[deliverable/linux.git] / arch / c6x / kernel / signal.c

/*
 *  Port on Texas Instruments TMS320C6x architecture
 *
 *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
 *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
 *
 *  Updated for 2.6.34: Mark Salter <msalter@redhat.com>
 *
 *  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/kernel.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>

#include <asm/ucontext.h>
#include <asm/cacheflush.h>


/*
 * Do a signal return, undo the signal stack.
 */

#define RETCODE_SIZE (9 << 2)	/* 9 instructions = 36 bytes */

struct rt_sigframe {
	struct siginfo __user *pinfo;
	void __user *puc;
	struct siginfo info;
	struct ucontext uc;
	unsigned long retcode[RETCODE_SIZE >> 2];
};

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

	/* The access_ok check was done by caller, so use __get_user here */
#define COPY(x)  (err |= __get_user(regs->x, &sc->sc_##x))

	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);

	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
	COPY(b28); COPY(b29); COPY(b30); COPY(b31);

	COPY(csr); COPY(pc);

#undef COPY

	return err;
}

asmlinkage int do_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;

	/*
	 * Since we stacked the signal on a dword boundary,
	 * 'sp' should be dword aligned here.  If it's
	 * not, then the user is trying to mess with us.
	 */
	if (regs->sp & 7)
		goto badframe;

	frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);

	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;

	return regs->a4;

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

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

	err |= __put_user(mask, &sc->sc_mask);

	/* The access_ok check was done by caller, so use __put_user here */
#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))

	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);

	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
	COPY(b28); COPY(b29); COPY(b30); COPY(b31);

	COPY(csr); COPY(pc);

#undef COPY

	return err;
}

static inline void __user *get_sigframe(struct k_sigaction *ka,
					struct pt_regs *regs,
					unsigned long framesize)
{
	unsigned long sp = regs->sp;

	/*
	 * This is the X/Open sanctioned signal stack switching.
	 */
	if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(sp) == 0)
		sp = current->sas_ss_sp + current->sas_ss_size;

	/*
	 * No matter what happens, 'sp' must be dword
	 * aligned. Otherwise, nasty things will happen
	 */
	return (void __user *)((sp - framesize) & ~7);
}

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

	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	err |= copy_siginfo_to_user(&frame->info, &ksig->info);

	/* Clear all the bits of the ucontext we don't use.  */
	err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));

	err |= setup_sigcontext(&frame->uc.uc_mcontext,	regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace */
	retcode = (unsigned long __user *) &frame->retcode;

	/* The access_ok check was done above, so use __put_user here */
#define COPY(x) (err |= __put_user(x, retcode++))

	COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
				/* MVK __NR_rt_sigreturn,B0 */
	COPY(0x10000000UL);	/* SWE */
	COPY(0x00006000UL);	/* NOP 4 */
	COPY(0x00006000UL);	/* NOP 4 */
	COPY(0x00006000UL);	/* NOP 4 */
	COPY(0x00006000UL);	/* NOP 4 */
	COPY(0x00006000UL);	/* NOP 4 */
	COPY(0x00006000UL);	/* NOP 4 */
	COPY(0x00006000UL);	/* NOP 4 */

#undef COPY

	if (err)
		return -EFAULT;

	flush_icache_range((unsigned long) &frame->retcode,
			   (unsigned long) &frame->retcode + RETCODE_SIZE);

	retcode = (unsigned long __user *) &frame->retcode;

	/* Change user context to branch to signal handler */
	regs->sp = (unsigned long) frame - 8;
	regs->b3 = (unsigned long) retcode;
	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;

	/* Give the signal number to the handler */
	regs->a4 = ksig->sig;

	/*
	 * For realtime signals we must also set the second and third
	 * arguments for the signal handler.
	 *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
	 */
	regs->b4 = (unsigned long)&frame->info;
	regs->a6 = (unsigned long)&frame->uc;

	return 0;
}

static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
	switch (regs->a4) {
	case -ERESTARTNOHAND:
		if (!has_handler)
			goto do_restart;
		regs->a4 = -EINTR;
		break;

	case -ERESTARTSYS:
		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
			regs->a4 = -EINTR;
			break;
		}
	/* fallthrough */
	case -ERESTARTNOINTR:
do_restart:
		regs->a4 = regs->orig_a4;
		regs->pc -= 4;
		break;
	}
}

