drivers/firmware/efi/libstub/fdt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * FDT related Helper functions used by the EFI stub on multiple
   4  * architectures. This should be #included by the EFI stub
   5  * implementation files.
   6  *
   7  * Copyright 2013 Linaro Limited; author Roy Franz
   8  */
   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 2
  17 #define EFI_DT_SIZE_CELLS_DEFAULT 2
  18
  19 static 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
  30 static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,
  31                                void *fdt, int new_fdt_size, char *cmdline_ptr,
  32                                u64 initrd_addr, u64 initrd_size)
  33 {
  34         int node, num_rsv;
  35         int status;
  36         u32 fdt_val32;
  37         u64 fdt_val64;
  38
  39         /* Do some checks on provided FDT, if it exists: */
  40         if (orig_fdt) {
  41                 if (fdt_check_header(orig_fdt)) {
  42                         pr_efi_err("Device Tree header not valid!\n");
  43                         return EFI_LOAD_ERROR;
  44                 }
  45                 /*
  46                  * We don't get the size of the FDT if we get if from a
  47                  * configuration table:
  48                  */
  49                 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
  50                         pr_efi_err("Truncated device tree! foo!\n");
  51                         return EFI_LOAD_ERROR;
  52                 }
  53         }
  54
  55         if (orig_fdt) {
  56                 status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
  57         } else {
  58                 status = fdt_create_empty_tree(fdt, new_fdt_size);
  59                 if (status == 0) {
  60                         /*
  61                          * Any failure from the following function is
  62                          * non-critical:
  63                          */
  64                         fdt_update_cell_size(fdt);
  65                 }
  66         }
  67
  68         if (status != 0)
  69                 goto fdt_set_fail;
  70
  71         /*
  72          * Delete all memory reserve map entries. When booting via UEFI,
  73          * kernel will use the UEFI memory map to find reserved regions.
  74          */
  75         num_rsv = fdt_num_mem_rsv(fdt);
  76         while (num_rsv-- > 0)
  77                 fdt_del_mem_rsv(fdt, num_rsv);
  78
  79         node = fdt_subnode_offset(fdt, 0, "chosen");
  80         if (node < 0) {
  81                 node = fdt_add_subnode(fdt, 0, "chosen");
  82                 if (node < 0) {
  83                         /* 'node' is an error code when negative: */
  84                         status = node;
  85                         goto fdt_set_fail;
  86                 }
  87         }
  88
  89         if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) {
  90                 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
  91                                      strlen(cmdline_ptr) + 1);
  92                 if (status)
  93                         goto fdt_set_fail;
  94         }
  95
  96         /* Set initrd address/end in device tree, if present */
  97         if (initrd_size != 0) {
  98                 u64 initrd_image_end;
  99                 u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
 100
 101                 status = fdt_setprop_var(fdt, node, "linux,initrd-start", initrd_image_start);
 102                 if (status)
 103                         goto fdt_set_fail;
 104
 105                 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
 106                 status = fdt_setprop_var(fdt, node, "linux,initrd-end", initrd_image_end);
 107                 if (status)
 108                         goto fdt_set_fail;
 109         }
 110
 111         /* Add FDT entries for EFI runtime services in chosen node. */
 112         node = fdt_subnode_offset(fdt, 0, "chosen");
 113         fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table());
 114
 115         status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64);
 116         if (status)
 117                 goto fdt_set_fail;
 118
 119         fdt_val64 = U64_MAX; /* placeholder */
 120
 121         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
 122         if (status)
 123                 goto fdt_set_fail;
 124
 125         fdt_val32 = U32_MAX; /* placeholder */
 126
 127         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
 128         if (status)
 129                 goto fdt_set_fail;
 130
 131         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
 132         if (status)
 133                 goto fdt_set_fail;
 134
 135         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
 136         if (status)
 137                 goto fdt_set_fail;
 138
 139         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 140                 efi_status_t efi_status;
 141
