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/* $Id: signal.c,v 1.1.1.1 2004-04-15 01:17:27 phoenix Exp $

 *

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

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson

 *

 *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima

 *

 */

#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 <linux/stddef.h>

#include <linux/personality.h>

#include <asm/ucontext.h>

#include <asm/uaccess.h>

#include <asm/pgtable.h>

#define DEBUG_SIG 0

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

asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset,

                         int from_syscall, unsigned long orig_r0);

int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)

{

        if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))

                return -EFAULT;

        if (from->si_code < 0)

                return __copy_to_user(to, from, sizeof(siginfo_t));

        else {

                int err;

                /* If you change siginfo_t structure, please be sure

                   this code is fixed accordingly.

                   It should never copy any pad contained in the structure

                   to avoid security leaks, but must copy the generic

                   3 ints plus the relevant union member.  */

                err = __put_user(from->si_signo, &to->si_signo);

                err |= __put_user(from->si_errno, &to->si_errno);

                err |= __put_user((short)from->si_code, &to->si_code);

                /* First 32bits of unions are always present.  */

                err |= __put_user(from->si_pid, &to->si_pid);

                switch (from->si_code >> 16) {

                case __SI_FAULT >> 16:

                        break;

                case __SI_CHLD >> 16:

                        err |= __put_user(from->si_utime, &to->si_utime);

                        err |= __put_user(from->si_stime, &to->si_stime);

                        err |= __put_user(from->si_status, &to->si_status);

                default:

                        err |= __put_user(from->si_uid, &to->si_uid);

                        break;

                /* case __SI_RT: This is not generated by the kernel as of now.  */

                }

                return err;

        }

}

/*

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

 */

asmlinkage int

sys_sigsuspend(old_sigset_t mask,

               unsigned long r5, unsigned long r6, unsigned long r7,

               struct pt_regs regs)

{

        sigset_t saveset;

        mask &= _BLOCKABLE;

        spin_lock_irq(&current->sigmask_lock);

        saveset = current->blocked;

        siginitset(&current->blocked, mask);

        recalc_sigpending(current);

        spin_unlock_irq(&current->sigmask_lock);

        regs.regs[0] = -EINTR;

        while (1) {

                current->state = TASK_INTERRUPTIBLE;

                schedule();

                if (do_signal(&regs, &saveset, 0, 0))

                        return -EINTR;

        }

}

asmlinkage int

sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,

                  unsigned long r6, unsigned long r7,

                  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 (copy_from_user(&newset, unewset, sizeof(newset)))

                return -EFAULT;

        sigdelsetmask(&newset, ~_BLOCKABLE);

        spin_lock_irq(&current->sigmask_lock);

        saveset = current->blocked;

        current->blocked = newset;

        recalc_sigpending(current);

        spin_unlock_irq(&current->sigmask_lock);

        regs.regs[0] = -EINTR;

        while (1) {

                current->state = TASK_INTERRUPTIBLE;

                schedule();

                if (do_signal(&regs, &saveset, 0, 0))

                        return -EINTR;

        }

}

asmlinkage int

sys_sigaction(int sig, const struct old_sigaction *act,

              struct old_sigaction *oact)

{

        struct k_sigaction new_ka, old_ka;

        int ret;

        if (act) {

                old_sigset_t mask;

                if (verify_area(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);

        }

        ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

        if (!ret && oact) {

                if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||

                    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||

                    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))

                        return -EFAULT;

                __put_user(old_ka.sa.sa_flags, &oact->sa_flags);

                __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);

        }

        return ret;

}

asmlinkage int

sys_sigaltstack(const stack_t *uss, stack_t *uoss,

                unsigned long r6, unsigned long r7,

                struct pt_regs regs)

{

        return do_sigaltstack(uss, uoss, regs.regs[15]);

}

/*

 * Do a signal return; undo the signal stack.

