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 struct screen_info * __weak alloc_screen_info(void) 51 { 52 return &screen_info; 53 } 54 55 void __weak free_screen_info(struct screen_info *si) 56 { 57 } 58 59 static struct screen_info *setup_graphics(void) 60 { 61 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; 62 efi_status_t status; 63 unsigned long size; 64 void **gop_handle = NULL; 65 struct screen_info *si = NULL; 66 67 size = 0; 68 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, 69 &gop_proto, NULL, &size, gop_handle); 70 if (status == EFI_BUFFER_TOO_SMALL) { 71 si = alloc_screen_info(); 72 if (!si) 73 return NULL; 74 status = efi_setup_gop(si, &gop_proto, size); 75 if (status != EFI_SUCCESS) { 76 free_screen_info(si); 77 return NULL; 78 } 79 } 80 return si; 81 } 82 83 static void install_memreserve_table(void) 84 { 85 struct linux_efi_memreserve *rsv; 86 efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID; 87 efi_status_t status; 88 89 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv), 90 (void **)&rsv); 91 if (status != EFI_SUCCESS) { 92 efi_err("Failed to allocate memreserve entry!\n"); 93 return; 94 } 95 96 rsv->next = 0; 97 rsv->size = 0; 98 atomic_set(&rsv->count, 0); 99 100 status = efi_bs_call(install_configuration_table, 101 &memreserve_table_guid, rsv); 102 if (status != EFI_SUCCESS) 103 efi_err("Failed to install memreserve config table!\n"); 104 } 105 106 static u32 get_supported_rt_services(void) 107 { 108 const efi_rt_properties_table_t *rt_prop_table; 109 u32 supported = EFI_RT_SUPPORTED_ALL; 110 111 rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID); 112 if (rt_prop_table) 113 supported &= rt_prop_table->runtime_services_supported; 114 115 return supported; 116 } 117 118 /* 119 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint 120 * that is described in the PE/COFF header. Most of the code is the same 121 * for both archictectures, with the arch-specific code provided in the 122 * handle_kernel_image() function. 123 */ 124 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, 125 efi_system_table_t *sys_table_arg) 126 { 127 efi_loaded_image_t *image; 128 efi_status_t status; 129 unsigned long image_addr; 130 unsigned long image_size = 0; 131 /* addr/point and size pairs for memory management*/ 132 char *cmdline_ptr = NULL; 133 int cmdline_size = 0; 134 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID; 135 unsigned long reserve_addr = 0; 136 unsigned long reserve_size = 0; 137 struct screen_info *si; 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_bs_call(handle_protocol, handle, &loaded_image_proto, 157 (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, handle); 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 efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr), 212 NULL); 213 214 efi_random_get_seed(); 215 216 /* force efi_novamap if SetVirtualAddressMap() is unsupported */ 217 efi_novamap |= !(get_supported_rt_services() & 218 EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP); 219 220 install_memreserve_table(); 221 222 status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr); 223 224 efi_free(image_size, image_addr); 225 efi_free(reserve_size, reserve_addr); 226 fail_free_screeninfo: 227 free_screen_info(si); 228 fail_free_cmdline: 229 efi_bs_call(free_pool, cmdline_ptr); 230 fail: 231 return status; 232 } 233 234 /* 235 * efi_allocate_virtmap() - create a pool allocation for the virtmap 236 * 237 * Create an allocation that is of sufficient size to hold all the memory 238 * descriptors that will be passed to SetVirtualAddressMap() to inform the 239 * firmware about the virtual mapping that will be used under the OS to call 240 * into the firmware. 241 */ 242 efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap, 243 unsigned long *desc_size, u32 *desc_ver) 244 { 245 unsigned long size, mmap_key; 246 efi_status_t status; 247 248 /* 249 * Use the size of the current memory map as an upper bound for the 250 * size of the buffer we need to pass to SetVirtualAddressMap() to 251 * cover all EFI_MEMORY_RUNTIME regions. 252 */ 253 size = 0; 254 status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size, 255 desc_ver); 256 if (status != EFI_BUFFER_TOO_SMALL) 257 return EFI_LOAD_ERROR; 258 259 return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, 260 (void **)virtmap); 261 } 262 263 /* 264 * efi_get_virtmap() - create a virtual mapping for the EFI memory map 265 * 266 * This function populates the virt_addr fields of all memory region descriptors 267 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors 268 * are also copied to @runtime_map, and their total count is returned in @count. 269 */ 270 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, 271 unsigned long desc_size, efi_memory_desc_t *runtime_map, 272 int *count) 273 { 274 u64 efi_virt_base = virtmap_base; 275 efi_memory_desc_t *in, *out = runtime_map; 276 int l; 277 278 *count = 0; 279 280 for (l = 0; l < map_size; l += desc_size) { 281 u64 paddr, size; 282 283 in = (void *)memory_map + l; 284 if (!(in->attribute & EFI_MEMORY_RUNTIME)) 285 continue; 286 287 paddr = in->phys_addr; 288 size = in->num_pages * EFI_PAGE_SIZE; 289 290 in->virt_addr = in->phys_addr + EFI_RT_VIRTUAL_OFFSET; 291 if (efi_novamap) { 292 continue; 293 } 294 295 /* 296 * Make the mapping compatible with 64k pages: this allows 297 * a 4k page size kernel to kexec a 64k page size kernel and 298 * vice versa. 299 */ 300 if (!flat_va_mapping) { 301 302 paddr = round_down(in->phys_addr, SZ_64K); 303 size += in->phys_addr - paddr; 304 305 /* 306 * Avoid wasting memory on PTEs by choosing a virtual 307 * base that is compatible with section mappings if this 308 * region has the appropriate size and physical 309 * alignment. (Sections are 2 MB on 4k granule kernels) 310 */ 311 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) 312 efi_virt_base = round_up(efi_virt_base, SZ_2M); 313 else 314 efi_virt_base = round_up(efi_virt_base, SZ_64K); 315 316 in->virt_addr += efi_virt_base - paddr; 317 efi_virt_base += size; 318 } 319 320 memcpy(out, in, desc_size); 321 out = (void *)out + desc_size; 322 ++*count; 323 } 324 } 325