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/*

 *  arch/s390/kernel/signal.c

 *

 *  S390 version

 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation

 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)

 *

 *    Based on Intel version

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

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

 */

#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 <linux/stddef.h>

#include <linux/personality.h>

#include <asm/ucontext.h>

#include <asm/uaccess.h>

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

typedef struct

{

        __u8 callee_used_stack[__SIGNAL_FRAMESIZE];

        struct sigcontext sc;

        _sigregs sregs;

        __u8 retcode[S390_SYSCALL_SIZE];

} sigframe;

typedef struct

{

        __u8 callee_used_stack[__SIGNAL_FRAMESIZE];

        __u8 retcode[S390_SYSCALL_SIZE];

        struct siginfo info;

        struct ucontext uc;

} rt_sigframe;

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

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 64bits of unions are always present.  */

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

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

                switch (from->si_code >> 16) {

                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:

                        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(struct pt_regs * regs,int history0, int history1, old_sigset_t mask)

{

        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->gprs[2] = -EINTR;

        while (1) {

                set_current_state(TASK_INTERRUPTIBLE);

                schedule();

                if (do_signal(regs, &saveset))

                        return -EINTR;

        }

}

asmlinkage int

sys_rt_sigsuspend(struct pt_regs * regs,sigset_t *unewset, size_t sigsetsize)

{

        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->gprs[2] = -EINTR;

        while (1) {

                set_current_state(TASK_INTERRUPTIBLE);

                schedule();

                if (do_signal(regs, &saveset))

                        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, struct pt_regs *regs)

{

        return do_sigaltstack(uss, uoss, regs->gprs[15]);

}

static int save_sigregs(struct pt_regs *regs,_sigregs *sregs)

{

        int err;

        s390_fp_regs fpregs;

        err = __copy_to_user(&sregs->regs,regs,sizeof(_s390_regs_common));

        if(!err)

        {

                save_fp_regs(&fpregs);

                err=__copy_to_user(&sregs->fpregs,&fpregs,sizeof(fpregs));

        }

        return(err);

}

static int restore_sigregs(struct pt_regs *regs,_sigregs *sregs)

{

        int err;

        s390_fp_regs fpregs;

        psw_t saved_psw=regs->psw;

        err=__copy_from_user(regs,&sregs->regs,sizeof(_s390_regs_common));

        if(!err)

        {

                regs->trap = -1;                /* disable syscall checks */

                regs->psw.mask=(saved_psw.mask&~PSW_MASK_DEBUGCHANGE)|

                (regs->psw.mask&PSW_MASK_DEBUGCHANGE);

                regs->psw.addr=(saved_psw.addr&~PSW_ADDR_DEBUGCHANGE)|

                (regs->psw.addr&PSW_ADDR_DEBUGCHANGE);

                err=__copy_from_user(&fpregs,&sregs->fpregs,sizeof(fpregs));

                if(!err)

                        restore_fp_regs(&fpregs);

        }

        return(err);

}

asmlinkage long sys_sigreturn(struct pt_regs *regs)

{

        sigframe *frame = (sigframe *)regs->gprs[15];

        sigset_t set;

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

                goto badframe;

        if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))

                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_sigregs(regs, &frame->sregs))

                goto badframe;

        return regs->gprs[2];

badframe:

        force_sig(SIGSEGV, current);

        return 0;

}

asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)

{

        rt_sigframe *frame = (rt_sigframe *)regs->gprs[15];

        sigset_t set;

        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_sigregs(regs, &frame->uc.uc_mcontext))

                goto badframe;

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

           call it and ignore errors.  */

        do_sigaltstack(&frame->uc.uc_stack, NULL, regs->gprs[15]);

        return regs->gprs[2];

badframe:

        force_sig(SIGSEGV, current);

        return 0;

}

/*

 * Set up a signal frame.

 */

/*

 * 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->gprs[15];

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

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

                if (! on_sig_stack(sp))

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

        }

        /* This is the legacy signal stack switching. */

        else if (!user_mode(regs) &&

                 !(ka->sa.sa_flags & SA_RESTORER) &&

                 ka->sa.sa_restorer) {

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

        }

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

}

static inline int map_signal(int sig)

{

        if (current->exec_domain

            && current->exec_domain->signal_invmap

            && sig < 32)

                return current->exec_domain->signal_invmap[sig];

        else

                return sig;

}

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

                        sigset_t *set, struct pt_regs * regs)

{

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

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

                goto give_sigsegv;

        if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))

                goto give_sigsegv;

        if (save_sigregs(regs, &frame->sregs))

                goto give_sigsegv;

        if (__put_user(&frame->sregs, &frame->sc.sregs))

                goto give_sigsegv;

