[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/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();

	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);

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