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1// SPDX-License-Identifier: GPL-2.0-only2/*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 Limited7 * Roy Franz <roy.franz@linaro.org8 * 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 ranges19 * for UEFI Runtime Services.20 *21 * For ARM/ARM64:22 * This is in the low TTBR0 range so that we can use23 * 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 purpose25 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can26 * 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 the29 * 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 used33 * EFI runtime virtual address for RISC-V. It also helps to use EFI runtime34 * services on both RV32/RV64. Keep the same runtime virtual address for RISC-V35 * as well to minimize the code churn.36 */37#define EFI_RT_VIRTUAL_BASE SZ_512M38 39/*40 * Some architectures map the EFI regions into the kernel's linear map using a41 * fixed offset.42 */43#ifndef EFI_RT_VIRTUAL_OFFSET44#define EFI_RT_VIRTUAL_OFFSET 045#endif46 47static u64 virtmap_base = EFI_RT_VIRTUAL_BASE;48static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0);49 50void __weak free_screen_info(struct screen_info *si)51{52}53 54static struct screen_info *setup_graphics(void)55{56 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;57 efi_status_t status;58 unsigned long size;59 void **gop_handle = NULL;60 struct screen_info *si = NULL;61 62 size = 0;63 status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,64 &gop_proto, NULL, &size, gop_handle);65 if (status == EFI_BUFFER_TOO_SMALL) {66 si = alloc_screen_info();67 if (!si)68 return NULL;69 status = efi_setup_gop(si, &gop_proto, size);70 if (status != EFI_SUCCESS) {71 free_screen_info(si);72 return NULL;73 }74 }75 return si;76}77 78static void install_memreserve_table(void)79{80 struct linux_efi_memreserve *rsv;81 efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID;82 efi_status_t status;83 84 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv),85 (void **)&rsv);86 if (status != EFI_SUCCESS) {87 efi_err("Failed to allocate memreserve entry!\n");88 return;89 }90 91 rsv->next = 0;92 rsv->size = 0;93 atomic_set(&rsv->count, 0);94 95 status = efi_bs_call(install_configuration_table,96 &memreserve_table_guid, rsv);97 if (status != EFI_SUCCESS)98 efi_err("Failed to install memreserve config table!\n");99}100 101static u32 get_supported_rt_services(void)102{103 const efi_rt_properties_table_t *rt_prop_table;104 u32 supported = EFI_RT_SUPPORTED_ALL;105 106 rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID);107 if (rt_prop_table)108 supported &= rt_prop_table->runtime_services_supported;109 110 return supported;111}112 113efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr)114{115 int cmdline_size = 0;116 efi_status_t status;117 char *cmdline;118 119 /*120 * Get the command line from EFI, using the LOADED_IMAGE121 * protocol. We are going to copy the command line into the122 * device tree, so this can be allocated anywhere.123 */124 cmdline = efi_convert_cmdline(image, &cmdline_size);125 if (!cmdline) {126 efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n");127 return EFI_OUT_OF_RESOURCES;128 }129 130 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||131 IS_ENABLED(CONFIG_CMDLINE_FORCE) ||132 cmdline_size == 0) {133 status = efi_parse_options(CONFIG_CMDLINE);134 if (status != EFI_SUCCESS) {135 efi_err("Failed to parse options\n");136 goto fail_free_cmdline;137 }138 }139 140 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) {141 status = efi_parse_options(cmdline);142 if (status != EFI_SUCCESS) {143 efi_err("Failed to parse options\n");144 goto fail_free_cmdline;145 }146 }147 148 *cmdline_ptr = cmdline;149 return EFI_SUCCESS;150 151fail_free_cmdline:152 efi_bs_call(free_pool, cmdline_ptr);153 return status;154}155 156efi_status_t efi_stub_common(efi_handle_t handle,157 efi_loaded_image_t *image,158 unsigned long image_addr,159 char *cmdline_ptr)160{161 struct screen_info *si;162 efi_status_t status;163 164 status = check_platform_features();165 if (status != EFI_SUCCESS)166 return status;167 168 si = setup_graphics();169 170 efi_retrieve_eventlog();171 172 /* Ask the firmware to clear memory on unclean shutdown */173 efi_enable_reset_attack_mitigation();174 175 efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr),176 NULL);177 178 efi_random_get_seed();179 180 /* force efi_novamap if SetVirtualAddressMap() is unsupported */181 efi_novamap |= !(get_supported_rt_services() &182 EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP);183 184 install_memreserve_table();185 186 status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr);187 188 free_screen_info(si);189 return status;190}191 192/*193 * efi_allocate_virtmap() - create a pool allocation for the virtmap194 *195 * Create an allocation that is of sufficient size to hold all the memory196 * descriptors that will be passed to SetVirtualAddressMap() to inform the197 * firmware about the virtual mapping that will be used under the OS to call198 * into the firmware.199 */200efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap,201 unsigned long *desc_size, u32 *desc_ver)202{203 unsigned long size, mmap_key;204 efi_status_t status;205 206 /*207 * Use the size of the current memory map as an upper bound for the208 * size of the buffer we need to pass to SetVirtualAddressMap() to209 * cover all EFI_MEMORY_RUNTIME regions.210 */211 size = 0;212 status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size,213 desc_ver);214 if (status != EFI_BUFFER_TOO_SMALL)215 return EFI_LOAD_ERROR;216 217 return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,218 (void **)virtmap);219}220 221/*222 * efi_get_virtmap() - create a virtual mapping for the EFI memory map223 *224 * This function populates the virt_addr fields of all memory region descriptors225 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors226 * are also copied to @runtime_map, and their total count is returned in @count.227 */228void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,229 unsigned long desc_size, efi_memory_desc_t *runtime_map,230 int *count)231{232 u64 efi_virt_base = virtmap_base;233 efi_memory_desc_t *in, *out = runtime_map;234 int l;235 236 *count = 0;237 238 for (l = 0; l < map_size; l += desc_size) {239 u64 paddr, size;240 241 in = (void *)memory_map + l;242 if (!(in->attribute & EFI_MEMORY_RUNTIME))243 continue;244 245 paddr = in->phys_addr;246 size = in->num_pages * EFI_PAGE_SIZE;247 248 in->virt_addr = in->phys_addr + EFI_RT_VIRTUAL_OFFSET;249 if (efi_novamap) {250 continue;251 }252 253 /*254 * Make the mapping compatible with 64k pages: this allows255 * a 4k page size kernel to kexec a 64k page size kernel and256 * vice versa.257 */258 if (!flat_va_mapping) {259 260 paddr = round_down(in->phys_addr, SZ_64K);261 size += in->phys_addr - paddr;262 263 /*264 * Avoid wasting memory on PTEs by choosing a virtual265 * base that is compatible with section mappings if this266 * region has the appropriate size and physical267 * alignment. (Sections are 2 MB on 4k granule kernels)268 */269 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)270 efi_virt_base = round_up(efi_virt_base, SZ_2M);271 else272 efi_virt_base = round_up(efi_virt_base, SZ_64K);273 274 in->virt_addr += efi_virt_base - paddr;275 efi_virt_base += size;276 }277 278 memcpy(out, in, desc_size);279 out = (void *)out + desc_size;280 ++*count;281 }282}283