[thirdparty/linux.git] / arch / alpha / kernel / signal.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/arch/alpha/kernel/signal.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  1997-11-02  Modified for POSIX.1b signals by Richard Henderson
 */

#include <linux/sched/signal.h>
#include <linux/sched/task_stack.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/bitops.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>

#include <linux/uaccess.h>
#include <asm/sigcontext.h>
#include <asm/ucontext.h>

#include "proto.h"


#define DEBUG_SIG 0

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

asmlinkage void ret_from_sys_call(void);

/*
 * The OSF/1 sigprocmask calling sequence is different from the
 * C sigprocmask() sequence..
 */
SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
{
	sigset_t oldmask;
	sigset_t mask;
	unsigned long res;

	siginitset(&mask, newmask & _BLOCKABLE);
	res = sigprocmask(how, &mask, &oldmask);
	if (!res) {
		force_successful_syscall_return();
		res = oldmask.sig[0];
	}
	return res;
}

SYSCALL_DEFINE3(osf_sigaction, int, sig,
		const struct osf_sigaction __user *, act,
		struct osf_sigaction __user *, oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	if (act) {
		old_sigset_t mask;
		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
		    __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
		    __get_user(mask, &act->sa_mask))
			return -EFAULT;
		siginitset(&new_ka.sa.sa_mask, mask);
		new_ka.ka_restorer = NULL;
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
		    __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
		    __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
			return -EFAULT;
	}

	return ret;
}

SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
		struct sigaction __user *, oact,
		size_t, sigsetsize, void __user *, restorer)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	if (act) {
		new_ka.ka_restorer = restorer;
		if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
			return -EFAULT;
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
			return -EFAULT;
	}

	return ret;
}

/*
 * Do a signal return; undo the signal stack.
 */

#if _NSIG_WORDS > 1
# error "Non SA_SIGINFO frame needs rearranging"
#endif

struct sigframe
{
	struct sigcontext sc;
	unsigned int retcode[3];
};

struct rt_sigframe
{
	struct siginfo info;
	struct ucontext uc;
	unsigned int retcode[3];
};

/* If this changes, userland unwinders that Know Things about our signal
   frame will break.  Do not undertake lightly.  It also implies an ABI
   change wrt the size of siginfo_t, which may cause some pain.  */
extern char compile_time_assert
        [offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1];

#define INSN_MOV_R30_R16	0x47fe0410
#define INSN_LDI_R0		0x201f0000
#define INSN_CALLSYS		0x00000083

static long
restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
{
	unsigned long usp;
	struct switch_stack *sw = (struct switch_stack *)regs - 1;
	long i, err = __get_user(regs->pc, &sc->sc_pc);

	current->restart_block.fn = do_no_restart_syscall;

	sw->r26 = (unsigned long) ret_from_sys_call;

	err |= __get_user(regs->r0, sc->sc_regs+0);
	err |= __get_user(regs->r1, sc->sc_regs+1);
	err |= __get_user(regs->r2, sc->sc_regs+2);
	err |= __get_user(regs->r3, sc->sc_regs+3);
	err |= __get_user(regs->r4, sc->sc_regs+4);
	err |= __get_user(regs->r5, sc->sc_regs+5);
	err |= __get_user(regs->r6, sc->sc_regs+6);
	err |= __get_user(regs->r7, sc->sc_regs+7);
	err |= __get_user(regs->r8, sc->sc_regs+8);
	err |= __get_user(sw->r9, sc->sc_regs+9);
	err |= __get_user(sw->r10, sc->sc_regs+10);
	err |= __get_user(sw->r11, sc->sc_regs+11);
	err |= __get_user(sw->r12, sc->sc_regs+12);
	err |= __get_user(sw->r13, sc->sc_regs+13);
	err |= __get_user(sw->r14, sc->sc_regs+14);
	err |= __get_user(sw->r15, sc->sc_regs+15);
	err |= __get_user(regs->r16, sc->sc_regs+16);
	err |= __get_user(regs->r17, sc->sc_regs+17);
	err |= __get_user(regs->r18, sc->sc_regs+18);
	err |= __get_user(regs->r19, sc->sc_regs+19);
	err |= __get_user(regs->r20, sc->sc_regs+20);
	err |= __get_user(regs->r21, sc->sc_regs+21);
	err |= __get_user(regs->r22, sc->sc_regs+22);
	err |= __get_user(regs->r23, sc->sc_regs+23);
	err |= __get_user(regs->r24, sc->sc_regs+24);
	err |= __get_user(regs->r25, sc->sc_regs+25);
	err |= __get_user(regs->r26, sc->sc_regs+26);
	err |= __get_user(regs->r27, sc->sc_regs+27);
	err |= __get_user(regs->r28, sc->sc_regs+28);
	err |= __get_user(regs->gp, sc->sc_regs+29);
	err |= __get_user(usp, sc->sc_regs+30);
	wrusp(usp);

	for (i = 0; i < 31; i++)
		err |= __get_user(sw->fp[i], sc->sc_fpregs+i);
	err |= __get_user(sw->fp[31], &sc->sc_fpcr);

	return err;
}

/* Note that this syscall is also used by setcontext(3) to install
   a given sigcontext.  This because it's impossible to set *all*
   registers and transfer control from userland.  */

asmlinkage void
do_sigreturn(struct sigcontext __user *sc)
{
	struct pt_regs *regs = current_pt_regs();
	sigset_t set;

