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 <asm/early_ioremap.h> 13 #include <linux/memblock.h> 14 #include <linux/slab.h> 15 16 static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size) 17 { 18 return memblock_alloc(size, 0); 19 } 20 21 static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size) 22 { 23 unsigned int order = get_order(size); 24 struct page *p = alloc_pages(GFP_KERNEL, order); 25 26 if (!p) 27 return 0; 28 29 return PFN_PHYS(page_to_pfn(p)); 30 } 31 32 /** 33 * efi_memmap_alloc - Allocate memory for the EFI memory map 34 * @num_entries: Number of entries in the allocated map. 35 * 36 * Depending on whether mm_init() has already been invoked or not, 37 * either memblock or "normal" page allocation is used. 38 * 39 * Returns the physical address of the allocated memory map on 40 * success, zero on failure. 41 */ 42 phys_addr_t __init efi_memmap_alloc(unsigned int num_entries) 43 { 44 unsigned long size = num_entries * efi.memmap.desc_size; 45 46 if (slab_is_available()) 47 return __efi_memmap_alloc_late(size); 48 49 return __efi_memmap_alloc_early(size); 50 } 51 52 /** 53 * __efi_memmap_init - Common code for mapping the EFI memory map 54 * @data: EFI memory map data 55 * @late: Use early or late mapping function? 56 * 57 * This function takes care of figuring out which function to use to 58 * map the EFI memory map in efi.memmap based on how far into the boot 59 * we are. 60 * 61 * During bootup @late should be %false since we only have access to 62 * the early_memremap*() functions as the vmalloc space isn't setup. 63 * Once the kernel is fully booted we can fallback to the more robust 64 * memremap*() API. 65 * 66 * Returns zero on success, a negative error code on failure. 67 */ 68 static int __init 69 __efi_memmap_init(struct efi_memory_map_data *data, bool late) 70 { 71 struct efi_memory_map map; 72 phys_addr_t phys_map; 73 74 if (efi_enabled(EFI_PARAVIRT)) 75 return 0; 76 77 phys_map = data->phys_map; 78 79 if (late) 80 map.map = memremap(phys_map, data->size, MEMREMAP_WB); 81 else 82 map.map = early_memremap(phys_map, data->size); 83 84 if (!map.map) { 85 pr_err("Could not map the memory map!\n"); 86 return -ENOMEM; 87 } 88 89 map.phys_map = data->phys_map; 90 map.nr_map = data->size / data->desc_size; 91 map.map_end = map.map + data->size; 92 93 map.desc_version = data->desc_version; 94 map.desc_size = data->desc_size; 95 map.late = late; 96 97 set_bit(EFI_MEMMAP, &efi.flags); 98 99 efi.memmap = map; 100 101 return 0; 102 } 103 104 /** 105 * efi_memmap_init_early - Map the EFI memory map data structure 106 * @data: EFI memory map data 107 * 108 * Use early_memremap() to map the passed in EFI memory map and assign 109 * it to efi.memmap. 110 */ 111 int __init efi_memmap_init_early(struct efi_memory_map_data *data) 112 { 113 /* Cannot go backwards */ 114 WARN_ON(efi.memmap.late); 115 116 return __efi_memmap_init(data, false); 117 } 118 119 void __init efi_memmap_unmap(void) 120 { 121 if (!efi.memmap.late) { 122 unsigned long size; 123 124 size = efi.memmap.desc_size * efi.memmap.nr_map; 125 early_memunmap(efi.memmap.map, size); 126 } else { 127 memunmap(efi.memmap.map); 128 } 129 130 efi.memmap.map = NULL; 131 clear_bit(EFI_MEMMAP, &efi.flags); 132 } 133 134 /** 135 * efi_memmap_init_late - Map efi.memmap with memremap() 136 * @phys_addr: Physical address of the new EFI memory map 137 * @size: Size in bytes of the new EFI memory map 138 * 139 * Setup a mapping of the EFI memory map using ioremap_cache(). This 140 * function should only be called once the vmalloc space has been 141 * setup and is therefore not suitable for calling during early EFI 142 * initialise, e.g. in efi_init(). Additionally, it expects 143 * efi_memmap_init_early() to have already been called. 144 * 145 * The reason there are two EFI memmap initialisation 146 * (efi_memmap_init_early() and this late version) is because the 147 * early EFI memmap should be explicitly unmapped once EFI 148 * initialisation is complete as the fixmap space used to map the EFI 149 * memmap (via early_memremap()) is a scarce resource. 150 * 151 * This late mapping is intended to persist for the duration of 152 * runtime so that things like efi_mem_desc_lookup() and 153 * efi_mem_attributes() always work. 154 * 155 * Returns zero on success, a negative error code on failure. 156 */ 157 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size) 158 { 159 struct efi_memory_map_data data = { 160 .phys_map = addr, 161 .size = size, 162 }; 163 164 /* Did we forget to unmap the early EFI memmap? */ 165 WARN_ON(efi.memmap.map); 166 167 /* Were we already called? */ 168 WARN_ON(efi.memmap.late); 169 170 /* 171 * It makes no sense to allow callers to register different 172 * values for the following fields. Copy them out of the 173 * existing early EFI memmap. 