/*
 * 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/system.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);
        sigdelsetmask(&newset, ~_BLOCKABLE);

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

        current->state = TASK_INTERRUPTIBLE;
        schedule();
        set_thread_flag(TIF_RESTORE_SIGMASK);
        return -ERESTARTNOHAND;
}

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;

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

        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
};