	/* Verify that it's a good sigcontext before using it */
	if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
		goto give_sigsegv;
	if (__get_user(set.sig[0], &sc->sc_mask))
		goto give_sigsegv;

	set_current_blocked(&set);

	if (restore_sigcontext(sc, regs))
		goto give_sigsegv;

	/* Send SIGTRAP if we're single-stepping: */
	if (ptrace_cancel_bpt (current)) {
		siginfo_t info;

		info.si_signo = SIGTRAP;
		info.si_errno = 0;
		info.si_code = TRAP_BRKPT;
		info.si_addr = (void __user *) regs->pc;
		info.si_trapno = 0;
		send_sig_info(SIGTRAP, &info, current);
	}
	return;

give_sigsegv:
	force_sig(SIGSEGV, current);
}

asmlinkage void
do_rt_sigreturn(struct rt_sigframe __user *frame)
{
	struct pt_regs *regs = current_pt_regs();
	sigset_t set;

	/* Verify that it's a good ucontext_t before using it */
	if (!access_ok(VERIFY_READ, &frame->uc, sizeof(frame->uc)))
		goto give_sigsegv;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto give_sigsegv;

	set_current_blocked(&set);

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

	/* Send SIGTRAP if we're single-stepping: */
	if (ptrace_cancel_bpt (current)) {
		siginfo_t info;

		info.si_signo = SIGTRAP;
		info.si_errno = 0;
		info.si_code = TRAP_BRKPT;
		info.si_addr = (void __user *) regs->pc;
		info.si_trapno = 0;
		send_sig_info(SIGTRAP, &info, current);
	}
	return;

give_sigsegv:
	force_sig(SIGSEGV, current);
}


/*
 * Set up a signal frame.
 */

static inline void __user *
get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
{
	return (void __user *)((sigsp(sp, ksig) - frame_size) & -32ul);
}

static long
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 
		 unsigned long mask, unsigned long sp)
{
	struct switch_stack *sw = (struct switch_stack *)regs - 1;
	long i, err = 0;

	err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
	err |= __put_user(mask, &sc->sc_mask);
	err |= __put_user(regs->pc, &sc->sc_pc);
	err |= __put_user(8, &sc->sc_ps);

	err |= __put_user(regs->r0 , sc->sc_regs+0);
	err |= __put_user(regs->r1 , sc->sc_regs+1);
	err |= __put_user(regs->r2 , sc->sc_regs+2);
	err |= __put_user(regs->r3 , sc->sc_regs+3);
	err |= __put_user(regs->r4 , sc->sc_regs+4);
	err |= __put_user(regs->r5 , sc->sc_regs+5);
	err |= __put_user(regs->r6 , sc->sc_regs+6);
	err |= __put_user(regs->r7 , sc->sc_regs+7);
	err |= __put_user(regs->r8 , sc->sc_regs+8);
	err |= __put_user(sw->r9   , sc->sc_regs+9);
	err |= __put_user(sw->r10  , sc->sc_regs+10);
	err |= __put_user(sw->r11  , sc->sc_regs+11);
	err |= __put_user(sw->r12  , sc->sc_regs+12);
	err |= __put_user(sw->r13  , sc->sc_regs+13);
	err |= __put_user(sw->r14  , sc->sc_regs+14);
	err |= __put_user(sw->r15  , sc->sc_regs+15);
	err |= __put_user(regs->r16, sc->sc_regs+16);
	err |= __put_user(regs->r17, sc->sc_regs+17);
	err |= __put_user(regs->r18, sc->sc_regs+18);
	err |= __put_user(regs->r19, sc->sc_regs+19);
	err |= __put_user(regs->r20, sc->sc_regs+20);
	err |= __put_user(regs->r21, sc->sc_regs+21);
	err |= __put_user(regs->r22, sc->sc_regs+22);
	err |= __put_user(regs->r23, sc->sc_regs+23);
	err |= __put_user(regs->r24, sc->sc_regs+24);
	err |= __put_user(regs->r25, sc->sc_regs+25);
	err |= __put_user(regs->r26, sc->sc_regs+26);
	err |= __put_user(regs->r27, sc->sc_regs+27);
	err |= __put_user(regs->r28, sc->sc_regs+28);
	err |= __put_user(regs->gp , sc->sc_regs+29);
	err |= __put_user(sp, sc->sc_regs+30);
	err |= __put_user(0, sc->sc_regs+31);

