/*      $NetBSD: linux_syscall.c,v 1.33 2023/10/05 19:41:03 ad Exp $ */

/*-
 * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum.
 *
 * 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: linux_syscall.c,v 1.33 2023/10/05 19:41:03 ad Exp $");

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

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/signal.h>
#include <sys/syscall.h>
#include <sys/syscallvar.h>

#include <machine/cpu.h>
#include <machine/psl.h>
#include <machine/userret.h>

#include <compat/linux/linux_syscall.h>
#include <compat/linux/common/linux_types.h>
#include <compat/linux/common/linux_errno.h>
#include <compat/linux/common/linux_signal.h>
#include <compat/linux/common/linux_siginfo.h>
#include <compat/linux/arch/amd64/linux_siginfo.h>
#include <compat/linux/arch/amd64/linux_machdep.h>

void linux_syscall_intern(struct proc *);
static void linux_syscall(struct trapframe *);

void
linux_syscall_intern(struct proc *p)
{

        p->p_md.md_syscall = linux_syscall;
}

/*
 * syscall(frame):
 *      System call request from POSIX system call gate interface to kernel.
 * Like trap(), argument is call by reference.
 */
static void
linux_syscall(struct trapframe *frame)
{
        const struct sysent *callp;
        struct proc *p;
        struct lwp *l;
        int error;
        register_t code, rval[2];
        #define args (&frame->tf_rdi)

        l = curlwp;
        p = l->l_proc;

        code = frame->tf_rax;

        callp = p->p_emul->e_sysent;

        code &= (LINUX_SYS_NSYSENT - 1);
        callp += code;

        /*
         * Linux system calls have a maximum of 6 arguments, they are
         * already adjacent in the syscall trapframe.
         */

        if (__predict_false(p->p_trace_enabled || KDTRACE_ENTRY(callp->sy_entry))
            && (error = trace_enter(code, callp, args)) != 0)
                goto out;

        rval[0] = 0;
        rval[1] = 0;
        error = sy_call(callp, l, args, rval);
out:
        switch (error) {
        case 0:
                frame->tf_rax = rval[0];
                break;
        case ERESTART:
                /*
                 * The offset to adjust the PC by depends on whether we entered
                 * the kernel through the trap or call gate.  We pushed the
                 * size of the instruction into tf_err on entry.
                 */
                frame->tf_rip -= frame->tf_err;
                break;
        case EJUSTRETURN:
                /* nothing to do */
                break;
        default:
                error = native_to_linux_errno[error];
                frame->tf_rax = error;
                break;
        }

        if (__predict_false(p->p_trace_enabled || KDTRACE_ENTRY(callp->sy_return)))
                trace_exit(code, callp, args, rval, error);

        userret(l);
}