/*
 * handle the actual delivery of a signal to userspace
 */
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
			  int syscall)
{
	int ret;

	/* Are we from a system call? */
	if (syscall) {
		/* If so, check system call restarting.. */
		switch (regs->a4) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->a4 = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
				regs->a4 = -EINTR;
				break;
			}

			/* fallthrough */
		case -ERESTARTNOINTR:
			regs->a4 = regs->orig_a4;
			regs->pc -= 4;
		}
	}

	/* Set up the stack frame */
	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
	signal_setup_done(ret, ksig, 0);
}

/*
 * handle a potential signal
 */
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 */
	if (!user_mode(regs))
		return;

	if (get_signal(&ksig)) {
		handle_signal(&ksig, regs, syscall);
		return;
	}

	/* did we come from a system call? */
	if (syscall) {
		/* restart the system call - no handlers present */
		switch (regs->a4) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->a4 = regs->orig_a4;
			regs->pc -= 4;
			break;

		case -ERESTART_RESTARTBLOCK:
			regs->a4 = regs->orig_a4;
			regs->b0 = __NR_restart_syscall;
			regs->pc -= 4;
			break;
		}
	}

	/* if there's no signal to deliver, we just put the saved sigmask
	 * back */
	restore_saved_sigmask();
}

/*
 * notification of userspace execution resumption
 * - triggered by current->work.notify_resume
 */
asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
				 int syscall)
{
	/* deal with pending signal delivery */
	if (thread_info_flags & (1 << TIF_SIGPENDING))
		do_signal(regs, syscall);

