signal.c

linux-2.6.15.6

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * arch/sh64/kernel/signal.c
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003  Paul Mundt
 * Copyright (C) 2004  Richard Curnow
 *
 * Started from sh version.
 *
 */
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/personality.h>
#include <linux/suspend.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>


#define REG_RET 9
#define REG_ARG1 2
#define REG_ARG2 3
#define REG_ARG3 4
#define REG_SP 15
#define REG_PR 18
#define REF_REG_RET regs->regs[REG_RET]
#define REF_REG_SP regs->regs[REG_SP]
#define DEREF_REG_PR regs->regs[REG_PR]

#define DEBUG_SIG 0

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

asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */

asmlinkage int
sys_sigsuspend(old_sigset_t mask,
	       unsigned long r3, unsigned long r4, unsigned long r5,
	       unsigned long r6, unsigned long r7,
	       struct pt_regs * regs)
{
	sigset_t saveset;

	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	REF_REG_RET = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		regs->pc += 4;    /* because sys_sigreturn decrements the pc */
		if (do_signal(regs, &saveset)) {
			/* pc now points at signal handler. Need to decrement
			   it because entry.S will increment it. */
			regs->pc -= 4;
			return -EINTR;
		}
	}
}

asmlinkage int
sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
	          unsigned long r4, unsigned long r5, unsigned long r6,
	          unsigned long r7,
	          struct pt_regs * regs)
{
	sigset_t saveset, newset;

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

	if (copy_from_user(&newset, unewset, sizeof(newset)))
		return -EFAULT;
	sigdelsetmask(&newset, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	REF_REG_RET = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		regs->pc += 4;    /* because sys_sigreturn decrements the pc */
		if (do_signal(regs, &saveset)) {
			/* pc now points at signal handler. Need to decrement
			   it because entry.S will increment it. */
			regs->pc -= 4;
			return -EINTR;
		}
	}
}

asmlinkage int
sys_sigaction(int sig, const struct old_sigaction __user *act,
	      struct old_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_restorer, &act->sa_restorer))
			return -EFAULT;
		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
		__get_user(mask, &act->sa_mask);
		siginitset(&new_ka.sa.sa_mask, mask);
	}

	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_restorer, &oact->sa_restorer))
			return -EFAULT;
		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	}

	return ret;
}

asmlinkage int
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
	        unsigned long r4, unsigned long r5, unsigned long r6,
	        unsigned long r7,
	        struct pt_regs * regs)
{
	return do_sigaltstack(uss, uoss, REF_REG_SP);
}


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

struct sigframe
{
	struct sigcontext sc;
	unsigned long extramask[_NSIG_WORDS-1];
	long long retcode[2];
};

struct rt_sigframe
{
	struct siginfo __user *pinfo;
	void *puc;
	struct siginfo info;
	struct ucontext uc;
	long long retcode[2];
};

#ifdef CONFIG_SH_FPU
static inline int
restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
{
	int err = 0;
	int fpvalid;

	err |= __get_user (fpvalid, &sc->sc_fpvalid);
	conditional_used_math(fpvalid);
	if (! fpvalid)
		return err;

	if (current == last_task_used_math) {
		last_task_used_math = NULL;
		regs->sr |= SR_FD;
	}

	err |= __copy_from_user(&current->thread.fpu.hard, &sc->sc_fpregs[0],
				(sizeof(long long) * 32) + (sizeof(int) * 1));

	return err;
}

static inline int
setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
{
	int err = 0;
	int fpvalid;

	fpvalid = !!used_math();
	err |= __put_user(fpvalid, &sc->sc_fpvalid);
	if (! fpvalid)
		return err;

	if (current == last_task_used_math) {
		grab_fpu();
		fpsave(&current->thread.fpu.hard);
		release_fpu();
		last_task_used_math = NULL;
		regs->sr |= SR_FD;
	}

	err |= __copy_to_user(&sc->sc_fpregs[0], &current->thread.fpu.hard,
			      (sizeof(long long) * 32) + (sizeof(int) * 1));
	clear_used_math();

	return err;
}
#else
static inline int
restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
{}
static inline int
setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
{}
#endif

static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, long long *r2_p)
{
	unsigned int err = 0;
        unsigned long long current_sr, new_sr;
#define SR_MASK 0xffff8cfd

