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

/*
 * Common signal handling code for both 32 and 64 bits
 *
 *    Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
 *    Extracted from signal_32.c and signal_64.c
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file README.legal in the main directory of
 * this archive for more details.
 */

#include <linux/freezer.h>
#include <linux/ptrace.h>
#include <linux/signal.h>
#include <asm/unistd.h>

#include "signal.h"


#ifdef CONFIG_PPC64
static inline int is_32bit_task(void)
{
	return test_thread_flag(TIF_32BIT);
}
#else
static inline int is_32bit_task(void)
{
	return 1;
}
#endif


/*
 * Restore the user process's signal mask
 */
void restore_sigmask(sigset_t *set)
{
	sigdelsetmask(set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = *set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
}

static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
				  int has_handler)
{
	unsigned long ret = regs->gpr[3];
	int restart = 1;

	/* syscall ? */
	if (TRAP(regs) != 0x0C00)
		return;

	/* error signalled ? */
	if (!(regs->ccr & 0x10000000))
		return;

	switch (ret) {
	case ERESTART_RESTARTBLOCK:
	case ERESTARTNOHAND:
		/* ERESTARTNOHAND means that the syscall should only be
		 * restarted if there was no handler for the signal, and since
		 * we only get here if there is a handler, we dont restart.
		 */
		restart = !has_handler;
		break;
	case ERESTARTSYS:
		/* ERESTARTSYS means to restart the syscall if there is no
		 * handler or the handler was registered with SA_RESTART
		 */
		restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
		break;
	case ERESTARTNOINTR:
		/* ERESTARTNOINTR means that the syscall should be
		 * called again after the signal handler returns.
		 */
		break;
	default:
		return;
	}
	if (restart) {
		if (ret == ERESTART_RESTARTBLOCK)
			regs->gpr[0] = __NR_restart_syscall;
		else
			regs->gpr[3] = regs->orig_gpr3;
		regs->nip -= 4;
		regs->result = 0;
	} else {
		regs->result = -EINTR;
		regs->gpr[3] = EINTR;
		regs->ccr |= 0x10000000;
	}
}

int do_signal(sigset_t *oldset, struct pt_regs *regs)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	int ret;
	int is32 = is_32bit_task();

#ifdef CONFIG_PPC32
	if (try_to_freeze()) {
		signr = 0;
		if (!signal_pending(current))
			goto no_signal;
	}
#endif

	if (test_thread_flag(TIF_RESTORE_SIGMASK))
		oldset = &current->saved_sigmask;
	else if (!oldset)
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

#ifdef CONFIG_PPC32
no_signal:
#endif
	/* Is there any syscall restart business here ? */
	check_syscall_restart(regs, &ka, signr > 0);

	if (signr <= 0) {
		/* No signal to deliver -- put the saved sigmask back */
		if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
			clear_thread_flag(TIF_RESTORE_SIGMASK);
			sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
		}
		return 0;               /* no signals delivered */
	}

#ifdef CONFIG_PPC64
        /*
	 * Reenable the DABR before delivering the signal to
	 * user space. The DABR will have been cleared if it
	 * triggered inside the kernel.
	 */
	if (current->thread.dabr)
		set_dabr(current->thread.dabr);
#endif

	if (is32) {
		unsigned int newsp;

		if ((ka.sa.sa_flags & SA_ONSTACK) &&
		    current->sas_ss_size && !on_sig_stack(regs->gpr[1]))
			newsp = current->sas_ss_sp + current->sas_ss_size;
		else
			newsp = regs->gpr[1];

        	if (ka.sa.sa_flags & SA_SIGINFO)
			ret = handle_rt_signal32(signr, &ka, &info, oldset,
					regs, newsp);
		else
			ret = handle_signal32(signr, &ka, &info, oldset,
					regs, newsp);
#ifdef CONFIG_PPC64
	} else {
		ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
#endif
	}

	if (ret) {
		spin_lock_irq(&current->sighand->siglock);
		sigorsets(&current->blocked, &current->blocked,
			  &ka.sa.sa_mask);
		if (!(ka.sa.sa_flags & SA_NODEFER))
			sigaddset(&current->blocked, signr);
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);

		/*
		 * A signal was successfully delivered; the saved sigmask is in
		 * its frame, and we can clear the TIF_RESTORE_SIGMASK flag.
		 */
		if (test_thread_flag(TIF_RESTORE_SIGMASK))
			clear_thread_flag(TIF_RESTORE_SIGMASK);
	}

