signal_n32.c

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/*
 * Copyright (C) 2003 Broadcom Corporation
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
#include <linux/cache.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.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/compat.h>
#include <linux/bitops.h>

#include <asm/abi.h>
#include <asm/asm.h>
#include <asm/cacheflush.h>
#include <asm/compat-signal.h>
#include <asm/sim.h>
#include <asm/uaccess.h>
#include <asm/ucontext.h>
#include <asm/fpu.h>
#include <asm/cpu-features.h>
#include <asm/war.h>
#include <asm/vdso.h>

#include "signal-common.h"

/*
 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
 */
#define __NR_N32_restart_syscall    6214

extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *);
extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);


/* IRIX compatible stack_t  */
typedef struct sigaltstack32 {
    s32 ss_sp;
    compat_size_t ss_size;
    int ss_flags;
} stack32_t;

struct ucontextn32 {
    u32                 uc_flags;
    s32                 uc_link;
    stack32_t           uc_stack;
    struct sigcontext   uc_mcontext;
    compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
};

struct rt_sigframe_n32 {
    u32 rs_ass[4];          /* argument save space for o32 */
    u32 rs_pad[2];          /* Was: signal trampoline */
    struct compat_siginfo rs_info;
    struct ucontextn32 rs_uc;
};

extern void sigset_from_compat(sigset_t *set, compat_sigset_t *compat);

asmlinkage int sysn32_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
{
    compat_sigset_t __user *unewset;
    compat_sigset_t uset;
    size_t sigsetsize;
    sigset_t newset;

    /* XXX Don't preclude handling different sized sigset_t's.  */
    sigsetsize = regs.regs[5];
    if (sigsetsize != sizeof(sigset_t))
        return -EINVAL;

    unewset = (compat_sigset_t __user *) regs.regs[4];
    if (copy_from_user(&uset, unewset, sizeof(uset)))
        return -EFAULT;
    sigset_from_compat(&newset, &uset);
    return sigsuspend(&newset);
}

asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
{
    struct rt_sigframe_n32 __user *frame;
    mm_segment_t old_fs;
    sigset_t set;
    stack_t st;
    s32 sp;
    int sig;

    frame = (struct rt_sigframe_n32 __user *) regs.regs[29];
    if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
        goto badframe;
    if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
        goto badframe;

    set_current_blocked(&set);

    sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
    if (sig < 0)
        goto badframe;
    else if (sig)
        force_sig(sig, current);

    /* The ucontext contains a stack32_t, so we must convert!  */
    if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
        goto badframe;
    st.ss_sp = (void __user *)(long) sp;
    if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
        goto badframe;
    if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
        goto badframe;

    /* It is more difficult to avoid calling this function than to
       call it and ignore errors.  */
    old_fs = get_fs();
    set_fs(KERNEL_DS);
    do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
    set_fs(old_fs);


    /*
     * Don't let your children do this ...
     */
    __asm__ __volatile__(
        "move\t$29, %0\n\t"
        "j\tsyscall_exit"
        :/* no outputs */
        :"r" (&regs));
    /* Unreached */

badframe:
    force_sig(SIGSEGV, current);
}

static int setup_rt_frame_n32(void *sig_return, struct k_sigaction *ka,
    struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info)
{
    struct rt_sigframe_n32 __user *frame;
    int err = 0;
    s32 sp;

    frame = get_sigframe(ka, regs, sizeof(*frame));
    if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
        goto give_sigsegv;

    /* Create siginfo.  */
    err |= copy_siginfo_to_user32(&frame->rs_info, info);

    /* Create the ucontext.  */
    err |= __put_user(0, &frame->rs_uc.uc_flags);
    err |= __put_user(0, &frame->rs_uc.uc_link);
    sp = (int) (long) current->sas_ss_sp;
    err |= __put_user(sp,
                      &frame->rs_uc.uc_stack.ss_sp);
    err |= __put_user(sas_ss_flags(regs->regs[29]),
                      &frame->rs_uc.uc_stack.ss_flags);
    err |= __put_user(current->sas_ss_size,
                      &frame->rs_uc.uc_stack.ss_size);
    err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
    err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);

    if (err)
        goto give_sigsegv;

    /*
     * Arguments to signal handler:
     *
     *   a0 = signal number
     *   a1 = 0 (should be cause)
     *   a2 = pointer to ucontext
     *
     * $25 and c0_epc point to the signal handler, $29 points to
     * the struct rt_sigframe.
     */
    regs->regs[ 4] = signr;
    regs->regs[ 5] = (unsigned long) &frame->rs_info;
    regs->regs[ 6] = (unsigned long) &frame->rs_uc;
    regs->regs[29] = (unsigned long) frame;
    regs->regs[31] = (unsigned long) sig_return;
    regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

    DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
           current->comm, current->pid,
           frame, regs->cp0_epc, regs->regs[31]);

    return 0;

give_sigsegv:
    force_sigsegv(signr, current);
    return -EFAULT;
}

struct mips_abi mips_abi_n32 = {
    .setup_rt_frame = setup_rt_frame_n32,
    .rt_signal_return_offset =
        offsetof(struct mips_vdso, n32_rt_signal_trampoline),
    .restart    = __NR_N32_restart_syscall
};