/*      $NetBSD: sunos_machdep.c,v 1.25 2025/04/24 01:52:38 riastradh Exp $     */

/*
 * Copyright (c) 1995 Matthew R. Green
 * All rights reserved.
 *
 * 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 AUTHOR ``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 AUTHOR 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: sunos_machdep.c,v 1.25 2025/04/24 01:52:38 riastradh Exp $");

#if defined(_KERNEL_OPT)
#include "opt_compat_netbsd.h"
#endif

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

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

#include <sys/syscallargs.h>
#include <compat/sunos/sunos.h>
#include <compat/sunos/sunos_syscallargs.h>

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

#ifdef DEBUG
int sunos_sigdebug = 0;
int sunos_sigpid = 0;
#define SDB_FOLLOW      0x01
#define SDB_KSTACK      0x02
#define SDB_FPSTATE     0x04
#endif

struct sunos_sigframe {
        int     sf_signo;               /* signal number */
        int     sf_code;                /* code */
        struct  sigcontext13 *sf_scp;   /* SunOS user addr of sigcontext */
        int     sf_addr;                /* SunOS compat, always 0 for now */
        struct  sigcontext13 sf_sc;     /* actual sigcontext */
};

void sunos_sendsig(const ksiginfo_t *ksi, const sigset_t *mask)
{
        struct lwp *l = curlwp;
        struct proc *p = l->l_proc;
        struct sunos_sigframe *fp;
        struct trapframe *tf;
        int addr, onstack, oldsp, newsp, error;
        int sig = ksi->ksi_signo;
        u_long code = ksi->ksi_code;
        sig_t catcher = SIGACTION(p, sig).sa_handler;
        struct sunos_sigframe sf;

        tf = l->l_md.md_tf;
        oldsp = tf->tf_out[6];

        /*
         * Compute new user stack addresses, subtract off
         * one signal frame, and align.
         */
        onstack =
            (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
            (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;

        if (onstack)
                fp = (struct sunos_sigframe *)
                     ((char *)l->l_sigstk.ss_sp + l->l_sigstk.ss_size);
        else
                fp = (struct sunos_sigframe *)oldsp;

        fp = (struct sunos_sigframe *)((int)(fp - 1) & ~STACK_ALIGNBYTES);

#ifdef DEBUG
        if ((sunos_sigdebug & SDB_KSTACK) && p->p_pid == sunos_sigpid)
                printf("sendsig: %s[%d] sig %d newusp %p scp %p\n",
                    p->p_comm, p->p_pid, sig, fp, &fp->sf_sc);
#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 = code;
        sf.sf_scp = &fp->sf_sc;
        sf.sf_addr = 0;                 /* XXX */

        /*
         * Build the signal context to be used by sigreturn.
         */
        sf.sf_sc.sc_onstack = l->l_sigstk.ss_flags & SS_ONSTACK;
        native_sigset_to_sigset13(mask, &sf.sf_sc.sc_mask);
        sf.sf_sc.sc_sp = oldsp;
        sf.sf_sc.sc_pc = tf->tf_pc;
        sf.sf_sc.sc_npc = tf->tf_npc;
        sf.sf_sc.sc_psr = tf->tf_psr;
        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 = (int)fp - sizeof(struct rwindow);
        write_user_windows();
        error = (rwindow_save(l) || copyout((void *)&sf, (void *)fp, sizeof sf) ||
            ustore_int((u_int *)&((struct rwindow *)newsp)->rw_in[6], oldsp));
        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
                if ((sunos_sigdebug & SDB_KSTACK) && p->p_pid == sunos_sigpid)
                        printf("sendsig: window save or copyout error\n");
#endif
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }
#ifdef DEBUG
        if (sunos_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.
         */
        addr = (int)catcher;    /* user does his own trampolining */
        tf->tf_pc = addr;
        tf->tf_npc = addr + 4;
        tf->tf_out[6] = newsp;

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

#ifdef DEBUG
        if ((sunos_sigdebug & SDB_KSTACK) && p->p_pid == sunos_sigpid)
                printf("sendsig: about to return to catcher\n");
#endif
}

int
sunos_sys_sigreturn(struct lwp *l, const struct sunos_sys_sigreturn_args *uap, register_t *retval)
{

        return (compat_13_sys_sigreturn(l,
                        (const struct compat_13_sys_sigreturn_args *)uap, retval));
}