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

/*
 * Signal support for Hexagon processor
 *
 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <linux/linkage.h>
#include <linux/syscalls.h>
#include <linux/freezer.h>
#include <linux/tracehook.h>
#include <asm/registers.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
#include <asm/uaccess.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
#include <asm/signal.h>
#include <asm/vdso.h>

struct rt_sigframe {
	unsigned long tramp[2];
	struct siginfo info;
	struct ucontext uc;
};

static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
			  size_t frame_size)
{
	unsigned long sp = regs->r29;

	/* Switch to signal stack if appropriate */
	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
		sp = current->sas_ss_sp + current->sas_ss_size;

	return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
}

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

	err |= copy_to_user(&sc->sc_regs.r0, &regs->r00,
			    32*sizeof(unsigned long));

	err |= __put_user(regs->sa0, &sc->sc_regs.sa0);
	err |= __put_user(regs->lc0, &sc->sc_regs.lc0);
	err |= __put_user(regs->sa1, &sc->sc_regs.sa1);
	err |= __put_user(regs->lc1, &sc->sc_regs.lc1);
	err |= __put_user(regs->m0, &sc->sc_regs.m0);
	err |= __put_user(regs->m1, &sc->sc_regs.m1);
	err |= __put_user(regs->usr, &sc->sc_regs.usr);
	err |= __put_user(regs->preds, &sc->sc_regs.p3_0);
	err |= __put_user(regs->gp, &sc->sc_regs.gp);
	err |= __put_user(regs->ugp, &sc->sc_regs.ugp);

	tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc);
	tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause);
	tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva);

	return err;
}

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

	err |= copy_from_user(&regs->r00, &sc->sc_regs.r0,
			      32 * sizeof(unsigned long));

	err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
	err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
	err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
	err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
	err |= __get_user(regs->m0, &sc->sc_regs.m0);
	err |= __get_user(regs->m1, &sc->sc_regs.m1);
	err |= __get_user(regs->usr, &sc->sc_regs.usr);
	err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
	err |= __get_user(regs->gp, &sc->sc_regs.gp);
	err |= __get_user(regs->ugp, &sc->sc_regs.ugp);

	err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);

	return err;
}

/*
 * Setup signal stack frame with siginfo structure
 */
static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
			  sigset_t *set,  struct pt_regs *regs)
{
	int err = 0;
	struct rt_sigframe __user *frame;
	struct hexagon_vdso *vdso = current->mm->context.vdso;

	frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
		goto	sigsegv;

	if (copy_siginfo_to_user(&frame->info, info))
		goto	sigsegv;

	/* The on-stack signal trampoline is no longer executed;
	 * however, the libgcc signal frame unwinding code checks for
	 * the presence of these two numeric magic values.
	 */
	err |= __put_user(0x7800d166, &frame->tramp[0]);
	err |= __put_user(0x5400c004, &frame->tramp[1]);
	err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto sigsegv;

	/* Load r0/r1 pair with signumber/siginfo pointer... */
	regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
		| (unsigned long long)signr;
	regs->r02 = (unsigned long) &frame->uc;
	regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
	pt_psp(regs) = (unsigned long) frame;
	pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);

	return 0;

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

/*
 * Setup invocation of signal handler
 */
static void handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
			 struct pt_regs *regs)
{
	/*
	 * If we're handling a signal that aborted a system call,
	 * set up the error return value before adding the signal
	 * frame to the stack.
	 */

	if (regs->syscall_nr >= 0) {
		switch (regs->r00) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->r00 = -EINTR;
			break;
		case -ERESTARTSYS:
			if (!(ka->sa.sa_flags & SA_RESTART)) {
				regs->r00 = -EINTR;
				break;
			}
			/* Fall through */
		case -ERESTARTNOINTR:
			regs->r06 = regs->syscall_nr;
			pt_set_elr(regs, pt_elr(regs) - 4);
			regs->r00 = regs->restart_r0;
			break;
		default:
			break;
		}
	}

	/*
	 * Set up the stack frame; not doing the SA_SIGINFO thing.  We
	 * only set up the rt_frame flavor.
	 */
	/* If there was an error on setup, no signal was delivered. */
	if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
		return;

	block_sigmask(ka, sig);
	tracehook_signal_handler(sig, info, ka, regs,
			test_thread_flag(TIF_SINGLESTEP));
}