	for (i = 0; i < 31; i++)
		err |= __put_user(sw->fp[i], sc->sc_fpregs+i);
	err |= __put_user(0, sc->sc_fpregs+31);
	err |= __put_user(sw->fp[31], &sc->sc_fpcr);

	err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0);
	err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1);
	err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2);

	return err;
}

static int
setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
{
	unsigned long oldsp, r26, err = 0;
	struct sigframe __user *frame;

	oldsp = rdusp();
	frame = get_sigframe(ksig, oldsp, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);
	if (err)
		return -EFAULT;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	r26 = (unsigned long) ksig->ka.ka_restorer;
	if (!r26) {
		err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
		err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1);
		err |= __put_user(INSN_CALLSYS, frame->retcode+2);
		imb();
		r26 = (unsigned long) frame->retcode;
	}

	/* Check that everything was written properly.  */
	if (err)
		return err;

	/* "Return" to the handler */
	regs->r26 = r26;
	regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
	regs->r16 = ksig->sig;			/* a0: signal number */
	regs->r17 = 0;				/* a1: exception code */
	regs->r18 = (unsigned long) &frame->sc;	/* a2: sigcontext pointer */
	wrusp((unsigned long) frame);
	
#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
		current->comm, current->pid, frame, regs->pc, regs->r26);
#endif
	return 0;
}

static int
setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
{
	unsigned long oldsp, r26, err = 0;
	struct rt_sigframe __user *frame;

	oldsp = rdusp();
	frame = get_sigframe(ksig, oldsp, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	err |= copy_siginfo_to_user(&frame->info, &ksig->info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
	err |= __save_altstack(&frame->uc.uc_stack, oldsp);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, 
				set->sig[0], oldsp);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		return -EFAULT;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	r26 = (unsigned long) ksig->ka.ka_restorer;
	if (!r26) {
		err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
		err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn,
				  frame->retcode+1);
		err |= __put_user(INSN_CALLSYS, frame->retcode+2);
		imb();
		r26 = (unsigned long) frame->retcode;
	}

	if (err)
		return -EFAULT;

	/* "Return" to the handler */
	regs->r26 = r26;
	regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
	regs->r16 = ksig->sig;			  /* a0: signal number */
	regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */
	regs->r18 = (unsigned long) &frame->uc;	  /* a2: ucontext pointer */
	wrusp((unsigned long) frame);

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
		current->comm, current->pid, frame, regs->pc, regs->r26);
#endif

	return 0;
}


/*
 * OK, we're invoking a handler.
 */
static inline void
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
	sigset_t *oldset = sigmask_to_save();
	int ret;

	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
		ret = setup_rt_frame(ksig, oldset, regs);
	else
		ret = setup_frame(ksig, oldset, regs);

	signal_setup_done(ret, ksig, 0);
}

static inline void
syscall_restart(unsigned long r0, unsigned long r19,
		struct pt_regs *regs, struct k_sigaction *ka)
{
	switch (regs->r0) {
	case ERESTARTSYS:
		if (!(ka->sa.sa_flags & SA_RESTART)) {
		case ERESTARTNOHAND:
			regs->r0 = EINTR;
			break;
		}
		/* fallthrough */
	case ERESTARTNOINTR:
		regs->r0 = r0;	/* reset v0 and a3 and replay syscall */
		regs->r19 = r19;
		regs->pc -= 4;
		break;
	case ERESTART_RESTARTBLOCK:
		regs->r0 = EINTR;
		break;
	}
}


/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 *
 * Note that we go through the signals twice: once to check the signals that
 * the kernel can handle, and then we build all the user-level signal handling
 * stack-frames in one go after that.
 *
 * "r0" and "r19" are the registers we need to restore for system call
 * restart. "r0" is also used as an indicator whether we can restart at
 * all (if we get here from anything but a syscall return, it will be 0)
 */
static void
do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
{
	unsigned long single_stepping = ptrace_cancel_bpt(current);
	struct ksignal ksig;

	/* This lets the debugger run, ... */
	if (get_signal(&ksig)) {
		/* ... so re-check the single stepping. */
		single_stepping |= ptrace_cancel_bpt(current);
		/* Whee!  Actually deliver the signal.  */
		if (r0)
			syscall_restart(r0, r19, regs, &ksig.ka);
		handle_signal(&ksig, regs);
	} else {
		single_stepping |= ptrace_cancel_bpt(current);
		if (r0) {
			switch (regs->r0) {
			case ERESTARTNOHAND:
			case ERESTARTSYS:
			case ERESTARTNOINTR:
				/* Reset v0 and a3 and replay syscall.  */
				regs->r0 = r0;
				regs->r19 = r19;
				regs->pc -= 4;
				break;
			case ERESTART_RESTARTBLOCK:
				/* Set v0 to the restart_syscall and replay */
				regs->r0 = __NR_restart_syscall;
				regs->pc -= 4;
				break;
			}
		}
		restore_saved_sigmask();
	}
	if (single_stepping)
		ptrace_set_bpt(current);	/* re-set breakpoint */
}

