
188	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
189	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
190
191	if (err)
192	goto out;
193
194	regs->r12 = sig;
195	regs->r11 = (unsigned long) &frame->info;
196	regs->r10 = (unsigned long) &frame->uc;
197	regs->sp = (unsigned long) frame;
198	if (ka->sa.sa_flags & SA_RESTORER)
199	regs->lr = (unsigned long)ka->sa.sa_restorer;
200	else {
201	printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
202	current->comm, current->pid);
203	regs->lr = (unsigned long) &frame->retcode;
204	}
205
206	pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
207	current->comm, current->pid, sig, regs->sp,
208	regs->pc, ka->sa.sa_handler, regs->lr);
209
210	regs->pc = (unsigned long) ka->sa.sa_handler;
211
212	out:
213	return err;
214	}
215
288ddad5	216	static inline void setup_syscall_restart(struct pt_regs *regs)
5f97f7f9 HS	217	{
	218	if (regs->r12 == -ERESTART_RESTARTBLOCK)
	219	regs->r8 = __NR_restart_syscall;
	220	else
	221	regs->r12 = regs->r12_orig;
	222	regs->pc -= 2;
	223	}
	224
	225	static inline void
	226	handle_signal(unsigned long sig, struct k_sigaction ka, siginfo_t info,
	227	sigset_t oldset, struct pt_regs regs, int syscall)
	228	{
	229	int ret;
	230
	231	/*
	232	* Set up the stack frame
	233	*/
	234	ret = setup_rt_frame(sig, ka, info, oldset, regs);
	235
	236	/*
	237	* Check that the resulting registers are sane
	238	*/
	239	ret \|= !valid_user_regs(regs);
	240
e1b1fd79 MF	241	if (ret != 0) {
	242	force_sigsegv(sig, current);
	243	return;
	244	}
	245
5f97f7f9	246	/*
e1b1fd79	247	* Block the signal if we were successful.
5f97f7f9	248	*/
54bbf3e3	249	block_sigmask(ka, sig);
fe49c1ce	250	clear_thread_flag(TIF_RESTORE_SIGMASK);
5f97f7f9 HS	251	}
	252
	253	/*
	254	* Note that 'init' is a special process: it doesn't get signals it
	255	* doesn't want to handle. Thus you cannot kill init even with a
	256	* SIGKILL even by mistake.
	257	*/
	258	int do_signal(struct pt_regs regs, sigset_t oldset, int syscall)
	259	{
	260	siginfo_t info;
	261	int signr;
	262	struct k_sigaction ka;
	263
	264	/*
	265	* We want the common case to go fast, which is why we may in
	266	* certain cases get here from kernel mode. Just return
	267	* without doing anything if so.
	268	*/
	269	if (!user_mode(regs))
	270	return 0;
	271
5f97f7f9 HS	272	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	273	oldset = &current->saved_sigmask;
	274	else if (!oldset)
	275	oldset = &current->blocked;
	276
	277	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
5f97f7f9 HS	278	if (syscall) {
	279	switch (regs->r12) {
	280	case -ERESTART_RESTARTBLOCK:
	281	case -ERESTARTNOHAND:
	282	if (signr > 0) {
	283	regs->r12 = -EINTR;
	284	break;
	285	}
	286	/* fall through */
	287	case -ERESTARTSYS:
	288	if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) {
	289	regs->r12 = -EINTR;
	290	break;
	291	}
	292	/* fall through */
	293	case -ERESTARTNOINTR:
288ddad5	294	setup_syscall_restart(regs);
5f97f7f9 HS	295	}
	296	}
	297
	298	if (signr == 0) {
	299	/* No signal to deliver -- put the saved sigmask back */
51a7b448	300	restore_saved_sigmask();
5f97f7f9 HS	301	return 0;
	302	}
	303
	304	handle_signal(signr, &ka, &info, oldset, regs, syscall);
	305	return 1;
	306	}
	307
	308	asmlinkage void do_notify_resume(struct pt_regs regs, struct thread_info ti)
	309	{
	310	int syscall = 0;
	311
	312	if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
	313	syscall = 1;
	314
	315	if (ti->flags & (_TIF_SIGPENDING \| _TIF_RESTORE_SIGMASK))
	316	do_signal(regs, &current->blocked, syscall);
d0420c83 DH	317
	318	if (ti->flags & _TIF_NOTIFY_RESUME) {
	319	clear_thread_flag(TIF_NOTIFY_RESUME);
	320	tracehook_notify_resume(regs);
	321	}
5f97f7f9	322	}