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/*

 *  linux/arch/i960/kernel/signal.c

 *

 *  Copyright (C) 1999  Keith Adams     <kma@cse.ogi.edu>

 *                      Oregon Graduate Institute

 *

 *  Based on:

 *

 *  linux/arch/m68k/kernel/signal.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

 * 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.

 */

#include <linux/config.h>

#include <linux/sched.h>

#include <linux/mm.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/setup.h>

#include <asm/segment.h>

#include <asm/pgtable.h>

#include <asm/traps.h>

#define _S(nr) (1<<((nr)-1))

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

int do_signal(struct pt_regs *regs);

/*

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

 */

asmlinkage int do_sigsuspend(struct pt_regs* regs)

{

        int err;

        sigset_t* set = (sigset_t*) regs->gregs[0];

        unsigned long mask;

        if ((err=verify_area(VERIFY_READ, set, 4)))

                return -EINTR;

        mask = current->blocked;

        current->blocked = *set & _BLOCKABLE;

        regs->gregs[0] = -EINTR;

        for (;;) {

                current->state = TASK_INTERRUPTIBLE;

                schedule();

                if (do_signal(regs))

                        return -EINTR;

        }

}

/*

 * We don't ever need this on i960; the function return path lets setup_frame

 * return straight to the faulting instruction.

 */

asmlinkage int do_sigreturn(unsigned long __unused)

{

        printk("killing %d for trying to sigreturn\n");

        do_exit(SIGSEGV);

        return -1;

}

#define STACK_ALIGN 16

static inline unsigned long stack_align(unsigned long sp)

{

        int lobits  = sp & (STACK_ALIGN -1);

        if (sp & lobits)

                sp += STACK_ALIGN - lobits;

        return sp;

}

/*

 * Note that 'init' is a special process: it doesn't get signals it doesn't

 * want to handle. Thus you cannot kill init even with a SIGKILL even by

 * mistake.

 *

 * Note that we go through the signals twice: once to check the signals

 * that the kernel can handle, and then we build all the user-level signal

 * handling stack-frames in one go after that.

 *

 * XXX: todo: sigcontext stuff.

 */

asmlinkage int do_signal(struct pt_regs *regs)

{

        unsigned long mask = ~current->blocked;

        unsigned long handler_signal = 0;

        unsigned long signr;

        struct sigaction * sa;

        while ((signr = current->signal & mask)) {

                signr = ffz(~signr);

                clear_bit(signr, &current->signal);

                sa = current->sig->action + signr;

                signr++;

                if ((current->flags & PF_PTRACED) && signr != SIGKILL) {

                        current->exit_code = signr;

                        current->state = TASK_STOPPED;

                        notify_parent(current, signr);

                        schedule();

                        if (!(signr = current->exit_code))

                                continue;

                        current->exit_code = 0;

                        if (signr == SIGSTOP)

                                continue;

                        if (_S(signr) & current->blocked) {

                                current->signal |= _S(signr);

                                continue;

                        }

                        sa = current->sig->action + signr - 1;

                }

                if (sa->sa_handler == SIG_IGN) {

                        if (signr != SIGCHLD)

                                continue;

                        /* SIGCHLD is special */

                        while (sys_waitpid(-1,0,WNOHANG) > 0)

                                ;

                        continue;

                }

                if (sa->sa_handler == SIG_DFL) {

                        if (current->pid == 1)

                                continue;

                        switch(signr) {

                        case SIGCONT: case SIGCHLD: case SIGWINCH:

                                      continue;

                        case SIGSTOP: case SIGTSTP: case SIGTTIN: case SIGTTOU:

                                if (current->flags & PF_PTRACED)

                                        continue;

                                current->state = TASK_STOPPED;

                                current->exit_code = signr;

                                if (!(current->p_pptr->sig->action[SIGCHLD-1].sa_flags &

                                                SA_NOCLDSTOP))

                                        notify_parent(current, signr);

                                schedule();

                                continue;

                        case SIGQUIT: case SIGILL: case SIGTRAP:

                        case SIGIOT: case SIGFPE: case SIGSEGV: case SIGBUS:

                                if (current->binfmt && current->binfmt->core_dump) {

                                        if (current->binfmt->core_dump(signr, regs))

                                                signr |= 0x80;

                                }

                                /* fall through */

                        default:

                                current->signal |= _S(signr & 0x7f);

                                current->flags |= PF_SIGNALED;

                                do_exit(signr);

                        }

                }

                /*

                 * OK, we're invoking a handler

                 */

#ifdef DEBUG

                printk("user-specified handler for signal: %d\n", signr);

#endif

                handler_signal |= 1 << (signr-1);

                mask &= ~sa->sa_mask;

        }

        if (! handler_signal)

                return 0;

        /*

         * We chain user frames for the various handlers together. Since we use

         * local regs to pass parameters, all RIPs go to the asm routine

         * signal_head found in entry.S; if we were an MMU-full system, we would

         * have to copy signal_head out to the user process's stack.

         */

        {

                extern void signal_head(void);

                struct frame {

                        unsigned long pfp;

                        unsigned long sp;

                        unsigned long rip;

                        unsigned long* args[13];

                } *userframe, *newframe;

                unsigned long type;

#ifdef DEBUG

                stack_trace();

#endif

                asm("flushreg");

                type = regs->lregs[PT_PFP] & 0x7;

#ifdef DEBUG

                printk("pfp, type: 0x%8x, 0x%8x\n", regs->lregs[PT_PFP], type);

#endif

                userframe = (struct frame*)

                        (((unsigned long) regs->lregs[PT_PFP]) & ~0x7);

#ifdef DEBUG

                printk("userframe: 0x%8x\n", userframe);

                stack_trace_from((unsigned long) userframe);

#endif

                for (sa=current->sig->action, signr=1, mask=1;

                     mask;

                     sa++, signr++, mask<<=1) {

                        if (mask > handler_signal)

                                break;

                        if ((!(mask & handler_signal)) || (!sa->sa_handler))

                                continue;

#ifdef DEBUG

                        printk("userframe->rip: 0x%8x\n", userframe->rip);

#endif

                        newframe = stack_align(userframe->sp);

                        newframe->rip = (unsigned long) signal_head;

                        newframe->args[0] = (unsigned long) sa->sa_handler;

                        newframe->args[1] = signr;

#ifdef DEBUG

                        printk("r3,r4: 0x%8x, %d\n", sa->sa_handler, signr);

#endif

                        newframe->pfp = (unsigned long) userframe;

                        newframe->sp = (unsigned long)(newframe) + 64;

                        userframe = newframe;

                }

#ifdef DEBUG

                printk("done; look:\n");

                stack_trace();

#endif

                regs->lregs[PT_PFP] = (unsigned long)userframe | type;

                asm("flushreg");

                /*

                 * appropriate syscalls should return EINTR

                 */

                if ((type & 6) == 2 &&

                    (regs->gregs[0] == -ERESTARTNOHAND ||

                     regs->gregs[0] == -ERESTARTSYS ||

                     regs->gregs[0] == -ERESTARTNOINTR))

                        regs->gregs[0] = -EINTR;

        }

        return 1;

}