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/*

 *  linux/arch/ppc64/kernel/signal.c

 *

 *  PowerPC version

 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)

 *

 *  Derived from "arch/i386/kernel/signal.c"

 *    Copyright (C) 1991, 1992 Linus Torvalds

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

 *

 *  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.

 */

#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/elf.h>

#include <asm/ppc32.h>

#include <asm/sigcontext.h>

#include <asm/ucontext.h>

#include <asm/uaccess.h>

#include <asm/pgtable.h>

#include <asm/ppcdebug.h>

#include <asm/unistd.h>

#define DEBUG_SIG 0

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

#ifndef MIN

#define MIN(a,b) (((a) < (b)) ? (a) : (b))

#endif

#define GP_REGS_SIZE    MIN(sizeof(elf_gregset_t), sizeof(struct pt_regs))

#define FP_REGS_SIZE    sizeof(elf_fpregset_t)

#define TRAMP_TRACEBACK 3

#define TRAMP_SIZE      6

/*

 * When we have signals to deliver, we set up on the user stack,

 * going down from the original stack pointer:

 *      1) a sigframe/rt_sigframe struct which contains the sigcontext/ucontext

 *      2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller

 *         frame for the signal handler.

 */

struct sigframe {

        /* sys_sigreturn requires the sigcontext be the first field */

        struct sigcontext sc;

        unsigned int tramp[TRAMP_SIZE];

        /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */

        char abigap[288];

};

struct rt_sigframe {

        /* sys_rt_sigreturn requires the ucontext be the first field */

        struct ucontext uc;

        unsigned long _unused[2];

        unsigned int tramp[TRAMP_SIZE];

        struct siginfo *pinfo;

        void *puc;

        struct siginfo info;

        /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */

        char abigap[288];

};

extern long sys_wait4(pid_t pid, unsigned int *stat_addr,

                     int options, /*unsigned long*/ struct rusage *ru);

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:

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

                        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;

        }

}

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

/*

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

 */

asmlinkage long

sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int p7,

               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->result = -EINTR;

        regs->gpr[3] = EINTR;

        regs->ccr |= 0x10000000;

        while (1) {

                current->state = TASK_INTERRUPTIBLE;

                schedule();

                if (do_signal(&saveset, regs))

                        /*

                         * If a signal handler needs to be called,

                         * do_signal() has set R3 to the signal number (the

                         * first argument of the signal handler), so don't

                         * overwrite that with EINTR !

                         * In the other cases, do_signal() doesn't touch

                         * R3, so it's still set to -EINTR (see above).

                         */

                        return regs->gpr[3];

        }

}

asmlinkage long

sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, int p3, int p4, int p6,

                  int p7, 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->result = -EINTR;

        regs->gpr[3] = EINTR;

        regs->ccr |= 0x10000000;

        while (1) {

                current->state = TASK_INTERRUPTIBLE;

                schedule();

                if (do_signal(&saveset, regs))

                        return regs->gpr[3];

        }

}

asmlinkage long

sys_sigaltstack(const stack_t *uss, stack_t *uoss, unsigned long r5,

                unsigned long r6, unsigned long r7, unsigned long r8,

                struct pt_regs *regs)

{

        return do_sigaltstack(uss, uoss, regs->gpr[1]);

}

asmlinkage long

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;

}

/*

 * Set up the sigcontext for the signal frame.

 */

static int

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

                 int signr, sigset_t *set, unsigned long handler)

{

        int err = 0;

        if (regs->msr & MSR_FP)

                giveup_fpu(current);

        current->thread.saved_msr = regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1);

        regs->msr = current->thread.saved_msr | current->thread.fpexc_mode;

        current->thread.saved_softe = regs->softe;

        err |= __put_user(&sc->gp_regs, &sc->regs);

        err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);

        err |= __copy_to_user(&sc->fp_regs, &current->thread.fpr, FP_REGS_SIZE);

        err |= __put_user(signr, &sc->signal);

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

        if (set != NULL)

                err |=  __put_user(set->sig[0], &sc->oldmask);

        regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);

        current->thread.fpscr = 0;

        return err;

}

/*

 * Restore the sigcontext from the signal frame.

