/* $NetBSD: vm_machdep.c,v 1.15 2023/12/20 06:13:58 thorpej 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 "opt_compat_netbsd32.h"
#include "opt_ddb.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.15 2023/12/20 06:13:58 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/cpu.h>
#include <sys/buf.h>
#include <sys/exec.h>
#include <sys/syslog.h>

#include <uvm/uvm_extern.h>

#include <aarch64/pcb.h>
#include <aarch64/frame.h>
#include <aarch64/machdep.h>
#include <aarch64/armreg.h>

/*
 * Special compilation symbols:
 *
 * STACKCHECKS - Fill undefined and supervisor stacks with a known pattern
 *               on forking and check the pattern on exit, reporting
 *               the amount of stack used.
 */

void
cpu_proc_fork(struct proc *p1, struct proc *p2)
{
}

/*
 * Finish a fork operation, with LWP l2 nearly set up.
 *
 * Copy and update the pcb and trapframe, making the child ready to run.
 *
 * Rig the child's kernel stack so that it will start out in
 * lwp_trampoline() which will call the specified func with the argument arg.
 *
 * If an alternate user-level stack is requested (with non-zero values
 * in both the stack and stacksize args), set up the user stack pointer
 * accordingly.
 */
void
cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize,
    void (*func)(void *), void *arg)
{
        const struct pcb * const pcb1 = lwp_getpcb(l1);
        struct pcb * const pcb2 = lwp_getpcb(l2);

#if 0
        printf("cpu_lwp_fork: lwp1=%p, lwp2=%p, curlwp=%p, lwp0=%p\n",
            l1, l2, curlwp, &lwp0);
#endif

        /* Copy the pcb */
        *pcb2 = *pcb1;

        /*
         * Disable FP for a newly created LWP but remember if the
         * FP state is valid.
         */
        l2->l_md.md_cpacr = CPACR_FPEN_NONE;
        KASSERT(l2->l_md.md_astpending == 0);

#ifdef ARMV83_PAC
        /*
         * Temporary kern PAC key, not really strong, but better than zero.
         * The real key gets generated by the new thread in lwp_trampoline().
         *
         * The reason we defer the generation, is because cpu_lwp_fork() can
         * be called early at boot time, when the CPRNG subsystem hasn't yet
         * been initialized.
         */
        l2->l_md.md_ia_kern[0] = (uintptr_t)l2;
        l2->l_md.md_ia_kern[1] = (uintptr_t)stack;

        /* inherit user PAC key */
        memcpy(l2->l_md.md_ia_user, l1->l_md.md_ia_user,
            sizeof(l2->l_md.md_ia_user));
        memcpy(l2->l_md.md_ib_user, l1->l_md.md_ib_user,
            sizeof(l2->l_md.md_ib_user));
        memcpy(l2->l_md.md_da_user, l1->l_md.md_da_user,
            sizeof(l2->l_md.md_da_user));
        memcpy(l2->l_md.md_db_user, l1->l_md.md_db_user,
            sizeof(l2->l_md.md_db_user));
        memcpy(l2->l_md.md_ga_user, l1->l_md.md_ga_user,
            sizeof(l2->l_md.md_ga_user));
#endif

        /*
         * Set up the kernel stack for the process.
         * Note: this stack is not in use if we are forking from p1
         */
        vaddr_t uv = uvm_lwp_getuarea(l2);

#ifdef STACKCHECKS
#define PCB_END(l)      ((char *)lwp_getpcb((l)) + sizeof(struct pcb))
#define UAREA_END(l)    ((char *)uvm_lwp_getuarea((l)) + USPACE)
        /* fill 0xdd for STACKCHECKS */
        memset(PCB_END(l2), 0xdd, UAREA_END(l2) - PCB_END(l2));
        printf("lwp %p: pcb=%p, stack=%p-%p\n", l2, lwp_getpcb(l2),
            PCB_END(l2), UAREA_END(l2));
#endif

        struct trapframe * const utf = (struct trapframe *)(uv + USPACE) - 1;
        l2->l_md.md_utf = utf;

