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!\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 structure 67 * @data: EFI memory map data 68 * 69 * Use early_memremap() to map the passed in EFI memory map and assign 70 * it to efi.memmap. 71 * 72 * Returns: zero on success, a negative error code on failure. 73 */ 74 int __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 83 void __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 map 104 * @size: Size in bytes of the new EFI memory map 105 * 106 * Setup a mapping of the EFI memory map using ioremap_cache(). This 107 * function should only be called once the vmalloc space has been 108 * setup and is therefore not suitable for calling during early EFI 109 * initialise, e.g. in efi_init(). Additionally, it expects 110 * efi_memmap_init_early() to have already been called. 111 * 112 * The reason there are two EFI memmap initialisation 113 * (efi_memmap_init_early() and this late version) is because the 114 * early EFI memmap should be explicitly unmapped once EFI 115 * initialisation is complete as the fixmap space used to map the EFI 116 * memmap (via early_memremap()) is a scarce resource. 117 * 118 * This late mapping is intended to persist for the duration of 119 * runtime so that things like efi_mem_desc_lookup() and 120 * efi_mem_attributes() always work. 121 * 122 * Returns: zero on success, a negative error code on failure. 123 */ 124 int __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 different 140 * values for the following fields. Copy them out of the 141 * 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