 */

static int

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

{

        unsigned int err = 0;

        if (regs->msr & MSR_FP)

                giveup_fpu(current);

        err |= __copy_from_user(regs, &sc->gp_regs, GP_REGS_SIZE);

        err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);

        current->thread.fpexc_mode = regs->msr & (MSR_FE0 | MSR_FE1);

        if (set != NULL)

                err |=  __get_user(set->sig[0], &sc->oldmask);

        /* Don't allow the signal handler to change these modulo FE{0,1} */

        regs->msr = current->thread.saved_msr & ~(MSR_FP | MSR_FE0 | MSR_FE1);

        regs->softe = current->thread.saved_softe;

        return err;

}

/*

 * Allocate space for the signal frame

 */

static inline void *

get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)

{

        unsigned long newsp;

        /* Default to using normal stack */

        newsp = regs->gpr[1];

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

                if (! on_sig_stack(regs->gpr[1]))

                        newsp = (current->sas_ss_sp + current->sas_ss_size);

        }

        /* The ABI requires quadword alignment for the stack. */

        return (void *)((newsp - frame_size) & -16ul);

}

static int

setup_trampoline(unsigned int syscall, unsigned int *tramp)

{

        int i, err = 0;

        /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */

        err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);

        /* li r0, __NR_[rt_]sigreturn| */

        err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);

        /* sc */

        err |= __put_user(0x44000002UL, &tramp[2]);

        /* Minimal traceback info */

        for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)

                err |= __put_user(0, &tramp[i]);

        if (!err)

                flush_icache_range((unsigned long) &tramp[0],

                           (unsigned long) &tramp[TRAMP_SIZE]);

        return err;

}

asmlinkage int

sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,

                 unsigned long r6, unsigned long r7, unsigned long r8,

                 struct pt_regs *regs)

{

        struct ucontext *uc = (struct ucontext *)regs->gpr[1];

        sigset_t set;

        stack_t st;

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

                goto badframe;

        if (__copy_from_user(&set, &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, NULL, &uc->uc_mcontext))

                goto badframe;

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

                goto badframe;

        /* This function sets back the stack flags into

           the current task structure.  */

        sys_sigaltstack(&st, NULL, 0, 0, 0, 0, regs);

        return regs->result;

badframe:

        do_exit(SIGSEGV);

}

static void

setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,

                sigset_t *set, struct pt_regs *regs)

{

        /* Handler is *really* a pointer to the function descriptor for

         * the signal routine.  The first entry in the function

         * descriptor is the entry address of signal and the second

         * entry is the TOC value we need to use.

         */

        func_descr_t *funct_desc_ptr;

        struct rt_sigframe *frame;

        unsigned long newsp;

        int err = 0;

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

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

                goto give_sigsegv;

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

        err |= __put_user(&frame->uc, &frame->puc);

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

        if (err)

                goto give_sigsegv;

        /* Create the ucontext.  */

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

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

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

        err |= __put_user(sas_ss_flags(regs->gpr[1]),

                          &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, signr, NULL,

                                (unsigned long)ka->sa.sa_handler);

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

        if (err)

                goto give_sigsegv;

        /* Set up to return from userspace. */

        err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);

        if (err)

                goto give_sigsegv;

        funct_desc_ptr = (func_descr_t *) ka->sa.sa_handler;

        /* Allocate a dummy caller frame for the signal handler. */

        newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;

        err |= put_user(0, (unsigned long *)newsp);

        /* Set up "regs" so we "return" to the signal handler. */

        err |= get_user(regs->nip, &funct_desc_ptr->entry);

        regs->link = (unsigned long) &frame->tramp[0];

        regs->gpr[1] = newsp;

        err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);

        regs->gpr[3] = signr;

        err |= get_user(regs->gpr[4], (unsigned long *)&frame->pinfo);

        err |= get_user(regs->gpr[5], (unsigned long *)&frame->puc);

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

        if (err)

                goto give_sigsegv;

        return;

give_sigsegv:

#if DEBUG_SIG

        printk("badframe in setup_rt_frame, regs=%p frame=%p, newsp=0x%lx\n",

                regs, frame, newsp);

#endif

        do_exit(SIGSEGV);

}

/*

 * Do a signal return; undo the signal stack.

 */

asmlinkage long

sys_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,

              unsigned long r6, unsigned long r7, unsigned long r8,

              struct pt_regs *regs)

{

        struct sigcontext *sc = (struct sigcontext *)regs->gpr[1];

        sigset_t set;

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

                goto badframe;

        if (restore_sigcontext(regs, &set, sc))

                goto badframe;

        sigdelsetmask(&set, ~_BLOCKABLE);

        spin_lock_irq(&current->sigmask_lock);

        current->blocked = set;

        recalc_sigpending(current);

        spin_unlock_irq(&current->sigmask_lock);

        return regs->result;

badframe:

        do_exit(SIGSEGV);

}

static void

setup_frame(int signr, struct k_sigaction *ka, sigset_t *set,

            struct pt_regs *regs)

{

        /* Handler is *really* a pointer to the function descriptor for

         * the signal routine.  The first entry in the function

         * descriptor is the entry address of signal and the second

         * entry is the TOC value we need to use.

