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

/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <asm/siginfo.h>
#include <asm/signal.h>
#include <asm/unistd.h>
#include <frame_kern.h>
#include <kern_util.h>

EXPORT_SYMBOL(block_signals);
EXPORT_SYMBOL(unblock_signals);

/*
 * OK, we're invoking a handler
 */
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
	sigset_t *oldset = sigmask_to_save();
	int singlestep = 0;
	unsigned long sp;
	int err;

	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
		singlestep = 1;

	/* Did we come from a system call? */
	if (PT_REGS_SYSCALL_NR(regs) >= 0) {
		/* If so, check system call restarting.. */
		switch (PT_REGS_SYSCALL_RET(regs)) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			PT_REGS_SYSCALL_RET(regs) = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
				PT_REGS_SYSCALL_RET(regs) = -EINTR;
				break;
			}
		/* fallthrough */
		case -ERESTARTNOINTR:
			PT_REGS_RESTART_SYSCALL(regs);
			PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
			break;
		}
	}

	sp = PT_REGS_SP(regs);
	if ((ksig->ka.sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
		sp = current->sas_ss_sp + current->sas_ss_size;

#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
	if (!(ksig->ka.sa.sa_flags & SA_SIGINFO))
		err = setup_signal_stack_sc(sp, ksig, regs, oldset);
	else
#endif
		err = setup_signal_stack_si(sp, ksig, regs, oldset);

	signal_setup_done(err, ksig, singlestep);
}

void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;
	int handled_sig = 0;

	while (get_signal(&ksig)) {
		handled_sig = 1;
		/* Whee!  Actually deliver the signal.  */
		handle_signal(&ksig, regs);
	}

	/* Did we come from a system call? */
	if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
		/* Restart the system call - no handlers present */
		switch (PT_REGS_SYSCALL_RET(regs)) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
			PT_REGS_RESTART_SYSCALL(regs);
			break;
		case -ERESTART_RESTARTBLOCK:
			PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
			PT_REGS_RESTART_SYSCALL(regs);
			break;
		}
	}

	/*
	 * This closes a way to execute a system call on the host.  If
	 * you set a breakpoint on a system call instruction and singlestep
	 * from it, the tracing thread used to PTRACE_SINGLESTEP the process
	 * rather than PTRACE_SYSCALL it, allowing the system call to execute
	 * on the host.  The tracing thread will check this flag and
	 * PTRACE_SYSCALL if necessary.
	 */
	if (current->ptrace & PT_DTRACE)
		current->thread.singlestep_syscall =
			is_syscall(PT_REGS_IP(&current->thread.regs));

