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

/*
 * Signal support for Hexagon processor
 *
 * Copyright (c) 2010-2012, The Linux Foundation. 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/tracehook.h>
#include <linux/sched/task_stack.h>

#include <asm/registers.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
#include <linux/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 ksignal *ksig, struct pt_regs *regs,
			  size_t frame_size)
{
	unsigned long sp = sigsp(regs->r29, ksig);

	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);
#if CONFIG_HEXAGON_ARCH_VERSION >= 4
	err |= __put_user(regs->cs0, &sc->sc_regs.cs0);
	err |= __put_user(regs->cs1, &sc->sc_regs.cs1);
#endif
	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);
#if CONFIG_HEXAGON_ARCH_VERSION >= 4
	err |= __get_user(regs->cs0, &sc->sc_regs.cs0);
	err |= __get_user(regs->cs1, &sc->sc_regs.cs1);
#endif
	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(struct ksignal *ksig, 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(ksig, regs, sizeof(struct rt_sigframe));

	if (!access_ok(frame, sizeof(struct rt_sigframe)))
		return -EFAULT;

	if (copy_siginfo_to_user(&frame->info, &ksig->info))
		return -EFAULT;

	/* 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));
	err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs));
	if (err)
		return -EFAULT;

	/* Load r0/r1 pair with signumber/siginfo pointer... */
	regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
		| (unsigned long long)ksig->sig;
	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)ksig->ka.sa.sa_handler);

	return 0;
}

/*
 * Setup invocation of signal handler
 */
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
	int ret;

	/*
	 * 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 (!(ksig->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. */
	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);

	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
}

/*
 * Called from return-from-event code.
 */
void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;

	if (!user_mode(regs))
		return;

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

	/*
	 * No (more) signals; 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();
}

/*
 * Architecture-specific wrappers for signal-related system calls
 */

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

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

	frame = (struct rt_sigframe __user *)pt_psp(regs);
	if (!access_ok(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;

	regs->syscall_nr = -1;

	if (restore_altstack(&frame->uc.uc_stack))
		goto badframe;