	if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
		clear_thread_flag(TIF_NOTIFY_RESUME);
		tracehook_notify_resume(regs);
	}
}
Commit	Line	Data
03a34755 AJ	1	/*
	2	* Port on Texas Instruments TMS320C6x architecture
	3	*
	4	* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
	5	* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
	6	*
	7	* Updated for 2.6.34: Mark Salter <msalter@redhat.com>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*/
	13
	14	#include <linux/kernel.h>
	15	#include <linux/uaccess.h>
	16	#include <linux/syscalls.h>
	17	#include <linux/tracehook.h>
	18
	19	#include <asm/ucontext.h>
	20	#include <asm/cacheflush.h>
	21
	22
03a34755 AJ	23	/*
	24	* Do a signal return, undo the signal stack.
	25	*/
	26
	27	#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
	28
	29	struct rt_sigframe {
	30	struct siginfo __user *pinfo;
	31	void __user *puc;
	32	struct siginfo info;
	33	struct ucontext uc;
	34	unsigned long retcode[RETCODE_SIZE >> 2];
	35	};
	36
	37	static int restore_sigcontext(struct pt_regs *regs,
	38	struct sigcontext __user *sc)
	39	{
	40	int err = 0;
	41
	42	/* The access_ok check was done by caller, so use __get_user here */
	43	#define COPY(x) (err \|= __get_user(regs->x, &sc->sc_##x))
	44
	45	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
	46	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
	47	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
	48
	49	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
	50	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
	51	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
	52	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
	53	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
	54	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
	55	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
	56	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
	57
	58	COPY(csr); COPY(pc);
	59
	60	#undef COPY
	61
	62	return err;
	63	}
	64
	65	asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
	66	{
	67	struct rt_sigframe __user *frame;
	68	sigset_t set;
	69
2a3fdc11 AV	70	/* Always make any pending restarted system calls return -EINTR */
	71	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	72
03a34755 AJ	73	/*
	74	* Since we stacked the signal on a dword boundary,
	75	* 'sp' should be dword aligned here. If it's
	76	* not, then the user is trying to mess with us.
	77	*/
	78	if (regs->sp & 7)
	79	goto badframe;
	80
	81	frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
	82
	83	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	84	goto badframe;
	85	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	86	goto badframe;
	87
6e61ee3b	88	set_current_blocked(&set);
03a34755 AJ	89
	90	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	91	goto badframe;
	92
	93	return regs->a4;
	94
	95	badframe:
	96	force_sig(SIGSEGV, current);
	97	return 0;
	98	}
	99
	100	static int setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs,
	101	unsigned long mask)
	102	{
	103	int err = 0;
	104
	105	err \|= __put_user(mask, &sc->sc_mask);
	106
	107	/* The access_ok check was done by caller, so use __put_user here */
	108	#define COPY(x) (err \|= __put_user(regs->x, &sc->sc_##x))
	109
	110	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
	111	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
	112	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
	113
	114	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
	115	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
	116	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
	117	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
	118	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
	119	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
	120	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
	121	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
	122
	123	COPY(csr); COPY(pc);
	124
	125	#undef COPY
	126
	127	return err;
	128	}
	129
	130	static inline void __user get_sigframe(struct k_sigaction ka,
	131	struct pt_regs *regs,
	132	unsigned long framesize)
	133	{
	134	unsigned long sp = regs->sp;
	135
	136	/*
	137	* This is the X/Open sanctioned signal stack switching.
	138	*/
	139	if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(sp) == 0)
	140	sp = current->sas_ss_sp + current->sas_ss_size;
	141
	142	/*
	143	* No matter what happens, 'sp' must be dword
	144	* aligned. Otherwise, nasty things will happen
	145	*/
	146	return (void __user *)((sp - framesize) & ~7);
	147	}
	148
e19c025b RW	149	static int setup_rt_frame(struct ksignal ksig, sigset_t set,
e19c025b RW	150	struct pt_regs *regs)
03a34755 AJ	151	{
	152	struct rt_sigframe __user *frame;
	153	unsigned long __user *retcode;
	154	int err = 0;
	155
e19c025b	156	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
03a34755 AJ	157
03a34755 AJ	158	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
e19c025b	159	return -EFAULT;
03a34755 AJ	160
	161	err \|= __put_user(&frame->info, &frame->pinfo);
