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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/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/wait.h>

#include <linux/ptrace.h>

#include <linux/unistd.h>

#include <asm/asm.h>

#include <asm/bitops.h>

#include <asm/pgalloc.h>

#include <asm/stackframe.h>

#include <asm/uaccess.h>

#include <asm/ucontext.h>

#include <asm/system.h>

#include <asm/fpu.h>

/*

 * Including <asm/unistd.h would give use the 64-bit syscall numbers ...

 */

#define __NR_N32_rt_sigreturn           6211

#define __NR_N32_restart_syscall        6214

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

/* IRIX compatible stack_t  */

typedef struct sigaltstack32 {

        s32 ss_sp;

        __kernel_size_t32 ss_size;

        int ss_flags;

} stack32_t;

struct ucontextn32 {

        u32                 uc_flags;

        s32                 uc_link;

        stack32_t           uc_stack;

        struct sigcontext   uc_mcontext;

        sigset_t            uc_sigmask;   /* mask last for extensibility */

};

struct rt_sigframe_n32 {

        u32 rs_ass[4];                  /* argument save space for o32 */

        u32 rs_code[2];                 /* signal trampoline */

        struct siginfo rs_info;

        struct ucontextn32 rs_uc;

};

extern asmlinkage int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc);

extern int inline setup_sigcontext(struct pt_regs *regs, struct sigcontext *sc);

asmlinkage void sysn32_rt_sigreturn(abi64_no_regargs, struct pt_regs regs)

{

        struct rt_sigframe_n32 *frame;

        sigset_t set;

        stack_t st;

        s32 sp;

        frame = (struct rt_sigframe_n32 *) regs.regs[29];

        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))

                goto badframe;

        if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))

                goto badframe;

        sigdelsetmask(&set, ~_BLOCKABLE);

        spin_lock_irq(&current->sigmask_lock);

        current->blocked = set;

        recalc_sigpending(current);

        spin_unlock_irq(&current->sigmask_lock);

        if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))

                goto badframe;

        /* 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_size = (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.  */

        do_sigaltstack(&st, NULL, regs.regs[29]);

        /*

         * Don't let your children do this ...

         */

        __asm__ __volatile__(

                "move\t$29, %0\n\t"

                "j\tret_from_sys_call"

                :/* no outputs */

                :"r" (&regs));

        /* Unreached */

badframe:

        force_sig(SIGSEGV, current);

}

/*

 * Determine which stack to use..

 */

static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,

        size_t frame_size)

{

        unsigned long sp;

        /* Default to using normal stack */

        sp = regs->regs[29];

        /*

         * FPU emulator may have it's own trampoline active just

         * above the user stack, 16-bytes before the next lowest

         * 16 byte boundary.  Try to avoid trashing it.

         */

        sp -= 32;

        /* This is the X/Open sanctioned signal stack switching.  */

        if ((ka->sa.sa_flags & SA_ONSTACK) && ! on_sig_stack(sp))

                sp = current->sas_ss_sp + current->sas_ss_size;

        return (void *)((sp - frame_size) & ALMASK);

}

void setup_rt_frame_n32(struct k_sigaction * ka,

        struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info)

{

        struct rt_sigframe_n32 *frame;

        int err = 0;

        s32 sp;

        frame = get_sigframe(ka, regs, sizeof(*frame));

        if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))

                goto give_sigsegv;

        /*

         * Set up the return code ...

         *

         *         li      v0, __NR_rt_sigreturn

         *         syscall

         */

        err |= __put_user(0x24020000 + __NR_N32_rt_sigreturn, frame->rs_code + 0);

        err |= __put_user(0x0000000c                    , frame->rs_code + 1);

        flush_cache_sigtramp((unsigned long) frame->rs_code);

        /* Create siginfo.  */

        err |= copy_siginfo_to_user(&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_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*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) frame->rs_code;

        regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

#if DEBUG_SIG

        printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",

               current->comm, current->pid,

               frame, regs->cp0_epc, regs->regs[31]);

#endif

        return;

give_sigsegv:

        if (signr == SIGSEGV)

                ka->sa.sa_handler = SIG_DFL;

        force_sig(SIGSEGV, current);

}