/*      $NetBSD: sunos_machdep.c,v 1.35 2023/12/20 05:33:59 thorpej 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 1.35 2023/12/20 05:33:59 thorpej Exp $");

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

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/filedesc.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/kernel.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
#include <sparc64/sparc64/sigdebug.h>
#endif

struct sunos_sigcontext {
        int     sc_onstack;             /* sigstack state to restore */
        int     sc_mask;                /* signal mask to restore (old style) */
        /* begin machine dependent portion */
        int     sc_sp;                  /* %sp to restore */
        int     sc_pc;                  /* pc to restore */
        int     sc_npc;                 /* npc to restore */
        int     sc_psr;                 /* pstate to restore */
        int     sc_g1;                  /* %g1 to restore */
        int     sc_o0;                  /* %o0 to restore */
};

struct sunos_sigframe {
        int     sf_signo;               /* signal number */
        int     sf_code;                /* code */
        uint32_t        sf_scp;                 /* SunOS user addr of sigcontext */
        int     sf_addr;                /* SunOS compat, always 0 for now */
        struct  sunos_sigcontext sf_sc; /* actual sigcontext */
};

void
sunos_sendsig(const ksiginfo_t *ksi, const sigset_t *mask)
{
        register struct lwp *l = curlwp;
        struct proc *p = l->l_proc;
        register struct sunos_sigframe *fp;
        register struct trapframe64 *tf;
        register int addr, onstack;
        struct rwindow32 *oldsp, *newsp;
        register32_t sp;
        int sig = ksi->ksi_signo, error;
        sig_t catcher = SIGACTION(p, sig).sa_handler;
        struct sunos_sigframe sf;

        tf = (struct trapframe64 *)l->l_md.md_tf;
        /* Need to attempt to zero extend this 32-bit pointer */
        oldsp = (struct rwindow32 *)(u_long)(u_int)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 *)((long)(fp - 1) & ~7);

#ifdef DEBUG
        sigpid = p->p_pid;
        if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid) {
                printf("sunos_sendsig: %s[%d] sig %d newusp %p scp %p oldsp %p\n",
                    p->p_comm, p->p_pid, sig, fp, &fp->sf_sc, oldsp);
#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;
        sf.sf_scp = (u_long)&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 = (long)oldsp;
        sf.sf_sc.sc_pc = tf->tf_pc;
        sf.sf_sc.sc_npc = tf->tf_npc;
        sf.sf_sc.sc_psr = TSTATECCR_TO_PSR(tf->tf_tstate); /* XXX */
        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 rwindow32 *)((long)fp - sizeof(struct rwindow32));
        write_user_windows();
#ifdef DEBUG
        if ((sigdebug & SDB_KSTACK))
            printf("sunos_sendsig: saving sf to %p, setting stack pointer %p to %p\n",
                   fp, &(((struct rwindow32 *)newsp)->rw_in[6]), oldsp);
#endif
        sp = (register32_t)(uintptr_t)oldsp;
        error = (rwindow_save(l) || 
            copyout((void *)&sf, (void *)fp, sizeof sf) || 
            copyout(&sp, &(((struct rwindow32 *)newsp)->rw_in[6]),
                sizeof(sp)));
        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 ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid)
                        printf("sunos_sendsig: window save or copyout error\n");
                printf("sunos_sendsig: stack was trashed trying to send sig %d, sending SIGILL\n", sig);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
#endif
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }

#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW) {
                printf("sunos_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 = (long)catcher;   /* user does his own trampolining */
        tf->tf_pc = addr;
        tf->tf_npc = addr + 4;
        tf->tf_out[6] = (uint64_t)(u_int)(u_long)newsp;
#ifdef DEBUG
        if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid) {
                printf("sunos_sendsig: about to return to catcher %p thru %p\n", 
                       catcher, (void *)(u_long)addr);
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
        }
#endif
}

int
sunos_sys_sigreturn(register struct lwp *l, const struct sunos_sys_sigreturn_args *uap, register_t *retval)
{
        struct proc *p = l->l_proc;
        struct sunos_sigcontext sc, *scp;
        sigset_t mask;
        struct trapframe64 *tf;

        /* First ensure consistent stack state (see sendsig). */
        write_user_windows();
        if (rwindow_save(l)) {
                mutex_enter(p->p_lock);
                sigexit(l, SIGILL);
        }
#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW) {
                printf("sunos_sigreturn: %s[%d], sigcntxp %p\n",
                    p->p_comm, p->p_pid, SCARG(uap, sigcntxp));
#ifdef DDB
                if (sigdebug & SDB_DDB) Debugger();
#endif
        }
#endif

        scp = (struct sunos_sigcontext *)SCARG(uap, sigcntxp);
        if ((vaddr_t)scp & 3 || (copyin((void *)scp, &sc, sizeof sc) != 0))
                return (EFAULT);
        scp = &sc;

        tf = (struct trapframe64 *)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 (((scp->sc_pc | scp->sc_npc) & 3) != 0 || scp->sc_pc == 0 || scp->sc_npc == 0)
#ifdef DEBUG
        {
                printf("sunos_sigreturn: pc %p or npc %p invalid\n", (void *)(u_long)scp->sc_pc, (void *)(u_long)scp->sc_npc);
#ifdef DDB
                Debugger();
#endif
                return (EINVAL);
        }
#endif
                return (EINVAL);
        /* take only psr ICC field */
        tf->tf_tstate = (int64_t)(tf->tf_tstate & ~TSTATE_CCR) | PSRCC_TO_TSTATE(scp->sc_psr);
        tf->tf_pc = scp->sc_pc;
        tf->tf_npc = scp->sc_npc;
        tf->tf_global[1] = scp->sc_g1;
        tf->tf_out[0] = scp->sc_o0;
        tf->tf_out[6] = scp->sc_sp;
#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW) {
                printf("sunos_sigreturn: return trapframe pc=%p sp=%p tstate=%llx\n",
                       (void *)(u_long)tf->tf_pc, (void *)(u_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);
        if (scp->sc_onstack & SS_ONSTACK)
                l->l_sigstk.ss_flags |= SS_ONSTACK;
        else
                l->l_sigstk.ss_flags &= ~SS_ONSTACK;
        /* Restore signal mask */
        native_sigset13_to_sigset(&scp->sc_mask, &mask);
        (void) sigprocmask1(l, SIG_SETMASK, &mask, 0);
        mutex_exit(p->p_lock);

        return (EJUSTRETURN);
}