void
do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
		 unsigned long r0, unsigned long r19)
{
	do {
		if (thread_flags & _TIF_NEED_RESCHED) {
			schedule();
		} else {
			local_irq_enable();
			if (thread_flags & _TIF_SIGPENDING) {
				do_signal(regs, r0, r19);
				r0 = 0;
			} else {
				clear_thread_flag(TIF_NOTIFY_RESUME);
				tracehook_notify_resume(regs);
			}
		}
		local_irq_disable();
		thread_flags = current_thread_info()->flags;
	} while (thread_flags & _TIF_WORK_MASK);
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/arch/alpha/kernel/signal.c
	4	*
	5	* Copyright (C) 1995 Linus Torvalds
	6	*
	7	* 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
	8	*/
	9
3f07c014	10	#include <linux/sched/signal.h>
68db0cf1	11	#include <linux/sched/task_stack.h>
1da177e4 LT	12	#include <linux/kernel.h>
	13	#include <linux/signal.h>
	14	#include <linux/errno.h>
	15	#include <linux/wait.h>
	16	#include <linux/ptrace.h>
	17	#include <linux/unistd.h>
	18	#include <linux/mm.h>
	19	#include <linux/smp.h>
1da177e4 LT	20	#include <linux/stddef.h>
	21	#include <linux/tty.h>
	22	#include <linux/binfmts.h>
	23	#include <linux/bitops.h>
e5d9a90c	24	#include <linux/syscalls.h>
733e5e4b	25	#include <linux/tracehook.h>
1da177e4	26
7c0f6ba6	27	#include <linux/uaccess.h>
1da177e4 LT	28	#include <asm/sigcontext.h>
	29	#include <asm/ucontext.h>
	30
	31	#include "proto.h"
	32
	33
	34	#define DEBUG_SIG 0
	35
	36	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	37
	38	asmlinkage void ret_from_sys_call(void);
1da177e4 LT	39
	40	/*
	41	* The OSF/1 sigprocmask calling sequence is different from the
	42	* C sigprocmask() sequence..
1da177e4	43	*/
c52c2ddc	44	SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
1da177e4	45	{
c52c2ddc AV	46	sigset_t oldmask;
	47	sigset_t mask;
	48	unsigned long res;
1da177e4	49
87400e54	50	siginitset(&mask, newmask & _BLOCKABLE);
0f44fbd2	51	res = sigprocmask(how, &mask, &oldmask);
c52c2ddc AV	52	if (!res) {
c52c2ddc AV	53	force_successful_syscall_return();
0f44fbd2	54	res = oldmask.sig[0];
1da177e4	55	}
c52c2ddc	56	return res;
1da177e4 LT	57	}
1da177e4 LT	58
e5d9a90c IK	59	SYSCALL_DEFINE3(osf_sigaction, int, sig,
	60	const struct osf_sigaction __user *, act,
	61	struct osf_sigaction __user *, oact)
1da177e4 LT	62	{
	63	struct k_sigaction new_ka, old_ka;
	64	int ret;
	65
	66	if (act) {
	67	old_sigset_t mask;
	68	if (!access_ok(VERIFY_READ, act, sizeof(*act)) \|\|
	69	__get_user(new_ka.sa.sa_handler, &act->sa_handler) \|\|
18e6bfa9 AV	70	__get_user(new_ka.sa.sa_flags, &act->sa_flags) \|\|
18e6bfa9 AV	71	__get_user(mask, &act->sa_mask))
1da177e4	72	return -EFAULT;
1da177e4 LT	73	siginitset(&new_ka.sa.sa_mask, mask);
	74	new_ka.ka_restorer = NULL;
	75	}
	76
	77	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
	78
	79	if (!ret && oact) {
	80	if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) \|\|
	81	__put_user(old_ka.sa.sa_handler, &oact->sa_handler) \|\|
18e6bfa9 AV	82	__put_user(old_ka.sa.sa_flags, &oact->sa_flags) \|\|
18e6bfa9 AV	83	__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
1da177e4	84	return -EFAULT;
1da177e4 LT	85	}
	86
	87	return ret;
	88	}
	89
e5d9a90c IK	90	SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
	91	struct sigaction __user *, oact,
	92	size_t, sigsetsize, void __user *, restorer)
1da177e4 LT	93	{
	94	struct k_sigaction new_ka, old_ka;
	95	int ret;
	96
	97	/* XXX: Don't preclude handling different sized sigset_t's. */
	98	if (sigsetsize != sizeof(sigset_t))
	99	return -EINVAL;
	100
	101	if (act) {
	102	new_ka.ka_restorer = restorer;
	103	if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
	104	return -EFAULT;
	105	}
	106
	107	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
	108
	109	if (!ret && oact) {
	110	if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
	111	return -EFAULT;
