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 <asm/efi.h> 14 15 #include "efistub.h" 16 17 /* 18 * This is the base address at which to start allocating virtual memory ranges 19 * for UEFI Runtime Services. 20 * 21 * For ARM/ARM64: 22 * This is in the low TTBR0 range so that we can use 23 * any allocation we choose, and eliminate the risk of a conflict after kexec. 24 * The value chosen is the largest non-zero power of 2 suitable for this purpose 25 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can 26 * be mapped efficiently. 27 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split, 28 * map everything below 1 GB. (512 MB is a reasonable upper bound for the 29 * entire footprint of the UEFI runtime services memory regions) 30 * 31 * For RISC-V: 32 * There is no specific reason for which, this address (512MB) can't be used 33 * EFI runtime virtual address for RISC-V. It also helps to use EFI runtime 34 * services on both RV32/RV64. Keep the same runtime virtual address for RISC-V 35 * as well to minimize the code churn. 36 */ 37 #define EFI_RT_VIRTUAL_BASE SZ_512M 38 39 /* 40 * Some architectures map the EFI regions into the kernel's linear map using a 41 * fixed offset. 42 */ 43 #ifndef EFI_RT_VIRTUAL_OFFSET 44 #define EFI_RT_VIRTUAL_OFFSET 0 45 #endif 46 47 static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; 48 static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0); 49 50 static struct screen_info *setup_graphics(void) 51 { 52 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; 53 efi_status_t status; 54 unsigned long size; 55 void **gop_handle = NULL; 56 struct screen_info *si = NULL; 57 58 size = 0; 59 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, 60 &gop_proto, NULL, &size, gop_handle); 61 if (status == EFI_BUFFER_TOO_SMALL) { 62 si = alloc_screen_info(); 63 if (!si) 64 return NULL; 65 status = efi_setup_gop(si, &gop_proto, size); 66 if (status != EFI_SUCCESS) { 67 free_screen_info(si); 68 return NULL; 69 } 70 } 71 return si; 72 } 73 74 static void install_memreserve_table(void) 75 { 76 struct linux_efi_memreserve *rsv; 77 efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID; 78 efi_status_t status; 79 80 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv), 81 (void **)&rsv); 82 if (status != EFI_SUCCESS) { 83 efi_err("Failed to allocate memreserve entry!\n"); 84 return; 85 } 86 87 rsv->next = 0; 88 rsv->size = 0; 89 atomic_set(&rsv->count, 0); 90 91 status = efi_bs_call(install_configuration_table, 92 &memreserve_table_guid, rsv); 93 if (status != EFI_SUCCESS) 94 efi_err("Failed to install memreserve config table!\n"); 95 } 96 97 static u32 get_supported_rt_services(void) 98 { 99 const efi_rt_properties_table_t *rt_prop_table; 100 u32 supported = EFI_RT_SUPPORTED_ALL; 101 102 rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID); 103 if (rt_prop_table) 104 supported &= rt_prop_table->runtime_services_supported; 105 106 return supported; 107 } 108 109 /* 110 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint 111 * that is described in the PE/COFF header. Most of the code is the same 112 * for both archictectures, with the arch-specific code provided in the 113 * handle_kernel_image() function. 114 */ 115 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, 116 efi_system_table_t *sys_table_arg) 117 { 118 efi_loaded_image_t *image; 119 efi_status_t status; 120 unsigned long image_addr; 121 unsigned long image_size = 0; 122 /* addr/point and size pairs for memory management*/ 123 char *cmdline_ptr = NULL; 124 int cmdline_size = 0; 125 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID; 126 unsigned long reserve_addr = 0; 127 unsigned long reserve_size = 0; 128 struct screen_info *si; 129 efi_properties_table_t *prop_tbl; 130 131 efi_system_table = sys_table_arg; 132 133 /* Check if we were booted by the EFI firmware */ 134 if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) { 135 status = EFI_INVALID_PARAMETER; 136 goto fail; 137 } 138 139 status = check_platform_features(); 140 if (status != EFI_SUCCESS) 141 goto fail; 142 143 /* 144 * Get a handle to the loaded image protocol. This is used to get 145 * information about the running image, such as size and the command 146 * line. 147 */ 148 status = efi_bs_call(handle_protocol, handle, &loaded_image_proto, 149 (void *)&image); 150 if (status != EFI_SUCCESS) { 151 efi_err("Failed to get loaded image protocol\n"); 152 goto fail; 153 } 154 155 /* 156 * Get the command line from EFI, using the LOADED_IMAGE 157 * protocol. We are going to copy the command line into the 158 * device tree, so this can be allocated anywhere. 