 */

#define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */

#define TRAP16   0xc310                 /* Syscall w/no args (NR in R3) */

#define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */

struct sigframe

{

        struct sigcontext sc;

        unsigned long extramask[_NSIG_WORDS-1];

        u16 retcode[8];

};

struct rt_sigframe

{

        struct siginfo info;

        struct ucontext uc;

        u16 retcode[8];

};

#if defined(__SH4__)

static inline int restore_sigcontext_fpu(struct sigcontext *sc)

{

        struct task_struct *tsk = current;

        tsk->used_math = 1;

        return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],

                                sizeof(long)*(16*2+2));

}

static inline int save_sigcontext_fpu(struct sigcontext *sc)

{

        struct task_struct *tsk = current;

        if (!tsk->used_math) {

                __put_user(0, &sc->sc_ownedfp);

                return 0;

        }

        __put_user(1, &sc->sc_ownedfp);

        /* This will cause a "finit" to be triggered by the next

           attempted FPU operation by the 'current' process.

           */

        tsk->used_math = 0;

        unlazy_fpu(tsk);

        return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,

                              sizeof(long)*(16*2+2));

}

#endif

static int

restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)

{

        unsigned int err = 0;

#define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)

        COPY(regs[0]);   COPY(regs[1]);

        COPY(regs[2]);  COPY(regs[3]);

        COPY(regs[4]);  COPY(regs[5]);

        COPY(regs[6]);  COPY(regs[7]);

        COPY(regs[8]);  COPY(regs[9]);

        COPY(regs[10]); COPY(regs[11]);

        COPY(regs[12]); COPY(regs[13]);

        COPY(regs[14]); COPY(regs[15]);

        COPY(gbr);      COPY(mach);

        COPY(macl);     COPY(pr);

        COPY(sr);       COPY(pc);

#undef COPY

#if defined(__SH4__)

        {

                int owned_fp;

                struct task_struct *tsk = current;

                regs->sr |= SR_FD; /* Release FPU */

                clear_fpu(tsk);

                current->used_math = 0;

                __get_user (owned_fp, &sc->sc_ownedfp);

                if (owned_fp)

                        err |= restore_sigcontext_fpu(sc);

        }

#endif

        return err;

}

asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,

                             unsigned long r6, unsigned long r7,

                             struct pt_regs regs)

{

        struct sigframe *frame = (struct sigframe *)regs.regs[15];

        sigset_t set;

        if (verify_area(VERIFY_READ, frame, sizeof(*frame)))

                goto badframe;

        if (__get_user(set.sig[0], &frame->sc.oldmask)

            || (_NSIG_WORDS > 1

                && __copy_from_user(&set.sig[1], &frame->extramask,

                                    sizeof(frame->extramask))))

                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->sc))

                goto badframe;

        return regs.regs[0];

badframe:

        force_sig(SIGSEGV, current);

        return 0;

}

asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,

                                unsigned long r6, unsigned long r7,

                                struct pt_regs regs)

{

        struct rt_sigframe *frame = (struct rt_sigframe *)regs.regs[15];

        sigset_t set;

        stack_t st;

        if (verify_area(VERIFY_READ, frame, sizeof(*frame)))

                goto badframe;

        if (__copy_from_user(&set, &frame->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->uc.uc_mcontext))

                goto badframe;

        if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))

                goto badframe;

        /* It is more difficult to avoid calling this function than to

           call it and ignore errors.  */

        do_sigaltstack(&st, NULL, regs.regs[15]);

        return regs.regs[0];

badframe:

        force_sig(SIGSEGV, current);

        return 0;

}

/*

 * Set up a signal frame.

 */

static int

setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,

                 unsigned long mask)

{

        int err = 0;

#define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)

        COPY(regs[0]);   COPY(regs[1]);

        COPY(regs[2]);  COPY(regs[3]);

        COPY(regs[4]);  COPY(regs[5]);

        COPY(regs[6]);  COPY(regs[7]);

        COPY(regs[8]);  COPY(regs[9]);

        COPY(regs[10]); COPY(regs[11]);

        COPY(regs[12]); COPY(regs[13]);

        COPY(regs[14]); COPY(regs[15]);

        COPY(gbr);      COPY(mach);

        COPY(macl);     COPY(pr);

        COPY(sr);       COPY(pc);

#undef COPY

#if defined(__SH4__)

        err |= save_sigcontext_fpu(sc);

#endif

        /* non-iBCS2 extensions.. */

        err |= __put_user(mask, &sc->oldmask);

        return err;

}

/*

 * Determine which stack to use..