 142                 efi_status = efi_get_random_bytes(sizeof(fdt_val64),
 143                                                   (u8 *)&fdt_val64);
 144                 if (efi_status == EFI_SUCCESS) {
 145                         status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);
 146                         if (status)
 147                                 goto fdt_set_fail;
 148                 } else if (efi_status != EFI_NOT_FOUND) {
 149                         return efi_status;
 150                 }
 151         }
 152
 153         /* Shrink the FDT back to its minimum size: */
 154         fdt_pack(fdt);
 155
 156         return EFI_SUCCESS;
 157
 158 fdt_set_fail:
 159         if (status == -FDT_ERR_NOSPACE)
 160                 return EFI_BUFFER_TOO_SMALL;
 161
 162         return EFI_LOAD_ERROR;
 163 }
 164
 165 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
 166 {
 167         int node = fdt_path_offset(fdt, "/chosen");
 168         u64 fdt_val64;
 169         u32 fdt_val32;
 170         int err;
 171
 172         if (node < 0)
 173                 return EFI_LOAD_ERROR;
 174
 175         fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
 176
 177         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
 178         if (err)
 179                 return EFI_LOAD_ERROR;
 180
 181         fdt_val32 = cpu_to_fdt32(*map->map_size);
 182
 183         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
 184         if (err)
 185                 return EFI_LOAD_ERROR;
 186
 187         fdt_val32 = cpu_to_fdt32(*map->desc_size);
 188
 189         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
 190         if (err)
 191                 return EFI_LOAD_ERROR;
 192
 193         fdt_val32 = cpu_to_fdt32(*map->desc_ver);
 194
 195         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
 196         if (err)
 197                 return EFI_LOAD_ERROR;
 198
 199         return EFI_SUCCESS;
 200 }
 201
 202 struct exit_boot_struct {
 203         efi_memory_desc_t       *runtime_map;
 204         int                     *runtime_entry_count;
 205         void                    *new_fdt_addr;
 206 };
 207
 208 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 209                                    void *priv)
 210 {
 211         struct exit_boot_struct *p = priv;
 212         /*
 213          * Update the memory map with virtual addresses. The function will also
 214          * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
 215          * entries so that we can pass it straight to SetVirtualAddressMap()
 216          */
 217         efi_get_virtmap(*map->map, *map->map_size, *map->desc_size,
 218                         p->runtime_map, p->runtime_entry_count);
 219
 220         return update_fdt_memmap(p->new_fdt_addr, map);
 221 }
 222
 223 #ifndef MAX_FDT_SIZE
 224 # define MAX_FDT_SIZE SZ_2M
 225 #endif
 226
 227 /*
 228  * Allocate memory for a new FDT, then add EFI, commandline, and
 229  * initrd related fields to the FDT.  This routine increases the
 230  * FDT allocation size until the allocated memory is large
 231  * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
 232  * which are fixed at 4K bytes, so in most cases the first
 233  * allocation should succeed.
 234  * EFI boot services are exited at the end of this function.
 235  * There must be no allocations between the get_memory_map()
 236  * call and the exit_boot_services() call, so the exiting of
 237  * boot services is very tightly tied to the creation of the FDT
 238  * with the final memory map in it.
 239  */
 240
 241 efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
 242                                             unsigned long *new_fdt_addr,
 243                                             unsigned long max_addr,
 244                                             u64 initrd_addr, u64 initrd_size,
 245                                             char *cmdline_ptr,
 246                                             unsigned long fdt_addr,
 247                                             unsigned long fdt_size)
 248 {
 249         unsigned long map_size, desc_size, buff_size;
 250         u32 desc_ver;
 251         unsigned long mmap_key;
 252         efi_memory_desc_t *memory_map, *runtime_map;
 253         efi_status_t status;
 254         int runtime_entry_count;
 255         struct efi_boot_memmap map;
 256         struct exit_boot_struct priv;
 257
 258         map.map         = &runtime_map;
 259         map.map_size    = &map_size;
 260         map.desc_size   = &desc_size;
 261         map.desc_ver    = &desc_ver;
 262         map.key_ptr     = &mmap_key;
 263         map.buff_size   = &buff_size;
 264
 265         /*
 266          * Get a copy of the current memory map that we will use to prepare
 267          * the input for SetVirtualAddressMap(). We don't have to worry about
 268          * subsequent allocations adding entries, since they could not affect
 269          * the number of EFI_MEMORY_RUNTIME regions.