159 */ 160 cmdline_ptr = efi_convert_cmdline(image, &cmdline_size); 161 if (!cmdline_ptr) { 162 efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n"); 163 status = EFI_OUT_OF_RESOURCES; 164 goto fail; 165 } 166 167 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || 168 IS_ENABLED(CONFIG_CMDLINE_FORCE) || 169 cmdline_size == 0) { 170 status = efi_parse_options(CONFIG_CMDLINE); 171 if (status != EFI_SUCCESS) { 172 efi_err("Failed to parse options\n"); 173 goto fail_free_cmdline; 174 } 175 } 176 177 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) { 178 status = efi_parse_options(cmdline_ptr); 179 if (status != EFI_SUCCESS) { 180 efi_err("Failed to parse options\n"); 181 goto fail_free_cmdline; 182 } 183 } 184 185 efi_info("Booting Linux Kernel...\n"); 186 187 si = setup_graphics(); 188 189 status = handle_kernel_image(&image_addr, &image_size, 190 &reserve_addr, 191 &reserve_size, 192 image, handle); 193 if (status != EFI_SUCCESS) { 194 efi_err("Failed to relocate kernel\n"); 195 goto fail_free_screeninfo; 196 } 197 198 efi_retrieve_tpm2_eventlog(); 199 200 /* Ask the firmware to clear memory on unclean shutdown */ 201 efi_enable_reset_attack_mitigation(); 202 203 efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr), 204 NULL); 205 206 efi_random_get_seed(); 207 208 /* 209 * If the NX PE data feature is enabled in the properties table, we 210 * should take care not to create a virtual mapping that changes the 211 * relative placement of runtime services code and data regions, as 212 * they may belong to the same PE/COFF executable image in memory. 213 * The easiest way to achieve that is to simply use a 1:1 mapping. 214 */ 215 prop_tbl = get_efi_config_table(EFI_PROPERTIES_TABLE_GUID); 216 flat_va_mapping |= prop_tbl && 217 (prop_tbl->memory_protection_attribute & 218 EFI_PROPERTIES_RUNTIME_MEMORY_PROTECTION_NON_EXECUTABLE_PE_DATA); 219 220 /* force efi_novamap if SetVirtualAddressMap() is unsupported */ 221 efi_novamap |= !(get_supported_rt_services() & 222 EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP); 223 224 install_memreserve_table(); 225 226 status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr); 227 228 efi_free(image_size, image_addr); 229 efi_free(reserve_size, reserve_addr); 230 fail_free_screeninfo: 231 free_screen_info(si); 232 fail_free_cmdline: 233 efi_bs_call(free_pool, cmdline_ptr); 234 fail: 235 return status; 236 } 237 238 /* 239 * efi_allocate_virtmap() - create a pool allocation for the virtmap 240 * 241 * Create an allocation that is of sufficient size to hold all the memory 242 * descriptors that will be passed to SetVirtualAddressMap() to inform the 243 * firmware about the virtual mapping that will be used under the OS to call 244 * into the firmware. 245 */ 246 efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap, 247 unsigned long *desc_size, u32 *desc_ver) 248 { 249 unsigned long size, mmap_key; 250 efi_status_t status; 251 252 /* 253 * Use the size of the current memory map as an upper bound for the 254 * size of the buffer we need to pass to SetVirtualAddressMap() to 255 * cover all EFI_MEMORY_RUNTIME regions. 256 */ 257 size = 0; 258 status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size, 259 desc_ver); 260 if (status != EFI_BUFFER_TOO_SMALL) 261 return EFI_LOAD_ERROR; 262 263 return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, 264 (void **)virtmap); 265 } 266 267 /* 268 * efi_get_virtmap() - create a virtual mapping for the EFI memory map 269 * 270 * This function populates the virt_addr fields of all memory region descriptors 271 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors 272 * are also copied to @runtime_map, and their total count is returned in @count. 273 */ 274 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, 275 unsigned long desc_size, efi_memory_desc_t *runtime_map, 276 int *count) 277 { 278 u64 efi_virt_base = virtmap_base; 279 efi_memory_desc_t *in, *out = runtime_map; 280 int l; 281 282 *count = 0; 283 284 for (l = 0; l < map_size; l += desc_size) { 285 u64 paddr, size; 286 287 in = (void *)memory_map + l; 288 if (!(in->attribute & EFI_MEMORY_RUNTIME)) 289 continue; 290 291 paddr = in->phys_addr; 292 size = in->num_pages * EFI_PAGE_SIZE; 293 294 in->virt_addr = in->phys_addr + EFI_RT_VIRTUAL_OFFSET; 295 if (efi_novamap) { 296 continue; 297 } 298 299 /* 300 * Make the mapping compatible with 64k pages: this allows 301 * a 4k page size kernel to kexec a 64k page size kernel and 302 * vice versa. 303 */ 304 if (!flat_va_mapping) { 305 306 paddr = round_down(in->phys_addr, SZ_64K); 307 size += in->phys_addr - paddr; 308 309 /* 310 * Avoid wasting memory on PTEs by choosing a virtual 311 * base that is compatible with section mappings if this 312 * region has the appropriate size and physical 313 * alignment. (Sections are 2 MB on 4k granule kernels) 314 */ 315 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) 316 efi_virt_base = round_up(efi_virt_base, SZ_2M); 317 else 318 efi_virt_base = round_up(efi_virt_base, SZ_64K); 319 320 in->virt_addr += efi_virt_base - paddr; 321 efi_virt_base += size; 322 } 323 324 memcpy(out, in, desc_size); 325 out = (void *)out + desc_size; 326 ++*count; 327 } 328 } 329