/*
 * Called from return-from-event code.
 */
static void do_signal(struct pt_regs *regs)
{
	struct k_sigaction sigact;
	siginfo_t info;
	int signo;

	if (!user_mode(regs))
		return;

	signo = get_signal_to_deliver(&info, &sigact, regs, NULL);

	if (signo > 0) {
		handle_signal(signo, &info, &sigact, regs);
		return;
	}

	/*
	 * If we came from a system call, handle the restart.
	 */
	if (regs->syscall_nr >= 0) {
		switch (regs->r00) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->r06 = regs->syscall_nr;
			break;
		case -ERESTART_RESTARTBLOCK:
			regs->r06 = __NR_restart_syscall;
			break;
		default:
			goto no_restart;
		}
		pt_set_elr(regs, pt_elr(regs) - 4);
		regs->r00 = regs->restart_r0;
	}

no_restart:
	/* If there's no signal to deliver, put the saved sigmask back */
	restore_saved_sigmask();
}

void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
{
	if (thread_info_flags & _TIF_SIGPENDING)
		do_signal(regs);

	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
		clear_thread_flag(TIF_NOTIFY_RESUME);
		tracehook_notify_resume(regs);
	}
}

/*
 * Architecture-specific wrappers for signal-related system calls
 */
asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
	struct pt_regs *regs = current_thread_info()->regs;

	return do_sigaltstack(uss, uoss, regs->r29);
}

asmlinkage int sys_rt_sigreturn(void)
{
	struct pt_regs *regs = current_thread_info()->regs;
	struct rt_sigframe __user *frame;
	sigset_t blocked;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	frame = (struct rt_sigframe __user *)pt_psp(regs);
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
		goto badframe;

	set_current_blocked(&blocked);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
		goto badframe;

	/* Restore the user's stack as well */
	pt_psp(regs) = regs->r29;

	/*
	 * Leave a trace in the stack frame that this was a sigreturn.
	 * If the system call is to replay, we've already restored the
	 * number in the GPR slot and it will be regenerated on the
	 * new system call trap entry. Note that if restore_sigcontext()
	 * did something other than a bulk copy of the pt_regs struct,
	 * we could avoid this assignment by simply not overwriting
	 * regs->syscall_nr.
	 */
	regs->syscall_nr = __NR_rt_sigreturn;

	/*
	 * If we were meticulous, we'd only call this if we knew that
	 * we were actually going to use an alternate stack, and we'd
	 * consider any error to be fatal.  What we do here, in common
	 * with many other architectures, is call it blindly and only
	 * consider the -EFAULT return case to be proof of a problem.
	 */
	if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT)
		goto badframe;

