/* $NetBSD: efi_machdep.c,v 1.14 2023/07/10 07:00:11 rin Exp $ */

/*-
 * Copyright (c) 2018 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jared McNeill <jmcneill@invisible.ca>.
 *
 * 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: efi_machdep.c,v 1.14 2023/07/10 07:00:11 rin Exp $");

#include <sys/param.h>

#include <uvm/uvm_extern.h>

#include <arm/cpufunc.h>
#include <arm/efirt.h>

#include <arm/arm/efi_runtime.h>

#include <aarch64/machdep.h>

static struct {
        struct faultbuf faultbuf;
        bool            fpu_used;
} arm_efirt_state;

static bool efi_userva = true;

void
cpu_efirt_map_range(vaddr_t va, paddr_t pa, size_t sz,
    enum cpu_efirt_mem_type type)
{
        int flags = 0;
        int prot = 0;

        switch (type) {
        case ARM_EFIRT_MEM_CODE:
                /* need write permission because fw devs */
                prot = VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
                break;
        case ARM_EFIRT_MEM_DATA:
                prot = VM_PROT_READ | VM_PROT_WRITE;
                break;
        case ARM_EFIRT_MEM_MMIO:
                prot = VM_PROT_READ | VM_PROT_WRITE;
                flags = PMAP_DEV;
                break;
        default:
                panic("%s: unsupported type %d", __func__, type);
        }

        /* even if TBI is disabled, AARCH64_ADDRTOP_TAG means KVA */
        bool kva = (va & AARCH64_ADDRTOP_TAG) != 0;
        if (kva) {
                if (va < EFI_RUNTIME_VA ||
                    va >= EFI_RUNTIME_VA + EFI_RUNTIME_SIZE) {
                        printf("Incorrect EFI mapping address %" PRIxVADDR "\n", va);
                    return;
                }
                efi_userva = false;
        } else {
                if (!efi_userva) {
                        printf("Can't mix EFI RT address spaces\n");
                        return;
                }
        }

        while (sz != 0) {
                if (kva) {
                        pmap_kenter_pa(va, pa, prot, flags);
                } else {
                        pmap_enter(pmap_efirt(), va, pa, prot, flags | PMAP_WIRED);
                }
                va += PAGE_SIZE;
                pa += PAGE_SIZE;
                sz -= PAGE_SIZE;
        }
        if (kva)
                pmap_update(pmap_kernel());
        else
                pmap_update(pmap_efirt());
}

int
arm_efirt_md_enter(void)
{
        kpreempt_disable();

        struct lwp * const l = curlwp;

        /* Save FPU state */
        arm_efirt_state.fpu_used = fpu_used_p(l) != 0;
        if (arm_efirt_state.fpu_used)
                fpu_save(l);

        /* Enable FP access (AArch64 UEFI calling convention) */
        reg_cpacr_el1_write(CPACR_FPEN_ALL);
        isb();

        /*
         * Install custom fault handler. EFI lock is held across calls so
         * shared faultbuf is safe here.
         */
        int err = cpu_set_onfault(&arm_efirt_state.faultbuf);
        if (err)
                return err;

        if (efi_userva) {
                if ((l->l_flag & LW_SYSTEM) == 0) {
                        pmap_deactivate(l);
                }
                pmap_activate_efirt();
        }

        return 0;
}

void
arm_efirt_md_exit(void)
{
        struct lwp * const l = curlwp;

        if (efi_userva) {
                pmap_deactivate_efirt();
                if ((l->l_flag & LW_SYSTEM) == 0) {
                        pmap_activate(l);
                }
        }

        /* Disable FP access */
        reg_cpacr_el1_write(CPACR_FPEN_NONE);
        isb();

        /* Restore FPU state */
        if (arm_efirt_state.fpu_used)
                fpu_load(l);

        /* Remove custom fault handler */
        cpu_unset_onfault();

        kpreempt_enable();
}