	112	}
	113
	114	return ret;
	115	}
	116
1da177e4 LT	117	/*
	118	* Do a signal return; undo the signal stack.
	119	*/
	120
	121	#if _NSIG_WORDS > 1
	122	# error "Non SA_SIGINFO frame needs rearranging"
	123	#endif
	124
	125	struct sigframe
	126	{
	127	struct sigcontext sc;
	128	unsigned int retcode[3];
	129	};
	130
	131	struct rt_sigframe
	132	{
	133	struct siginfo info;
	134	struct ucontext uc;
	135	unsigned int retcode[3];
	136	};
	137
	138	/* If this changes, userland unwinders that Know Things about our signal
	139	frame will break. Do not undertake lightly. It also implies an ABI
	140	change wrt the size of siginfo_t, which may cause some pain. */
	141	extern char compile_time_assert
	142	[offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1];
	143
	144	#define INSN_MOV_R30_R16 0x47fe0410
	145	#define INSN_LDI_R0 0x201f0000
	146	#define INSN_CALLSYS 0x00000083
	147
	148	static long
b960f303	149	restore_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
1da177e4 LT	150	{
1da177e4 LT	151	unsigned long usp;
b960f303	152	struct switch_stack sw = (struct switch_stack )regs - 1;
1da177e4 LT	153	long i, err = __get_user(regs->pc, &sc->sc_pc);
1da177e4 LT	154
f56141e3	155	current->restart_block.fn = do_no_restart_syscall;
2deba1bd	156
1da177e4 LT	157	sw->r26 = (unsigned long) ret_from_sys_call;
	158
	159	err \|= __get_user(regs->r0, sc->sc_regs+0);
	160	err \|= __get_user(regs->r1, sc->sc_regs+1);
	161	err \|= __get_user(regs->r2, sc->sc_regs+2);
	162	err \|= __get_user(regs->r3, sc->sc_regs+3);
	163	err \|= __get_user(regs->r4, sc->sc_regs+4);
	164	err \|= __get_user(regs->r5, sc->sc_regs+5);
	165	err \|= __get_user(regs->r6, sc->sc_regs+6);
	166	err \|= __get_user(regs->r7, sc->sc_regs+7);
	167	err \|= __get_user(regs->r8, sc->sc_regs+8);
	168	err \|= __get_user(sw->r9, sc->sc_regs+9);
	169	err \|= __get_user(sw->r10, sc->sc_regs+10);
	170	err \|= __get_user(sw->r11, sc->sc_regs+11);
	171	err \|= __get_user(sw->r12, sc->sc_regs+12);
	172	err \|= __get_user(sw->r13, sc->sc_regs+13);
	173	err \|= __get_user(sw->r14, sc->sc_regs+14);
	174	err \|= __get_user(sw->r15, sc->sc_regs+15);
	175	err \|= __get_user(regs->r16, sc->sc_regs+16);
	176	err \|= __get_user(regs->r17, sc->sc_regs+17);
	177	err \|= __get_user(regs->r18, sc->sc_regs+18);
	178	err \|= __get_user(regs->r19, sc->sc_regs+19);
	179	err \|= __get_user(regs->r20, sc->sc_regs+20);
	180	err \|= __get_user(regs->r21, sc->sc_regs+21);
	181	err \|= __get_user(regs->r22, sc->sc_regs+22);
	182	err \|= __get_user(regs->r23, sc->sc_regs+23);
	183	err \|= __get_user(regs->r24, sc->sc_regs+24);
	184	err \|= __get_user(regs->r25, sc->sc_regs+25);
	185	err \|= __get_user(regs->r26, sc->sc_regs+26);
	186	err \|= __get_user(regs->r27, sc->sc_regs+27);
	187	err \|= __get_user(regs->r28, sc->sc_regs+28);
	188	err \|= __get_user(regs->gp, sc->sc_regs+29);
	189	err \|= __get_user(usp, sc->sc_regs+30);
	190	wrusp(usp);
	191
	192	for (i = 0; i < 31; i++)
	193	err \|= __get_user(sw->fp[i], sc->sc_fpregs+i);
	194	err \|= __get_user(sw->fp[31], &sc->sc_fpcr);
	195
	196	return err;
	197	}
	198
	199	/* Note that this syscall is also used by setcontext(3) to install
	200	a given sigcontext. This because it's impossible to set all
	201	registers and transfer control from userland. */
	202
	203	asmlinkage void
b960f303	204	do_sigreturn(struct sigcontext __user *sc)
1da177e4	205	{
b960f303	206	struct pt_regs *regs = current_pt_regs();
1da177e4 LT	207	sigset_t set;
	208
	209	/* Verify that it's a good sigcontext before using it */
	210	if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
	211	goto give_sigsegv;
	212	if (__get_user(set.sig[0], &sc->sc_mask))
	213	goto give_sigsegv;
	214
2561b069	215	set_current_blocked(&set);
1da177e4	216
b960f303	217	if (restore_sigcontext(sc, regs))
1da177e4 LT	218	goto give_sigsegv;
	219
