/*      $NetBSD: compat_16_machdep.c,v 1.18 2021/10/27 04:15:00 thorpej Exp $ */

/*-
 * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: compat_16_machdep.c,v 1.18 2021/10/27 04:15:00 thorpej Exp $");

#ifdef _KERNEL_OPT
#include "opt_compat_netbsd.h"
#endif

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

#include <machine/signal.h>
#include <machine/frame.h>

#if defined(COMPAT_16)
#include <compat/sys/signal.h>
#include <compat/sys/signalvar.h>

#ifdef DEBUG
/* See sigdebug.h */
#include <sparc64/sparc64/sigdebug.h>
#endif

#ifdef __arch64__
#define STACK_OFFSET    BIAS
#define CPOUTREG(l,v)   copyout(&(v), (l), sizeof(v))
#undef CCFSZ
#define CCFSZ   CC64FSZ
#else
#define STACK_OFFSET    0
#define CPOUTREG(l,v)   copyout(&(v), (l), sizeof(v))
#endif

struct sigframe_sigcontext {
        int     sf_signo;               /* signal number */
        int     sf_code;                /* code */
#ifndef __arch64__
        struct  sigcontext *sf_scp;     /* SunOS user addr of sigcontext */
        int     sf_addr;                /* SunOS compat, always 0 for now */
#endif
        struct  sigcontext sf_sc;       /* actual sigcontext */
};

/*
 * Send an interrupt to process.
 */
void
sendsig_sigcontext(const ksiginfo_t *ksi, const sigset_t *mask)
{
        struct lwp *l = curlwp;
        struct proc *p = l->l_proc;
        struct sigacts *ps = p->p_sigacts;
        const void *addr;
        struct rwindow *newsp;
#ifdef NOT_DEBUG
        struct rwindow tmpwin;
#endif
        int onstack, error;
        int sig = ksi->ksi_signo;
        struct sigframe_sigcontext *fp = getframe(l, sig, &onstack);
        struct sigframe_sigcontext sf;
        sig_t catcher = SIGACTION(p, sig).sa_handler;
        struct trapframe64 *tf = l->l_md.md_tf;
        /* Allocate an aligned sigframe */
        fp = (void *)((u_long)(fp - 1) & ~0x0f);

#ifdef DEBUG
        sigpid = p->p_pid;
        if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid) {
                printf("sendsig_sigcontext: %s[%d] sig %d newusp %p scp %p\n",
                    p->p_comm, p->p_pid, sig, fp, &fp->sf_sc);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
        }
#endif

        /*
         * Now set up the signal frame.  We build it in kernel space
         * and then copy it out.  We probably ought to just build it
         * directly in user space....
         */
        sf.sf_signo = sig;
        sf.sf_code = ksi->ksi_trap;
#ifndef __arch64__
        sf.sf_scp = 0;
        sf.sf_addr = 0;                 /* XXX */
#endif

        /*
         * Build the signal context to be used by sigreturn.
         */
        sf.sf_sc.sc_onstack = l->l_sigstk.ss_flags & SS_ONSTACK;
        sf.sf_sc.sc_mask = *mask;
#ifdef COMPAT_13
        /*
         * XXX We always have to save an old style signal mask because
         * XXX we might be delivering a signal to a process which will
         * XXX escape from the signal in a non-standard way and invoke
         * XXX sigreturn() directly.
         */
        native_sigset_to_sigset13(mask, &sf.sf_sc.__sc_mask13);
#endif
        /* Save register context. */
        sf.sf_sc.sc_sp = (long)tf->tf_out[6];
        sf.sf_sc.sc_pc = tf->tf_pc;
        sf.sf_sc.sc_npc = tf->tf_npc;
#ifdef __arch64__
        sf.sf_sc.sc_tstate = tf->tf_tstate; /* XXX */
#else
        sf.sf_sc.sc_psr = TSTATECCR_TO_PSR(tf->tf_tstate); /* XXX */
#endif
        sf.sf_sc.sc_g1 = tf->tf_global[1];
        sf.sf_sc.sc_o0 = tf->tf_out[0];

        /*
         * Put the stack in a consistent state before we whack away
         * at it.  Note that write_user_windows may just dump the
         * registers into the pcb; we need them in the process's memory.
         * We also need to make sure that when we start the signal handler,
         * its %i6 (%fp), which is loaded from the newly allocated stack area,
         * joins seamlessly with the frame it was in when the signal occurred,
         * so that the debugger and _longjmp code can back up through it.
         */
        sendsig_reset(l, sig);
        mutex_exit(p->p_lock);
        newsp = (struct rwindow *)((vaddr_t)fp - sizeof(struct rwindow));
        write_user_windows();
#ifdef DEBUG
        if ((sigdebug & SDB_KSTACK))
            printf("sendsig: saving sf to %p, setting stack pointer %p to %p\n",
                   fp, &(((struct rwindow *)newsp)->rw_in[6]),
                   (void *)(unsigned long)tf->tf_out[6]);
#endif
        error = (rwindow_save(l) || copyout((void *)&sf, (void *)fp, sizeof sf) || 
#ifdef NOT_DEBUG
            copyin(oldsp, &tmpwin, sizeof(tmpwin)) || copyout(&tmpwin, newsp, sizeof(tmpwin)) ||
#endif
            CPOUTREG(&(((struct rwindow *)newsp)->rw_in[6]), tf->tf_out[6]));
        mutex_enter(p->p_lock);

        if (error) {
                /*
                 * Process has trashed its stack; give it an illegal
                 * instruction to halt it in its tracks.
                 */
#ifdef DEBUG
                mutex_exit(p->p_lock);
                if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid)
                        printf("sendsig: window save or copyout error\n");
                printf("sendsig: stack was trashed trying to send sig %d, sending SIGILL\n", sig);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
                mutex_enter(p->p_lock);
#endif
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }

