// SPDX-License-Identifier: GPL-2.0-only
/*
 * EFI stub implementation that is shared by arm and arm64 architectures.
 * This should be #included by the EFI stub implementation files.
 *
 * Copyright (C) 2013,2014 Linaro Limited
 *     Roy Franz <roy.franz@linaro.org
 * Copyright (C) 2013 Red Hat, Inc.
 *     Mark Salter <msalter@redhat.com>
 */

#include <linux/efi.h>
#include <linux/sysfb.h>
#include <asm/efi.h>

#include "efistub.h"

/*
 * This is the base address at which to start allocating virtual memory ranges
 * for UEFI Runtime Services.
 *
 * For ARM/ARM64:
 * This is in the low TTBR0 range so that we can use
 * any allocation we choose, and eliminate the risk of a conflict after kexec.
 * The value chosen is the largest non-zero power of 2 suitable for this purpose
 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
 * be mapped efficiently.
 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
 * map everything below 1 GB. (512 MB is a reasonable upper bound for the
 * entire footprint of the UEFI runtime services memory regions)
 *
 * For RISC-V:
 * There is no specific reason for which, this address (512MB) can't be used
 * EFI runtime virtual address for RISC-V. It also helps to use EFI runtime
 * services on both RV32/RV64. Keep the same runtime virtual address for RISC-V
 * as well to minimize the code churn.
 */
#define EFI_RT_VIRTUAL_BASE     SZ_512M

/*
 * Some architectures map the EFI regions into the kernel's linear map using a
 * fixed offset.
 */
#ifndef EFI_RT_VIRTUAL_OFFSET
#define EFI_RT_VIRTUAL_OFFSET   0
#endif

static u64 virtmap_base = EFI_RT_VIRTUAL_BASE;
static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0);

void __weak free_primary_display(struct sysfb_display_info *dpy)
{ }

static struct sysfb_display_info *setup_primary_display(void)
{
        struct sysfb_display_info *dpy;
        struct screen_info *screen = NULL;
        struct edid_info *edid = NULL;
        efi_status_t status;

        dpy = alloc_primary_display();
        if (!dpy)
                return NULL;
        screen = &dpy->screen;
#if defined(CONFIG_FIRMWARE_EDID)
        edid = &dpy->edid;
#endif

        status = efi_setup_graphics(screen, edid);
        if (status != EFI_SUCCESS)
                goto err_free_primary_display;

        return dpy;

err_free_primary_display:
        free_primary_display(dpy);
        return NULL;
}

static void install_memreserve_table(void)
{
        struct linux_efi_memreserve *rsv;
        efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID;
        efi_status_t status;

        status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv),
                             (void **)&rsv);
        if (status != EFI_SUCCESS) {
                efi_err("Failed to allocate memreserve entry!\n");
                return;
        }

        rsv->next = 0;
        rsv->size = 0;
        atomic_set(&rsv->count, 0);

        status = efi_bs_call(install_configuration_table,
                             &memreserve_table_guid, rsv);
        if (status != EFI_SUCCESS)
                efi_err("Failed to install memreserve config table!\n");
}

static u32 get_supported_rt_services(void)
{
        const efi_rt_properties_table_t *rt_prop_table;
        u32 supported = EFI_RT_SUPPORTED_ALL;

        rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID);
        if (rt_prop_table)
                supported &= rt_prop_table->runtime_services_supported;

        return supported;
}

efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr)
{
        char *cmdline __free(efi_pool) = NULL;
        efi_status_t status;

        /*
         * Get the command line from EFI, using the LOADED_IMAGE
         * protocol. We are going to copy the command line into the
         * device tree, so this can be allocated anywhere.
         */
        cmdline = efi_convert_cmdline(image);
        if (!cmdline) {
                efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n");
                return EFI_OUT_OF_RESOURCES;
        }

        if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {
                status = efi_parse_options(cmdline);
                if (status != EFI_SUCCESS) {
                        efi_err("Failed to parse EFI load options\n");
                        return status;
                }
        }

        if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
            IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
            cmdline[0] == 0) {
                status = efi_parse_options(CONFIG_CMDLINE);
                if (status != EFI_SUCCESS) {
                        efi_err("Failed to parse built-in command line\n");
                        return status;
                }
        }

