[linux-2.6-block.git] / arch / c6x / kernel / signal.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  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>
 */

#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->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(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);
	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 ksignal *ksig,
					struct pt_regs *regs,
					unsigned long framesize)
{
	unsigned long sp = sigsp(regs->sp, ksig);

	/*
	 * 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, regs, sizeof(*frame));

	if (!access_ok(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))
		tracehook_notify_resume(regs);
}
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
03a34755 AJ	2	/*
	3	* Port on Texas Instruments TMS320C6x architecture
	4	*
	5	* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
	6	* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
	7	*
	8	* Updated for 2.6.34: Mark Salter <msalter@redhat.com>
03a34755 AJ	9	*/
	10
	11	#include <linux/kernel.h>
	12	#include <linux/uaccess.h>
	13	#include <linux/syscalls.h>
	14	#include <linux/tracehook.h>
	15
	16	#include <asm/ucontext.h>
	17	#include <asm/cacheflush.h>
	18
	19
03a34755 AJ	20	/*
	21	* Do a signal return, undo the signal stack.
	22	*/
	23
	24	#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
	25
	26	struct rt_sigframe {
	27	struct siginfo __user *pinfo;
	28	void __user *puc;
	29	struct siginfo info;
	30	struct ucontext uc;
	31	unsigned long retcode[RETCODE_SIZE >> 2];
	32	};
	33
	34	static int restore_sigcontext(struct pt_regs *regs,
	35	struct sigcontext __user *sc)
	36	{
	37	int err = 0;
	38
	39	/* The access_ok check was done by caller, so use __get_user here */
	40	#define COPY(x) (err \|= __get_user(regs->x, &sc->sc_##x))
	41
	42	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
	43	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
	44	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
	45
	46	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
	47	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
	48	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
	49	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
	50	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
	51	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
	52	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
	53	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
	54
	55	COPY(csr); COPY(pc);
	56
	57	#undef COPY
	58
	59	return err;
	60	}
	61
	62	asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
	63	{
	64	struct rt_sigframe __user *frame;
	65	sigset_t set;
	66
2a3fdc11	67	/* Always make any pending restarted system calls return -EINTR */
f56141e3	68	current->restart_block.fn = do_no_restart_syscall;
2a3fdc11	69
03a34755 AJ	70	/*
	71	* Since we stacked the signal on a dword boundary,
	72	* 'sp' should be dword aligned here. If it's
	73	* not, then the user is trying to mess with us.
	74	*/
	75	if (regs->sp & 7)
	76	goto badframe;
	77
	78	frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
	79
96d4f267	80	if (!access_ok(frame, sizeof(*frame)))
03a34755 AJ	81	goto badframe;
	82	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	83	goto badframe;
	84
6e61ee3b	85	set_current_blocked(&set);
03a34755 AJ	86
	87	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	88	goto badframe;
	89
	90	return regs->a4;
	91
	92	badframe:
3cf5d076	93	force_sig(SIGSEGV);
03a34755 AJ	94	return 0;
	95	}
	96
	97	static int setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs,
	98	unsigned long mask)
	99	{
	100	int err = 0;
	101
	102	err \|= __put_user(mask, &sc->sc_mask);
	103
	104	/* The access_ok check was done by caller, so use __put_user here */
	105	#define COPY(x) (err \|= __put_user(regs->x, &sc->sc_##x))
	106
	107	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
	108	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
	109	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
	110
	111	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
	112	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
	113	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
	114	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
	115	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
	116	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
	117	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
	118	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
	119
	120	COPY(csr); COPY(pc);
	121
	122	#undef COPY
	123
	124	return err;
	125	}
	126
615869e4	127	static inline void __user get_sigframe(struct ksignal ksig,
03a34755 AJ	128	struct pt_regs *regs,
	129	unsigned long framesize)
	130	{
615869e4	131	unsigned long sp = sigsp(regs->sp, ksig);
03a34755 AJ	132
	133	/*
	134	* No matter what happens, 'sp' must be dword
	135	* aligned. Otherwise, nasty things will happen
	136	*/
	137	return (void __user *)((sp - framesize) & ~7);
	138	}
	139
e19c025b RW	140	static int setup_rt_frame(struct ksignal ksig, sigset_t set,
e19c025b RW	141	struct pt_regs *regs)
03a34755 AJ	142	{
	143	struct rt_sigframe __user *frame;
	144	unsigned long __user *retcode;
	145	int err = 0;