	return 0;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}
Commit	Line	Data
cd5b61d6 RK	1	/*
	2	* Signal support for Hexagon processor
	3	*
	4	* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 and
	8	* only version 2 as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	18	* 02110-1301, USA.
	19	*/
	20
	21	#include <linux/linkage.h>
	22	#include <linux/syscalls.h>
	23	#include <linux/freezer.h>
	24	#include <linux/tracehook.h>
	25	#include <asm/registers.h>
	26	#include <asm/thread_info.h>
	27	#include <asm/unistd.h>
	28	#include <asm/uaccess.h>
	29	#include <asm/ucontext.h>
	30	#include <asm/cacheflush.h>
	31	#include <asm/signal.h>
	32	#include <asm/vdso.h>
	33
cd5b61d6 RK	34	struct rt_sigframe {
	35	unsigned long tramp[2];
	36	struct siginfo info;
	37	struct ucontext uc;
	38	};
	39
	40	static void __user get_sigframe(struct k_sigaction ka, struct pt_regs *regs,
	41	size_t frame_size)
	42	{
	43	unsigned long sp = regs->r29;
	44
	45	/* Switch to signal stack if appropriate */
	46	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
	47	sp = current->sas_ss_sp + current->sas_ss_size;
	48
	49	return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
	50	}
	51
	52	static int setup_sigcontext(struct pt_regs regs, struct sigcontext __user sc)
	53	{
	54	unsigned long tmp;
	55	int err = 0;
	56
	57	err \|= copy_to_user(&sc->sc_regs.r0, &regs->r00,
	58	32*sizeof(unsigned long));
	59
	60	err \|= __put_user(regs->sa0, &sc->sc_regs.sa0);
	61	err \|= __put_user(regs->lc0, &sc->sc_regs.lc0);
	62	err \|= __put_user(regs->sa1, &sc->sc_regs.sa1);
	63	err \|= __put_user(regs->lc1, &sc->sc_regs.lc1);
	64	err \|= __put_user(regs->m0, &sc->sc_regs.m0);
	65	err \|= __put_user(regs->m1, &sc->sc_regs.m1);
	66	err \|= __put_user(regs->usr, &sc->sc_regs.usr);
	67	err \|= __put_user(regs->preds, &sc->sc_regs.p3_0);
	68	err \|= __put_user(regs->gp, &sc->sc_regs.gp);
	69	err \|= __put_user(regs->ugp, &sc->sc_regs.ugp);
	70
	71	tmp = pt_elr(regs); err \|= __put_user(tmp, &sc->sc_regs.pc);
	72	tmp = pt_cause(regs); err \|= __put_user(tmp, &sc->sc_regs.cause);
	73	tmp = pt_badva(regs); err \|= __put_user(tmp, &sc->sc_regs.badva);
	74
	75	return err;
	76	}
	77
	78	static int restore_sigcontext(struct pt_regs *regs,
	79	struct sigcontext __user *sc)
	80	{
	81	unsigned long tmp;
	82	int err = 0;
	83
	84	err \|= copy_from_user(&regs->r00, &sc->sc_regs.r0,
	85	32 * sizeof(unsigned long));
	86
	87	err \|= __get_user(regs->sa0, &sc->sc_regs.sa0);
	88	err \|= __get_user(regs->lc0, &sc->sc_regs.lc0);
	89	err \|= __get_user(regs->sa1, &sc->sc_regs.sa1);
	90	err \|= __get_user(regs->lc1, &sc->sc_regs.lc1);
	91	err \|= __get_user(regs->m0, &sc->sc_regs.m0);
	92	err \|= __get_user(regs->m1, &sc->sc_regs.m1);
	93	err \|= __get_user(regs->usr, &sc->sc_regs.usr);
	94	err \|= __get_user(regs->preds, &sc->sc_regs.p3_0);
	95	err \|= __get_user(regs->gp, &sc->sc_regs.gp);
	96	err \|= __get_user(regs->ugp, &sc->sc_regs.ugp);
	97
98	err \|= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
99
100	return err;
101	}
102
103	/*
104	* Setup signal stack frame with siginfo structure
105	*/
106	static int setup_rt_frame(int signr, struct k_sigaction ka, siginfo_t info,
107	sigset_t set, struct pt_regs regs)
108	{
109	int err = 0;
110	struct rt_sigframe __user *frame;
111	struct hexagon_vdso *vdso = current->mm->context.vdso;
112
113	frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
114
115	if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
116	goto sigsegv;
117
118	if (copy_siginfo_to_user(&frame->info, info))
119	goto sigsegv;
120
121	/* The on-stack signal trampoline is no longer executed;
122	* however, the libgcc signal frame unwinding code checks for
123	* the presence of these two numeric magic values.
124	*/
125	err \|= __put_user(0x7800d166, &frame->tramp[0]);
126	err \|= __put_user(0x5400c004, &frame->tramp[1]);
127	err \|= setup_sigcontext(regs, &frame->uc.uc_mcontext);
128	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
129	if (err)
130	goto sigsegv;
131
132	/* Load r0/r1 pair with signumber/siginfo pointer... */
133	regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
134	\| (unsigned long long)signr;
135	regs->r02 = (unsigned long) &frame->uc;
136	regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
137	pt_psp(regs) = (unsigned long) frame;
138	pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);
139
140	return 0;
141
142	sigsegv:
143	force_sigsegv(signr, current);
144	return -EFAULT;
145	}
146
147	/*
148	* Setup invocation of signal handler
149	*/
a610d6e6	150	static void handle_signal(int sig, siginfo_t info, struct k_sigaction ka,
b7f9a11a	151	struct pt_regs *regs)
