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1// SPDX-License-Identifier: GPL-2.02/*3 * Common EFI memory map functions.4 */5 6#define pr_fmt(fmt) "efi: " fmt7 8#include <linux/init.h>9#include <linux/kernel.h>10#include <linux/efi.h>11#include <linux/io.h>12#include <linux/memblock.h>13#include <linux/slab.h>14 15#include <asm/early_ioremap.h>16#include <asm/efi.h>17 18/**19 * __efi_memmap_init - Common code for mapping the EFI memory map20 * @data: EFI memory map data21 *22 * This function takes care of figuring out which function to use to23 * map the EFI memory map in efi.memmap based on how far into the boot24 * we are.25 *26 * During bootup EFI_MEMMAP_LATE in data->flags should be clear since we27 * only have access to the early_memremap*() functions as the vmalloc28 * space isn't setup. Once the kernel is fully booted we can fallback29 * to the more robust memremap*() API.30 *31 * Returns: zero on success, a negative error code on failure.32 */33int __init __efi_memmap_init(struct efi_memory_map_data *data)34{35 struct efi_memory_map map;36 phys_addr_t phys_map;37 38 phys_map = data->phys_map;39 40 if (data->flags & EFI_MEMMAP_LATE)41 map.map = memremap(phys_map, data->size, MEMREMAP_WB);42 else43 map.map = early_memremap(phys_map, data->size);44 45 if (!map.map) {46 pr_err("Could not map the memory map!\n");47 return -ENOMEM;48 }49 50 map.phys_map = data->phys_map;51 map.nr_map = data->size / data->desc_size;52 map.map_end = map.map + data->size;53 54 map.desc_version = data->desc_version;55 map.desc_size = data->desc_size;56 map.flags = data->flags;57 58 set_bit(EFI_MEMMAP, &efi.flags);59 60 efi.memmap = map;61 62 return 0;63}64 65/**66 * efi_memmap_init_early - Map the EFI memory map data structure67 * @data: EFI memory map data68 *69 * Use early_memremap() to map the passed in EFI memory map and assign70 * it to efi.memmap.71 *72 * Returns: zero on success, a negative error code on failure.73 */74int __init efi_memmap_init_early(struct efi_memory_map_data *data)75{76 /* Cannot go backwards */77 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);78 79 data->flags = 0;80 return __efi_memmap_init(data);81}82 83void __init efi_memmap_unmap(void)84{85 if (!efi_enabled(EFI_MEMMAP))86 return;87 88 if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) {89 unsigned long size;90 91 size = efi.memmap.desc_size * efi.memmap.nr_map;92 early_memunmap(efi.memmap.map, size);93 } else {94 memunmap(efi.memmap.map);95 }96 97 efi.memmap.map = NULL;98 clear_bit(EFI_MEMMAP, &efi.flags);99}100 101/**102 * efi_memmap_init_late - Map efi.memmap with memremap()103 * @addr: Physical address of the new EFI memory map104 * @size: Size in bytes of the new EFI memory map105 *106 * Setup a mapping of the EFI memory map using ioremap_cache(). This107 * function should only be called once the vmalloc space has been108 * setup and is therefore not suitable for calling during early EFI109 * initialise, e.g. in efi_init(). Additionally, it expects110 * efi_memmap_init_early() to have already been called.111 *112 * The reason there are two EFI memmap initialisation113 * (efi_memmap_init_early() and this late version) is because the114 * early EFI memmap should be explicitly unmapped once EFI115 * initialisation is complete as the fixmap space used to map the EFI116 * memmap (via early_memremap()) is a scarce resource.117 *118 * This late mapping is intended to persist for the duration of119 * runtime so that things like efi_mem_desc_lookup() and120 * efi_mem_attributes() always work.121 *122 * Returns: zero on success, a negative error code on failure.123 */124int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)125{126 struct efi_memory_map_data data = {127 .phys_map = addr,128 .size = size,129 .flags = EFI_MEMMAP_LATE,130 };131 132 /* Did we forget to unmap the early EFI memmap? */133 WARN_ON(efi.memmap.map);134 135 /* Were we already called? */136 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);137 138 /*139 * It makes no sense to allow callers to register different140 * values for the following fields. Copy them out of the141 * existing early EFI memmap.142 */143 data.desc_version = efi.memmap.desc_version;144 data.desc_size = efi.memmap.desc_size;145 146 return __efi_memmap_init(&data);147}148