 */

static inline void *

get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)

{

        if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp))

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

        return (void *)((sp - frame_size) & -8ul);

}

static void setup_frame(int sig, struct k_sigaction *ka,

                        sigset_t *set, struct pt_regs *regs)

{

        struct sigframe *frame;

        int err = 0;

        int signal;

        frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));

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

                goto give_sigsegv;

        signal = current->exec_domain

                && current->exec_domain->signal_invmap

                && sig < 32

                ? current->exec_domain->signal_invmap[sig]

                : sig;

        err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);

        if (_NSIG_WORDS > 1) {

                err |= __copy_to_user(frame->extramask, &set->sig[1],

                                      sizeof(frame->extramask));

        }

        /* Set up to return from userspace.  If provided, use a stub

           already in userspace.  */

        if (ka->sa.sa_flags & SA_RESTORER) {

                regs->pr = (unsigned long) ka->sa.sa_restorer;

        } else {

                /* Generate return code (system call to sigreturn) */

                err |= __put_user(MOVW(7), &frame->retcode[0]);

                err |= __put_user(TRAP16, &frame->retcode[1]);

                err |= __put_user(OR_R0_R0, &frame->retcode[2]);

                err |= __put_user(OR_R0_R0, &frame->retcode[3]);

                err |= __put_user(OR_R0_R0, &frame->retcode[4]);

                err |= __put_user(OR_R0_R0, &frame->retcode[5]);

                err |= __put_user(OR_R0_R0, &frame->retcode[6]);

                err |= __put_user((__NR_sigreturn), &frame->retcode[7]);

                regs->pr = (unsigned long) frame->retcode;

        }

        if (err)

                goto give_sigsegv;

        /* Set up registers for signal handler */

        regs->regs[15] = (unsigned long) frame;

        regs->regs[4] = signal; /* Arg for signal handler */

        regs->regs[5] = 0;

        regs->regs[6] = (unsigned long) &frame->sc;

        regs->pc = (unsigned long) ka->sa.sa_handler;

        set_fs(USER_DS);

#if DEBUG_SIG

        printk("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",

                current->comm, current->pid, frame, regs->pc, regs->pr);

#endif

        flush_cache_sigtramp(regs->pr);

        if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))

                flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);

        return;

give_sigsegv:

        if (sig == SIGSEGV)

                ka->sa.sa_handler = SIG_DFL;

        force_sig(SIGSEGV, current);

}

static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,

                           sigset_t *set, struct pt_regs *regs)

{

        struct rt_sigframe *frame;

        int err = 0;

        int signal;

        frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));

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

                goto give_sigsegv;

        signal = current->exec_domain

                && current->exec_domain->signal_invmap

                && sig < 32

                ? current->exec_domain->signal_invmap[sig]

                : sig;

        err |= copy_siginfo_to_user(&frame->info, info);

        /* Create the ucontext.  */

        err |= __put_user(0, &frame->uc.uc_flags);

        err |= __put_user(0, &frame->uc.uc_link);

        err |= __put_user((void *)current->sas_ss_sp,

                          &frame->uc.uc_stack.ss_sp);

        err |= __put_user(sas_ss_flags(regs->regs[15]),

                          &frame->uc.uc_stack.ss_flags);

        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);

        err |= setup_sigcontext(&frame->uc.uc_mcontext,

                                regs, set->sig[0]);

        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

        /* Set up to return from userspace.  If provided, use a stub

           already in userspace.  */

        if (ka->sa.sa_flags & SA_RESTORER) {

                regs->pr = (unsigned long) ka->sa.sa_restorer;

