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 efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr) 119 { 120 int cmdline_size = 0; 121 efi_status_t status; 122 char *cmdline; 123 124 /* 125 * Get the command line from EFI, using the LOADED_IMAGE 126 * protocol. We are going to copy the command line into the 127 * device tree, so this can be allocated anywhere. 128 */ 129 cmdline = efi_convert_cmdline(image, &cmdline_size); 130 if (!cmdline) { 131 efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n"); 132 return EFI_OUT_OF_RESOURCES; 133 } 134 135 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || 136 IS_ENABLED(CONFIG_CMDLINE_FORCE) || 137 cmdline_size == 0) { 138 status = efi_parse_options(CONFIG_CMDLINE); 139 if (status != EFI_SUCCESS) { 140 efi_err("Failed to parse options\n"); 141 goto fail_free_cmdline; 142 } 143 } 144 145 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) { 146 status = efi_parse_options(cmdline); 147 if (status != EFI_SUCCESS) { 148 efi_err("Failed to parse options\n"); 149 goto fail_free_cmdline; 150 } 151 } 152 153 *cmdline_ptr = cmdline; 154 return EFI_SUCCESS; 155 156 fail_free_cmdline: 157 efi_bs_call(free_pool, cmdline_ptr); 158 return status; 159 } 160 161 efi_status_t efi_stub_common(efi_handle_t handle, 162 efi_loaded_image_t *image, 163 unsigned long image_addr, 164 char *cmdline_ptr) 165 { 166 struct screen_info *si; 167 efi_status_t status; 168 169 status = check_platform_features(); 170 if (status != EFI_SUCCESS) 171 return status; 172 173 si = setup_graphics(); 174 175 efi_retrieve_tpm2_eventlog(); 176 177 /* Ask the firmware to clear memory on unclean shutdown */ 178 efi_enable_reset_attack_mitigation(); 179 180 efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr), 181 NULL); 182 183 efi_random_get_seed(); 184 185 /* force efi_novamap if SetVirtualAddressMap() is unsupported */ 186 efi_novamap |= !(get_supported_rt_services() & 187 EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP); 188 189 install_memreserve_table(); 190 191 status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr); 192 193 free_screen_info(si); 194 return status; 195 } 196 197 /* 198 * efi_allocate_virtmap() - create a pool allocation for the virtmap 199 * 200 * Create an allocation that is of sufficient size to hold all the memory 201 * descriptors that will be passed to SetVirtualAddressMap() to inform the 202 * firmware about the virtual mapping that will be used under the OS to call 203 * into the firmware. 204 */ 205 efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap, 206 unsigned long *desc_size, u32 *desc_ver) 207 { 208 unsigned long size, mmap_key; 209 efi_status_t status; 210 211 /* 212 * Use the size of the current memory map as an upper bound for the 213 * size of the buffer we need to pass to SetVirtualAddressMap() to 214 * cover all EFI_MEMORY_RUNTIME regions. 215 */ 216 size = 0; 217 status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size, 218 desc_ver); 219 if (status != EFI_BUFFER_TOO_SMALL) 220 return EFI_LOAD_ERROR; 221 222 return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, 223 (void **)virtmap); 224 } 225 226 /* 227 * efi_get_virtmap() - create a virtual mapping for the EFI memory map 228 * 229 * This function populates the virt_addr fields of all memory region descriptors 230 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors 231 * are also copied to @runtime_map, and their total count is returned in @count. 232 */ 233 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, 234 unsigned long desc_size, efi_memory_desc_t *runtime_map, 235 int *count) 236 { 237 u64 efi_virt_base = virtmap_base; 238 efi_memory_desc_t *in, *out = runtime_map; 239 int l; 240 241 *count = 0; 242 243 for (l = 0; l < map_size; l += desc_size) { 244 u64 paddr, size; 245 246 in = (void *)memory_map + l; 247 if (!(in->attribute & EFI_MEMORY_RUNTIME)) 248 continue; 249 250 paddr = in->phys_addr; 251 size = in->num_pages * EFI_PAGE_SIZE; 252 253 in->virt_addr = in->phys_addr + EFI_RT_VIRTUAL_OFFSET; 254 if (efi_novamap) { 255 continue; 256 } 257 258 /* 259 * Make the mapping compatible with 64k pages: this allows 260 * a 4k page size kernel to kexec a 64k page size kernel and 261 * vice versa. 262 */ 263 if (!flat_va_mapping) { 264 265 paddr = round_down(in->phys_addr, SZ_64K); 266 size += in->phys_addr - paddr; 267 268 /* 269 * Avoid wasting memory on PTEs by choosing a virtual 270 * base that is compatible with section mappings if this 271 * region has the appropriate size and physical 272 * alignment. (Sections are 2 MB on 4k granule kernels) 273 */ 274 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) 275 efi_virt_base = round_up(efi_virt_base, SZ_2M); 276 else 277 efi_virt_base = round_up(efi_virt_base, SZ_64K); 278 279 in->virt_addr += efi_virt_base - paddr; 280 efi_virt_base += size; 281 } 282 283 memcpy(out, in, desc_size); 284 out = (void *)out + desc_size; 285 ++*count; 286 } 287 } 288