        *cmdline_ptr = no_free_ptr(cmdline);
        return EFI_SUCCESS;
}

efi_status_t efi_stub_common(efi_handle_t handle,
                             efi_loaded_image_t *image,
                             unsigned long image_addr,
                             char *cmdline_ptr)
{
        struct sysfb_display_info *dpy;
        efi_status_t status;

        status = check_platform_features();
        if (status != EFI_SUCCESS)
                return status;

        dpy = setup_primary_display();

        efi_retrieve_eventlog();

        /* Ask the firmware to clear memory on unclean shutdown */
        efi_enable_reset_attack_mitigation();

        efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr),
                        NULL);

        efi_random_get_seed();

        /* force efi_novamap if SetVirtualAddressMap() is unsupported */
        efi_novamap |= !(get_supported_rt_services() &
                         EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP);

        install_memreserve_table();

        status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr);

        free_primary_display(dpy);

        return status;
}

/*
 * efi_allocate_virtmap() - create a pool allocation for the virtmap
 *
 * Create an allocation that is of sufficient size to hold all the memory
 * descriptors that will be passed to SetVirtualAddressMap() to inform the
 * firmware about the virtual mapping that will be used under the OS to call
 * into the firmware.
 */
efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap,
                               unsigned long *desc_size, u32 *desc_ver)
{
        unsigned long size, mmap_key;
        efi_status_t status;

        /*
         * Use the size of the current memory map as an upper bound for the
         * size of the buffer we need to pass to SetVirtualAddressMap() to
         * cover all EFI_MEMORY_RUNTIME regions.
         */
        size = 0;
        status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size,
                             desc_ver);
        if (status != EFI_BUFFER_TOO_SMALL)
                return EFI_LOAD_ERROR;

        return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
                           (void **)virtmap);
}

/*
 * efi_get_virtmap() - create a virtual mapping for the EFI memory map
 *
 * This function populates the virt_addr fields of all memory region descriptors
 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
 * are also copied to @runtime_map, and their total count is returned in @count.
 */
void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
                     unsigned long desc_size, efi_memory_desc_t *runtime_map,
                     int *count)
{
        u64 efi_virt_base = virtmap_base;
        efi_memory_desc_t *in, *out = runtime_map;
        int l;

        *count = 0;

        for (l = 0; l < map_size; l += desc_size) {
                u64 paddr, size;

                in = (void *)memory_map + l;
                if (!(in->attribute & EFI_MEMORY_RUNTIME))
                        continue;

                paddr = in->phys_addr;
                size = in->num_pages * EFI_PAGE_SIZE;

                in->virt_addr = in->phys_addr + EFI_RT_VIRTUAL_OFFSET;
                if (efi_novamap) {
                        continue;
                }

                /*
                 * Make the mapping compatible with 64k pages: this allows
                 * a 4k page size kernel to kexec a 64k page size kernel and
                 * vice versa.
                 */
                if (!flat_va_mapping) {

                        paddr = round_down(in->phys_addr, SZ_64K);
                        size += in->phys_addr - paddr;

                        /*
                         * Avoid wasting memory on PTEs by choosing a virtual
                         * base that is compatible with section mappings if this
                         * region has the appropriate size and physical
                         * alignment. (Sections are 2 MB on 4k granule kernels)
                         */
                        if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
                                efi_virt_base = round_up(efi_virt_base, SZ_2M);
                        else
                                efi_virt_base = round_up(efi_virt_base, SZ_64K);

                        in->virt_addr += efi_virt_base - paddr;
                        efi_virt_base += size;
                }

                memcpy(out, in, desc_size);
                out = (void *)out + desc_size;
                ++*count;
        }
}