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1// SPDX-License-Identifier: GPL-2.02/*3 * FDT related Helper functions used by the EFI stub on multiple4 * architectures. This should be #included by the EFI stub5 * implementation files.6 *7 * Copyright 2013 Linaro Limited; author Roy Franz8 */9 10#include <linux/efi.h>11#include <linux/libfdt.h>12#include <asm/efi.h>13 14#include "efistub.h"15 16#define EFI_DT_ADDR_CELLS_DEFAULT 217#define EFI_DT_SIZE_CELLS_DEFAULT 218 19static void fdt_update_cell_size(void *fdt)20{21 int offset;22 23 offset = fdt_path_offset(fdt, "/");24 /* Set the #address-cells and #size-cells values for an empty tree */25 26 fdt_setprop_u32(fdt, offset, "#address-cells", EFI_DT_ADDR_CELLS_DEFAULT);27 fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT);28}29 30static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,31 void *fdt, int new_fdt_size, char *cmdline_ptr)32{33 int node, num_rsv;34 int status;35 u32 fdt_val32;36 u64 fdt_val64;37 38 /* Do some checks on provided FDT, if it exists: */39 if (orig_fdt) {40 if (fdt_check_header(orig_fdt)) {41 efi_err("Device Tree header not valid!\n");42 return EFI_LOAD_ERROR;43 }44 /*45 * We don't get the size of the FDT if we get if from a46 * configuration table:47 */48 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {49 efi_err("Truncated device tree! foo!\n");50 return EFI_LOAD_ERROR;51 }52 }53 54 if (orig_fdt) {55 status = fdt_open_into(orig_fdt, fdt, new_fdt_size);56 } else {57 status = fdt_create_empty_tree(fdt, new_fdt_size);58 if (status == 0) {59 /*60 * Any failure from the following function is61 * non-critical:62 */63 fdt_update_cell_size(fdt);64 }65 }66 67 if (status != 0)68 goto fdt_set_fail;69 70 /*71 * Delete all memory reserve map entries. When booting via UEFI,72 * kernel will use the UEFI memory map to find reserved regions.73 */74 num_rsv = fdt_num_mem_rsv(fdt);75 while (num_rsv-- > 0)76 fdt_del_mem_rsv(fdt, num_rsv);77 78 node = fdt_subnode_offset(fdt, 0, "chosen");79 if (node < 0) {80 node = fdt_add_subnode(fdt, 0, "chosen");81 if (node < 0) {82 /* 'node' is an error code when negative: */83 status = node;84 goto fdt_set_fail;85 }86 }87 88 if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) {89 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,90 strlen(cmdline_ptr) + 1);91 if (status)92 goto fdt_set_fail;93 }94 95 /* Add FDT entries for EFI runtime services in chosen node. */96 node = fdt_subnode_offset(fdt, 0, "chosen");97 fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table);98 99 status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64);100 if (status)101 goto fdt_set_fail;102 103 fdt_val64 = U64_MAX; /* placeholder */104 105 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);106 if (status)107 goto fdt_set_fail;108 109 fdt_val32 = U32_MAX; /* placeholder */110 111 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);112 if (status)113 goto fdt_set_fail;114 115 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);116 if (status)117 goto fdt_set_fail;118 119 status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);120 if (status)121 goto fdt_set_fail;122 123 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {124 efi_status_t efi_status;125 126 efi_status = efi_get_random_bytes(sizeof(fdt_val64),127 (u8 *)&fdt_val64);128 if (efi_status == EFI_SUCCESS) {129 status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);130 if (status)131 goto fdt_set_fail;132 }133 }134 135 /* Shrink the FDT back to its minimum size: */136 fdt_pack(fdt);137 138 return EFI_SUCCESS;139 140fdt_set_fail:141 if (status == -FDT_ERR_NOSPACE)142 return EFI_BUFFER_TOO_SMALL;143 144 return EFI_LOAD_ERROR;145}146 147static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)148{149 int node = fdt_path_offset(fdt, "/chosen");150 u64 fdt_val64;151 u32 fdt_val32;152 int err;153 154 if (node < 0)155 return EFI_LOAD_ERROR;156 157 fdt_val64 = cpu_to_fdt64((unsigned long)map->map);158 159 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);160 if (err)161 return EFI_LOAD_ERROR;162 163 fdt_val32 = cpu_to_fdt32(map->map_size);164 165 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);166 if (err)167 return EFI_LOAD_ERROR;168 169 fdt_val32 = cpu_to_fdt32(map->desc_size);170 171 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);172 if (err)173 return EFI_LOAD_ERROR;174 175 fdt_val32 = cpu_to_fdt32(map->desc_ver);176 177 err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);178 if (err)179 return EFI_LOAD_ERROR;180 181 return EFI_SUCCESS;182}183 184struct exit_boot_struct {185 struct efi_boot_memmap *boot_memmap;186 efi_memory_desc_t *runtime_map;187 int runtime_entry_count;188 void *new_fdt_addr;189};190 191static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)192{193 struct exit_boot_struct *p = priv;194 195 p->boot_memmap = map;196 197 /*198 * Update the memory map with virtual addresses. The function will also199 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME200 * entries so that we can pass it straight to SetVirtualAddressMap()201 */202 