	return ret;
}

long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
		unsigned long r5, unsigned long r6, unsigned long r7,
		unsigned long r8, struct pt_regs *regs)
{
	return do_sigaltstack(uss, uoss, regs->gpr[1]);
}
Commit	Line	Data
22e38f29 BH	1	/*
	2	* Common signal handling code for both 32 and 64 bits
	3	*
	4	* Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
	5	* Extracted from signal_32.c and signal_64.c
	6	*
	7	* This file is subject to the terms and conditions of the GNU General
	8	* Public License. See the file README.legal in the main directory of
	9	* this archive for more details.
	10	*/
	11
f478f543	12	#include <linux/freezer.h>
22e38f29 BH	13	#include <linux/ptrace.h>
	14	#include <linux/signal.h>
	15	#include <asm/unistd.h>
	16
db277e9a CH	17	#include "signal.h"
	18
	19
f478f543 CH	20	#ifdef CONFIG_PPC64
	21	static inline int is_32bit_task(void)
	22	{
	23	return test_thread_flag(TIF_32BIT);
	24	}
	25	#else
	26	static inline int is_32bit_task(void)
	27	{
	28	return 1;
	29	}
	30	#endif
	31
	32
db277e9a CH	33	/*
	34	* Restore the user process's signal mask
	35	*/
	36	void restore_sigmask(sigset_t *set)
	37	{
	38	sigdelsetmask(set, ~_BLOCKABLE);
	39	spin_lock_irq(&current->sighand->siglock);
	40	current->blocked = *set;
	41	recalc_sigpending();
	42	spin_unlock_irq(&current->sighand->siglock);
	43	}
	44
f478f543 CH	45	static void check_syscall_restart(struct pt_regs regs, struct k_sigaction ka,
f478f543 CH	46	int has_handler)
22e38f29 BH	47	{
	48	unsigned long ret = regs->gpr[3];
	49	int restart = 1;
	50
	51	/* syscall ? */
	52	if (TRAP(regs) != 0x0C00)
	53	return;
	54
	55	/* error signalled ? */
	56	if (!(regs->ccr & 0x10000000))
	57	return;
	58
	59	switch (ret) {
	60	case ERESTART_RESTARTBLOCK:
	61	case ERESTARTNOHAND:
	62	/* ERESTARTNOHAND means that the syscall should only be
	63	* restarted if there was no handler for the signal, and since
	64	* we only get here if there is a handler, we dont restart.
	65	*/
	66	restart = !has_handler;
	67	break;
	68	case ERESTARTSYS:
	69	/* ERESTARTSYS means to restart the syscall if there is no
	70	* handler or the handler was registered with SA_RESTART
	71	*/
	72	restart = !has_handler \|\| (ka->sa.sa_flags & SA_RESTART) != 0;
	73	break;
	74	case ERESTARTNOINTR:
	75	/* ERESTARTNOINTR means that the syscall should be
	76	* called again after the signal handler returns.
	77	*/
	78	break;
	79	default:
	80	return;
	81	}
	82	if (restart) {
	83	if (ret == ERESTART_RESTARTBLOCK)
	84	regs->gpr[0] = __NR_restart_syscall;
	85	else
	86	regs->gpr[3] = regs->orig_gpr3;
	87	regs->nip -= 4;
	88	regs->result = 0;
	89	} else {
	90	regs->result = -EINTR;
	91	regs->gpr[3] = EINTR;
	92	regs->ccr \|= 0x10000000;
	93	}
	94	}
69d15f6b	95
f478f543 CH	96	int do_signal(sigset_t oldset, struct pt_regs regs)
	97	{
	98	siginfo_t info;
	99	int signr;
	100	struct k_sigaction ka;
	101	int ret;
	102	int is32 = is_32bit_task();
	103
	104	#ifdef CONFIG_PPC32
	105	if (try_to_freeze()) {
	106	signr = 0;
	107	if (!signal_pending(current))
	108	goto no_signal;
	109	}
	110	#endif
	111
	112	if (test_thread_flag(TIF_RESTORE_SIGMASK))
	113	oldset = &current->saved_sigmask;
	114	else if (!oldset)
	115	oldset = &current->blocked;
	116
	117	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	118
	119	#ifdef CONFIG_PPC32
	120	no_signal:
	121	#endif
	122	/* Is there any syscall restart business here ? */
	123	check_syscall_restart(regs, &ka, signr > 0);
	124
	125	if (signr <= 0) {
	126	/* No signal to deliver -- put the saved sigmask back */
	127	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
	128	clear_thread_flag(TIF_RESTORE_SIGMASK);
	129	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	130	}
	131	return 0; /* no signals delivered */
	132	}
	133
	134	#ifdef CONFIG_PPC64
	135	/*
	136	* Reenable the DABR before delivering the signal to
	137	* user space. The DABR will have been cleared if it
	138	* triggered inside the kernel.
	139	*/
	140	if (current->thread.dabr)
	141	set_dabr(current->thread.dabr);
	142	#endif
	143
	144	if (is32) {
	145	unsigned int newsp;
	146
	147	if ((ka.sa.sa_flags & SA_ONSTACK) &&
	148	current->sas_ss_size && !on_sig_stack(regs->gpr[1]))
	149	newsp = current->sas_ss_sp + current->sas_ss_size;
	150	else
	151	newsp = regs->gpr[1];
	152
	153	if (ka.sa.sa_flags & SA_SIGINFO)
	154	ret = handle_rt_signal32(signr, &ka, &info, oldset,
	155	regs, newsp);
	156	else
	157	ret = handle_signal32(signr, &ka, &info, oldset,
	158	regs, newsp);
	159	#ifdef CONFIG_PPC64
160	} else {
161	ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
162	#endif
163	}
164
165	if (ret) {
166	spin_lock_irq(&current->sighand->siglock);
167	sigorsets(&current->blocked, &current->blocked,
168	&ka.sa.sa_mask);
169	if (!(ka.sa.sa_flags & SA_NODEFER))
170	sigaddset(&current->blocked, signr);
171	recalc_sigpending();
172	spin_unlock_irq(&current->sighand->siglock);
173
174	/*
175	* A signal was successfully delivered; the saved sigmask is in
176	* its frame, and we can clear the TIF_RESTORE_SIGMASK flag.
177	*/
178	if (test_thread_flag(TIF_RESTORE_SIGMASK))
179	clear_thread_flag(TIF_RESTORE_SIGMASK);
180	}
181
182	return ret;
183	}
184
69d15f6b CH	185	long sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	186	unsigned long r5, unsigned long r6, unsigned long r7,
	187	unsigned long r8, struct pt_regs *regs)
	188	{
	189	return do_sigaltstack(uss, uoss, regs->gpr[1]);
	190	}