	146
615869e4	147	frame = get_sigframe(ksig, regs, sizeof(*frame));
03a34755	148
96d4f267	149	if (!access_ok(frame, sizeof(*frame)))
e19c025b	150	return -EFAULT;
03a34755 AJ	151
	152	err \|= __put_user(&frame->info, &frame->pinfo);
	153	err \|= __put_user(&frame->uc, &frame->puc);
e19c025b	154	err \|= copy_siginfo_to_user(&frame->info, &ksig->info);
03a34755 AJ	155
	156	/* Clear all the bits of the ucontext we don't use. */
	157	err \|= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
	158
	159	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
	160	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	161
	162	/* Set up to return from userspace */
	163	retcode = (unsigned long __user *) &frame->retcode;
	164
	165	/* The access_ok check was done above, so use __put_user here */
	166	#define COPY(x) (err \|= __put_user(x, retcode++))
	167
	168	COPY(0x0000002AUL \| (__NR_rt_sigreturn << 7));
	169	/* MVK __NR_rt_sigreturn,B0 */
	170	COPY(0x10000000UL); /* SWE */
	171	COPY(0x00006000UL); /* NOP 4 */
	172	COPY(0x00006000UL); /* NOP 4 */
	173	COPY(0x00006000UL); /* NOP 4 */
	174	COPY(0x00006000UL); /* NOP 4 */
	175	COPY(0x00006000UL); /* NOP 4 */
	176	COPY(0x00006000UL); /* NOP 4 */
	177	COPY(0x00006000UL); /* NOP 4 */
	178
	179	#undef COPY
	180
	181	if (err)
e19c025b	182	return -EFAULT;
03a34755 AJ	183
	184	flush_icache_range((unsigned long) &frame->retcode,
	185	(unsigned long) &frame->retcode + RETCODE_SIZE);
	186
	187	retcode = (unsigned long __user *) &frame->retcode;
	188
	189	/* Change user context to branch to signal handler */
	190	regs->sp = (unsigned long) frame - 8;
	191	regs->b3 = (unsigned long) retcode;
e19c025b	192	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
03a34755 AJ	193
03a34755 AJ	194	/* Give the signal number to the handler */
e19c025b	195	regs->a4 = ksig->sig;
03a34755 AJ	196
	197	/*
	198	* For realtime signals we must also set the second and third
	199	* arguments for the signal handler.
	200	* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
	201	*/
	202	regs->b4 = (unsigned long)&frame->info;
	203	regs->a6 = (unsigned long)&frame->uc;
	204
	205	return 0;
03a34755 AJ	206	}
	207
	208	static inline void
	209	handle_restart(struct pt_regs regs, struct k_sigaction ka, int has_handler)
	210	{
	211	switch (regs->a4) {
	212	case -ERESTARTNOHAND:
	213	if (!has_handler)
	214	goto do_restart;
	215	regs->a4 = -EINTR;
	216	break;
	217
	218	case -ERESTARTSYS:
	219	if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
	220	regs->a4 = -EINTR;
	221	break;
	222	}
df561f66	223	fallthrough;
03a34755 AJ	224	case -ERESTARTNOINTR:
	225	do_restart:
	226	regs->a4 = regs->orig_a4;
	227	regs->pc -= 4;
	228	break;
	229	}
	230	}
	231
	232	/*
	233	* handle the actual delivery of a signal to userspace
	234	*/
e19c025b RW	235	static void handle_signal(struct ksignal ksig, struct pt_regs regs,
e19c025b RW	236	int syscall)
03a34755	237	{
e19c025b RW	238	int ret;
e19c025b RW	239
03a34755 AJ	240	/* Are we from a system call? */
	241	if (syscall) {
	242	/* If so, check system call restarting.. */
	243	switch (regs->a4) {
	244	case -ERESTART_RESTARTBLOCK:
	245	case -ERESTARTNOHAND:
	246	regs->a4 = -EINTR;
	247	break;
	248
	249	case -ERESTARTSYS:
e19c025b	250	if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
03a34755 AJ	251	regs->a4 = -EINTR;
	252	break;
	253	}
	254
df561f66	255	fallthrough;
03a34755 AJ	256	case -ERESTARTNOINTR:
	257	regs->a4 = regs->orig_a4;
	258	regs->pc -= 4;
	259	}
	260	}
	261
	262	/* Set up the stack frame */
e19c025b RW	263	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
e19c025b RW	264	signal_setup_done(ret, ksig, 0);
03a34755 AJ	265	}
	266
	267	/*
	268	* handle a potential signal
	269	*/
	270	static void do_signal(struct pt_regs *regs, int syscall)
	271	{
e19c025b	272	struct ksignal ksig;
03a34755 AJ	273
	274	/* we want the common case to go fast, which is why we may in certain
	275	* cases get here from kernel mode */
	276	if (!user_mode(regs))
	277	return;
	278
e19c025b RW	279	if (get_signal(&ksig)) {
e19c025b RW	280	handle_signal(&ksig, regs, syscall);
03a34755 AJ	281	return;
	282	}
	283
	284	/* did we come from a system call? */
	285	if (syscall) {
	286	/* restart the system call - no handlers present */
	287	switch (regs->a4) {
	288	case -ERESTARTNOHAND:
	289	case -ERESTARTSYS:
	290	case -ERESTARTNOINTR:
	291	regs->a4 = regs->orig_a4;
	292	regs->pc -= 4;
	293	break;
	294
	295	case -ERESTART_RESTARTBLOCK:
	296	regs->a4 = regs->orig_a4;
	297	regs->b0 = __NR_restart_syscall;
	298	regs->pc -= 4;
	299	break;
	300	}
	301	}
	302
	303	/* if there's no signal to deliver, we just put the saved sigmask
	304	* back */
51a7b448	305	restore_saved_sigmask();
03a34755 AJ	306	}
	307
	308	/*
	309	* notification of userspace execution resumption
	310	* - triggered by current->work.notify_resume
	311	*/
	312	asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
	313	int syscall)
	314	{
	315	/* deal with pending signal delivery */
6fd84c08	316	if (thread_info_flags & (1 << TIF_SIGPENDING))
03a34755 AJ	317	do_signal(regs, syscall);
03a34755 AJ	318
3c532798	319	if (thread_info_flags & (1 << TIF_NOTIFY_RESUME))
03a34755	320	tracehook_notify_resume(regs);
03a34755	321	}