 270          */
 271         status = efi_get_memory_map(&map);
 272         if (status != EFI_SUCCESS) {
 273                 pr_efi_err("Unable to retrieve UEFI memory map.\n");
 274                 return status;
 275         }
 276
 277         pr_efi("Exiting boot services and installing virtual address map...\n");
 278
 279         map.map = &memory_map;
 280         status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, max_addr);
 281         if (status != EFI_SUCCESS) {
 282                 pr_efi_err("Unable to allocate memory for new device tree.\n");
 283                 goto fail;
 284         }
 285
 286         /*
 287          * Now that we have done our final memory allocation (and free)
 288          * we can get the memory map key needed for exit_boot_services().
 289          */
 290         status = efi_get_memory_map(&map);
 291         if (status != EFI_SUCCESS)
 292                 goto fail_free_new_fdt;
 293
 294         status = update_fdt((void *)fdt_addr, fdt_size,
 295                             (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,
 296                             initrd_addr, initrd_size);
 297
 298         if (status != EFI_SUCCESS) {
 299                 pr_efi_err("Unable to construct new device tree.\n");
 300                 goto fail_free_new_fdt;
 301         }
 302
 303         runtime_entry_count             = 0;
 304         priv.runtime_map                = runtime_map;
 305         priv.runtime_entry_count        = &runtime_entry_count;
 306         priv.new_fdt_addr               = (void *)*new_fdt_addr;
 307
 308         status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
 309
 310         if (status == EFI_SUCCESS) {
 311                 efi_set_virtual_address_map_t *svam;
 312
 313                 if (novamap())
 314                         return EFI_SUCCESS;
 315
 316                 /* Install the new virtual address map */
 317                 svam = efi_system_table()->runtime->set_virtual_address_map;
 318                 status = svam(runtime_entry_count * desc_size, desc_size,
 319                               desc_ver, runtime_map);
 320
 321                 /*
 322                  * We are beyond the point of no return here, so if the call to
 323                  * SetVirtualAddressMap() failed, we need to signal that to the
 324                  * incoming kernel but proceed normally otherwise.
 325                  */
 326                 if (status != EFI_SUCCESS) {
 327                         int l;
 328
 329                         /*
 330                          * Set the virtual address field of all
 331                          * EFI_MEMORY_RUNTIME entries to 0. This will signal
 332                          * the incoming kernel that no virtual translation has
 333                          * been installed.
 334                          */
 335                         for (l = 0; l < map_size; l += desc_size) {
 336                                 efi_memory_desc_t *p = (void *)memory_map + l;
 337
 338                                 if (p->attribute & EFI_MEMORY_RUNTIME)
 339                                         p->virt_addr = 0;
 340                         }
 341                 }
 342                 return EFI_SUCCESS;
 343         }
 344
 345         pr_efi_err("Exit boot services failed.\n");
 346
 347 fail_free_new_fdt:
 348         efi_free(MAX_FDT_SIZE, *new_fdt_addr);
 349
 350 fail:
 351         efi_system_table()->boottime->free_pool(runtime_map);
 352
 353         return EFI_LOAD_ERROR;
 354 }
 355
 356 void *get_fdt(unsigned long *fdt_size)
 357 {
 358         void *fdt;
 359
 360         fdt = get_efi_config_table(DEVICE_TREE_GUID);
 361
 362         if (!fdt)
 363                 return NULL;
 364
 365         if (fdt_check_header(fdt) != 0) {
 366                 pr_efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n");
 367                 return NULL;
 368         }
 369         *fdt_size = fdt_totalsize(fdt);
 370         return fdt;
 371 }