signal_32.c

linux-2.6.15.6

/*
 * Signal handling for 32bit PPC and 32bit tasks on 64bit PPC
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas ([e-mail])
 * Copyright (C) 2001 IBM
 * Copyright (C) 1997,1998 Jakub Jelinek ([e-mail])
 * Copyright (C) 1997 David S. Miller ([e-mail])
 *
 *  Derived from "arch/i386/kernel/signal.c"
 *    Copyright (C) 1991, 1992 Linus Torvalds
 *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/config.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/elf.h>
#ifdef CONFIG_PPC64
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/ptrace.h>
#else
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/suspend.h>
#endif

#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/sigcontext.h>
#include <asm/vdso.h>
#ifdef CONFIG_PPC64
#include "ppc32.h"
#include <asm/unistd.h>
#else
#include <asm/ucontext.h>
#include <asm/pgtable.h>
#endif

#undef DEBUG_SIG

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

#ifdef CONFIG_PPC64
#define do_signal	do_signal32
#define sys_sigsuspend	compat_sys_sigsuspend
#define sys_rt_sigsuspend	compat_sys_rt_sigsuspend
#define sys_rt_sigreturn	compat_sys_rt_sigreturn
#define sys_sigaction	compat_sys_sigaction
#define sys_swapcontext	compat_sys_swapcontext
#define sys_sigreturn	compat_sys_sigreturn

#define old_sigaction	old_sigaction32
#define sigcontext	sigcontext32
#define mcontext	mcontext32
#define ucontext	ucontext32

/*
 * Returning 0 means we return to userspace via
 * ret_from_except and thus restore all user
 * registers from *regs.  This is what we need
 * to do when a signal has been delivered.
 */
#define sigreturn_exit(regs)	return 0

#define GP_REGS_SIZE	min(sizeof(elf_gregset_t32), sizeof(struct pt_regs32))
#undef __SIGNAL_FRAMESIZE
#define __SIGNAL_FRAMESIZE	__SIGNAL_FRAMESIZE32
#undef ELF_NVRREG
#define ELF_NVRREG	ELF_NVRREG32

/*
 * Functions for flipping sigsets (thanks to brain dead generic
 * implementation that makes things simple for little endian only)
 */
static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
{
	compat_sigset_t	cset;

	switch (_NSIG_WORDS) {
	case 4: cset.sig[5] = set->sig[3] & 0xffffffffull;
		cset.sig[7] = set->sig[3] >> 32;
	case 3: cset.sig[4] = set->sig[2] & 0xffffffffull;
		cset.sig[5] = set->sig[2] >> 32;
	case 2: cset.sig[2] = set->sig[1] & 0xffffffffull;
		cset.sig[3] = set->sig[1] >> 32;
	case 1: cset.sig[0] = set->sig[0] & 0xffffffffull;
		cset.sig[1] = set->sig[0] >> 32;
	}
	return copy_to_user(uset, &cset, sizeof(*uset));
}

static inline int get_sigset_t(sigset_t *set,
			       const compat_sigset_t __user *uset)
{
	compat_sigset_t s32;

	if (copy_from_user(&s32, uset, sizeof(*uset)))
		return -EFAULT;

	/*
	 * Swap the 2 words of the 64-bit sigset_t (they are stored
	 * in the "wrong" endian in 32-bit user storage).
	 */
	switch (_NSIG_WORDS) {
	case 4: set->sig[3] = s32.sig[6] | (((long)s32.sig[7]) << 32);
	case 3: set->sig[2] = s32.sig[4] | (((long)s32.sig[5]) << 32);
	case 2: set->sig[1] = s32.sig[2] | (((long)s32.sig[3]) << 32);
	case 1: set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
	}
	return 0;
}

static inline int get_old_sigaction(struct k_sigaction *new_ka,
		struct old_sigaction __user *act)
{
	compat_old_sigset_t mask;
	compat_uptr_t handler, restorer;

	if (get_user(handler, &act->sa_handler) ||
	    __get_user(restorer, &act->sa_restorer) ||
	    __get_user(new_ka->sa.sa_flags, &act->sa_flags) ||
	    __get_user(mask, &act->sa_mask))
		return -EFAULT;
	new_ka->sa.sa_handler = compat_ptr(handler);
	new_ka->sa.sa_restorer = compat_ptr(restorer);
	siginitset(&new_ka->sa.sa_mask, mask);
	return 0;
}

static inline compat_uptr_t to_user_ptr(void *kp)
{
	return (compat_uptr_t)(u64)kp;
}

#define from_user_ptr(p)	compat_ptr(p)

static inline int save_general_regs(struct pt_regs *regs,
		struct mcontext __user *frame)
{
	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
	int i;

	for (i = 0; i <= PT_RESULT; i ++)
		if (__put_user((unsigned int)gregs[i], &frame->mc_gregs[i]))
			return -EFAULT;
	return 0;
}

static inline int restore_general_regs(struct pt_regs *regs,
		struct mcontext __user *sr)
{
	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
	int i;

	for (i = 0; i <= PT_RESULT; i++) {
		if ((i == PT_MSR) || (i == PT_SOFTE))
			continue;
		if (__get_user(gregs[i], &sr->mc_gregs[i]))
			return -EFAULT;
	}
	return 0;
}

#else /* CONFIG_PPC64 */

extern void sigreturn_exit(struct pt_regs *);

