1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * EFI stub implementation that is shared by arm and arm64 architectures. 4 * This should be #included by the EFI stub implementation files. 5 * 6 * Copyright (C) 2013,2014 Linaro Limited 7 * Roy Franz <roy.franz@linaro.org 8 * Copyright (C) 2013 Red Hat, Inc. 9 * Mark Salter <msalter@redhat.com> 10 */ 11 12 #include <linux/efi.h> 13 #include <linux/libfdt.h> 14 #include <asm/efi.h> 15 16 #include "efistub.h" 17 18 /* 19 * This is the base address at which to start allocating virtual memory ranges 20 * for UEFI Runtime Services. 21 * 22 * For ARM/ARM64: 23 * This is in the low TTBR0 range so that we can use 24 * any allocation we choose, and eliminate the risk of a conflict after kexec. 25 * The value chosen is the largest non-zero power of 2 suitable for this purpose 26 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can 27 * be mapped efficiently. 28 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split, 29 * map everything below 1 GB. (512 MB is a reasonable upper bound for the 30 * entire footprint of the UEFI runtime services memory regions) 31 * 32 * For RISC-V: 33 * There is no specific reason for which, this address (512MB) can't be used 34 * EFI runtime virtual address for RISC-V. It also helps to use EFI runtime 35 * services on both RV32/RV64. Keep the same runtime virtual address for RISC-V 36 * as well to minimize the code churn. 37 */ 38 #define EFI_RT_VIRTUAL_BASE SZ_512M 39 #define EFI_RT_VIRTUAL_SIZE SZ_512M 40 41 #ifdef CONFIG_ARM64 42 # define EFI_RT_VIRTUAL_LIMIT DEFAULT_MAP_WINDOW_64 43 #else 44 # define EFI_RT_VIRTUAL_LIMIT TASK_SIZE 45 #endif 46 47 static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; 48 static bool flat_va_mapping; 49 50 const efi_system_table_t *efi_system_table; 51 52 static struct screen_info *setup_graphics(void) 53 { 54 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; 55 efi_status_t status; 56 unsigned long size; 57 void **gop_handle = NULL; 58 struct screen_info *si = NULL; 59 60 size = 0; 61 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, 62 &gop_proto, NULL, &size, gop_handle); 63 if (status == EFI_BUFFER_TOO_SMALL) { 64 si = alloc_screen_info(); 65 if (!si) 66 return NULL; 67 status = efi_setup_gop(si, &gop_proto, size); 68 if (status != EFI_SUCCESS) { 69 free_screen_info(si); 70 return NULL; 71 } 72 } 73 return si; 74 } 75 76 static void install_memreserve_table(void) 77 { 78 struct linux_efi_memreserve *rsv; 79 efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID; 80 efi_status_t status; 81 82 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv), 83 (void **)&rsv); 84 if (status != EFI_SUCCESS) { 85 efi_err("Failed to allocate memreserve entry!\n"); 86 return; 87 } 88 89 rsv->next = 0; 90 rsv->size = 0; 91 atomic_set(&rsv->count, 0); 92 93 status = efi_bs_call(install_configuration_table, 94 &memreserve_table_guid, rsv); 95 if (status != EFI_SUCCESS) 96 efi_err("Failed to install memreserve config table!\n"); 97 } 98 99 static u32 get_supported_rt_services(void) 100 { 101 const efi_rt_properties_table_t *rt_prop_table; 102 u32 supported = EFI_RT_SUPPORTED_ALL; 103 104 rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID); 105 if (rt_prop_table) 106 supported &= rt_prop_table->runtime_services_supported; 107 108 return supported; 109 } 110 111 /* 112 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint 113 * that is described in the PE/COFF header. Most of the code is the same 114 * for both archictectures, with the arch-specific code provided in the 115 * handle_kernel_image() function. 