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 #ifndef __efi_memmap_free 19 #define __efi_memmap_free(phys, size, flags) do { } while (0) 20 #endif 21 22 /** 23 * __efi_memmap_init - Common code for mapping the EFI memory map 24 * @data: EFI memory map data 25 * 26 * This function takes care of figuring out which function to use to 27 * map the EFI memory map in efi.memmap based on how far into the boot 28 * we are. 29 * 30 * During bootup EFI_MEMMAP_LATE in data->flags should be clear since we 31 * only have access to the early_memremap*() functions as the vmalloc 32 * space isn't setup. Once the kernel is fully booted we can fallback 33 * to the more robust memremap*() API. 34 * 35 * Returns zero on success, a negative error code on failure. 36 */ 37 int __init __efi_memmap_init(struct efi_memory_map_data *data) 38 { 39 struct efi_memory_map map; 40 phys_addr_t phys_map; 41 42 phys_map = data->phys_map; 43 44 if (data->flags & EFI_MEMMAP_LATE) 45 map.map = memremap(phys_map, data->size, MEMREMAP_WB); 46 else 47 map.map = early_memremap(phys_map, data->size); 48 49 if (!map.map) { 50 pr_err("Could not map the memory map!\n"); 51 return -ENOMEM; 52 } 53 54 if (efi.memmap.flags & (EFI_MEMMAP_MEMBLOCK | EFI_MEMMAP_SLAB)) 55 __efi_memmap_free(efi.memmap.phys_map, 56 efi.memmap.desc_size * efi.memmap.nr_map, 57 efi.memmap.flags); 58 59 map.phys_map = data->phys_map; 60 map.nr_map = data->size / data->desc_size; 61 map.map_end = map.map + data->size; 62 63 map.desc_version = data->desc_version; 64 map.desc_size = data->desc_size; 65 map.flags = data->flags; 66 67 set_bit(EFI_MEMMAP, &efi.flags); 68 69 efi.memmap = map; 70 71 return 0; 72 } 73 74 /** 75 * efi_memmap_init_early - Map the EFI memory map data structure 76 * @data: EFI memory map data 77 * 78 * Use early_memremap() to map the passed in EFI memory map and assign 79 * it to efi.memmap. 80 */ 81 int __init efi_memmap_init_early(struct efi_memory_map_data *data) 82 { 83 /* Cannot go backwards */ 84 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE); 85 86 data->flags = 0; 87 return __efi_memmap_init(data); 88 } 89 90 void __init efi_memmap_unmap(void) 91 { 92 if (!efi_enabled(EFI_MEMMAP)) 93 return; 94 95 if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) { 96 unsigned long size; 97 98 size = efi.memmap.desc_size * efi.memmap.nr_map; 99 early_memunmap(efi.memmap.map, size); 100 } else { 101 memunmap(efi.memmap.map); 102 } 103 104 efi.memmap.map = NULL; 105 clear_bit(EFI_MEMMAP, &efi.flags); 106 } 107 108 /** 109 * efi_memmap_init_late - Map efi.memmap with memremap() 110 * @phys_addr: Physical address of the new EFI memory map 111 * @size: Size in bytes of the new EFI memory map 112 * 113 * Setup a mapping of the EFI memory map using ioremap_cache(). This 114 * function should only be called once the vmalloc space has been 115 * setup and is therefore not suitable for calling during early EFI 116 * initialise, e.g. in efi_init(). Additionally, it expects 117 * efi_memmap_init_early() to have already been called. 118 * 119 * The reason there are two EFI memmap initialisation 120 * (efi_memmap_init_early() and this late version) is because the 121 * early EFI memmap should be explicitly unmapped once EFI 122 * initialisation is complete as the fixmap space used to map the EFI 123 * memmap (via early_memremap()) is a scarce resource. 124 * 125 * This late mapping is intended to persist for the duration of 126 * runtime so that things like efi_mem_desc_lookup() and 127 * efi_mem_attributes() always work. 128 * 129 * Returns zero on success, a negative error code on failure. 130 */ 131 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size) 132 { 133 struct efi_memory_map_data data = { 134 .phys_map = addr, 135 .size = size, 136 .flags = EFI_MEMMAP_LATE, 137 }; 138 139 /* Did we forget to unmap the early EFI memmap? */ 140 WARN_ON(efi.memmap.map); 141 142 /* Were we already called? */ 143 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE); 144 145 /* 146 * It makes no sense to allow callers to register different 147 * values for the following fields. Copy them out of the 148 * existing early EFI memmap. 149 */ 150 data.desc_version = efi.memmap.desc_version; 151 data.desc_size = efi.memmap.desc_size; 152 153 return __efi_memmap_init(&data); 154 } 155