efi_get_virtmap(map->map, map->map_size, map->desc_size,203 p->runtime_map, &p->runtime_entry_count);204 205 return update_fdt_memmap(p->new_fdt_addr, map);206}207 208#ifndef MAX_FDT_SIZE209# define MAX_FDT_SIZE SZ_2M210#endif211 212/*213 * Allocate memory for a new FDT, then add EFI and commandline related fields214 * to the FDT. This routine increases the FDT allocation size until the215 * allocated memory is large enough. EFI allocations are in EFI_PAGE_SIZE216 * granules, which are fixed at 4K bytes, so in most cases the first allocation217 * should succeed. EFI boot services are exited at the end of this function.218 * There must be no allocations between the get_memory_map() call and the219 * exit_boot_services() call, so the exiting of boot services is very tightly220 * tied to the creation of the FDT with the final memory map in it.221 */222static223efi_status_t allocate_new_fdt_and_exit_boot(void *handle,224 efi_loaded_image_t *image,225 unsigned long *new_fdt_addr,226 char *cmdline_ptr)227{228 unsigned long desc_size;229 u32 desc_ver;230 efi_status_t status;231 struct exit_boot_struct priv;232 unsigned long fdt_addr = 0;233 unsigned long fdt_size = 0;234 235 if (!efi_novamap) {236 status = efi_alloc_virtmap(&priv.runtime_map, &desc_size,237 &desc_ver);238 if (status != EFI_SUCCESS) {239 efi_err("Unable to retrieve UEFI memory map.\n");240 return status;241 }242 }243 244 /*245 * Unauthenticated device tree data is a security hazard, so ignore246 * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure247 * boot is enabled if we can't determine its state.248 */249 if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) ||250 efi_get_secureboot() != efi_secureboot_mode_disabled) {251 if (strstr(cmdline_ptr, "dtb="))252 efi_err("Ignoring DTB from command line.\n");253 } else {254 status = efi_load_dtb(image, &fdt_addr, &fdt_size);255 256 if (status != EFI_SUCCESS && status != EFI_NOT_READY) {257 efi_err("Failed to load device tree!\n");258 goto fail;259 }260 }261 262 if (fdt_addr) {263 efi_info("Using DTB from command line\n");264 } else {265 /* Look for a device tree configuration table entry. */266 fdt_addr = (uintptr_t)get_fdt(&fdt_size);267 if (fdt_addr)268 efi_info("Using DTB from configuration table\n");269 }270 271 if (!fdt_addr)272 efi_info("Generating empty DTB\n");273 274 efi_info("Exiting boot services...\n");275 276 status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX);277 if (status != EFI_SUCCESS) {278 efi_err("Unable to allocate memory for new device tree.\n");279 goto fail;280 }281 282 status = update_fdt((void *)fdt_addr, fdt_size,283 (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr);284 285 if (status != EFI_SUCCESS) {286 efi_err("Unable to construct new device tree.\n");287 goto fail_free_new_fdt;288 }289 290 priv.new_fdt_addr = (void *)*new_fdt_addr;291 292 status = efi_exit_boot_services(handle, &priv, exit_boot_func);293 294 if (status == EFI_SUCCESS) {295 efi_set_virtual_address_map_t *svam;296 297 if (efi_novamap)298 return EFI_SUCCESS;299 300 /* Install the new virtual address map */301 svam = efi_system_table->runtime->set_virtual_address_map;302 status = svam(priv.runtime_entry_count * desc_size, desc_size,303 desc_ver, priv.runtime_map);304 305 /*306 * We are beyond the point of no return here, so if the call to307 * SetVirtualAddressMap() failed, we need to signal that to the308 * incoming kernel but proceed normally otherwise.309 */310 if (status != EFI_SUCCESS) {311 efi_memory_desc_t *p;312 int l;313 314 /*315 * Set the virtual address field of all316 * EFI_MEMORY_RUNTIME entries to U64_MAX. This will317 * signal the incoming kernel that no virtual318 * translation has been installed.319 */320 for (l = 0; l < priv.boot_memmap->map_size;321 l += priv.boot_memmap->desc_size) {322 p = (void *)priv.boot_memmap->map + l;323 324 if (p->attribute & EFI_MEMORY_RUNTIME)325 p->virt_addr = U64_MAX;326 }327 }328 return EFI_SUCCESS;329 }330 331 efi_err("Exit boot services failed.\n");332 333fail_free_new_fdt:334 efi_free(MAX_FDT_SIZE, *new_fdt_addr);335 336fail:337 efi_free(fdt_size, fdt_addr);338 if (!efi_novamap)339 efi_bs_call(free_pool, priv.runtime_map);340 341 return EFI_LOAD_ERROR;342}343 344efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,345 unsigned long kernel_addr, char *cmdline_ptr)346{347 unsigned long fdt_addr;348 efi_status_t status;349 350 status = allocate_new_fdt_and_exit_boot(handle, image, &fdt_addr,351 cmdline_ptr);352 if (status != EFI_SUCCESS) {353 efi_err("Failed to update FDT and exit boot services\n");354 return status;355 }356 357 if (IS_ENABLED(CONFIG_ARM))358 efi_handle_post_ebs_state();359 360 efi_enter_kernel(kernel_addr, fdt_addr, fdt_totalsize((void *)fdt_addr));361 /* not reached */362}363 364void *get_fdt(unsigned long *fdt_size)365{366 void *fdt;367 368 fdt = get_efi_config_table(DEVICE_TREE_GUID);369 370 if (!fdt)371 return NULL;372 373 if (fdt_check_header(fdt) != 0) {374 efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n");375 return NULL;376 }377 *fdt_size = fdt_totalsize(fdt);378 return fdt;379}380