116 */ 117 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, 118 efi_system_table_t *sys_table_arg) 119 { 120 efi_loaded_image_t *image; 121 efi_status_t status; 122 unsigned long image_addr; 123 unsigned long image_size = 0; 124 /* addr/point and size pairs for memory management*/ 125 unsigned long initrd_addr = 0; 126 unsigned long initrd_size = 0; 127 unsigned long fdt_addr = 0; /* Original DTB */ 128 unsigned long fdt_size = 0; 129 char *cmdline_ptr = NULL; 130 int cmdline_size = 0; 131 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID; 132 unsigned long reserve_addr = 0; 133 unsigned long reserve_size = 0; 134 enum efi_secureboot_mode secure_boot; 135 struct screen_info *si; 136 efi_properties_table_t *prop_tbl; 137 unsigned long max_addr; 138 139 efi_system_table = sys_table_arg; 140 141 /* Check if we were booted by the EFI firmware */ 142 if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) { 143 status = EFI_INVALID_PARAMETER; 144 goto fail; 145 } 146 147 status = check_platform_features(); 148 if (status != EFI_SUCCESS) 149 goto fail; 150 151 /* 152 * Get a handle to the loaded image protocol. This is used to get 153 * information about the running image, such as size and the command 154 * line. 155 */ 156 status = efi_system_table->boottime->handle_protocol(handle, 157 &loaded_image_proto, (void *)&image); 158 if (status != EFI_SUCCESS) { 159 efi_err("Failed to get loaded image protocol\n"); 160 goto fail; 161 } 162 163 /* 164 * Get the command line from EFI, using the LOADED_IMAGE 165 * protocol. We are going to copy the command line into the 166 * device tree, so this can be allocated anywhere. 167 */ 168 cmdline_ptr = efi_convert_cmdline(image, &cmdline_size); 169 if (!cmdline_ptr) { 170 efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n"); 171 status = EFI_OUT_OF_RESOURCES; 172 goto fail; 173 } 174 175 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || 176 IS_ENABLED(CONFIG_CMDLINE_FORCE) || 177 cmdline_size == 0) { 178 status = efi_parse_options(CONFIG_CMDLINE); 179 if (status != EFI_SUCCESS) { 180 efi_err("Failed to parse options\n"); 181 goto fail_free_cmdline; 182 } 183 } 184 185 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) { 186 status = efi_parse_options(cmdline_ptr); 187 if (status != EFI_SUCCESS) { 188 efi_err("Failed to parse options\n"); 189 goto fail_free_cmdline; 190 } 191 } 192 193 efi_info("Booting Linux Kernel...\n"); 194 195 si = setup_graphics(); 196 197 status = handle_kernel_image(&image_addr, &image_size, 198 &reserve_addr, 199 &reserve_size, 200 image); 201 if (status != EFI_SUCCESS) { 202 efi_err("Failed to relocate kernel\n"); 203 goto fail_free_screeninfo; 204 } 205 206 efi_retrieve_tpm2_eventlog(); 207 208 /* Ask the firmware to clear memory on unclean shutdown */ 209 efi_enable_reset_attack_mitigation(); 210 211 secure_boot = efi_get_secureboot(); 212 213 /* 214 * Unauthenticated device tree data is a security hazard, so ignore 215 * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure 216 * boot is enabled if we can't determine its state. 217 */ 218 if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) || 219 secure_boot != efi_secureboot_mode_disabled) { 220 if (strstr(cmdline_ptr, "dtb=")) 221 efi_err("Ignoring DTB from command line.\n"); 222 } else { 223 status = efi_load_dtb(image, &fdt_addr, &fdt_size); 224 225 if (status != EFI_SUCCESS) { 226 efi_err("Failed to load device tree!\n"); 227 goto fail_free_image; 228 } 229 } 230 231 if (fdt_addr) { 232 efi_info("Using DTB from command line\n"); 233 } else { 234 /* Look for a device tree configuration table entry. */ 235 fdt_addr = (uintptr_t)get_fdt(&fdt_size); 236 if (fdt_addr) 237 efi_info("Using DTB from configuration table\n"); 238 } 239 240 if (!fdt_addr) 241 efi_info("Generating empty DTB\n"); 242 243 if (!efi_noinitrd) { 244 max_addr = efi_get_max_initrd_addr(image_addr); 245 status = efi_load_initrd(image, &initrd_addr, &initrd_size, 246 ULONG_MAX, max_addr); 247 if (status != EFI_SUCCESS) 248 efi_err("Failed to load initrd!\n"); 249 } 250 251 efi_random_get_seed(); 252 253 /* 254 * If the NX PE data feature is enabled in the properties table, we 255 * should take care not to create a virtual mapping that changes the 256 * relative placement of runtime services code and data regions, as 257 * they may belong to the same PE/COFF executable image in memory. 