cd5b61d6	152	{
cd5b61d6 RK	153	/*
	154	* If we're handling a signal that aborted a system call,
	155	* set up the error return value before adding the signal
	156	* frame to the stack.
	157	*/
	158
	159	if (regs->syscall_nr >= 0) {
	160	switch (regs->r00) {
	161	case -ERESTART_RESTARTBLOCK:
	162	case -ERESTARTNOHAND:
	163	regs->r00 = -EINTR;
	164	break;
	165	case -ERESTARTSYS:
	166	if (!(ka->sa.sa_flags & SA_RESTART)) {
	167	regs->r00 = -EINTR;
	168	break;
	169	}
	170	/* Fall through */
	171	case -ERESTARTNOINTR:
	172	regs->r06 = regs->syscall_nr;
	173	pt_set_elr(regs, pt_elr(regs) - 4);
	174	regs->r00 = regs->restart_r0;
	175	break;
	176	default:
	177	break;
	178	}
	179	}
	180
	181	/*
	182	* Set up the stack frame; not doing the SA_SIGINFO thing. We
	183	* only set up the rt_frame flavor.
	184	*/
cd5b61d6	185	/* If there was an error on setup, no signal was delivered. */
a610d6e6 AV	186	if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
a610d6e6 AV	187	return;
cd5b61d6	188
43aca324	189	block_sigmask(ka, sig);
a610d6e6 AV	190	tracehook_signal_handler(sig, info, ka, regs,
a610d6e6 AV	191	test_thread_flag(TIF_SINGLESTEP));
cd5b61d6 RK	192	}
	193
	194	/*
	195	* Called from return-from-event code.
	196	*/
	197	static void do_signal(struct pt_regs *regs)
	198	{
	199	struct k_sigaction sigact;
	200	siginfo_t info;
	201	int signo;
	202
	203	if (!user_mode(regs))
	204	return;
	205
cd5b61d6 RK	206	signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
	207
	208	if (signo > 0) {
a610d6e6	209	handle_signal(signo, &info, &sigact, regs);
cd5b61d6 RK	210	return;
	211	}
	212
cd5b61d6 RK	213	/*
	214	* If we came from a system call, handle the restart.
	215	*/
	216	if (regs->syscall_nr >= 0) {
	217	switch (regs->r00) {
	218	case -ERESTARTNOHAND:
	219	case -ERESTARTSYS:
	220	case -ERESTARTNOINTR:
	221	regs->r06 = regs->syscall_nr;
	222	break;
	223	case -ERESTART_RESTARTBLOCK:
	224	regs->r06 = __NR_restart_syscall;
	225	break;
	226	default:
	227	goto no_restart;
	228	}
	229	pt_set_elr(regs, pt_elr(regs) - 4);
	230	regs->r00 = regs->restart_r0;
	231	}
	232
	233	no_restart:
	234	/* If there's no signal to deliver, put the saved sigmask back */
51a7b448	235	restore_saved_sigmask();
cd5b61d6 RK	236	}
	237
	238	void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
	239	{
	240	if (thread_info_flags & _TIF_SIGPENDING)
	241	do_signal(regs);
	242
	243	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
	244	clear_thread_flag(TIF_NOTIFY_RESUME);
3334bf12	245	tracehook_notify_resume(regs);
cd5b61d6 RK	246	}
	247	}
	248
	249	/*
	250	* Architecture-specific wrappers for signal-related system calls
	251	*/
	252	asmlinkage int sys_sigaltstack(const stack_t __user uss, stack_t __user uoss)
	253	{
	254	struct pt_regs *regs = current_thread_info()->regs;
	255
	256	return do_sigaltstack(uss, uoss, regs->r29);
	257	}
	258
	259	asmlinkage int sys_rt_sigreturn(void)
	260	{
	261	struct pt_regs *regs = current_thread_info()->regs;
	262	struct rt_sigframe __user *frame;
	263	sigset_t blocked;
	264
ef9b122f AV	265	/* Always make any pending restarted system calls return -EINTR */
	266	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	267
cd5b61d6 RK	268	frame = (struct rt_sigframe __user *)pt_psp(regs);
	269	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	270	goto badframe;
	271	if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
	272	goto badframe;
	273
43aca324	274	set_current_blocked(&blocked);
cd5b61d6 RK	275
	276	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	277	goto badframe;
	278
	279	/* Restore the user's stack as well */
	280	pt_psp(regs) = regs->r29;
	281
	282	/*
	283	* Leave a trace in the stack frame that this was a sigreturn.
	284	* If the system call is to replay, we've already restored the
	285	* number in the GPR slot and it will be regenerated on the
	286	* new system call trap entry. Note that if restore_sigcontext()
	287	* did something other than a bulk copy of the pt_regs struct,
	288	* we could avoid this assignment by simply not overwriting
	289	* regs->syscall_nr.
	290	*/
	291	regs->syscall_nr = __NR_rt_sigreturn;
	292
	293	/*
	294	* If we were meticulous, we'd only call this if we knew that
	295	* we were actually going to use an alternate stack, and we'd
	296	* consider any error to be fatal. What we do here, in common
	297	* with many other architectures, is call it blindly and only
	298	* consider the -EFAULT return case to be proof of a problem.
	299	*/
	300	if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT)
	301	goto badframe;
	302
	303	return 0;
	304
	305	badframe:
	306	force_sig(SIGSEGV, current);
	307	return 0;
	308	}