#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW) {
                printf("sendsig: %s[%d] sig %d scp %p\n",
                       p->p_comm, p->p_pid, sig, &fp->sf_sc);
        }
#endif

        /*
         * Arrange to continue execution at the code copied out in exec().
         * It needs the function to call in %g1, and a new stack pointer.
         */
        switch (ps->sa_sigdesc[sig].sd_vers) {
        case __SIGTRAMP_SIGCODE_VERSION:        /* legacy on-stack sigtramp */
                addr = p->p_sigctx.ps_sigcode;
                break;

        case __SIGTRAMP_SIGCONTEXT_VERSION:
                addr = ps->sa_sigdesc[sig].sd_tramp;
                break;

        default:
                addr = NULL; /* XXX: gcc */
                /* Don't know what trampoline version; kill it. */
                sigexit(l, SIGILL);
        }

        tf->tf_global[1] = (vaddr_t)catcher;
        tf->tf_pc = (const vaddr_t)addr;
        tf->tf_npc = (const vaddr_t)addr + 4;
        tf->tf_out[6] = (vaddr_t)newsp - STACK_OFFSET;

        /* Remember that we're now on the signal stack. */
        if (onstack)
                l->l_sigstk.ss_flags |= SS_ONSTACK;

#ifdef DEBUG
        if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid) {
                mutex_exit(p->p_lock);
                printf("sendsig: about to return to catcher %p thru %p\n", 
                       catcher, (void *)(unsigned long)addr);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
                mutex_enter(p->p_lock);
        }
#endif
}

/*
 * System call to cleanup state after a signal
 * has been taken.  Reset signal mask and
 * stack state from context left by sendsig (above),
 * and return to the given trap frame (if there is one).
 * Check carefully to make sure that the user has not
 * modified the state to gain improper privileges or to cause
 * a machine fault.
 */
int compat_16_sys___sigreturn14(struct lwp *, const struct compat_16_sys___sigreturn14_args *, register_t *);

/* ARGSUSED */
int
compat_16_sys___sigreturn14(struct lwp *l, const struct compat_16_sys___sigreturn14_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct sigcontext *) sigcntxp;
        } */
        struct sigcontext sc, *scp;
        struct trapframe64 *tf;
        int error = EINVAL;
        struct proc *p = l->l_proc;

        /* First ensure consistent stack state (see sendsig). */
        write_user_windows();
        if (rwindow_save(l)) {
#ifdef DEBUG
                printf("sigreturn14: rwindow_save(%p) failed, sending SIGILL\n", p);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
#endif
                mutex_enter(p->p_lock);
                sigexit(l, SIGILL);
        }
#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW) {
                printf("sigreturn14: %s[%d], sigcntxp %p\n",
                    p->p_comm, p->p_pid, SCARG(uap, sigcntxp));
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
        }
#endif
        scp = SCARG(uap, sigcntxp);
        if (((vaddr_t)scp & 3) != 0 ||
            (error = copyin((void *)scp, &sc, sizeof sc)) != 0)
#ifdef DEBUG
        {
                printf("sigreturn14: copyin failed: scp=%p\n", scp);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
                return (error);
        }
#else
                return (error);
#endif
        scp = &sc;

        tf = l->l_md.md_tf;
        /*
         * Only the icc bits in the psr are used, so it need not be
         * verified.  pc and npc must be multiples of 4.  This is all
         * that is required; if it holds, just do it.
         */
        if (((sc.sc_pc | sc.sc_npc) & 3) != 0 || (sc.sc_pc == 0) || (sc.sc_npc == 0))
#ifdef DEBUG
        {
                printf("sigreturn14: pc %p or npc %p invalid\n",
                   (void *)(unsigned long)sc.sc_pc,
                   (void *)(unsigned long)sc.sc_npc);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
                return (EINVAL);
        }
#else
                return (EINVAL);
#endif
        /* take only psr ICC field */
#ifdef __arch64__
        tf->tf_tstate = (uint64_t)(tf->tf_tstate & ~TSTATE_CCR) | (scp->sc_tstate & TSTATE_CCR);
#else
        tf->tf_tstate = (uint64_t)(tf->tf_tstate & ~TSTATE_CCR) | PSRCC_TO_TSTATE(scp->sc_psr);
#endif
        tf->tf_pc = (uint64_t)scp->sc_pc;
        tf->tf_npc = (uint64_t)scp->sc_npc;
        tf->tf_global[1] = (uint64_t)scp->sc_g1;
        tf->tf_out[0] = (uint64_t)scp->sc_o0;
        tf->tf_out[6] = (uint64_t)scp->sc_sp;
#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW) {
                printf("sigreturn14: return trapframe pc=%p sp=%p tstate=%llx\n",
                       (void *)(unsigned long)tf->tf_pc,
                       (void *)(unsigned long)tf->tf_out[6],
                       (unsigned long long)tf->tf_tstate);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
        }
#endif

        mutex_enter(p->p_lock);
        /* Restore signal stack. */
        if (sc.sc_onstack & SS_ONSTACK)
                l->l_sigstk.ss_flags |= SS_ONSTACK;
        else
                l->l_sigstk.ss_flags &= ~SS_ONSTACK;
        /* Restore signal mask. */
        (void) sigprocmask1(l, SIG_SETMASK, &sc.sc_mask, 0);
        mutex_exit(p->p_lock);

        return (EJUSTRETURN);
}
#endif /* COMPAT_16 */