1 /* 2 * Common EFI memory map functions. 3 */ 4 5 #define pr_fmt(fmt) "efi: " fmt 6 7 #include <linux/init.h> 8 #include <linux/kernel.h> 9 #include <linux/efi.h> 10 #include <linux/io.h> 11 #include <asm/early_ioremap.h> 12 #include <linux/memblock.h> 13 #include <linux/slab.h> 14 15 static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size) 16 { 17 return memblock_alloc(size, 0); 18 } 19 20 static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size) 21 { 22 unsigned int order = get_order(size); 23 struct page *p = alloc_pages(GFP_KERNEL, order); 24 25 if (!p) 26 return 0; 27 28 return PFN_PHYS(page_to_pfn(p)); 29 } 30 31 /** 32 * efi_memmap_alloc - Allocate memory for the EFI memory map 33 * @num_entries: Number of entries in the allocated map. 34 * 35 * Depending on whether mm_init() has already been invoked or not, 36 * either memblock or "normal" page allocation is used. 37 * 38 * Returns the physical address of the allocated memory map on 39 * success, zero on failure. 40 */ 41 phys_addr_t __init efi_memmap_alloc(unsigned int num_entries) 42 { 43 unsigned long size = num_entries * efi.memmap.desc_size; 44 45 if (slab_is_available()) 46 return __efi_memmap_alloc_late(size); 47 48 return __efi_memmap_alloc_early(size); 49 } 50 51 /** 52 * __efi_memmap_init - Common code for mapping the EFI memory map 53 * @data: EFI memory map data 54 * @late: Use early or late mapping function? 55 * 56 * This function takes care of figuring out which function to use to 57 * map the EFI memory map in efi.memmap based on how far into the boot 58 * we are. 59 * 60 * During bootup @late should be %false since we only have access to 61 * the early_memremap*() functions as the vmalloc space isn't setup. 62 * Once the kernel is fully booted we can fallback to the more robust 63 * memremap*() API. 64 * 65 * Returns zero on success, a negative error code on failure. 66 */ 67 static int __init 68 __efi_memmap_init(struct efi_memory_map_data *data, bool late) 69 { 70 struct efi_memory_map map; 71 phys_addr_t phys_map; 72 73 if (efi_enabled(EFI_PARAVIRT)) 74 return 0; 75 76 phys_map = data->phys_map; 77 78 if (late) 79 map.map = memremap(phys_map, data->size, MEMREMAP_WB); 80 else 81 map.map = early_memremap(phys_map, data->size); 82 83 if (!map.map) { 84 pr_err("Could not map the memory map!\n"); 85 return -ENOMEM; 86 } 87 88 map.phys_map = data->phys_map; 89 map.nr_map = data->size / data->desc_size; 90 map.map_end = map.map + data->size; 91 92 map.desc_version = data->desc_version; 93 map.desc_size = data->desc_size; 94 map.late = late; 95 96 set_bit(EFI_MEMMAP, &efi.flags); 97 98 efi.memmap = map; 99 100 return 0; 101 } 102 103 /** 104 * efi_memmap_init_early - Map the EFI memory map data structure 105 * @data: EFI memory map data 106 * 107 * Use early_memremap() to map the passed in EFI memory map and assign 108 * it to efi.memmap. 109 */ 110 int __init efi_memmap_init_early(struct efi_memory_map_data *data) 111 { 112 /* Cannot go backwards */ 113 WARN_ON(efi.memmap.late); 114 115 return __efi_memmap_init(data, false); 116 } 117 118 void __init efi_memmap_unmap(void) 119 { 120 if (!efi.memmap.late) { 121 unsigned long size; 122 123 size = efi.memmap.desc_size * efi.memmap.nr_map; 124 early_memunmap(efi.memmap.map, size); 125 } else { 126 memunmap(efi.memmap.map); 127 } 128 129 efi.memmap.map = NULL; 130 clear_bit(EFI_MEMMAP, &efi.flags); 131 } 132 133 /** 134 * efi_memmap_init_late - Map efi.memmap with memremap() 135 * @phys_addr: Physical address of the new EFI memory map 136 * @size: Size in bytes of the new EFI memory map 137 * 138 * Setup a mapping of the EFI memory map using ioremap_cache(). This 139 * function should only be called once the vmalloc space has been 140 * setup and is therefore not suitable for calling during early EFI 141 * initialise, e.g. in efi_init(). Additionally, it expects 142 * efi_memmap_init_early() to have already been called. 143 * 144 * The reason there are two EFI memmap initialisation 145 * (efi_memmap_init_early() and this late version) is because the 146 * early EFI memmap should be explicitly unmapped once EFI 147 * initialisation is complete as the fixmap space used to map the EFI 148 * memmap (via early_memremap()) is a scarce resource. 149 * 150 * This late mapping is intended to persist for the duration of 151 * runtime so that things like efi_mem_desc_lookup() and 152 * efi_mem_attributes() always work. 153 * 154 * Returns zero on success, a negative error code on failure. 155 */ 156 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size) 157 { 158 struct efi_memory_map_data data = { 159 .phys_map = addr, 160 .size = size, 161 }; 162 163 /* Did we forget to unmap the early EFI memmap? */ 164 WARN_ON(efi.memmap.map); 165 166 /* Were we already called? */ 167 WARN_ON(efi.memmap.late); 168 169 /* 170 * It makes no sense to allow callers to register different 171 * values for the following fields. Copy them out of the 172 * existing early EFI memmap. 