/*      $NetBSD: linux_machdep.c,v 1.34 2021/09/07 11:43:04 riastradh Exp $     */

/*-
 * Copyright (c) 1995, 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Frank van der Linden.
 *
 * 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_machdep.c,v 1.34 2021/09/07 11:43:04 riastradh Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/reboot.h>
#include <sys/conf.h>
#include <sys/exec.h>
#include <sys/file.h>
#include <sys/callout.h>
#include <sys/mbuf.h>
#include <sys/msgbuf.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/device.h>
#include <sys/syscallargs.h>
#include <sys/filedesc.h>
#include <sys/exec_elf.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>

#include <miscfs/specfs/specdev.h>

#include <compat/linux/common/linux_types.h>
#include <compat/linux/common/linux_signal.h>
#include <compat/linux/common/linux_util.h>
#include <compat/linux/common/linux_ioctl.h>
#include <compat/linux/common/linux_hdio.h>
#include <compat/linux/common/linux_exec.h>
#include <compat/linux/common/linux_machdep.h>
#include <compat/linux/linux_syscallargs.h>

#include <arm/locore.h>

void
linux_setregs(struct lwp *l, struct exec_package *epp, vaddr_t stack)
{

        setregs(l, epp, stack);
}

void
linux_sendsig(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);
        struct linux_sigframe *fp, frame;
        int onstack, error;
        const int sig = ksi->ksi_signo;
        sig_t catcher = SIGACTION(p, sig).sa_handler;


        /*
         * The Linux version of this code is in
         * linux/arch/arm/kernel/signal.c.
         */

        /* Do we need to jump onto the signal stack? */
        onstack =
            (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
            (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;

        /* Allocate space for the signal handler context. */
        if (onstack)
                fp = (struct linux_sigframe *)((char *)l->l_sigstk.ss_sp +
                                          l->l_sigstk.ss_size);
        else
                fp = (struct linux_sigframe *)tf->tf_usr_sp;
        fp--;

        /* Build stack frame for signal trampoline. */

        memset(&frame, 0, sizeof(frame));

        /* Save register context. */
        frame.sf_sc.sc_r0     = tf->tf_r0;
        frame.sf_sc.sc_r1     = tf->tf_r1;
        frame.sf_sc.sc_r2     = tf->tf_r2;
        frame.sf_sc.sc_r3     = tf->tf_r3;
        frame.sf_sc.sc_r4     = tf->tf_r4;
        frame.sf_sc.sc_r5     = tf->tf_r5;
        frame.sf_sc.sc_r6     = tf->tf_r6;
        frame.sf_sc.sc_r7     = tf->tf_r7;
        frame.sf_sc.sc_r8     = tf->tf_r8;
        frame.sf_sc.sc_r9     = tf->tf_r9;
        frame.sf_sc.sc_r10    = tf->tf_r10;
        frame.sf_sc.sc_r11    = tf->tf_r11;
        frame.sf_sc.sc_r12    = tf->tf_r12;
        frame.sf_sc.sc_sp     = tf->tf_usr_sp;
        frame.sf_sc.sc_lr     = tf->tf_usr_lr;
        frame.sf_sc.sc_pc     = tf->tf_pc;
        frame.sf_sc.sc_cpsr   = tf->tf_spsr;

        /* Save signal stack. */
        /* Linux doesn't save the onstack flag in sigframe */

        /* Save signal mask. */
        native_to_linux_old_extra_sigset(&frame.sf_sc.sc_mask,
            frame.sf_extramask, mask);

        /* Other state (mostly faked) */
        /*
         * trapno should indicate the trap that caused the signal:
         * 6  -> undefined instruction
         * 11 -> address exception
         * 14 -> data/prefetch abort
         */
        frame.sf_sc.sc_trapno = 0;
        frame.sf_sc.sc_error_code = 0;
        frame.sf_sc.sc_fault_address = (u_int32_t) ksi->ksi_addr;
        sendsig_reset(l, sig);

        mutex_exit(p->p_lock);
        error = copyout(&frame, fp, sizeof(frame));
        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 */
        }
        /*
         * Build context to run handler in.
         */
        tf->tf_r0 = native_to_linux_signo[sig];
        tf->tf_r1 = 0; /* XXX Should be a siginfo_t */
        tf->tf_r2 = 0;
        tf->tf_r3 = (register_t)catcher;
        tf->tf_usr_sp = (register_t)fp;
        tf->tf_pc = (register_t)p->p_sigctx.ps_sigcode;

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

}

#if 0
/*
 * System call to cleanup state after a signal
 * has been taken.  Reset signal mask and
 * stack state from context left by sendsig (above).
 * Return to previous pc and psl as specified by
 * context left by sendsig. Check carefully to
 * make sure that the user has not modified the
 * psl to gain improper privileges or to cause
 * a machine fault.
 */
int
linux_sys_rt_sigreturn(struct proc *p, void *v, register_t *retval)
{
        /* XXX XAX write me */
        return(ENOSYS);
}
#endif

int
linux_sys_sigreturn(struct lwp *l, const struct linux_sys_sigreturn_args *v,
        register_t *retval)
{
        struct trapframe * const tf = lwp_trapframe(l);
        struct proc * const p = l->l_proc;
        struct linux_sigframe *sfp, frame;
        sigset_t mask;

        /*
         * The trampoline code hands us the context.
         * It is unsafe to keep track of it ourselves, in the event that a
         * program jumps out of a signal handler.
         */
        sfp = (struct linux_sigframe *)tf->tf_usr_sp;
        if (copyin((void *)sfp, &frame, sizeof(*sfp)) != 0)
                return (EFAULT);

        /*
         * Make sure the processor mode has not been tampered with and
         * interrupts have not been disabled.
         */
        if (!VALID_PSR(frame.sf_sc.sc_cpsr))
                return EINVAL;

        /* Restore register context. */
        tf->tf_r0    = frame.sf_sc.sc_r0;
        tf->tf_r1    = frame.sf_sc.sc_r1;
        tf->tf_r2    = frame.sf_sc.sc_r2;
        tf->tf_r3    = frame.sf_sc.sc_r3;
        tf->tf_r4    = frame.sf_sc.sc_r4;
        tf->tf_r5    = frame.sf_sc.sc_r5;
        tf->tf_r6    = frame.sf_sc.sc_r6;
        tf->tf_r7    = frame.sf_sc.sc_r7;
        tf->tf_r8    = frame.sf_sc.sc_r8;
        tf->tf_r9    = frame.sf_sc.sc_r9;
        tf->tf_r10   = frame.sf_sc.sc_r10;
        tf->tf_r11   = frame.sf_sc.sc_r11;
        tf->tf_r12   = frame.sf_sc.sc_r12;
        tf->tf_usr_sp = frame.sf_sc.sc_sp;
        tf->tf_usr_lr = frame.sf_sc.sc_lr;
        tf->tf_pc    = frame.sf_sc.sc_pc;
        tf->tf_spsr  = frame.sf_sc.sc_cpsr;

        mutex_enter(p->p_lock);

        /* Restore signal stack. */
        l->l_sigstk.ss_flags &= ~SS_ONSTACK;

        /* Restore signal mask. */
        linux_old_extra_to_native_sigset(&mask, &frame.sf_sc.sc_mask,
            frame.sf_extramask);
        (void) sigprocmask1(l, SIG_SETMASK, &mask, 0);

        mutex_exit(p->p_lock);

        return (EJUSTRETURN);
}

/*
 * major device numbers remapping
 */
dev_t
linux_fakedev(dev_t dev, int raw)
{
        /* XXX write me */
        return dev;
}

/*
 * We come here in a last attempt to satisfy a Linux ioctl() call
 */
int
linux_machdepioctl(struct lwp *l, const struct linux_sys_ioctl_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) fd;
                syscallarg(u_long) com;
                syscallarg(void *) data;
        } */
        struct sys_ioctl_args bia;
        u_long com;

        SCARG(&bia, fd) = SCARG(uap, fd);
        SCARG(&bia, data) = SCARG(uap, data);
        com = SCARG(uap, com);

        switch (com) {
        default:
                printf("linux_machdepioctl: invalid ioctl %08lx\n", com);
                return EINVAL;
        }
        SCARG(&bia, com) = com;

        return sys_ioctl(l, &bia, retval);
}

int
linux_usertrap(struct lwp *l, vaddr_t trapaddr, void *arg)
{
        return 0;
}