	220	/* Send SIGTRAP if we're single-stepping: */
	221	if (ptrace_cancel_bpt (current)) {
	222	siginfo_t info;
	223
	224	info.si_signo = SIGTRAP;
	225	info.si_errno = 0;
	226	info.si_code = TRAP_BRKPT;
	227	info.si_addr = (void __user *) regs->pc;
	228	info.si_trapno = 0;
	229	send_sig_info(SIGTRAP, &info, current);
	230	}
	231	return;
	232
	233	give_sigsegv:
	234	force_sig(SIGSEGV, current);
	235	}
	236
	237	asmlinkage void
b960f303	238	do_rt_sigreturn(struct rt_sigframe __user *frame)
1da177e4	239	{
b960f303	240	struct pt_regs *regs = current_pt_regs();
1da177e4 LT	241	sigset_t set;
	242
	243	/* Verify that it's a good ucontext_t before using it */
	244	if (!access_ok(VERIFY_READ, &frame->uc, sizeof(frame->uc)))
	245	goto give_sigsegv;
	246	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	247	goto give_sigsegv;
	248
2561b069	249	set_current_blocked(&set);
1da177e4	250
b960f303	251	if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
1da177e4 LT	252	goto give_sigsegv;
	253
	254	/* Send SIGTRAP if we're single-stepping: */
	255	if (ptrace_cancel_bpt (current)) {
	256	siginfo_t info;
	257
	258	info.si_signo = SIGTRAP;
	259	info.si_errno = 0;
	260	info.si_code = TRAP_BRKPT;
	261	info.si_addr = (void __user *) regs->pc;
	262	info.si_trapno = 0;
	263	send_sig_info(SIGTRAP, &info, current);
	264	}
	265	return;
	266
	267	give_sigsegv:
	268	force_sig(SIGSEGV, current);
	269	}
	270
	271
	272	/*
	273	* Set up a signal frame.
	274	*/
	275
	276	static inline void __user *
cfd60c07	277	get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
1da177e4	278	{
cfd60c07	279	return (void __user *)((sigsp(sp, ksig) - frame_size) & -32ul);
1da177e4 LT	280	}
	281
	282	static long
	283	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs,
d9d0738a	284	unsigned long mask, unsigned long sp)
1da177e4	285	{
d9d0738a	286	struct switch_stack sw = (struct switch_stack )regs - 1;
1da177e4 LT	287	long i, err = 0;
	288
	289	err \|= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
	290	err \|= __put_user(mask, &sc->sc_mask);
	291	err \|= __put_user(regs->pc, &sc->sc_pc);
	292	err \|= __put_user(8, &sc->sc_ps);
	293
	294	err \|= __put_user(regs->r0 , sc->sc_regs+0);
	295	err \|= __put_user(regs->r1 , sc->sc_regs+1);
	296	err \|= __put_user(regs->r2 , sc->sc_regs+2);
	297	err \|= __put_user(regs->r3 , sc->sc_regs+3);
	298	err \|= __put_user(regs->r4 , sc->sc_regs+4);
	299	err \|= __put_user(regs->r5 , sc->sc_regs+5);
	300	err \|= __put_user(regs->r6 , sc->sc_regs+6);
	301	err \|= __put_user(regs->r7 , sc->sc_regs+7);
	302	err \|= __put_user(regs->r8 , sc->sc_regs+8);
	303	err \|= __put_user(sw->r9 , sc->sc_regs+9);
	304	err \|= __put_user(sw->r10 , sc->sc_regs+10);
	305	err \|= __put_user(sw->r11 , sc->sc_regs+11);
	306	err \|= __put_user(sw->r12 , sc->sc_regs+12);
	307	err \|= __put_user(sw->r13 , sc->sc_regs+13);
	308	err \|= __put_user(sw->r14 , sc->sc_regs+14);
	309	err \|= __put_user(sw->r15 , sc->sc_regs+15);
	310	err \|= __put_user(regs->r16, sc->sc_regs+16);
	311	err \|= __put_user(regs->r17, sc->sc_regs+17);
	312	err \|= __put_user(regs->r18, sc->sc_regs+18);
	313	err \|= __put_user(regs->r19, sc->sc_regs+19);
	314	err \|= __put_user(regs->r20, sc->sc_regs+20);
	315	err \|= __put_user(regs->r21, sc->sc_regs+21);
	316	err \|= __put_user(regs->r22, sc->sc_regs+22);
	317	err \|= __put_user(regs->r23, sc->sc_regs+23);
	318	err \|= __put_user(regs->r24, sc->sc_regs+24);
	319	err \|= __put_user(regs->r25, sc->sc_regs+25);
	320	err \|= __put_user(regs->r26, sc->sc_regs+26);
	321	err \|= __put_user(regs->r27, sc->sc_regs+27);
	322	err \|= __put_user(regs->r28, sc->sc_regs+28);
	323	err \|= __put_user(regs->gp , sc->sc_regs+29);
	324	err \|= __put_user(sp, sc->sc_regs+30);
	325	err \|= __put_user(0, sc->sc_regs+31);
	326
	327	for (i = 0; i < 31; i++)
	328	err \|= __put_user(sw->fp[i], sc->sc_fpregs+i);