	return regs->r00;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}
Commit	Line	Data
cd5b61d6 RK	1	/*
	2	* Signal support for Hexagon processor
	3	*
7c6a5df4	4	* Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
cd5b61d6 RK	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>
cd5b61d6	23	#include <linux/tracehook.h>
68db0cf1 IM	24	#include <linux/sched/task_stack.h>
68db0cf1 IM	25
cd5b61d6 RK	26	#include <asm/registers.h>
	27	#include <asm/thread_info.h>
	28	#include <asm/unistd.h>
7c0f6ba6	29	#include <linux/uaccess.h>
cd5b61d6 RK	30	#include <asm/ucontext.h>
	31	#include <asm/cacheflush.h>
	32	#include <asm/signal.h>
	33	#include <asm/vdso.h>
	34
cd5b61d6 RK	35	struct rt_sigframe {
	36	unsigned long tramp[2];
	37	struct siginfo info;
	38	struct ucontext uc;
	39	};
	40
8bc77aa4	41	static void __user get_sigframe(struct ksignal ksig, struct pt_regs *regs,
cd5b61d6 RK	42	size_t frame_size)
cd5b61d6 RK	43	{
8bc77aa4	44	unsigned long sp = sigsp(regs->r29, ksig);
cd5b61d6 RK	45
	46	return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
	47	}
	48
	49	static int setup_sigcontext(struct pt_regs regs, struct sigcontext __user sc)
	50	{
	51	unsigned long tmp;
	52	int err = 0;
	53
	54	err \|= copy_to_user(&sc->sc_regs.r0, &regs->r00,
	55	32*sizeof(unsigned long));
	56
	57	err \|= __put_user(regs->sa0, &sc->sc_regs.sa0);
	58	err \|= __put_user(regs->lc0, &sc->sc_regs.lc0);
	59	err \|= __put_user(regs->sa1, &sc->sc_regs.sa1);
	60	err \|= __put_user(regs->lc1, &sc->sc_regs.lc1);
	61	err \|= __put_user(regs->m0, &sc->sc_regs.m0);
	62	err \|= __put_user(regs->m1, &sc->sc_regs.m1);
	63	err \|= __put_user(regs->usr, &sc->sc_regs.usr);
	64	err \|= __put_user(regs->preds, &sc->sc_regs.p3_0);
	65	err \|= __put_user(regs->gp, &sc->sc_regs.gp);
	66	err \|= __put_user(regs->ugp, &sc->sc_regs.ugp);
60c4ba99 RK	67	#if CONFIG_HEXAGON_ARCH_VERSION >= 4
	68	err \|= __put_user(regs->cs0, &sc->sc_regs.cs0);
	69	err \|= __put_user(regs->cs1, &sc->sc_regs.cs1);
	70	#endif
cd5b61d6 RK	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);
60c4ba99 RK	97	#if CONFIG_HEXAGON_ARCH_VERSION >= 4
	98	err \|= __get_user(regs->cs0, &sc->sc_regs.cs0);
	99	err \|= __get_user(regs->cs1, &sc->sc_regs.cs1);
	100	#endif
cd5b61d6 RK	101	err \|= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
	102
	103	return err;
	104	}
	105
	106	/*
	107	* Setup signal stack frame with siginfo structure
	108	*/
ac443624 RW	109	static int setup_rt_frame(struct ksignal ksig, sigset_t set,
ac443624 RW	110	struct pt_regs *regs)
cd5b61d6 RK	111	{
	112	int err = 0;
	113	struct rt_sigframe __user *frame;
	114	struct hexagon_vdso *vdso = current->mm->context.vdso;
	115
8bc77aa4	116	frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe));
cd5b61d6	117
96d4f267	118	if (!access_ok(frame, sizeof(struct rt_sigframe)))
ac443624	119	return -EFAULT;
cd5b61d6	120
ac443624 RW	121	if (copy_siginfo_to_user(&frame->info, &ksig->info))
ac443624 RW	122	return -EFAULT;
cd5b61d6 RK	123
	124	/* The on-stack signal trampoline is no longer executed;
	125	* however, the libgcc signal frame unwinding code checks for
	126	* the presence of these two numeric magic values.
	127	*/
	128	err \|= __put_user(0x7800d166, &frame->tramp[0]);
	129	err \|= __put_user(0x5400c004, &frame->tramp[1]);
	130	err \|= setup_sigcontext(regs, &frame->uc.uc_mcontext);
	131	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
da36f98a	132	err \|= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs));
cd5b61d6	133	if (err)
ac443624	134	return -EFAULT;
cd5b61d6 RK	135
	136	/* Load r0/r1 pair with signumber/siginfo pointer... */
	137	regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
ac443624	138	\| (unsigned long long)ksig->sig;
cd5b61d6 RK	139	regs->r02 = (unsigned long) &frame->uc;
