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/sysfb.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 40 /* 41 * Some architectures map the EFI regions into the kernel's linear map using a 42 * fixed offset. 43 */ 44 #ifndef EFI_RT_VIRTUAL_OFFSET 45 #define EFI_RT_VIRTUAL_OFFSET 0 46 #endif 47 48 static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; 49 static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0); 50 51 void __weak free_primary_display(struct sysfb_display_info *dpy) 52 { } 53 54 static struct sysfb_display_info *setup_primary_display(void) 55 { 56 struct sysfb_display_info *dpy; 57 struct screen_info *screen = NULL; 58 struct edid_info *edid = NULL; 59 efi_status_t status; 60 61 dpy = alloc_primary_display(); 62 if (!dpy) 63 return NULL; 64 screen = &dpy->screen; 65 #if defined(CONFIG_FIRMWARE_EDID) 66 edid = &dpy->edid; 67 #endif 68 69 status = efi_setup_graphics(screen, edid); 70 if (status != EFI_SUCCESS) 71 goto err_free_primary_display; 72 73 return dpy; 74 75 err_free_primary_display: 76 free_primary_display(dpy); 77 return NULL; 78 } 79 80 static void install_memreserve_table(void) 81 { 82 struct linux_efi_memreserve *rsv; 83 efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID; 84 efi_status_t status; 85 86 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv), 87 (void **)&rsv); 88 if (status != EFI_SUCCESS) { 89 efi_err("Failed to allocate memreserve entry!\n"); 90 return; 91 } 92 93 rsv->next = 0; 94 rsv->size = 0; 95 atomic_set(&rsv->count, 0); 96 97 status = efi_bs_call(install_configuration_table, 98 &memreserve_table_guid, rsv); 99 if (status != EFI_SUCCESS) 100 efi_err("Failed to install memreserve config table!\n"); 101 } 102 103 static u32 get_supported_rt_services(void) 104 { 105 const efi_rt_properties_table_t *rt_prop_table; 106 u32 supported = EFI_RT_SUPPORTED_ALL; 107 108 rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID); 109 if (rt_prop_table) 110 supported &= rt_prop_table->runtime_services_supported; 111 112 return supported; 113 } 114 115 efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr) 116 { 117 char *cmdline __free(efi_pool) = NULL; 118 efi_status_t status; 119 120 /* 121 * Get the command line from EFI, using the LOADED_IMAGE 122 * protocol. We are going to copy the command line into the 123 * device tree, so this can be allocated anywhere. 124 */ 125 cmdline = efi_convert_cmdline(image); 126 if (!cmdline) { 127 efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n"); 128 return EFI_OUT_OF_RESOURCES; 129 } 130 131 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) { 132 status = efi_parse_options(cmdline); 133 if (status != EFI_SUCCESS) { 134 efi_err("Failed to parse EFI load options\n"); 135 return status; 136 } 137 } 138 139 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || 140 IS_ENABLED(CONFIG_CMDLINE_FORCE) || 141 cmdline[0] == 0) { 142 status = efi_parse_options(CONFIG_CMDLINE); 143 if (status != EFI_SUCCESS) { 144 efi_err("Failed to parse built-in command line\n"); 145 return status; 146 } 147 } 148 149 *cmdline_ptr = no_free_ptr(cmdline); 150 return EFI_SUCCESS; 151 } 152 153 efi_status_t efi_stub_common(efi_handle_t handle, 154 efi_loaded_image_t *image, 155 unsigned long image_addr, 156 char *cmdline_ptr) 157 { 158 struct sysfb_display_info *dpy; 159 efi_status_t status; 160 161 status = check_platform_features(); 162 if (status != EFI_SUCCESS) 163 return status; 164 165 dpy = setup_primary_display(); 166 167 efi_retrieve_eventlog(); 168 169 /* Ask the firmware to clear memory on unclean shutdown */ 170 efi_enable_reset_attack_mitigation(); 171 172 efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr), 173 NULL); 174 175 efi_random_get_seed(); 176 177 /* force efi_novamap if SetVirtualAddressMap() is unsupported */ 178 efi_novamap |= !(get_supported_rt_services() & 179 EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP); 180 181 install_memreserve_table(); 182 183 status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr); 184 185 free_primary_display(dpy); 186 187 return status; 188 } 189 190 /* 191 * efi_allocate_virtmap() - create a pool allocation for the virtmap 192 * 193 * Create an allocation that is of sufficient size to hold all the memory 194 * descriptors that will be passed to SetVirtualAddressMap() to inform the 195 * firmware about the virtual mapping that will be used under the OS to call 196 * into the firmware. 197 */ 198 efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap, 199 unsigned long *desc_size, u32 *desc_ver) 200 { 201 unsigned long size, mmap_key; 202 efi_status_t status; 203 204 /* 205 * Use the size of the current memory map as an upper bound for the 206 * size of the buffer we need to pass to SetVirtualAddressMap() to 207 * cover all EFI_MEMORY_RUNTIME regions. 208 */ 209 size = 0; 210 status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size, 211 desc_ver); 212 if (status != EFI_BUFFER_TOO_SMALL) 213 return EFI_LOAD_ERROR; 214 215 return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, 216 (void **)virtmap); 217 } 218 219 /* 220 * efi_get_virtmap() - create a virtual mapping for the EFI memory map 221 * 222 * This function populates the virt_addr fields of all memory region descriptors 223 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors 224 * are also copied to @runtime_map, and their total count is returned in @count. 225 */ 226 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, 227 unsigned long desc_size, efi_memory_desc_t *runtime_map, 228 int *count) 229 { 230 u64 efi_virt_base = virtmap_base; 231 efi_memory_desc_t *in, *out = runtime_map; 232 int l; 233 234 *count = 0; 235 236 for (l = 0; l < map_size; l += desc_size) { 237 u64 paddr, size; 238 239 in = (void *)memory_map + l; 240 if (!(in->attribute & EFI_MEMORY_RUNTIME)) 241 continue; 242 243 paddr = in->phys_addr; 244 size = in->num_pages * EFI_PAGE_SIZE; 245 246 in->virt_addr = in->phys_addr + EFI_RT_VIRTUAL_OFFSET; 247 if (efi_novamap) { 248 continue; 249 } 250 251 /* 252 * Make the mapping compatible with 64k pages: this allows 253 * a 4k page size kernel to kexec a 64k page size kernel and 254 * vice versa. 255 */ 256 if (!flat_va_mapping) { 257 258 paddr = round_down(in->phys_addr, SZ_64K); 259 size += in->phys_addr - paddr; 260 261 /* 262 * Avoid wasting memory on PTEs by choosing a virtual 263 * base that is compatible with section mappings if this 264 * region has the appropriate size and physical 265 * alignment. (Sections are 2 MB on 4k granule kernels) 266 */ 267 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) 268 efi_virt_base = round_up(efi_virt_base, SZ_2M); 269 else 270 efi_virt_base = round_up(efi_virt_base, SZ_64K); 271 272 in->virt_addr += efi_virt_base - paddr; 273 efi_virt_base += size; 274 } 275 276 memcpy(out, in, desc_size); 277 out = (void *)out + desc_size; 278 ++*count; 279 } 280 } 281