	329	err \|= __put_user(0, sc->sc_fpregs+31);
	330	err \|= __put_user(sw->fp[31], &sc->sc_fpcr);
	331
	332	err \|= __put_user(regs->trap_a0, &sc->sc_traparg_a0);
	333	err \|= __put_user(regs->trap_a1, &sc->sc_traparg_a1);
	334	err \|= __put_user(regs->trap_a2, &sc->sc_traparg_a2);
	335
	336	return err;
	337	}
	338
b927b3e2	339	static int
cfd60c07	340	setup_frame(struct ksignal ksig, sigset_t set, struct pt_regs *regs)
1da177e4 LT	341	{
	342	unsigned long oldsp, r26, err = 0;
	343	struct sigframe __user *frame;
	344
	345	oldsp = rdusp();
cfd60c07	346	frame = get_sigframe(ksig, oldsp, sizeof(*frame));
1da177e4	347	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
cbdfb9ff	348	return -EFAULT;
1da177e4	349
d9d0738a	350	err \|= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);
1da177e4	351	if (err)
cbdfb9ff	352	return -EFAULT;
1da177e4 LT	353
	354	/* Set up to return from userspace. If provided, use a stub
	355	already in userspace. */
cfd60c07 AV	356	r26 = (unsigned long) ksig->ka.ka_restorer;
cfd60c07 AV	357	if (!r26) {
1da177e4 LT	358	err \|= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
	359	err \|= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1);
	360	err \|= __put_user(INSN_CALLSYS, frame->retcode+2);
	361	imb();
	362	r26 = (unsigned long) frame->retcode;
	363	}
	364
	365	/* Check that everything was written properly. */
	366	if (err)
cbdfb9ff	367	return err;
1da177e4 LT	368
	369	/* "Return" to the handler */
	370	regs->r26 = r26;
cfd60c07 AV	371	regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
cfd60c07 AV	372	regs->r16 = ksig->sig; /* a0: signal number */
1da177e4 LT	373	regs->r17 = 0; /* a1: exception code */
	374	regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */
	375	wrusp((unsigned long) frame);
	376
	377	#if DEBUG_SIG
	378	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
	379	current->comm, current->pid, frame, regs->pc, regs->r26);
	380	#endif
b927b3e2	381	return 0;
1da177e4 LT	382	}
1da177e4 LT	383
b927b3e2	384	static int
cfd60c07	385	setup_rt_frame(struct ksignal ksig, sigset_t set, struct pt_regs *regs)
1da177e4 LT	386	{
	387	unsigned long oldsp, r26, err = 0;
	388	struct rt_sigframe __user *frame;
	389
	390	oldsp = rdusp();
cfd60c07	391	frame = get_sigframe(ksig, oldsp, sizeof(*frame));
1da177e4	392	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
cbdfb9ff	393	return -EFAULT;
1da177e4	394
cfd60c07	395	err \|= copy_siginfo_to_user(&frame->info, &ksig->info);
1da177e4 LT	396
	397	/* Create the ucontext. */
	398	err \|= __put_user(0, &frame->uc.uc_flags);
	399	err \|= __put_user(0, &frame->uc.uc_link);
	400	err \|= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
50ececcf	401	err \|= __save_altstack(&frame->uc.uc_stack, oldsp);
d9d0738a	402	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs,
1da177e4 LT	403	set->sig[0], oldsp);
	404	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	405	if (err)
cbdfb9ff	406	return -EFAULT;
1da177e4 LT	407
	408	/* Set up to return from userspace. If provided, use a stub
	409	already in userspace. */
cfd60c07 AV	410	r26 = (unsigned long) ksig->ka.ka_restorer;
cfd60c07 AV	411	if (!r26) {
1da177e4 LT	412	err \|= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
	413	err \|= __put_user(INSN_LDI_R0+__NR_rt_sigreturn,
	414	frame->retcode+1);
	415	err \|= __put_user(INSN_CALLSYS, frame->retcode+2);
	416	imb();
	417	r26 = (unsigned long) frame->retcode;
	418	}
	419
	420	if (err)
cbdfb9ff	421	return -EFAULT;
1da177e4 LT	422
	423	/* "Return" to the handler */
	424	regs->r26 = r26;
cfd60c07 AV	425	regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
cfd60c07 AV	426	regs->r16 = ksig->sig; /* a0: signal number */
1da177e4 LT	427	regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */
	428	regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */
	429	wrusp((unsigned long) frame);
	430
	431	#if DEBUG_SIG
	432	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
	433	current->comm, current->pid, frame, regs->pc, regs->r26);
	434	#endif
	435
b927b3e2	436	return 0;
1da177e4 LT	437	}
	438
	439
	440	/*
	441	* OK, we're invoking a handler.
	442	*/
cbdfb9ff	443	static inline void
cfd60c07	444	handle_signal(struct ksignal ksig, struct pt_regs regs)
1da177e4	445	{
b7f9a11a	446	sigset_t *oldset = sigmask_to_save();
b927b3e2 RH	447	int ret;
b927b3e2 RH	448
cfd60c07 AV	449	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
cfd60c07 AV	450	ret = setup_rt_frame(ksig, oldset, regs);
1da177e4	451	else
cfd60c07	452	ret = setup_frame(ksig, oldset, regs);
1da177e4	453
cfd60c07	454	signal_setup_done(ret, ksig, 0);
1da177e4 LT	455	}
	456
	457	static inline void
	458	syscall_restart(unsigned long r0, unsigned long r19,
	459	struct pt_regs regs, struct k_sigaction ka)
	460	{
	461	switch (regs->r0) {
	462	case ERESTARTSYS:
	463	if (!(ka->sa.sa_flags & SA_RESTART)) {
	464	case ERESTARTNOHAND:
	465	regs->r0 = EINTR;
	466	break;
	467	}
	468	/* fallthrough */
	469	case ERESTARTNOINTR:
	470	regs->r0 = r0; /* reset v0 and a3 and replay syscall */
	471	regs->r19 = r19;
	472	regs->pc -= 4;
	473	break;
	474	case ERESTART_RESTARTBLOCK:
1da177e4 LT	475	regs->r0 = EINTR;
	476	break;
	477	}
	478	}
	479
	480
	481	/*
	482	* Note that 'init' is a special process: it doesn't get signals it doesn't
	483	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	484	* mistake.
	485	*
	486	* Note that we go through the signals twice: once to check the signals that
	487	* the kernel can handle, and then we build all the user-level signal handling
	488	* stack-frames in one go after that.
	489	*
	490	* "r0" and "r19" are the registers we need to restore for system call
	491	* restart. "r0" is also used as an indicator whether we can restart at
	492	* all (if we get here from anything but a syscall return, it will be 0)
	493	*/
b927b3e2	494	static void
d9d0738a	495	do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
1da177e4	496	{
1da177e4	497	unsigned long single_stepping = ptrace_cancel_bpt(current);
cfd60c07	498	struct ksignal ksig;
1da177e4 LT	499
1da177e4 LT	500	/* This lets the debugger run, ... */
cfd60c07 AV	501	if (get_signal(&ksig)) {
	502	/* ... so re-check the single stepping. */
	503	single_stepping \|= ptrace_cancel_bpt(current);
1da177e4	504	/* Whee! Actually deliver the signal. */
b927b3e2	505	if (r0)
cfd60c07 AV	506	syscall_restart(r0, r19, regs, &ksig.ka);
	507	handle_signal(&ksig, regs);
	508	} else {
	509	single_stepping \|= ptrace_cancel_bpt(current);
	510	if (r0) {
	511	switch (regs->r0) {
	512	case ERESTARTNOHAND:
	513	case ERESTARTSYS:
	514	case ERESTARTNOINTR:
	515	/* Reset v0 and a3 and replay syscall. */
	516	regs->r0 = r0;
	517	regs->r19 = r19;
	518	regs->pc -= 4;
	519	break;
	520	case ERESTART_RESTARTBLOCK:
	521	/* Set v0 to the restart_syscall and replay */
	522	regs->r0 = __NR_restart_syscall;
	523	regs->pc -= 4;
	524	break;
	525	}
1da177e4	526	}
cfd60c07	527	restore_saved_sigmask();
1da177e4 LT	528	}
	529	if (single_stepping)
	530	ptrace_set_bpt(current); /* re-set breakpoint */
1da177e4 LT	531	}
	532
	533	void
cb450766	534	do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
b927b3e2	535	unsigned long r0, unsigned long r19)
1da177e4	536	{
6972d6f2 AV	537	do {
	538	if (thread_flags & _TIF_NEED_RESCHED) {
	539	schedule();
	540	} else {
	541	local_irq_enable();
	542	if (thread_flags & _TIF_SIGPENDING) {
d9d0738a	543	do_signal(regs, r0, r19);
6972d6f2 AV	544	r0 = 0;
	545	} else {
	546	clear_thread_flag(TIF_NOTIFY_RESUME);
	547	tracehook_notify_resume(regs);
	548	}
	549	}
	550	local_irq_disable();
	551	thread_flags = current_thread_info()->flags;
	552	} while (thread_flags & _TIF_WORK_MASK);
1da177e4	553	}