/* $NetBSD: compat_13_machdep.c,v 1.22 2017/03/16 16:13:20 chs Exp $ */

/*
 * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Chris G. Demetriou
 *
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#include <sys/cdefs.h>                  /* RCS ID & Copyright macro defns */

__KERNEL_RCSID(0, "$NetBSD: compat_13_machdep.c,v 1.22 2017/03/16 16:13:20 chs Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>

#include <compat/sys/signal.h>
#include <compat/sys/signalvar.h>

#include <machine/cpu.h>
#include <machine/reg.h>
#include <machine/alpha.h>

/*
 * System call to cleanup state after a signal
 * has been taken.  Reset signal mask and
 * stack state from context left by sendsig (above).
 * Return to previous pc and psl as specified by
 * context left by sendsig. Check carefully to
 * make sure that the user has not modified the
 * psl to gain improper privileges or to cause
 * a machine fault.
 */
/* ARGSUSED */
int
compat_13_sys_sigreturn(struct lwp *l, const struct compat_13_sys_sigreturn_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct sigcontext13 *) sigcntxp;
        } */
        struct sigcontext13 *scp, ksc;
        struct proc *p = l->l_proc;
        struct pcb *pcb;
        sigset13_t mask13;
        sigset_t mask;

        /*
         * The trampoline code hands us the context.
         * It is unsafe to keep track of it ourselves, in the event that a
         * program jumps out of a signal handler.
         */
        scp = SCARG(uap, sigcntxp);
        if (ALIGN(scp) != (uint64_t)scp)
                return (EINVAL);

        if (copyin((void *)scp, &ksc, sizeof(ksc)) != 0)
                return (EFAULT);

        if (ksc.sc_regs[R_ZERO] != 0xACEDBADE)          /* magic number */
                return (EINVAL);

        /* Restore register context. */
        l->l_md.md_tf->tf_regs[FRAME_PC] = ksc.sc_pc;
        l->l_md.md_tf->tf_regs[FRAME_PS] =
            (ksc.sc_ps | ALPHA_PSL_USERSET) & ~ALPHA_PSL_USERCLR;

        regtoframe((struct reg *)ksc.sc_regs, l->l_md.md_tf);
        alpha_pal_wrusp(ksc.sc_regs[R_SP]);

        /* XXX ksc.sc_ownedfp ? */
        pcb = lwp_getpcb(l);
        fpu_discard(l, true);
        memcpy(&pcb->pcb_fp, (struct fpreg *)ksc.sc_fpregs,
            sizeof(struct fpreg));
        /* XXX ksc.sc_fp_control ? */

        mutex_enter(p->p_lock);
        /* Restore signal stack. */
        if (ksc.sc_onstack & SS_ONSTACK)
                l->l_sigstk.ss_flags |= SS_ONSTACK;
        else
                l->l_sigstk.ss_flags &= ~SS_ONSTACK;
        /*
         * Restore signal mask.  Note the mask is a "long" in the stack
         * frame.
         */
        mask13 = ksc.sc_mask;
        native_sigset13_to_sigset(&mask13, &mask);
        (void) sigprocmask1(l, SIG_SETMASK, &mask, 0);
        mutex_exit(p->p_lock);

        return (EJUSTRETURN);
}