/*      $NetBSD: sig_machdep.c,v 1.6 2024/08/04 08:16:26 skrll Exp $    */

/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * 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>

#ifndef COMPATNAME1
__RCSID("$NetBSD: sig_machdep.c,v 1.6 2024/08/04 08:16:26 skrll Exp $");
#endif

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

#include <riscv/locore.h>
#include <riscv/frame.h>

#ifndef COMPATNAME1
#define COMPATNAME1(x)          x
#define COMPATNAME2(x)          x
#define COMPATTYPE(x)           __CONCAT(x,_t)
#define UCLINK_SET(uc,c)        ((uc)->uc_link = (c))
#define COPY_SIGINFO(d,s)       ((d)->sf_si._info = (s)->ksi_info)

void *
cpu_sendsig_getframe(struct lwp *l, int signo, bool *onstack)
{
        struct trapframe * const tf = l->l_md.md_utf;
        struct proc * const p = l->l_proc;

        /* Do we need to jump onto the signal stack? */
        *onstack = (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0
            && (SIGACTION(p, signo).sa_flags & SA_ONSTACK) != 0;
        if (*onstack)
                return (char *)stack_align((intptr_t)l->l_sigstk.ss_sp + l->l_sigstk.ss_size);
        return (void *)(intptr_t)stack_align(tf->tf_sp);
}
#endif

#ifdef COMPATINC
#include COMPATINC
#endif

struct COMPATNAME2(sigframe_siginfo) {
        COMPATTYPE(siginfo) sf_si __aligned(__BIGGEST_ALIGNMENT__);
        COMPATTYPE(ucontext) sf_uc;
};

/*
 * Send a signal to process.
 */
void
sendsig_siginfo(const ksiginfo_t *ksi, const sigset_t *mask)
{
        struct lwp * const l = curlwp;
        struct proc * const p = l->l_proc;
        struct sigacts * const sa = p->p_sigacts;
        struct trapframe * const tf = l->l_md.md_utf;
        const int signo = ksi->ksi_signo;
        const sig_t catcher = SIGACTION(p, signo).sa_handler;
        bool onstack;
        struct COMPATNAME2(sigframe_siginfo) *sf =
            cpu_sendsig_getframe(l, signo, &onstack);
        struct COMPATNAME2(sigframe_siginfo) ksf;

        sf--;           // allocate sigframe

        memset(&ksf, 0, sizeof(ksf));
        COPY_SIGINFO(&ksf, ksi);
        ksf.sf_uc.uc_flags = _UC_SIGMASK
            | (l->l_sigstk.ss_flags & SS_ONSTACK ? _UC_SETSTACK : _UC_CLRSTACK);
        ksf.sf_uc.uc_sigmask = *mask;
        UCLINK_SET(&ksf.sf_uc, l->l_ctxlink);
        memset(&ksf.sf_uc.uc_stack, 0, sizeof(ksf.sf_uc.uc_stack));
        sendsig_reset(l, signo);

        mutex_exit(p->p_lock);
        COMPATNAME2(cpu_getmcontext)(l, &ksf.sf_uc.uc_mcontext,
            &ksf.sf_uc.uc_flags);
        int error = copyout(&ksf, sf, sizeof(ksf));
        mutex_enter(p->p_lock);

        if (error != 0) {
                /*
                 * Process has trashed its stack; give it an illegal
                 * instruction to halt it in its tracks.
                 */
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }

        /*
         * Set up the registers to directly invoke the signal
         * handler.  The return address will be set up to point
         * to the signal trampoline to bounce us back.
         */
        tf->tf_a0 = signo;
        tf->tf_a1 = (intptr_t)&sf->sf_si;
        tf->tf_a2 = (intptr_t)&sf->sf_uc;

        tf->tf_pc = (intptr_t)catcher;
        tf->tf_sp = (intptr_t)sf;
        tf->tf_ra = (intptr_t)sa->sa_sigdesc[signo].sd_tramp;

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