	/*
	 * if there's no signal to deliver, we just put the saved sigmask
	 * back
	 */
	if (!handled_sig)
		restore_saved_sigmask();
}
Commit	Line	Data
1d3468a6	1	/*
ba180fd4	2	* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
1da177e4 LT	3	* Licensed under the GPL
	4	*/
	5
c5d4bb17 JD	6	#include <linux/module.h>
	7	#include <linux/ptrace.h>
	8	#include <linux/sched.h>
	9	#include <asm/siginfo.h>
	10	#include <asm/signal.h>
	11	#include <asm/unistd.h>
37185b33 AV	12	#include <frame_kern.h>
37185b33 AV	13	#include <kern_util.h>
1da177e4 LT	14
	15	EXPORT_SYMBOL(block_signals);
	16	EXPORT_SYMBOL(unblock_signals);
	17
1da177e4 LT	18	/*
1da177e4 LT	19	* OK, we're invoking a handler
1d3468a6	20	*/
307627ee	21	static void handle_signal(struct ksignal ksig, struct pt_regs regs)
1da177e4	22	{
b7f9a11a	23	sigset_t *oldset = sigmask_to_save();
f9a38eac	24	int singlestep = 0;
1da177e4 LT	25	unsigned long sp;
	26	int err;
	27
f9a38eac AV	28	if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
	29	singlestep = 1;
	30
1da177e4	31	/* Did we come from a system call? */
ba180fd4	32	if (PT_REGS_SYSCALL_NR(regs) >= 0) {
1da177e4	33	/* If so, check system call restarting.. */
c5d4bb17	34	switch (PT_REGS_SYSCALL_RET(regs)) {
1da177e4 LT	35	case -ERESTART_RESTARTBLOCK:
	36	case -ERESTARTNOHAND:
	37	PT_REGS_SYSCALL_RET(regs) = -EINTR;
	38	break;
	39
	40	case -ERESTARTSYS:
307627ee	41	if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
1da177e4 LT	42	PT_REGS_SYSCALL_RET(regs) = -EINTR;
	43	break;
	44	}
	45	/* fallthrough */
	46	case -ERESTARTNOINTR:
	47	PT_REGS_RESTART_SYSCALL(regs);
	48	PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
	49	break;
	50	}
	51	}
	52
	53	sp = PT_REGS_SP(regs);
307627ee	54	if ((ksig->ka.sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
1da177e4 LT	55	sp = current->sas_ss_sp + current->sas_ss_size;
	56
	57	#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
307627ee RW	58	if (!(ksig->ka.sa.sa_flags & SA_SIGINFO))
307627ee RW	59	err = setup_signal_stack_sc(sp, ksig, regs, oldset);
1da177e4 LT	60	else
1da177e4 LT	61	#endif
307627ee	62	err = setup_signal_stack_si(sp, ksig, regs, oldset);
1da177e4	63
307627ee	64	signal_setup_done(err, ksig, singlestep);
1da177e4 LT	65	}
1da177e4 LT	66
ccaee5f8	67	void do_signal(struct pt_regs *regs)
1da177e4	68	{
307627ee RW	69	struct ksignal ksig;
307627ee RW	70	int handled_sig = 0;
1da177e4	71
322740ef	72	while (get_signal(&ksig)) {
1da177e4 LT	73	handled_sig = 1;
1da177e4 LT	74	/* Whee! Actually deliver the signal. */
307627ee	75	handle_signal(&ksig, regs);
1da177e4 LT	76	}
	77
	78	/* Did we come from a system call? */
ba180fd4	79	if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
1da177e4	80	/* Restart the system call - no handlers present */
c5d4bb17	81	switch (PT_REGS_SYSCALL_RET(regs)) {
2fc10620 JD	82	case -ERESTARTNOHAND:
	83	case -ERESTARTSYS:
	84	case -ERESTARTNOINTR:
1da177e4 LT	85	PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
1da177e4 LT	86	PT_REGS_RESTART_SYSCALL(regs);
2fc10620 JD	87	break;
2fc10620 JD	88	case -ERESTART_RESTARTBLOCK:
1d3468a6	89	PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
1da177e4	90	PT_REGS_RESTART_SYSCALL(regs);
2fc10620	91	break;
ba180fd4	92	}
1da177e4 LT	93	}
1da177e4 LT	94
ba180fd4 JD	95	/*
ba180fd4 JD	96	* This closes a way to execute a system call on the host. If
1da177e4 LT	97	* you set a breakpoint on a system call instruction and singlestep
	98	* from it, the tracing thread used to PTRACE_SINGLESTEP the process
	99	* rather than PTRACE_SYSCALL it, allowing the system call to execute
1d3468a6	100	* on the host. The tracing thread will check this flag and
1da177e4 LT	101	* PTRACE_SYSCALL if necessary.
1da177e4 LT	102	*/
ba180fd4	103	if (current->ptrace & PT_DTRACE)
1da177e4 LT	104	current->thread.singlestep_syscall =
1da177e4 LT	105	is_syscall(PT_REGS_IP(&current->thread.regs));
2fc10620	106
ba180fd4 JD	107	/*
	108	* if there's no signal to deliver, we just put the saved sigmask
	109	* back
	110	*/
51a7b448 AV	111	if (!handled_sig)
51a7b448 AV	112	restore_saved_sigmask();
1da177e4	113	}