1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Common EFI memory map functions. 4 */ 5 6 #define pr_fmt(fmt) "efi: " fmt 7 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 map 20 * @data: EFI memory map data 21 * 22 * This function takes care of figuring out which function to use to 23 * map the EFI memory map in efi.memmap based on how far into the boot 24 * we are. 25 * 26 * During bootup EFI_MEMMAP_LATE in data->flags should be clear since we 27 * only have access to the early_memremap*() functions as the vmalloc 28 * space isn't setup. Once the kernel is fully booted we can fallback 29 * to the more robust memremap*() API. 30 * 31 * Returns: zero on success, a negative error code on failure. 32 */ 33 int __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 else 43 map.map = early_memremap(phys_map, data->size); 44 45 if (!map.map) { 46 pr_err("Could not map the memory map! phys_map=%pa, size=0x%lx\n", 47 &phys_map, data->size); 48 return -ENOMEM; 49 } 50 51 map.phys_map = data->phys_map; 52 map.nr_map = data->size / data->desc_size; 53 map.map_end = map.map + data->size; 54 55 map.desc_version = data->desc_version; 56 map.desc_size = data->desc_size; 57 map.flags = data->flags; 58 59 set_bit(EFI_MEMMAP, &efi.flags); 60 61 efi.memmap = map; 62 63 return 0; 64 } 65 66 /** 67 * efi_memmap_init_early - Map the EFI memory map data structure 68 * @data: EFI memory map data 69 * 70 * Use early_memremap() to map the passed in EFI memory map and assign 71 * it to efi.memmap. 72 * 73 * Returns: zero on success, a negative error code on failure. 74 */ 75 int __init efi_memmap_init_early(struct efi_memory_map_data *data) 76 { 77 /* Cannot go backwards */ 78 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE); 79 80 data->flags = 0; 81 return __efi_memmap_init(data); 82 } 83 84 void __init efi_memmap_unmap(void) 85 { 86 if (!efi_enabled(EFI_MEMMAP)) 87 return; 88 89 if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) { 90 unsigned long size; 91 92 size = efi.memmap.desc_size * efi.memmap.nr_map; 93 early_memunmap(efi.memmap.map, size); 94 } else { 95 memunmap(efi.memmap.map); 96 } 97 98 efi.memmap.map = NULL; 99 clear_bit(EFI_MEMMAP, &efi.flags); 100 } 101 102 /** 103 * efi_memmap_init_late - Map efi.memmap with memremap() 104 * @addr: Physical address of the new EFI memory map 105 * @size: Size in bytes of the new EFI memory map 106 * 107 * Setup a mapping of the EFI memory map using ioremap_cache(). This 108 * function should only be called once the vmalloc space has been 109 * setup and is therefore not suitable for calling during early EFI 110 * initialise, e.g. in efi_init(). Additionally, it expects 111 * efi_memmap_init_early() to have already been called. 112 * 113 * The reason there are two EFI memmap initialisation 114 * (efi_memmap_init_early() and this late version) is because the 115 * early EFI memmap should be explicitly unmapped once EFI 116 * initialisation is complete as the fixmap space used to map the EFI 117 * memmap (via early_memremap()) is a scarce resource. 118 * 119 * This late mapping is intended to persist for the duration of 120 * runtime so that things like efi_mem_desc_lookup() and 121 * efi_mem_attributes() always work. 122 * 123 * Returns: zero on success, a negative error code on failure. 124 */ 125 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size) 126 { 127 struct efi_memory_map_data data = { 128 .phys_map = addr, 129 .size = size, 130 .flags = EFI_MEMMAP_LATE, 131 }; 132 133 /* Did we forget to unmap the early EFI memmap? */ 134 WARN_ON(efi.memmap.map); 135 136 /* Were we already called? */ 137 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE); 138 139 /* 140 * It makes no sense to allow callers to register different 141 * values for the following fields. Copy them out of the 142 * existing early EFI memmap. 143 */ 144 data.desc_version = efi.memmap.desc_version; 145 data.desc_size = efi.memmap.desc_size; 146 147 return __efi_memmap_init(&data); 148 } 149