173 */ 174 data.desc_version = efi.memmap.desc_version; 175 data.desc_size = efi.memmap.desc_size; 176 177 return __efi_memmap_init(&data, true); 178 } 179 180 /** 181 * efi_memmap_install - Install a new EFI memory map in efi.memmap 182 * @addr: Physical address of the memory map 183 * @nr_map: Number of entries in the memory map 184 * 185 * Unlike efi_memmap_init_*(), this function does not allow the caller 186 * to switch from early to late mappings. It simply uses the existing 187 * mapping function and installs the new memmap. 188 * 189 * Returns zero on success, a negative error code on failure. 190 */ 191 int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map) 192 { 193 struct efi_memory_map_data data; 194 195 efi_memmap_unmap(); 196 197 data.phys_map = addr; 198 data.size = efi.memmap.desc_size * nr_map; 199 data.desc_version = efi.memmap.desc_version; 200 data.desc_size = efi.memmap.desc_size; 201 202 return __efi_memmap_init(&data, efi.memmap.late); 203 } 204 205 /** 206 * efi_memmap_split_count - Count number of additional EFI memmap entries 207 * @md: EFI memory descriptor to split 208 * @range: Address range (start, end) to split around 209 * 210 * Returns the number of additional EFI memmap entries required to 211 * accomodate @range. 212 */ 213 int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range) 214 { 215 u64 m_start, m_end; 216 u64 start, end; 217 int count = 0; 218 219 start = md->phys_addr; 220 end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1; 221 222 /* modifying range */ 223 m_start = range->start; 224 m_end = range->end; 225 226 if (m_start <= start) { 227 /* split into 2 parts */ 228 if (start < m_end && m_end < end) 229 count++; 230 } 231 232 if (start < m_start && m_start < end) { 233 /* split into 3 parts */ 234 if (m_end < end) 235 count += 2; 236 /* split into 2 parts */ 237 if (end <= m_end) 238 count++; 239 } 240 241 return count; 242 } 243 244 /** 245 * efi_memmap_insert - Insert a memory region in an EFI memmap 246 * @old_memmap: The existing EFI memory map structure 247 * @buf: Address of buffer to store new map 248 * @mem: Memory map entry to insert 249 * 250 * It is suggested that you call efi_memmap_split_count() first 251 * to see how large @buf needs to be. 252 */ 253 void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf, 254 struct efi_mem_range *mem) 255 { 256 u64 m_start, m_end, m_attr; 257 efi_memory_desc_t *md; 258 u64 start, end; 259 void *old, *new; 260 261 /* modifying range */ 262 m_start = mem->range.start; 263 m_end = mem->range.end; 264 m_attr = mem->attribute; 265 266 /* 267 * The EFI memory map deals with regions in EFI_PAGE_SIZE 268 * units. Ensure that the region described by 'mem' is aligned 269 * correctly. 270 */ 271 if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) || 272 !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) { 273 WARN_ON(1); 274 return; 275 } 276 277 for (old = old_memmap->map, new = buf; 278 old < old_memmap->map_end; 279 old += old_memmap->desc_size, new += old_memmap->desc_size) { 280 281 /* copy original EFI memory descriptor */ 282 memcpy(new, old, old_memmap->desc_size); 283 md = new; 284 start = md->phys_addr; 285 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1; 286 287 if (m_start <= start && end <= m_end) 288 md->attribute |= m_attr; 289 290 if (m_start <= start && 291 (start < m_end && m_end < end)) { 292 /* first part */ 293 md->attribute |= m_attr; 294 md->num_pages = (m_end - md->phys_addr + 1) >> 295 EFI_PAGE_SHIFT; 296 /* latter part */ 297 new += old_memmap->desc_size; 298 memcpy(new, old, old_memmap->desc_size); 299 md = new; 300 md->phys_addr = m_end + 1; 301 md->num_pages = (end - md->phys_addr + 1) >> 302 EFI_PAGE_SHIFT; 303 } 304 305 if ((start < m_start && m_start < end) && m_end < end) { 306 /* first part */ 307 md->num_pages = (m_start - md->phys_addr) >> 308 EFI_PAGE_SHIFT; 309 /* middle part */ 310 new += old_memmap->desc_size; 311 memcpy(new, old, old_memmap->desc_size); 312 md = new; 313 md->attribute |= m_attr; 314 md->phys_addr = m_start; 315 md->num_pages = (m_end - m_start + 1) >> 316 EFI_PAGE_SHIFT; 317 /* last part */ 318 new += old_memmap->desc_size; 319 memcpy(new, old, old_memmap->desc_size); 320 md = new; 321 md->phys_addr = m_end + 1; 322 md->num_pages = (end - m_end) >> 323 EFI_PAGE_SHIFT; 324 } 325 326 if ((start < m_start && m_start < end) && 327 (end <= m_end)) { 328 /* first part */ 329 md->num_pages = (m_start - md->phys_addr) >> 330 EFI_PAGE_SHIFT; 331 /* latter part */ 332 new += old_memmap->desc_size; 333 memcpy(new, old, old_memmap->desc_size); 334 md = new; 335 md->phys_addr = m_start; 336 md->num_pages = (end - md->phys_addr + 1) >> 337 EFI_PAGE_SHIFT; 338 md->attribute |= m_attr; 339 } 340 } 341 } 342