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

           already in userspace.  */

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

                regs->gprs[14] = FIX_PSW(ka->sa.sa_restorer);

        } else {

                regs->gprs[14] = FIX_PSW(frame->retcode);

                if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,

                               (u16 *)(frame->retcode)))

                        goto give_sigsegv;

        }

        /* Set up backchain. */

        if (__put_user(regs->gprs[15], (addr_t *) frame))

                goto give_sigsegv;

        /* Set up registers for signal handler */

        regs->gprs[15] = (addr_t)frame;

        regs->psw.addr = FIX_PSW(ka->sa.sa_handler);

        regs->psw.mask = _USER_PSW_MASK;

        regs->gprs[2] = map_signal(sig);

        regs->gprs[3] = (addr_t)&frame->sc;

        /* We forgot to include these in the sigcontext.

           To avoid breaking binary compatibility, they are passed as args. */

        regs->gprs[4] = current->thread.trap_no;

        regs->gprs[5] = current->thread.prot_addr;

        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)

{

        int err = 0;

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

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

                goto give_sigsegv;

        if (copy_siginfo_to_user(&frame->info, info))

                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->gprs[15]),

                          &frame->uc.uc_stack.ss_flags);

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

        err |= save_sigregs(regs, &frame->uc.uc_mcontext);

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

        if (err)

                goto give_sigsegv;

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

           already in userspace.  */

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

                regs->gprs[14] = FIX_PSW(ka->sa.sa_restorer);

        } else {

                regs->gprs[14] = FIX_PSW(frame->retcode);

                err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,

                                  (u16 *)(frame->retcode));

        }

        /* Set up backchain. */

        if (__put_user(regs->gprs[15], (addr_t *) frame))

                goto give_sigsegv;

        /* Set up registers for signal handler */

        regs->gprs[15] = (addr_t)frame;

        regs->psw.addr = FIX_PSW(ka->sa.sa_handler);

        regs->psw.mask = _USER_PSW_MASK;

        regs->gprs[2] = map_signal(sig);

        regs->gprs[3] = (addr_t)&frame->info;

        regs->gprs[4] = (addr_t)&frame->uc;

        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)

{

        /* Are we from a system call? */

        if (regs->trap == __LC_SVC_OLD_PSW) {

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

                switch (regs->gprs[2]) {

                        case -ERESTARTNOHAND:

                                regs->gprs[2] = -EINTR;

                                break;

                        case -ERESTARTSYS:

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

                                        regs->gprs[2] = -EINTR;

                                        break;

                                }

                        /* fallthrough */

                        case -ERESTARTNOINTR:

                                regs->gprs[2] = regs->orig_gpr2;

                                regs->psw.addr -= 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)

{

        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;

#ifdef CONFIG_S390_SUPPORT 

        if (current->thread.flags & S390_FLAG_31BIT) {

                extern asmlinkage int do_signal32(struct pt_regs *regs, sigset_t *oldset);

                return do_signal32(regs, oldset);

        }

#endif 

        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;

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

                        /* Let the debugger run.  */

                        current->exit_code = signr;

                        set_current_state(TASK_STOPPED);

                        notify_parent(current, SIGCHLD);

                        schedule();

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

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

                                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:

                                continue;

                        case SIGTSTP: case SIGTTIN: case SIGTTOU:

                                if (is_orphaned_pgrp(current->pgrp))

                                        continue;

                                /* FALLTHRU */

                        case SIGSTOP: {

                                struct signal_struct *sig;

                                set_current_state(TASK_STOPPED);

                                current->exit_code = signr;

                                sig = current->p_pptr->sig;

                                if (sig && !(sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))

                                        notify_parent(current, SIGCHLD);

                                schedule();

                                continue;

                        }

                        case SIGQUIT: case SIGILL: case SIGTRAP:

                        case SIGABRT: case SIGFPE: case SIGSEGV:

                        case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:

                                if (do_coredump(signr, regs))

                                        exit_code |= 0x80;

                                /* FALLTHRU */

                        default:

                                sig_exit(signr, exit_code, &info);

                                /* NOTREACHED */

                        }

                }

                /* Whee!  Actually deliver the signal.  */

                handle_signal(signr, ka, &info, oldset, regs);

                return 1;

        }

        /* Did we come from a system call? */

        if ( regs->trap == __LC_SVC_OLD_PSW /* System Call! */ ) {

                /* Restart the system call - no handlers present */

                if (regs->gprs[2] == -ERESTARTNOHAND ||

                    regs->gprs[2] == -ERESTARTSYS ||

                    regs->gprs[2] == -ERESTARTNOINTR) {

                        regs->gprs[2] = regs->orig_gpr2;

                        regs->psw.addr -= 2;

                }

        }

        return 0;

}