#define COPY(x)		err |= __get_user(regs->x, &sc->sc_##x)

	COPY(regs[0]);	COPY(regs[1]);	COPY(regs[2]);	COPY(regs[3]);
	COPY(regs[4]);	COPY(regs[5]);	COPY(regs[6]);	COPY(regs[7]);
	COPY(regs[8]);	COPY(regs[9]);  COPY(regs[10]);	COPY(regs[11]);
	COPY(regs[12]);	COPY(regs[13]);	COPY(regs[14]);	COPY(regs[15]);
	COPY(regs[16]);	COPY(regs[17]);	COPY(regs[18]);	COPY(regs[19]);
	COPY(regs[20]);	COPY(regs[21]);	COPY(regs[22]);	COPY(regs[23]);
	COPY(regs[24]);	COPY(regs[25]);	COPY(regs[26]);	COPY(regs[27]);
	COPY(regs[28]);	COPY(regs[29]);	COPY(regs[30]);	COPY(regs[31]);
	COPY(regs[32]);	COPY(regs[33]);	COPY(regs[34]);	COPY(regs[35]);
	COPY(regs[36]);	COPY(regs[37]);	COPY(regs[38]);	COPY(regs[39]);
	COPY(regs[40]);	COPY(regs[41]);	COPY(regs[42]);	COPY(regs[43]);
	COPY(regs[44]);	COPY(regs[45]);	COPY(regs[46]);	COPY(regs[47]);
	COPY(regs[48]);	COPY(regs[49]);	COPY(regs[50]);	COPY(regs[51]);
	COPY(regs[52]);	COPY(regs[53]);	COPY(regs[54]);	COPY(regs[55]);
	COPY(regs[56]);	COPY(regs[57]);	COPY(regs[58]);	COPY(regs[59]);
	COPY(regs[60]);	COPY(regs[61]);	COPY(regs[62]);
	COPY(tregs[0]);	COPY(tregs[1]);	COPY(tregs[2]);	COPY(tregs[3]);
	COPY(tregs[4]);	COPY(tregs[5]);	COPY(tregs[6]);	COPY(tregs[7]);

        /* Prevent the signal handler manipulating SR in a way that can
           crash the kernel. i.e. only allow S, Q, M, PR, SZ, FR to be
           modified */
        current_sr = regs->sr;
        err |= __get_user(new_sr, &sc->sc_sr);
        regs->sr &= SR_MASK;
        regs->sr |= (new_sr & ~SR_MASK);

	COPY(pc);

#undef COPY

	/* Must do this last in case it sets regs->sr.fd (i.e. after rest of sr
	 * has been restored above.) */
	err |= restore_sigcontext_fpu(regs, sc);

	regs->syscall_nr = -1;		/* disable syscall checks */
	err |= __get_user(*r2_p, &sc->sc_regs[REG_RET]);
	return err;
}

asmlinkage int sys_sigreturn(unsigned long r2, unsigned long r3,
				   unsigned long r4, unsigned long r5,
				   unsigned long r6, unsigned long r7,
				   struct pt_regs * regs)
{
	struct sigframe __user *frame = (struct sigframe __user *) (long) REF_REG_SP;
	sigset_t set;
	long long ret;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;

	if (__get_user(set.sig[0], &frame->sc.oldmask)
	    || (_NSIG_WORDS > 1
		&& __copy_from_user(&set.sig[1], &frame->extramask,
				    sizeof(frame->extramask))))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);

	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext(regs, &frame->sc, &ret))
		goto badframe;
	regs->pc -= 4;

	return (int) ret;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3,
				unsigned long r4, unsigned long r5,
				unsigned long r6, unsigned long r7,
				struct pt_regs * regs)
{
	struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (long) REF_REG_SP;
	sigset_t set;
	stack_t __user st;
	long long ret;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;

	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ret))
		goto badframe;
	regs->pc -= 4;

	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
		goto badframe;
	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	do_sigaltstack(&st, NULL, REF_REG_SP);

	return (int) ret;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

/*
 * Set up a signal frame.
 */