/* $NetBSD: sig_machdep.c,v 1.9 2024/04/14 12:51:16 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>

__KERNEL_RCSID(1, "$NetBSD: sig_machdep.c,v 1.9 2024/04/14 12:51:16 skrll Exp $");

#include <sys/param.h>
#include <sys/types.h>
#include <sys/cpu.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/siginfo.h>

#include <aarch64/frame.h>

void
sendsig_siginfo(const ksiginfo_t *ksi, const sigset_t *mask)
{
        struct lwp * const l = curlwp;
        struct proc * const p = l->l_proc;
        struct trapframe * const tf = lwp_trapframe(l);
        stack_t * const ss = &l->l_sigstk;
        const struct sigact_sigdesc * const sd =
            &p->p_sigacts->sa_sigdesc[ksi->ksi_signo];

        const uintptr_t handler = (uintptr_t) sd->sd_sigact.sa_handler;
        const bool onstack_p = (ss->ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0
            && (sd->sd_sigact.sa_flags & SA_ONSTACK) != 0;

        vaddr_t sp;

        /*
         * The user stack isn't guaranteed to be aligned to 16 bytes. Align
         * it before pushing anything onto it.
         */
        sp = onstack_p ? ((vaddr_t)ss->ss_sp + ss->ss_size) : tf->tf_sp;
        sp &= -16;

        __CTASSERT(sizeof(ucontext_t) % 16 == 0);
        sp -= sizeof(ucontext_t);
        const vaddr_t ucp = sp;

        sp -= roundup(sizeof(siginfo_t), 16);
        const vaddr_t sip = sp;

        ucontext_t uc;
        memset(&uc, 0, sizeof(uc));
        uc.uc_flags = _UC_SIGMASK;
        uc.uc_sigmask = *mask;
        uc.uc_link = l->l_ctxlink;
        uc.uc_flags |= (l->l_sigstk.ss_flags & SS_ONSTACK)
            ? _UC_SETSTACK : _UC_CLRSTACK;
        sendsig_reset(l, ksi->ksi_signo);
        mutex_exit(p->p_lock);
        cpu_getmcontext(l, &uc.uc_mcontext, &uc.uc_flags);

        /*
         * Copy the siginfo and ucontext onto the user's stack.
         */
        int error = copyout(&ksi->ksi_info, (void *)sip, sizeof(ksi->ksi_info));
        if (error == 0) {
                error = copyout(&uc, (void *)ucp, sizeof(uc));
        }

        mutex_enter(p->p_lock);

        if (error || sd->sd_vers != __SIGTRAMP_SIGINFO_VERSION) {
                /*
                 * Thread has trashed its stack.  Blow it away.
                 */
                if (error == 0) {
                        printf("pid %d.%d(%s): %p(sig %d): bad version %d\n",
                            p->p_pid, l->l_lid, p->p_comm, __func__,
                            ksi->ksi_signo, sd->sd_vers);
                }
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }

        tf->tf_reg[0] = ksi->ksi_signo;
        tf->tf_reg[1] = sip;
        tf->tf_reg[2] = ucp;
        tf->tf_reg[28] = ucp;   /* put in a callee saved register */

        tf->tf_sp = sp;
        tf->tf_lr = (uint64_t)sd->sd_tramp;
        tf->tf_pc = handler;

        /*
         * Remember if we're now on the signal stack.
         */
        if (onstack_p)
                ss->ss_flags |= SS_ONSTACK;
}