174 */ 175 data.desc_version = efi.memmap.desc_version; 176 data.desc_size = efi.memmap.desc_size; 177 178 return __efi_memmap_init(&data, true); 179 } 180 181 /** 182 * efi_memmap_install - Install a new EFI memory map in efi.memmap 183 * @addr: Physical address of the memory map 184 * @nr_map: Number of entries in the memory map 185 * 186 * Unlike efi_memmap_init_*(), this function does not allow the caller 187 * to switch from early to late mappings. It simply uses the existing 188 * mapping function and installs the new memmap. 189 * 190 * Returns zero on success, a negative error code on failure. 191 */ 192 int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map) 193 { 194 struct efi_memory_map_data data; 195 196 efi_memmap_unmap(); 197 198 data.phys_map = addr; 199 data.size = efi.memmap.desc_size * nr_map; 200 data.desc_version = efi.memmap.desc_version; 201 data.desc_size = efi.memmap.desc_size; 202 203 return __efi_memmap_init(&data, efi.memmap.late); 204 } 205 206 /** 207 * efi_memmap_split_count - Count number of additional EFI memmap entries 208 * @md: EFI memory descriptor to split 209 * @range: Address range (start, end) to split around 210 * 211 * Returns the number of additional EFI memmap entries required to 212 * accomodate @range. 213 */ 214 int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range) 215 { 216 u64 m_start, m_end; 217 u64 start, end; 218 int count = 0; 219 220 start = md->phys_addr; 221 end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1; 222 223 /* modifying range */ 224 m_start = range->start; 225 m_end = range->end; 226 227 if (m_start <= start) { 228 /* split into 2 parts */ 229 if (start < m_end && m_end < end) 230 count++; 231 } 232 233 if (start < m_start && m_start < end) { 234 /* split into 3 parts */ 235 if (m_end < end) 236 count += 2; 237 /* split into 2 parts */ 238 if (end <= m_end) 239 count++; 240 } 241 242 return count; 243 } 244 245 /** 246 * efi_memmap_insert - Insert a memory region in an EFI memmap 247 * @old_memmap: The existing EFI memory map structure 248 * @buf: Address of buffer to store new map 249 * @mem: Memory map entry to insert 250 * 251 * It is suggested that you call efi_memmap_split_count() first 252 * to see how large @buf needs to be. 253 */ 254 void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf, 255 struct efi_mem_range *mem) 256 { 257 u64 m_start, m_end, m_attr; 258 efi_memory_desc_t *md; 259 u64 start, end; 260 void *old, *new; 261 262 /* modifying range */ 263 m_start = mem->range.start; 264 m_end = mem->range.end; 265 m_attr = mem->attribute; 266 267 /* 268 * The EFI memory map deals with regions in EFI_PAGE_SIZE 269 * units. Ensure that the region described by 'mem' is aligned 270 * correctly. 271 */ 272 if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) || 273 !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) { 274 WARN_ON(1); 275 return; 276 } 277 278 for (old = old_memmap->map, new = buf; 279 old < old_memmap->map_end; 280 old += old_memmap->desc_size, new += old_memmap->desc_size) { 281 282 /* copy original EFI memory descriptor */ 283 memcpy(new, old, old_memmap->desc_size); 284 md = new; 285 start = md->phys_addr; 286 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1; 287 288 if (m_start <= start && end <= m_end) 289 md->attribute |= m_attr; 290 291 if (m_start <= start && 292 (start < m_end && m_end < end)) { 293 /* first part */ 294 md->attribute |= m_attr; 295 md->num_pages = (m_end - md->phys_addr + 1) >> 296 EFI_PAGE_SHIFT; 297 /* latter part */ 298 new += old_memmap->desc_size; 299 memcpy(new, old, old_memmap->desc_size); 300 md = new; 301 md->phys_addr = m_end + 1; 302 md->num_pages = (end - md->phys_addr + 1) >> 303 EFI_PAGE_SHIFT; 304 } 305 306 if ((start < m_start && m_start < end) && m_end < end) { 307 /* first part */ 308 md->num_pages = (m_start - md->phys_addr) >> 309 EFI_PAGE_SHIFT; 310 /* middle part */ 311 new += old_memmap->desc_size; 312 memcpy(new, old, old_memmap->desc_size); 313 md = new; 314 md->attribute |= m_attr; 315 md->phys_addr = m_start; 316 md->num_pages = (m_end - m_start + 1) >> 317 EFI_PAGE_SHIFT; 318 /* last part */ 319 new += old_memmap->desc_size; 320 memcpy(new, old, old_memmap->desc_size); 321 md = new; 322 md->phys_addr = m_end + 1; 323 md->num_pages = (end - m_end) >> 324 EFI_PAGE_SHIFT; 325 } 326 327 if ((start < m_start && m_start < end) && 328 (end <= m_end)) { 329 /* first part */ 330 md->num_pages = (m_start - md->phys_addr) >> 331 EFI_PAGE_SHIFT; 332 /* latter part */ 333 new += old_memmap->desc_size; 334 memcpy(new, old, old_memmap->desc_size); 335 md = new; 336 md->phys_addr = m_start; 337 md->num_pages = (end - md->phys_addr + 1) >> 338 EFI_PAGE_SHIFT; 339 md->attribute |= m_attr; 340 } 341 } 342 } 343