        *utf = *l1->l_md.md_utf;

        /*
         * If specified, give the child a different stack (make sure it's
         * 16- or 8-byte aligned for 64- or 32-bit processes, respectively).
         */
        if (stack != NULL) {
                utf->tf_sp = (vaddr_t)(stack) + stacksize;
#ifdef COMPAT_NETBSD32
                if (__predict_false(l2->l_proc->p_flag & PK_32)) {
                        utf->tf_sp &= -8;
                        utf->tf_reg[13] = utf->tf_sp;
                } else
#endif
                        utf->tf_sp &= -16;
        }

        /* build a new switchframe */
        struct trapframe * const ktf = utf - 1;
        ktf->tf_reg[27] = (uint64_t)func;
        ktf->tf_reg[28] = (uint64_t)arg;
        ktf->tf_lr = (uintptr_t)lwp_trampoline;
#ifdef DDB
        ktf->tf_reg[29] = (uint64_t)utf;
        ktf->tf_pc = (uint64_t)&&backtrace_here;
        ktf->tf_sp = 0; /* mark as switchframe */
 backtrace_here:
#endif

        pcb2->pcb_tf = ktf;
}

/*
 * cpu_exit is called as the last action during exit.
 *
 * We clean up a little and then call switch_exit() with the old proc as an
 * argument.  switch_exit() first switches to lwp0's context, and finally
 * jumps into switch() to wait for another process to wake up.
 */
void
cpu_lwp_free(struct lwp *l, int proc)
{
#ifdef STACKCHECKS
        /* Report how much stack has been used - debugging */
        u_char *stop, *sbottom, *ptr;
        u_int cnt;

        stop = PCB_END(l);
        sbottom = UAREA_END(l);
        for (cnt = 0, ptr = stop; *ptr == 0xdd && ptr <= sbottom; cnt++, ptr++)
                ;
        log(LOG_INFO, "lwp %p: %u/%ld bytes are used for EL1 stack\n",
            l, cnt, sbottom - stop);
#endif
}

void
cpu_lwp_free2(struct lwp *l)
{
}

/*
 * 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().
 */
int
vmapbuf(struct buf *bp, vsize_t len)
{
        vaddr_t faddr, taddr, off;
        paddr_t fpa;


        if ((bp->b_flags & B_PHYS) == 0)
                panic("vmapbuf");

        bp->b_saveaddr = bp->b_data;
        faddr = trunc_page((vaddr_t)bp->b_data);
        off = (vaddr_t)bp->b_data - faddr;
        len = round_page(off + len);
        taddr = uvm_km_alloc(phys_map, len, atop(faddr) & uvmexp.colormask,
            UVM_KMF_VAONLY | UVM_KMF_WAITVA | UVM_KMF_COLORMATCH);
        bp->b_data = (void *)(taddr + off);

        /*
         * The region is locked, so we expect that pmap_extract() will return
         * true.
         */
        while (len) {
                (void)pmap_extract(vm_map_pmap(&bp->b_proc->p_vmspace->vm_map),
                    faddr, &fpa);
                pmap_enter(pmap_kernel(), taddr, fpa,
                    VM_PROT_READ | VM_PROT_WRITE,
                    VM_PROT_READ | VM_PROT_WRITE | PMAP_WIRED);
                faddr += PAGE_SIZE;
                taddr += PAGE_SIZE;
                len -= PAGE_SIZE;
        }
        pmap_update(pmap_kernel());

        return 0;
}

/*
 * 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");

        /*
         * Make sure the cache does not have dirty data for the
         * pages we had mapped.
         */
        addr = trunc_page((vaddr_t)bp->b_data);
        off = (vaddr_t)bp->b_data - addr;
        len = round_page(off + len);

        pmap_remove(pmap_kernel(), addr, addr + len);
        pmap_update(pmap_kernel());
        uvm_km_free(phys_map, addr, len, UVM_KMF_VAONLY);
        bp->b_data = bp->b_saveaddr;
        bp->b_saveaddr = 0;
}