[GitHub/mt8127/android_kernel_alcatel_ttab.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(int signr, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	unsigned long __user *retcode;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto segv_and_exit;

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

	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) ka->sa.sa_handler;

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

	/*
	 * 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;

segv_and_exit:
	force_sigsegv(signr, current);
	return -EFAULT;
}

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(int sig,
			 siginfo_t *info, struct k_sigaction *ka,
			 struct pt_regs *regs, int syscall)
{
	/* 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 (!(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 */
	if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
		return;
	signal_delivered(sig, info, ka, regs, 0);
}

/*
 * handle a potential signal
 */
static void do_signal(struct pt_regs *regs, int syscall)
{
	struct k_sigaction ka;
	siginfo_t info;
	int signr;

	/* 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;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		handle_signal(signr, &info, &ka, 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
	149	static int setup_rt_frame(int signr, struct k_sigaction ka, siginfo_t info,
	150	sigset_t set, struct pt_regs regs)
	151	{
	152	struct rt_sigframe __user *frame;
153	unsigned long __user *retcode;
154	int err = 0;
155
156	frame = get_sigframe(ka, regs, sizeof(*frame));
157
158	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
159	goto segv_and_exit;
160
161	err \|= __put_user(&frame->info, &frame->pinfo);
162	err \|= __put_user(&frame->uc, &frame->puc);
163	err \|= copy_siginfo_to_user(&frame->info, info);
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)
191	goto segv_and_exit;
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;
201	regs->pc = (unsigned long) ka->sa.sa_handler;
202
203	/* Give the signal number to the handler */
204	regs->a4 = signr;
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;
215
216	segv_and_exit:
217	force_sigsegv(signr, current);
218	return -EFAULT;
219	}
220
221	static inline void
222	handle_restart(struct pt_regs regs, struct k_sigaction ka, int has_handler)
223	{
224	switch (regs->a4) {
225	case -ERESTARTNOHAND:
226	if (!has_handler)
227	goto do_restart;
228	regs->a4 = -EINTR;
229	break;
230
231	case -ERESTARTSYS:
232	if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
233	regs->a4 = -EINTR;
234	break;
235	}
236	/* fallthrough */
237	case -ERESTARTNOINTR:
238	do_restart:
239	regs->a4 = regs->orig_a4;
240	regs->pc -= 4;
241	break;
242	}
243	}
244
245	/*
246	* handle the actual delivery of a signal to userspace
247	*/
a610d6e6	248	static void handle_signal(int sig,
03a34755	249	siginfo_t info, struct k_sigaction ka,
b7f9a11a	250	struct pt_regs *regs, int syscall)
03a34755	251	{
03a34755 AJ	252	/* Are we from a system call? */
	253	if (syscall) {
	254	/* If so, check system call restarting.. */
	255	switch (regs->a4) {
	256	case -ERESTART_RESTARTBLOCK:
	257	case -ERESTARTNOHAND:
	258	regs->a4 = -EINTR;
	259	break;
	260
	261	case -ERESTARTSYS:
	262	if (!(ka->sa.sa_flags & SA_RESTART)) {
	263	regs->a4 = -EINTR;
	264	break;
	265	}
	266
	267	/* fallthrough */
	268	case -ERESTARTNOINTR:
	269	regs->a4 = regs->orig_a4;
	270	regs->pc -= 4;
	271	}
	272	}
	273
	274	/* Set up the stack frame */
a610d6e6 AV	275	if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
a610d6e6 AV	276	return;
efee984c	277	signal_delivered(sig, info, ka, regs, 0);
03a34755 AJ	278	}
	279
	280	/*
	281	* handle a potential signal
	282	*/
	283	static void do_signal(struct pt_regs *regs, int syscall)
	284	{
	285	struct k_sigaction ka;
	286	siginfo_t info;
03a34755 AJ	287	int signr;
	288
	289	/* we want the common case to go fast, which is why we may in certain
	290	* cases get here from kernel mode */
	291	if (!user_mode(regs))
	292	return;
	293
03a34755 AJ	294	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
03a34755 AJ	295	if (signr > 0) {
a610d6e6	296	handle_signal(signr, &info, &ka, regs, syscall);
03a34755 AJ	297	return;
	298	}
	299
	300	/* did we come from a system call? */
	301	if (syscall) {
	302	/* restart the system call - no handlers present */
	303	switch (regs->a4) {
	304	case -ERESTARTNOHAND:
	305	case -ERESTARTSYS:
	306	case -ERESTARTNOINTR:
	307	regs->a4 = regs->orig_a4;
	308	regs->pc -= 4;
	309	break;
	310
	311	case -ERESTART_RESTARTBLOCK:
	312	regs->a4 = regs->orig_a4;
	313	regs->b0 = __NR_restart_syscall;
	314	regs->pc -= 4;
	315	break;
	316	}
	317	}
	318
	319	/* if there's no signal to deliver, we just put the saved sigmask
	320	* back */
51a7b448	321	restore_saved_sigmask();
03a34755 AJ	322	}
	323
	324	/*
	325	* notification of userspace execution resumption
	326	* - triggered by current->work.notify_resume
	327	*/
	328	asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
	329	int syscall)
	330	{
	331	/* deal with pending signal delivery */
6fd84c08	332	if (thread_info_flags & (1 << TIF_SIGPENDING))
03a34755 AJ	333	do_signal(regs, syscall);
	334
	335	if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
	336	clear_thread_flag(TIF_NOTIFY_RESUME);
	337	tracehook_notify_resume(regs);
03a34755 AJ	338	}
03a34755 AJ	339	}