        } else {

                /* Generate return code (system call to rt_sigreturn) */

                err |= __put_user(MOVW(7), &frame->retcode[0]);

                err |= __put_user(TRAP16, &frame->retcode[1]);

                err |= __put_user(OR_R0_R0, &frame->retcode[2]);

                err |= __put_user(OR_R0_R0, &frame->retcode[3]);

                err |= __put_user(OR_R0_R0, &frame->retcode[4]);

                err |= __put_user(OR_R0_R0, &frame->retcode[5]);

                err |= __put_user(OR_R0_R0, &frame->retcode[6]);

                err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);

                regs->pr = (unsigned long) frame->retcode;

        }

        if (err)

                goto give_sigsegv;

        /* Set up registers (SP, PC, and args) for signal handler */

        regs->regs[15] = (unsigned long) frame;         /* Stack pointer */

        regs->regs[4] = signal;                         /* Arg1 (signal) */

        regs->regs[5] = (unsigned long)&frame->info;    /* Arg2 (siginfo) */

        regs->regs[6] = (unsigned long)&frame->uc;      /* Arg3 (context) */

        regs->pc = (unsigned long) ka->sa.sa_handler;   /* Program counter */

        set_fs(USER_DS);

#if DEBUG_SIG

        printk("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",

                current->comm, current->pid, frame, regs->pc, regs->pr);

#endif

        flush_cache_sigtramp(regs->pr);

        if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))

                flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);

        return;

give_sigsegv:

        if (sig == SIGSEGV)

                ka->sa.sa_handler = SIG_DFL;

        force_sig(SIGSEGV, current);

}

/*

 * OK, we're invoking a handler

 */

static void

handle_signal(unsigned long sig, struct k_sigaction *ka,

              siginfo_t *info, sigset_t *oldset, struct pt_regs *regs,

              int from_syscall, unsigned long orig_r0)

{

        /* Are we from a system call? */

        if (from_syscall) {

                /* If so, check system call restarting.. */

                switch (regs->regs[0]) {

                        case -ERESTARTNOHAND:

                                regs->regs[0] = -EINTR;

                                break;

                        case -ERESTARTSYS:

                                if (!(ka->sa.sa_flags & SA_RESTART)) {

                                        regs->regs[0] = -EINTR;

                                        break;

                                }

                        /* fallthrough */

                        case -ERESTARTNOINTR:

                                regs->regs[0] = orig_r0;

                                regs->pc -= 2;

                }

        } else {

                /* gUSA handling */

                if (regs->regs[15] >= 0xc0000000) {

                        int offset = (int)regs->regs[15];

                        /* Reset stack pointer: clear critical region mark */

                        regs->regs[15] = regs->regs[1];

                        if (regs->pc < regs->regs[0])

                                /* Go to rewind point #1 */

                                regs->pc = regs->regs[0] + offset - 2;

                }

        }

        /* Set up the stack frame */

        if (ka->sa.sa_flags & SA_SIGINFO)

                setup_rt_frame(sig, ka, info, oldset, regs);

        else

                setup_frame(sig, ka, oldset, regs);

        if (ka->sa.sa_flags & SA_ONESHOT)

                ka->sa.sa_handler = SIG_DFL;

        if (!(ka->sa.sa_flags & SA_NODEFER)) {

                spin_lock_irq(&current->sigmask_lock);

                sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);

                sigaddset(&current->blocked,sig);

                recalc_sigpending(current);

                spin_unlock_irq(&current->sigmask_lock);

        }

}

/*

 * 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.

 */

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

              int from_syscall, unsigned long orig_r0)

{

        siginfo_t info;

        struct k_sigaction *ka;

        /*

         * We want the common case to go fast, which

         * is why we may in certain cases get here from

         * kernel mode. Just return without doing anything

         * if so.

         */

        if (!user_mode(regs))

                return 1;

        if (!oldset)

                oldset = &current->blocked;

        for (;;) {

                unsigned long signr;

                spin_lock_irq(&current->sigmask_lock);

                signr = dequeue_signal(&current->blocked, &info);

                spin_unlock_irq(&current->sigmask_lock);

                if (!signr)

                        break;