	140	regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
	141	pt_psp(regs) = (unsigned long) frame;
ac443624	142	pt_set_elr(regs, (unsigned long)ksig->ka.sa.sa_handler);
cd5b61d6 RK	143
cd5b61d6 RK	144	return 0;
cd5b61d6 RK	145	}
	146
	147	/*
	148	* Setup invocation of signal handler
	149	*/
ac443624	150	static void handle_signal(struct ksignal ksig, struct pt_regs regs)
cd5b61d6	151	{
ac443624 RW	152	int ret;
ac443624 RW	153
cd5b61d6 RK	154	/*
	155	* If we're handling a signal that aborted a system call,
	156	* set up the error return value before adding the signal
	157	* frame to the stack.
	158	*/
	159
	160	if (regs->syscall_nr >= 0) {
	161	switch (regs->r00) {
	162	case -ERESTART_RESTARTBLOCK:
	163	case -ERESTARTNOHAND:
	164	regs->r00 = -EINTR;
	165	break;
	166	case -ERESTARTSYS:
ac443624	167	if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
cd5b61d6 RK	168	regs->r00 = -EINTR;
	169	break;
	170	}
	171	/* Fall through */
	172	case -ERESTARTNOINTR:
	173	regs->r06 = regs->syscall_nr;
	174	pt_set_elr(regs, pt_elr(regs) - 4);
	175	regs->r00 = regs->restart_r0;
	176	break;
	177	default:
	178	break;
	179	}
	180	}
	181
	182	/*
	183	* Set up the stack frame; not doing the SA_SIGINFO thing. We
	184	* only set up the rt_frame flavor.
	185	*/
cd5b61d6	186	/* If there was an error on setup, no signal was delivered. */
ac443624	187	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
cd5b61d6	188
ac443624	189	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
cd5b61d6 RK	190	}
	191
	192	/*
	193	* Called from return-from-event code.
	194	*/
a11e67c2	195	void do_signal(struct pt_regs *regs)
cd5b61d6	196	{
ac443624	197	struct ksignal ksig;
cd5b61d6 RK	198
	199	if (!user_mode(regs))
	200	return;
	201
ac443624 RW	202	if (get_signal(&ksig)) {
ac443624 RW	203	handle_signal(&ksig, regs);
cd5b61d6 RK	204	return;
	205	}
	206
cd5b61d6	207	/*
a11e67c2	208	* No (more) signals; if we came from a system call, handle the restart.
cd5b61d6	209	*/
a11e67c2	210
cd5b61d6 RK	211	if (regs->syscall_nr >= 0) {
	212	switch (regs->r00) {
	213	case -ERESTARTNOHAND:
	214	case -ERESTARTSYS:
	215	case -ERESTARTNOINTR:
	216	regs->r06 = regs->syscall_nr;
	217	break;
	218	case -ERESTART_RESTARTBLOCK:
	219	regs->r06 = __NR_restart_syscall;
	220	break;
	221	default:
	222	goto no_restart;
	223	}
	224	pt_set_elr(regs, pt_elr(regs) - 4);
	225	regs->r00 = regs->restart_r0;
	226	}
	227
	228	no_restart:
	229	/* If there's no signal to deliver, put the saved sigmask back */
51a7b448	230	restore_saved_sigmask();
cd5b61d6 RK	231	}
cd5b61d6 RK	232
cd5b61d6 RK	233	/*
	234	* Architecture-specific wrappers for signal-related system calls
	235	*/
cd5b61d6 RK	236
	237	asmlinkage int sys_rt_sigreturn(void)
	238	{
99521855	239	struct pt_regs *regs = current_pt_regs();
cd5b61d6 RK	240	struct rt_sigframe __user *frame;
	241	sigset_t blocked;
	242
ef9b122f	243	/* Always make any pending restarted system calls return -EINTR */
f56141e3	244	current->restart_block.fn = do_no_restart_syscall;
ef9b122f	245
cd5b61d6	246	frame = (struct rt_sigframe __user *)pt_psp(regs);
96d4f267	247	if (!access_ok(frame, sizeof(*frame)))
cd5b61d6 RK	248	goto badframe;
	249	if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
	250	goto badframe;
	251
43aca324	252	set_current_blocked(&blocked);
cd5b61d6 RK	253
	254	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
	255	goto badframe;
	256
	257	/* Restore the user's stack as well */
	258	pt_psp(regs) = regs->r29;
	259
a11e67c2	260	regs->syscall_nr = -1;
cd5b61d6	261
1e974c21	262	if (restore_altstack(&frame->uc.uc_stack))
cd5b61d6 RK	263	goto badframe;
cd5b61d6 RK	264
a11e67c2	265	return regs->r00;
cd5b61d6 RK	266
	267	badframe:
	268	force_sig(SIGSEGV, current);
	269	return 0;
	270	}