/*      $NetBSD: linux_machdep.c,v 1.52 2021/09/07 11:43:03 riastradh Exp $     */

/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Eric Haszlakiewicz.
 *
 * 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.
 *
 * Based on sys/arch/i386/i386/linux_machdep.c:
 *      linux_machdep.c,v 1.42 1998/09/11 12:50:06 mycroft Exp
 *      written by Frank van der Linden
 *
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: linux_machdep.c,v 1.52 2021/09/07 11:43:03 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/ioctl.h>
#include <sys/kauth.h>

#include <uvm/uvm_extern.h>

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

#include <compat/linux/linux_syscallargs.h>

#include <machine/alpha.h>
#include <machine/reg.h>

#if defined(_KERNEL_OPT)
#include "wsdisplay.h"
#endif
#if (NWSDISPLAY >0)
#include <dev/wscons/wsdisplay_usl_io.h>
#endif
#ifdef DEBUG
#include <machine/sigdebug.h>
#endif

/*
 * Deal with some alpha-specific things in the Linux emulation code.
 */

void
linux_setregs(struct lwp *l, struct exec_package *epp, vaddr_t stack)
{
#ifdef DEBUG
        struct trapframe *tfp = l->l_md.md_tf;
#endif

        setregs(l, epp, stack);
#ifdef DEBUG
        /*
         * Linux has registers set to zero on entry; for DEBUG kernels
         * the alpha setregs() fills registers with 0xbabefacedeadbeef.
         */
        memset(tfp->tf_regs, 0, FRAME_SIZE * sizeof tfp->tf_regs[0]);
#endif
}

void
setup_linux_rt_sigframe(struct trapframe *tf, const ksiginfo_t *ksi,
    const sigset_t *mask)
{
        struct lwp *l = curlwp;
        struct proc *p = l->l_proc;
        struct linux_rt_sigframe *sfp, sigframe;
        int onstack, error;
        int fsize, rndfsize;
        int sig = ksi->ksi_signo;
        extern char linux_rt_sigcode[], linux_rt_esigcode[];

        /* 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.  */
        fsize = sizeof(struct linux_rt_sigframe);
        rndfsize = ((fsize + 15) / 16) * 16;

        if (onstack)
                sfp = (struct linux_rt_sigframe *)
                    ((char *)l->l_sigstk.ss_sp + l->l_sigstk.ss_size);
        else
                sfp = (struct linux_rt_sigframe *)(alpha_pal_rdusp());
        sfp = (struct linux_rt_sigframe *)((char *)sfp - rndfsize);

#ifdef DEBUG
        if ((sigdebug & SDB_KSTACK) && (p->p_pid == sigpid))
                printf("linux_sendsig(%d): sig %d ssp %p usp %p\n", p->p_pid,
                    sig, &onstack, sfp);
#endif /* DEBUG */

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

        /*
         * Build the signal context to be used by sigreturn.
         */
        memset(&sigframe.uc, 0, sizeof(struct linux_ucontext));
        sigframe.uc.uc_mcontext.sc_onstack = onstack;

        /* Setup potentially partial signal mask in sc_mask. */
        /* But get all of it in uc_sigmask */
        native_to_linux_old_sigset(&sigframe.uc.uc_mcontext.sc_mask, mask);
        native_to_linux_sigset(&sigframe.uc.uc_sigmask, mask);

        sigframe.uc.uc_mcontext.sc_pc = tf->tf_regs[FRAME_PC];
        sigframe.uc.uc_mcontext.sc_ps = ALPHA_PSL_USERMODE;
        frametoreg(tf, (struct reg *)sigframe.uc.uc_mcontext.sc_regs);
        sigframe.uc.uc_mcontext.sc_regs[R_SP] = alpha_pal_rdusp();

        fpu_load();
        alpha_pal_wrfen(1);
        sigframe.uc.uc_mcontext.sc_fpcr = alpha_read_fpcr();
        sigframe.uc.uc_mcontext.sc_fp_control = alpha_read_fp_c(l);
        alpha_pal_wrfen(0);

        sigframe.uc.uc_mcontext.sc_traparg_a0 = tf->tf_regs[FRAME_A0];
        sigframe.uc.uc_mcontext.sc_traparg_a1 = tf->tf_regs[FRAME_A1];
        sigframe.uc.uc_mcontext.sc_traparg_a2 = tf->tf_regs[FRAME_A2];
        native_to_linux_siginfo(&sigframe.info, &ksi->ksi_info);
        sendsig_reset(l, sig);
        mutex_exit(p->p_lock);
        error = copyout((void *)&sigframe, (void *)sfp, fsize);
        mutex_enter(p->p_lock);

        if (error != 0) {
#ifdef DEBUG
                if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid)
                        printf("sendsig(%d): copyout failed on sig %d\n",
                            p->p_pid, sig);
#endif
                /*
                 * Process has trashed its stack; give it an illegal
                 * instruction to halt it in its tracks.
                 */
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }

        /* Pass pointers to siginfo and ucontext in the regs */
        tf->tf_regs[FRAME_A1] = (unsigned long)&sfp->info;
        tf->tf_regs[FRAME_A2] = (unsigned long)&sfp->uc;

        /* Address of trampoline code.  End up at this PC after mi_switch */
        tf->tf_regs[FRAME_PC] =
            (u_int64_t)(p->p_psstrp - (linux_rt_esigcode - linux_rt_sigcode));

        /* Adjust the stack */
        alpha_pal_wrusp((unsigned long)sfp);

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

void setup_linux_sigframe(struct trapframe *tf, const ksiginfo_t *ksi,
    const sigset_t *mask)
{
        struct lwp *l = curlwp;
        struct proc *p = l->l_proc;
        struct linux_sigframe *sfp, sigframe;
        int onstack, error;
        int fsize, rndfsize;
        int sig = ksi->ksi_signo;
        extern char linux_sigcode[], linux_esigcode[];

        /* 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.  */
        fsize = sizeof(struct linux_sigframe);
        rndfsize = ((fsize + 15) / 16) * 16;

        if (onstack)
                sfp = (struct linux_sigframe *)
                    ((char *)l->l_sigstk.ss_sp + l->l_sigstk.ss_size);
        else
                sfp = (struct linux_sigframe *)(alpha_pal_rdusp());
        sfp = (struct linux_sigframe *)((char *)sfp - rndfsize);

#ifdef DEBUG
        if ((sigdebug & SDB_KSTACK) && (p->p_pid == sigpid))
                printf("linux_sendsig(%d): sig %d ssp %p usp %p\n", p->p_pid,
                    sig, &onstack, sfp);
#endif /* DEBUG */

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

        /*
         * Build the signal context to be used by sigreturn.
         */
        memset(&sigframe.sf_sc, 0, sizeof(struct linux_sigcontext));
        sigframe.sf_sc.sc_onstack = onstack;
        native_to_linux_old_sigset(&sigframe.sf_sc.sc_mask, mask);
        sigframe.sf_sc.sc_pc = tf->tf_regs[FRAME_PC];
        sigframe.sf_sc.sc_ps = ALPHA_PSL_USERMODE;
        frametoreg(tf, (struct reg *)sigframe.sf_sc.sc_regs);
        sigframe.sf_sc.sc_regs[R_SP] = alpha_pal_rdusp();

        if (fpu_valid_p(l)) {
                struct pcb *pcb = lwp_getpcb(l);

                fpu_save(l);
                sigframe.sf_sc.sc_fpcr = pcb->pcb_fp.fpr_cr;
        }
        /* XXX ownedfp ? etc...? */

        sigframe.sf_sc.sc_traparg_a0 = tf->tf_regs[FRAME_A0];
        sigframe.sf_sc.sc_traparg_a1 = tf->tf_regs[FRAME_A1];
        sigframe.sf_sc.sc_traparg_a2 = tf->tf_regs[FRAME_A2];

        sendsig_reset(l, sig);
        mutex_exit(p->p_lock);
        error = copyout((void *)&sigframe, (void *)sfp, fsize);
        mutex_enter(p->p_lock);

        if (error != 0) {
#ifdef DEBUG
                if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid)
                        printf("sendsig(%d): copyout failed on sig %d\n",
                            p->p_pid, sig);
#endif
                /*
                 * Process has trashed its stack; give it an illegal
                 * instruction to halt it in its tracks.
                 */
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }

        /* Pass pointers to sigcontext in the regs */
        tf->tf_regs[FRAME_A1] = 0;
        tf->tf_regs[FRAME_A2] = (unsigned long)&sfp->sf_sc;

        /* Address of trampoline code.  End up at this PC after mi_switch */
        tf->tf_regs[FRAME_PC] =
            (u_int64_t)(p->p_psstrp - (linux_esigcode - linux_sigcode));

        /* Adjust the stack */
        alpha_pal_wrusp((unsigned long)sfp);

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

/*
 * Send an interrupt to process.
 *
 * Stack is set up to allow sigcode stored
 * in u. to call routine, followed by kcall
 * to sigreturn routine below.  After sigreturn
 * resets the signal mask, the stack, and the
 * frame pointer, it returns to the user
 * specified pc, psl.
 */
void
linux_sendsig(const ksiginfo_t *ksi, const sigset_t *mask)
{
        struct lwp *l = curlwp;
        struct proc *p = l->l_proc;
        struct trapframe *tf = l->l_md.md_tf;
        const int sig = ksi->ksi_signo;
        sig_t catcher = SIGACTION(p, sig).sa_handler;
#ifdef notyet
        struct linux_emuldata *edp;

        /* Setup the signal frame (and part of the trapframe) */
        /*OLD: if (p->p_sigacts->ps_siginfo & sigmask(sig))*/
/*      XXX XAX this is broken now.  need someplace to store what
        XXX XAX kind of signal handler a signal has.*/
#if 0
        edp = (struct linux_emuldata *)p->p_emuldata;
#else
        edp = 0;
#endif
        if (edp && sigismember(&edp->ps_siginfo, sig))
                setup_linux_rt_sigframe(tf, ksi, mask);
        else
#endif /* notyet */
                setup_linux_sigframe(tf, ksi, mask);

        /* Signal handler for trampoline code */
        tf->tf_regs[FRAME_T12] = (u_int64_t)catcher;
        tf->tf_regs[FRAME_A0] = native_to_linux_signo[sig];

        /*
         * Linux has a custom restorer option.  To support it we would
         * need to store an array of restorers and a sigcode block
         * which knew to use it.  Doesn't seem worth the trouble.
         * -erh
         */

#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW)
                printf("sendsig(%d): pc %lx, catcher %lx\n", l->l_proc->p_pid,
                    tf->tf_regs[FRAME_PC], tf->tf_regs[FRAME_A3]);
        if ((sigdebug & SDB_KSTACK) && l->l_proc->p_pid == sigpid)
                printf("sendsig(%d): sig %d returns\n", l->l_proc->p_pid, sig);
#endif
}

/*
 * 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 as specified by context
 * left by sendsig.
 * Linux real-time signals use a different sigframe,
 * but the sigcontext is the same.
 */

int
linux_restore_sigcontext(struct lwp *l, struct linux_sigcontext context,
                         sigset_t *mask)
{
        struct proc *p = l->l_proc;
        struct pcb *pcb;

        /*
         * Linux doesn't (yet) have alternate signal stacks.
         * However, the OSF/1 sigcontext which they use has
         * an onstack member.  This could be needed in the future.
         */
        mutex_enter(p->p_lock);
        if (context.sc_onstack & LINUX_SA_ONSTACK)
            l->l_sigstk.ss_flags |= SS_ONSTACK;
        else
            l->l_sigstk.ss_flags &= ~SS_ONSTACK;

        /* Reset the signal mask */
        (void) sigprocmask1(l, SIG_SETMASK, mask, 0);
        mutex_exit(p->p_lock);

        /*
         * Check for security violations.
         * Linux doesn't allow any changes to the PSL.
         */
        if (context.sc_ps != ALPHA_PSL_USERMODE)
            return(EINVAL);

        l->l_md.md_tf->tf_regs[FRAME_PC] = context.sc_pc;
        l->l_md.md_tf->tf_regs[FRAME_PS] = context.sc_ps;

        regtoframe((struct reg *)context.sc_regs, l->l_md.md_tf);
        alpha_pal_wrusp(context.sc_regs[R_SP]);

        /* Restore fp regs and fpr_cr */
        pcb = lwp_getpcb(l);
        memcpy(&pcb->pcb_fp, (struct fpreg *)context.sc_fpregs,
            sizeof(struct fpreg));
        /* XXX sc_ownedfp ? */
        /* XXX sc_fp_control ? */

#ifdef DEBUG
        if (sigdebug & SDB_FOLLOW)
                printf("linux_rt_sigreturn(%d): returns\n", p->p_pid);
#endif
        return (EJUSTRETURN);
}

int
linux_sys_rt_sigreturn(struct lwp *l, const struct linux_sys_rt_sigreturn_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct linux_rt_sigframe *) sfp;
        } */
        struct linux_rt_sigframe *sfp, sigframe;
        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 = SCARG(uap, sfp);

        if (ALIGN(sfp) != (u_int64_t)sfp)
                return(EINVAL);

        /*
         * Fetch the frame structure.
         */
        if (copyin((void *)sfp, &sigframe,
                        sizeof(struct linux_rt_sigframe)) != 0)
                return (EFAULT);

        /* Grab the signal mask */
        linux_to_native_sigset(&mask, &sigframe.uc.uc_sigmask);

        return(linux_restore_sigcontext(l, sigframe.uc.uc_mcontext, &mask));
}


int
linux_sys_sigreturn(struct lwp *l, const struct linux_sys_sigreturn_args *uap, register_t *retval)
{
        /* {
                syscallarg(struct linux_sigframe *) sfp;
        } */
        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 = SCARG(uap, sfp);
        if (ALIGN(sfp) != (u_int64_t)sfp)
                return(EINVAL);

        /*
         * Fetch the frame structure.
         */
        if (copyin((void *)sfp, &frame, sizeof(struct linux_sigframe)) != 0)
                return(EFAULT);

        /* Grab the signal mask. */
        /* XXX use frame.extramask */
        linux_old_to_native_sigset(&mask, frame.sf_sc.sc_mask);

        return(linux_restore_sigcontext(l, frame.sf_sc, &mask));
}

/*
 * We come here in a last attempt to satisfy a Linux ioctl() call
 */
/* XXX XAX update this, add maps, etc... */
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);
}

/* XXX XAX fix this */
dev_t
linux_fakedev(dev_t dev, int raw)
{
        return dev;
}

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