#define GP_REGS_SIZE	min(sizeof(elf_gregset_t), sizeof(struct pt_regs))

static inline int put_sigset_t(sigset_t __user *uset, sigset_t *set)
{
	return copy_to_user(uset, set, sizeof(*uset));
}

static inline int get_sigset_t(sigset_t *set, const sigset_t __user *uset)
{
	return copy_from_user(set, uset, sizeof(*uset));
}

static inline int get_old_sigaction(struct k_sigaction *new_ka,
		struct old_sigaction __user *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);
	return 0;
}

#define to_user_ptr(p)		(p)
#define from_user_ptr(p)	(p)

static inline int save_general_regs(struct pt_regs *regs,
		struct mcontext __user *frame)
{
	return __copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE);
}

static inline int restore_general_regs(struct pt_regs *regs,
		struct mcontext __user *sr)
{
	/* copy up to but not including MSR */
	if (__copy_from_user(regs, &sr->mc_gregs,
				PT_MSR * sizeof(elf_greg_t)))
		return -EFAULT;
	/* copy from orig_r3 (the word after the MSR) up to the end */
	if (__copy_from_user(&regs->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
				GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t)))
		return -EFAULT;
	return 0;
}

#endif /* CONFIG_PPC64 */

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

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
long sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int p7,
	       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);

	regs->result = -EINTR;
	regs->gpr[3] = EINTR;
	regs->ccr |= 0x10000000;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, regs))
			sigreturn_exit(regs);
	}
}

long sys_rt_sigsuspend(
#ifdef CONFIG_PPC64
		compat_sigset_t __user *unewset,
#else
		sigset_t __user *unewset,
#endif
		size_t sigsetsize, int p3, int p4,
		int p6, int p7, 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 (get_sigset_t(&newset, unewset))
		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);

	regs->result = -EINTR;
	regs->gpr[3] = EINTR;
	regs->ccr |= 0x10000000;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, regs))
			sigreturn_exit(regs);
	}
}

#ifdef CONFIG_PPC32
long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, int r5,
		int r6, int r7, int r8, struct pt_regs *regs)
{
	return do_sigaltstack(uss, uoss, regs->gpr[1]);
}
#endif

long sys_sigaction(int sig, struct old_sigaction __user *act,
		struct old_sigaction __user *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

#ifdef CONFIG_PPC64
	if (sig < 0)
		sig = -sig;
#endif

	if (act) {
		if (get_old_sigaction(&new_ka, act))
			return -EFAULT;
	}

	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(to_user_ptr(old_ka.sa.sa_handler),
			    &oact->sa_handler) ||
		    __put_user(to_user_ptr(old_ka.sa.sa_restorer),
			    &oact->sa_restorer) ||
		    __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;
}

/*
 * When we have signals to deliver, we set up on the
 * user stack, going down from the original stack pointer:
 *	a sigregs struct
 *	a sigcontext struct
 *	a gap of __SIGNAL_FRAMESIZE bytes
 *
 * Each of these things must be a multiple of 16 bytes in size.
 *
 */
struct sigregs {
	struct mcontext	mctx;		/* all the register values */
	/*
	 * Programs using the rs6000/xcoff abi can save up to 19 gp
	 * regs and 18 fp regs below sp before decrementing it.
	 */
	int			abigap[56];
};

/* We use the mc_pad field for the signal return trampoline. */
#define tramp	mc_pad

/*
 *  When we have rt signals to deliver, we set up on the
 *  user stack, going down from the original stack pointer:
 *	one rt_sigframe struct (siginfo + ucontext + ABI gap)
 *	a gap of __SIGNAL_FRAMESIZE+16 bytes
 *  (the +16 is to get the siginfo and ucontext in the same
 *  positions as in older kernels).
 *
 *  Each of these things must be a multiple of 16 bytes in size.
 *
 */
struct rt_sigframe {
#ifdef CONFIG_PPC64
	compat_siginfo_t info;
#else
	struct siginfo info;
#endif
	struct ucontext	uc;
	/*
	 * Programs using the rs6000/xcoff abi can save up to 19 gp
	 * regs and 18 fp regs below sp before decrementing it.
	 */
	int			abigap[56];
};

/*
 * Save the current user registers on the user stack.
 * We only save the altivec/spe registers if the process has used
 * altivec/spe instructions at some point.
 */
static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
		int sigret)
{
#ifdef CONFIG_PPC32
	CHECK_FULL_REGS(regs);
#endif
	/* Make sure floating point registers are stored in regs */
	flush_fp_to_thread(current);

	/* save general and floating-point registers */
	if (save_general_regs(regs, frame) ||
	    __copy_to_user(&frame->mc_fregs, current->thread.fpr,
		    ELF_NFPREG * sizeof(double)))
		return 1;

#ifdef CONFIG_ALTIVEC
	/* save altivec registers */
	if (current->thread.used_vr) {
		flush_altivec_to_thread(current);
		if (__copy_to_user(&frame->mc_vregs, current->thread.vr,
				   ELF_NVRREG * sizeof(vector128)))
			return 1;
		/* set MSR_VEC in the saved MSR value to indicate that
		   frame->mc_vregs contains valid data */
		if (__put_user(regs->msr | MSR_VEC, &frame->mc_gregs[PT_MSR]))
			return 1;
	}
	/* else assert((regs->msr & MSR_VEC) == 0) */

	/* We always copy to/from vrsave, it's 0 if we don't have or don't
	 * use altivec. Since VSCR only contains 32 bits saved in the least
	 * significant bits of a vector, we "cheat" and stuff VRSAVE in the
	 * most significant bits of that same vector. --BenH