258 * The easiest way to achieve that is to simply use a 1:1 mapping. 259 */ 260 prop_tbl = get_efi_config_table(EFI_PROPERTIES_TABLE_GUID); 261 flat_va_mapping = prop_tbl && 262 (prop_tbl->memory_protection_attribute & 263 EFI_PROPERTIES_RUNTIME_MEMORY_PROTECTION_NON_EXECUTABLE_PE_DATA); 264 265 /* force efi_novamap if SetVirtualAddressMap() is unsupported */ 266 efi_novamap |= !(get_supported_rt_services() & 267 EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP); 268 269 /* hibernation expects the runtime regions to stay in the same place */ 270 if (!IS_ENABLED(CONFIG_HIBERNATION) && !efi_nokaslr && !flat_va_mapping) { 271 /* 272 * Randomize the base of the UEFI runtime services region. 273 * Preserve the 2 MB alignment of the region by taking a 274 * shift of 21 bit positions into account when scaling 275 * the headroom value using a 32-bit random value. 276 */ 277 static const u64 headroom = EFI_RT_VIRTUAL_LIMIT - 278 EFI_RT_VIRTUAL_BASE - 279 EFI_RT_VIRTUAL_SIZE; 280 u32 rnd; 281 282 status = efi_get_random_bytes(sizeof(rnd), (u8 *)&rnd); 283 if (status == EFI_SUCCESS) { 284 virtmap_base = EFI_RT_VIRTUAL_BASE + 285 (((headroom >> 21) * rnd) >> (32 - 21)); 286 } 287 } 288 289 install_memreserve_table(); 290 291 status = allocate_new_fdt_and_exit_boot(handle, &fdt_addr, 292 initrd_addr, initrd_size, 293 cmdline_ptr, fdt_addr, fdt_size); 294 if (status != EFI_SUCCESS) 295 goto fail_free_initrd; 296 297 if (IS_ENABLED(CONFIG_ARM)) 298 efi_handle_post_ebs_state(); 299 300 efi_enter_kernel(image_addr, fdt_addr, fdt_totalsize((void *)fdt_addr)); 301 /* not reached */ 302 303 fail_free_initrd: 304 efi_err("Failed to update FDT and exit boot services\n"); 305 306 efi_free(initrd_size, initrd_addr); 307 efi_free(fdt_size, fdt_addr); 308 309 fail_free_image: 310 efi_free(image_size, image_addr); 311 efi_free(reserve_size, reserve_addr); 312 fail_free_screeninfo: 313 free_screen_info(si); 314 fail_free_cmdline: 315 efi_bs_call(free_pool, cmdline_ptr); 316 fail: 317 return status; 318 } 319 320 /* 321 * efi_get_virtmap() - create a virtual mapping for the EFI memory map 322 * 323 * This function populates the virt_addr fields of all memory region descriptors 324 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors 325 * are also copied to @runtime_map, and their total count is returned in @count. 326 */ 327 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, 328 unsigned long desc_size, efi_memory_desc_t *runtime_map, 329 int *count) 330 { 331 u64 efi_virt_base = virtmap_base; 332 efi_memory_desc_t *in, *out = runtime_map; 333 int l; 334 335 for (l = 0; l < map_size; l += desc_size) { 336 u64 paddr, size; 337 338 in = (void *)memory_map + l; 339 if (!(in->attribute & EFI_MEMORY_RUNTIME)) 340 continue; 341 342 paddr = in->phys_addr; 343 size = in->num_pages * EFI_PAGE_SIZE; 344 345 in->virt_addr = in->phys_addr; 346 if (efi_novamap) { 347 continue; 348 } 349 350 /* 351 * Make the mapping compatible with 64k pages: this allows 352 * a 4k page size kernel to kexec a 64k page size kernel and 353 * vice versa. 354 */ 355 if (!flat_va_mapping) { 356 357 paddr = round_down(in->phys_addr, SZ_64K); 358 size += in->phys_addr - paddr; 359 360 /* 361 * Avoid wasting memory on PTEs by choosing a virtual 362 * base that is compatible with section mappings if this 363 * region has the appropriate size and physical 364 * alignment. (Sections are 2 MB on 4k granule kernels) 365 */ 366 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) 367 efi_virt_base = round_up(efi_virt_base, SZ_2M); 368 else 369 efi_virt_base = round_up(efi_virt_base, SZ_64K); 370 371 in->virt_addr += efi_virt_base - paddr; 372 efi_virt_base += size; 373 } 374 375 memcpy(out, in, desc_size); 376 out = (void *)out + desc_size; 377 ++*count; 378 } 379 } 380