root/drivers/firmware/efi/libstub/fdt.c

DEFINITIONS

1. fdt_update_cell_size
2. update_fdt
3. update_fdt_memmap
4. exit_boot_func
5. allocate_new_fdt_and_exit_boot
6. get_fdt

   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(efi_system_table_t *sys_table, 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(efi_system_table_t *sys_table, void *orig_fdt,
  31                                unsigned long orig_fdt_size,
  32                                void *fdt, int new_fdt_size, char *cmdline_ptr,
  33                                u64 initrd_addr, u64 initrd_size)
  34 {
  35         int node, num_rsv;
  36         int status;
  37         u32 fdt_val32;
  38         u64 fdt_val64;
  39 
  40         /* Do some checks on provided FDT, if it exists: */
  41         if (orig_fdt) {
  42                 if (fdt_check_header(orig_fdt)) {
  43                         pr_efi_err(sys_table, "Device Tree header not valid!\n");
  44                         return EFI_LOAD_ERROR;
  45                 }
  46                 /*
  47                  * We don't get the size of the FDT if we get if from a
  48                  * configuration table:
  49                  */
  50                 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
  51                         pr_efi_err(sys_table, "Truncated device tree! foo!\n");
  52                         return EFI_LOAD_ERROR;
  53                 }
  54         }
  55 
  56         if (orig_fdt) {
  57                 status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
  58         } else {
  59                 status = fdt_create_empty_tree(fdt, new_fdt_size);
  60                 if (status == 0) {
  61                         /*
  62                          * Any failure from the following function is
  63                          * non-critical:
  64                          */
  65                         fdt_update_cell_size(sys_table, fdt);
  66                 }
  67         }
  68 
  69         if (status != 0)
  70                 goto fdt_set_fail;
  71 
  72         /*
  73          * Delete all memory reserve map entries. When booting via UEFI,
  74          * kernel will use the UEFI memory map to find reserved regions.
  75          */
  76         num_rsv = fdt_num_mem_rsv(fdt);
  77         while (num_rsv-- > 0)
  78                 fdt_del_mem_rsv(fdt, num_rsv);
  79 
  80         node = fdt_subnode_offset(fdt, 0, "chosen");
  81         if (node < 0) {
  82                 node = fdt_add_subnode(fdt, 0, "chosen");
  83                 if (node < 0) {
  84                         /* 'node' is an error code when negative: */
  85                         status = node;
  86                         goto fdt_set_fail;
  87                 }
  88         }
  89 
  90         if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) {
  91                 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
  92                                      strlen(cmdline_ptr) + 1);
  93                 if (status)
  94                         goto fdt_set_fail;
  95         }
  96 
  97         /* Set initrd address/end in device tree, if present */
  98         if (initrd_size != 0) {
  99                 u64 initrd_image_end;
 100                 u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
 101 
 102                 status = fdt_setprop_var(fdt, node, "linux,initrd-start", initrd_image_start);
 103                 if (status)
 104                         goto fdt_set_fail;
 105 
 106                 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
 107                 status = fdt_setprop_var(fdt, node, "linux,initrd-end", initrd_image_end);
 108                 if (status)
 109                         goto fdt_set_fail;
 110         }
 111 
 112         /* Add FDT entries for EFI runtime services in chosen node. */
 113         node = fdt_subnode_offset(fdt, 0, "chosen");
 114         fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
 115 
 116         status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64);
 117         if (status)
 118                 goto fdt_set_fail;
 119 
 120         fdt_val64 = U64_MAX; /* placeholder */
 121 
 122         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
 123         if (status)
 124                 goto fdt_set_fail;
 125 
 126         fdt_val32 = U32_MAX; /* placeholder */
 127 
 128         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
 129         if (status)
 130                 goto fdt_set_fail;
 131 
 132         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
 133         if (status)
 134                 goto fdt_set_fail;
 135 
 136         status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
 137         if (status)
 138                 goto fdt_set_fail;
 139 
 140         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 141                 efi_status_t efi_status;
 142 
 143                 efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64),
 144                                                   (u8 *)&fdt_val64);
 145                 if (efi_status == EFI_SUCCESS) {
 146                         status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);
 147                         if (status)
 148                                 goto fdt_set_fail;
 149                 } else if (efi_status != EFI_NOT_FOUND) {
 150                         return efi_status;
 151                 }
 152         }
 153 
 154         /* Shrink the FDT back to its minimum size: */
 155         fdt_pack(fdt);
 156 
 157         return EFI_SUCCESS;
 158 
 159 fdt_set_fail:
 160         if (status == -FDT_ERR_NOSPACE)
 161                 return EFI_BUFFER_TOO_SMALL;
 162 
 163         return EFI_LOAD_ERROR;
 164 }
 165 
 166 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
 167 {
 168         int node = fdt_path_offset(fdt, "/chosen");
 169         u64 fdt_val64;
 170         u32 fdt_val32;
 171         int err;
 172 
 173         if (node < 0)
 174                 return EFI_LOAD_ERROR;
 175 
 176         fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
 177 
 178         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
 179         if (err)
 180                 return EFI_LOAD_ERROR;
 181 
 182         fdt_val32 = cpu_to_fdt32(*map->map_size);
 183 
 184         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
 185         if (err)
 186                 return EFI_LOAD_ERROR;
 187 
 188         fdt_val32 = cpu_to_fdt32(*map->desc_size);
 189 
 190         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
 191         if (err)
 192                 return EFI_LOAD_ERROR;
 193 
 194         fdt_val32 = cpu_to_fdt32(*map->desc_ver);
 195 
 196         err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
 197         if (err)
 198                 return EFI_LOAD_ERROR;
 199 
 200         return EFI_SUCCESS;
 201 }
 202 
 203 #ifndef EFI_FDT_ALIGN
 204 # define EFI_FDT_ALIGN EFI_PAGE_SIZE
 205 #endif
 206 
 207 struct exit_boot_struct {
 208         efi_memory_desc_t       *runtime_map;
 209         int                     *runtime_entry_count;
 210         void                    *new_fdt_addr;
 211 };
 212 
 213 static efi_status_t exit_boot_func(efi_system_table_t *sys_table_arg,
 214                                    struct efi_boot_memmap *map,
 215                                    void *priv)
 216 {
 217         struct exit_boot_struct *p = priv;
 218         /*
 219          * Update the memory map with virtual addresses. The function will also
 220          * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
 221          * entries so that we can pass it straight to SetVirtualAddressMap()
 222          */
 223         efi_get_virtmap(*map->map, *map->map_size, *map->desc_size,
 224                         p->runtime_map, p->runtime_entry_count);
 225 
 226         return update_fdt_memmap(p->new_fdt_addr, map);
 227 }
 228 
 229 #ifndef MAX_FDT_SIZE
 230 # define MAX_FDT_SIZE SZ_2M
 231 #endif
 232 
 233 /*
 234  * Allocate memory for a new FDT, then add EFI, commandline, and
 235  * initrd related fields to the FDT.  This routine increases the
 236  * FDT allocation size until the allocated memory is large
 237  * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
 238  * which are fixed at 4K bytes, so in most cases the first
 239  * allocation should succeed.
 240  * EFI boot services are exited at the end of this function.
 241  * There must be no allocations between the get_memory_map()
 242  * call and the exit_boot_services() call, so the exiting of
 243  * boot services is very tightly tied to the creation of the FDT
 244  * with the final memory map in it.
 245  */
 246 
 247 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
 248                                             void *handle,
 249                                             unsigned long *new_fdt_addr,
 250                                             unsigned long max_addr,
 251                                             u64 initrd_addr, u64 initrd_size,
 252                                             char *cmdline_ptr,
 253                                             unsigned long fdt_addr,
 254                                             unsigned long fdt_size)
 255 {
 256         unsigned long map_size, desc_size, buff_size;
 257         u32 desc_ver;
 258         unsigned long mmap_key;
 259         efi_memory_desc_t *memory_map, *runtime_map;
 260         efi_status_t status;
 261         int runtime_entry_count;
 262         struct efi_boot_memmap map;
 263         struct exit_boot_struct priv;
 264 
 265         map.map         = &runtime_map;
 266         map.map_size    = &map_size;
 267         map.desc_size   = &desc_size;
 268         map.desc_ver    = &desc_ver;
 269         map.key_ptr     = &mmap_key;
 270         map.buff_size   = &buff_size;
 271 
 272         /*
 273          * Get a copy of the current memory map that we will use to prepare
 274          * the input for SetVirtualAddressMap(). We don't have to worry about
 275          * subsequent allocations adding entries, since they could not affect
 276          * the number of EFI_MEMORY_RUNTIME regions.
 277          */
 278         status = efi_get_memory_map(sys_table, &map);
 279         if (status != EFI_SUCCESS) {
 280                 pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
 281                 return status;
 282         }
 283 
 284         pr_efi(sys_table, "Exiting boot services and installing virtual address map...\n");
 285 
 286         map.map = &memory_map;
 287         status = efi_high_alloc(sys_table, MAX_FDT_SIZE, EFI_FDT_ALIGN,
 288                                 new_fdt_addr, max_addr);
 289         if (status != EFI_SUCCESS) {
 290                 pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
 291                 goto fail;
 292         }
 293 
 294         /*
 295          * Now that we have done our final memory allocation (and free)
 296          * we can get the memory map key needed for exit_boot_services().
 297          */
 298         status = efi_get_memory_map(sys_table, &map);
 299         if (status != EFI_SUCCESS)
 300                 goto fail_free_new_fdt;
 301 
 302         status = update_fdt(sys_table, (void *)fdt_addr, fdt_size,
 303                             (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,
 304                             initrd_addr, initrd_size);
 305 
 306         if (status != EFI_SUCCESS) {
 307                 pr_efi_err(sys_table, "Unable to construct new device tree.\n");
 308                 goto fail_free_new_fdt;
 309         }
 310 
 311         runtime_entry_count             = 0;
 312         priv.runtime_map                = runtime_map;
 313         priv.runtime_entry_count        = &runtime_entry_count;
 314         priv.new_fdt_addr               = (void *)*new_fdt_addr;
 315 
 316         status = efi_exit_boot_services(sys_table, handle, &map, &priv, exit_boot_func);
 317 
 318         if (status == EFI_SUCCESS) {
 319                 efi_set_virtual_address_map_t *svam;
 320 
 321                 if (novamap())
 322                         return EFI_SUCCESS;
 323 
 324                 /* Install the new virtual address map */
 325                 svam = sys_table->runtime->set_virtual_address_map;
 326                 status = svam(runtime_entry_count * desc_size, desc_size,
 327                               desc_ver, runtime_map);
 328 
 329                 /*
 330                  * We are beyond the point of no return here, so if the call to
 331                  * SetVirtualAddressMap() failed, we need to signal that to the
 332                  * incoming kernel but proceed normally otherwise.
 333                  */
 334                 if (status != EFI_SUCCESS) {
 335                         int l;
 336 
 337                         /*
 338                          * Set the virtual address field of all
 339                          * EFI_MEMORY_RUNTIME entries to 0. This will signal
 340                          * the incoming kernel that no virtual translation has
 341                          * been installed.
 342                          */
 343                         for (l = 0; l < map_size; l += desc_size) {
 344                                 efi_memory_desc_t *p = (void *)memory_map + l;
 345 
 346                                 if (p->attribute & EFI_MEMORY_RUNTIME)
 347                                         p->virt_addr = 0;
 348                         }
 349                 }
 350                 return EFI_SUCCESS;
 351         }
 352 
 353         pr_efi_err(sys_table, "Exit boot services failed.\n");
 354 
 355 fail_free_new_fdt:
 356         efi_free(sys_table, MAX_FDT_SIZE, *new_fdt_addr);
 357 
 358 fail:
 359         sys_table->boottime->free_pool(runtime_map);
 360 
 361         return EFI_LOAD_ERROR;
 362 }
 363 
 364 void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
 365 {
 366         void *fdt;
 367 
 368         fdt = get_efi_config_table(sys_table, DEVICE_TREE_GUID);
 369 
 370         if (!fdt)
 371                 return NULL;
 372 
 373         if (fdt_check_header(fdt) != 0) {
 374                 pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
 375                 return NULL;
 376         }
 377         *fdt_size = fdt_totalsize(fdt);
 378         return fdt;
 379 }