	162	err \|= __put_user(&frame->uc, &frame->puc);
e19c025b	163	err \|= copy_siginfo_to_user(&frame->info, &ksig->info);
03a34755 AJ	164
	165	/* Clear all the bits of the ucontext we don't use. */
	166	err \|= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
	167
	168	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
	169	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	170
	171	/* Set up to return from userspace */
	172	retcode = (unsigned long __user *) &frame->retcode;
	173
	174	/* The access_ok check was done above, so use __put_user here */
	175	#define COPY(x) (err \|= __put_user(x, retcode++))
	176
	177	COPY(0x0000002AUL \| (__NR_rt_sigreturn << 7));
	178	/* MVK __NR_rt_sigreturn,B0 */
	179	COPY(0x10000000UL); /* SWE */
	180	COPY(0x00006000UL); /* NOP 4 */
	181	COPY(0x00006000UL); /* NOP 4 */
	182	COPY(0x00006000UL); /* NOP 4 */
	183	COPY(0x00006000UL); /* NOP 4 */
	184	COPY(0x00006000UL); /* NOP 4 */
	185	COPY(0x00006000UL); /* NOP 4 */
	186	COPY(0x00006000UL); /* NOP 4 */
	187
	188	#undef COPY
	189
	190	if (err)
e19c025b	191	return -EFAULT;
03a34755 AJ	192
	193	flush_icache_range((unsigned long) &frame->retcode,
	194	(unsigned long) &frame->retcode + RETCODE_SIZE);
	195
	196	retcode = (unsigned long __user *) &frame->retcode;
	197
	198	/* Change user context to branch to signal handler */
	199	regs->sp = (unsigned long) frame - 8;
	200	regs->b3 = (unsigned long) retcode;
e19c025b	201	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
03a34755 AJ	202
03a34755 AJ	203	/* Give the signal number to the handler */
e19c025b	204	regs->a4 = ksig->sig;
03a34755 AJ	205
	206	/*
	207	* For realtime signals we must also set the second and third
	208	* arguments for the signal handler.
	209	* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
	210	*/
	211	regs->b4 = (unsigned long)&frame->info;
	212	regs->a6 = (unsigned long)&frame->uc;
	213
	214	return 0;
03a34755 AJ	215	}
	216
	217	static inline void
	218	handle_restart(struct pt_regs regs, struct k_sigaction ka, int has_handler)
	219	{
	220	switch (regs->a4) {
	221	case -ERESTARTNOHAND:
	222	if (!has_handler)
	223	goto do_restart;
	224	regs->a4 = -EINTR;
	225	break;
	226
	227	case -ERESTARTSYS:
	228	if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
	229	regs->a4 = -EINTR;
	230	break;
	231	}
	232	/* fallthrough */
	233	case -ERESTARTNOINTR:
	234	do_restart:
	235	regs->a4 = regs->orig_a4;
	236	regs->pc -= 4;
	237	break;
	238	}
	239	}
	240
	241	/*
	242	* handle the actual delivery of a signal to userspace
	243	*/
e19c025b RW	244	static void handle_signal(struct ksignal ksig, struct pt_regs regs,
e19c025b RW	245	int syscall)
03a34755	246	{
e19c025b RW	247	int ret;
e19c025b RW	248
03a34755 AJ	249	/* Are we from a system call? */
	250	if (syscall) {
	251	/* If so, check system call restarting.. */
	252	switch (regs->a4) {
	253	case -ERESTART_RESTARTBLOCK:
	254	case -ERESTARTNOHAND:
	255	regs->a4 = -EINTR;
	256	break;
	257
	258	case -ERESTARTSYS:
e19c025b	259	if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
03a34755 AJ	260	regs->a4 = -EINTR;
	261	break;
	262	}
	263
	264	/* fallthrough */
	265	case -ERESTARTNOINTR:
	266	regs->a4 = regs->orig_a4;
	267	regs->pc -= 4;
	268	}
	269	}
	270
	271	/* Set up the stack frame */
e19c025b RW	272	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
e19c025b RW	273	signal_setup_done(ret, ksig, 0);
03a34755 AJ	274	}
	275
	276	/*
	277	* handle a potential signal
	278	*/
	279	static void do_signal(struct pt_regs *regs, int syscall)
	280	{
e19c025b	281	struct ksignal ksig;
03a34755 AJ	282
	283	/* we want the common case to go fast, which is why we may in certain
	284	* cases get here from kernel mode */
	285	if (!user_mode(regs))
	286	return;
	287
e19c025b RW	288	if (get_signal(&ksig)) {
e19c025b RW	289	handle_signal(&ksig, regs, syscall);
03a34755 AJ	290	return;
	291	}
	292
	293	/* did we come from a system call? */
	294	if (syscall) {
	295	/* restart the system call - no handlers present */
	296	switch (regs->a4) {
	297	case -ERESTARTNOHAND:
	298	case -ERESTARTSYS:
	299	case -ERESTARTNOINTR:
	300	regs->a4 = regs->orig_a4;
	301	regs->pc -= 4;
	302	break;
	303
	304	case -ERESTART_RESTARTBLOCK:
	305	regs->a4 = regs->orig_a4;
	306	regs->b0 = __NR_restart_syscall;
	307	regs->pc -= 4;
	308	break;
	309	}
	310	}
	311
	312	/* if there's no signal to deliver, we just put the saved sigmask
	313	* back */
51a7b448	314	restore_saved_sigmask();
03a34755 AJ	315	}
	316
	317	/*
	318	* notification of userspace execution resumption
	319	* - triggered by current->work.notify_resume
	320	*/
	321	asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
	322	int syscall)
	323	{
	324	/* deal with pending signal delivery */
6fd84c08	325	if (thread_info_flags & (1 << TIF_SIGPENDING))
03a34755 AJ	326	do_signal(regs, syscall);
	327
	328	if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
	329	clear_thread_flag(TIF_NOTIFY_RESUME);
	330	tracehook_notify_resume(regs);
03a34755 AJ	331	}
03a34755 AJ	332	}