         */

        func_descr_t *funct_desc_ptr;

        struct sigframe *frame;

        unsigned long newsp;

        int err = 0;

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

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

                goto badframe;

        err |= setup_sigcontext(&frame->sc, regs, signr, set,

                                (unsigned long)ka->sa.sa_handler);

        /* Set up to return from userspace. */

        err |= setup_trampoline(__NR_sigreturn, &frame->tramp[0]);

        if (err)

                goto badframe;

        funct_desc_ptr = (func_descr_t *) ka->sa.sa_handler;

        /* Allocate a dummy caller frame for the signal handler. */

        newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;

        err |= put_user(0, (unsigned long *)newsp);

        /* Set up "regs" so we "return" to the signal handler. */

        err |= get_user(regs->nip, &funct_desc_ptr->entry);

        regs->link = (unsigned long) &frame->tramp[0];

        regs->gpr[1] = newsp;

        err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);

        regs->gpr[3] = signr;

        regs->gpr[4] = (unsigned long) &frame->sc;

        if (err)

                goto badframe;

        return;

badframe:

#if DEBUG_SIG

        printk("badframe in setup_frame, regs=%p frame=%p newsp=%lx\n",

               regs, frame, newsp);

#endif

        do_exit(SIGSEGV);

}

/*

 * 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)

{

        /* Set up Signal 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);

        }

}

static inline void

syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)

{

        switch ((int)regs->result) {

                case -ERESTARTNOHAND:

                        /* ERESTARTNOHAND means that the syscall should only

                           be restarted if there was no handler for the signal,

                           and since we only get here if there is a handler,

                           we dont restart */

                        regs->result = -EINTR;

                        break;

                case -ERESTARTSYS:

                        /* ERESTARTSYS means to restart the syscall if there is

                           no handler or the handler was registered with SA_RESTART */

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

                                regs->result = -EINTR;

                                break;

                        }

                /* fallthrough */

                case -ERESTARTNOINTR:

                        /* ERESTARTNOINTR means that the syscall should be

                           called again after the signal handler returns */

                        regs->gpr[3] = regs->orig_gpr3;

                        regs->nip -= 4;

                        regs->result = 0;

        }

}

static int

get_signal_to_deliver(siginfo_t *info, struct pt_regs *regs)

{

        for (;;) {

                unsigned long signr;

                struct k_sigaction *ka;

                spin_lock_irq(&current->sigmask_lock);

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

                spin_unlock_irq(&current->sigmask_lock);

                if (!signr)

                        break;

                if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {

                        /* Let the debugger run.  */

                        current->exit_code = signr;

                        current->state = TASK_STOPPED;

                        notify_parent(current, SIGCHLD);

                        schedule();

                        /* We're back.  Did the debugger cancel the sig?  */

                        signr = current->exit_code;

                        if (signr == 0)

                                continue;

                        current->exit_code = 0;

                        /* The debugger continued.  Ignore SIGSTOP.  */

                        if (signr == SIGSTOP)

                                continue;

                        /* Update the siginfo structure.  Is this good?  */

                        if (signr != info->si_signo) {

                                info->si_signo = signr;

                                info->si_errno = 0;

                                info->si_code = SI_USER;

                                info->si_pid = current->p_pptr->pid;

                                info->si_uid = current->p_pptr->uid;

                        }

                        /* If the (new) signal is now blocked, requeue it.  */

                        if (sigismember(&current->blocked, signr)) {

                                send_sig_info(signr, info, current);

                                continue;

                        }

                }

                ka = &current->sig->action[signr-1];

                if (ka->sa.sa_handler == SIG_IGN) {

                        if (signr != SIGCHLD)

                                continue;

                        /* Check for SIGCHLD: it's special.  */

                        while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)

                                /* nothing */;

                        continue;

                }

                if (ka->sa.sa_handler == SIG_DFL) {

                        int exit_code = signr;

                        /* Init gets no signals it doesn't want.  */

                        if (current->pid == 1)

                                continue;

                        switch (signr) {

                        case SIGCONT: case SIGCHLD: case SIGWINCH: case SIGURG: