root/sys/arch/arm64/arm64/vm_machdep.c
/*      $OpenBSD: vm_machdep.c,v 1.14 2025/05/21 09:06:58 mpi Exp $     */
/*      $NetBSD: vm_machdep.c,v 1.1 2003/04/26 18:39:33 fvdl Exp $      */

/*-
 * Copyright (c) 1995 Charles M. Hannum.  All rights reserved.
 * Copyright (c) 1982, 1986 The Regents of the University of California.
 * Copyright (c) 1989, 1990 William Jolitz
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department, and William Jolitz.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      @(#)vm_machdep.c        7.3 (Berkeley) 5/13/91
 */

/*
 *      Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/buf.h>
#include <sys/user.h>
#include <sys/exec.h>
#include <sys/ptrace.h>
#include <sys/signalvar.h>

#include <uvm/uvm_extern.h>

#include <machine/cpu.h>
#include <machine/fpu.h>
#include <machine/reg.h>

/*
 * Finish a fork operation, with process p2 nearly set up.
 * Copy and update the kernel stack and pcb, making the child
 * ready to run, and marking it so that it can return differently
 * than the parent.  Returns 1 in the child process, 0 in the parent.
 */
void
cpu_fork(struct proc *p1, struct proc *p2, void *stack, void *tcb,
    void (*func)(void *), void *arg)
{
        struct pmap *pm = p2->p_vmspace->vm_map.pmap;
        struct pmap *pm1 = p1->p_vmspace->vm_map.pmap;
        struct pcb *pcb = &p2->p_addr->u_pcb;
        struct pcb *pcb1 = &p1->p_addr->u_pcb;
        struct trapframe *tf;
        struct switchframe *sf;

        memcpy(pm->pm_apiakey, pm1->pm_apiakey, sizeof(pm->pm_apiakey));
        memcpy(pm->pm_apdakey, pm1->pm_apdakey, sizeof(pm->pm_apdakey));
        memcpy(pm->pm_apibkey, pm1->pm_apibkey, sizeof(pm->pm_apibkey));
        memcpy(pm->pm_apdbkey, pm1->pm_apdbkey, sizeof(pm->pm_apdbkey));
        memcpy(pm->pm_apgakey, pm1->pm_apgakey, sizeof(pm->pm_apgakey));

        /* Save FPU state to PCB if necessary. */
        if (pcb1->pcb_flags & PCB_FPU)
                fpu_save(p1);

        /* Copy the pcb. */
        *pcb = p1->p_addr->u_pcb;

        pmap_activate(p2);

        tf = (struct trapframe *)((u_long)p2->p_addr
            + USPACE
            - sizeof(struct trapframe)
            - 0x10);

        tf = (struct trapframe *)STACKALIGN(tf);
        pcb->pcb_tf = tf;
        *tf = *p1->p_addr->u_pcb.pcb_tf;

        if (stack != NULL)
                tf->tf_sp = STACKALIGN(stack);
        if (tcb != NULL)
                pcb->pcb_tcb = tcb;

        sf = (struct switchframe *)tf - 1;
        sf->sf_x19 = (uint64_t)func;
        sf->sf_x20 = (uint64_t)arg;
        sf->sf_lr = (uint64_t)&proc_trampoline;
        pcb->pcb_sp = (uint64_t)sf;
}

void
cpu_exit(struct proc *p)
{
}

struct kmem_va_mode kv_physwait = {
        .kv_map = &phys_map,
        .kv_wait = 1,
};

/*
 * Map a user I/O request into kernel virtual address space.
 * Note: the pages are already locked by uvm_vslock(), so we
 * do not need to pass an access_type to pmap_enter().
 */
void
vmapbuf(struct buf *bp, vsize_t len)
{
        vaddr_t faddr, taddr, off;
        paddr_t fpa;

        if ((bp->b_flags & B_PHYS) == 0)
                panic("vmapbuf");
        faddr = trunc_page((vaddr_t)(bp->b_saveaddr = bp->b_data));
        off = (vaddr_t)bp->b_data - faddr;
        len = round_page(off + len);
        taddr = (vaddr_t)km_alloc(len, &kv_physwait, &kp_none, &kd_waitok);
        bp->b_data = (caddr_t)(taddr + off);
        /*
         * The region is locked, so we expect that pmap_pte() will return
         * non-NULL.
         * XXX: unwise to expect this in a multithreaded environment.
         * anything can happen to a pmap between the time we lock a
         * region, release the pmap lock, and then relock it for
         * the pmap_extract().
         *
         * no need to flush TLB since we expect nothing to be mapped
         * where we just allocated (TLB will be flushed when our
         * mapping is removed).
         */
        while (len) {
                (void) pmap_extract(vm_map_pmap(&bp->b_proc->p_vmspace->vm_map),
                    faddr, &fpa);
                pmap_kenter_pa(taddr, fpa, PROT_READ | PROT_WRITE);
                faddr += PAGE_SIZE;
                taddr += PAGE_SIZE;
                len -= PAGE_SIZE;
        }
        pmap_update(pmap_kernel());
}

/*
 * Unmap a previously-mapped user I/O request.
 */
void
vunmapbuf(struct buf *bp, vsize_t len)
{
        vaddr_t addr, off;

        if ((bp->b_flags & B_PHYS) == 0)
                panic("vunmapbuf");
        addr = trunc_page((vaddr_t)bp->b_data);
        off = (vaddr_t)bp->b_data - addr;
        len = round_page(off + len);
        pmap_kremove(addr, len);
        pmap_update(pmap_kernel());
        km_free((void *)addr, len, &kv_physwait, &kp_none);
        bp->b_data = bp->b_saveaddr;
        bp->b_saveaddr = NULL;
}