drivers/firmware/efi/libstub/fdt.c

   1 /*
   2  * FDT related Helper functions used by the EFI stub on multiple
   3  * architectures. This should be #included by the EFI stub
   4  * implementation files.
   5  *
   6  * Copyright 2013 Linaro Limited; author Roy Franz
   7  *
   8  * This file is part of the Linux kernel, and is made available
   9  * under the terms of the GNU General Public License version 2.
  10  *
  11  */
  12
  13 #include <linux/efi.h>
  14 #include <linux/libfdt.h>
  15 #include <asm/efi.h>
  16
  17 #include "efistub.h"
  18
  19 #define EFI_DT_ADDR_CELLS_DEFAULT 2
  20 #define EFI_DT_SIZE_CELLS_DEFAULT 2
  21
  22 static void fdt_update_cell_size(efi_system_table_t *sys_table, void *fdt)
  23 {
  24         int offset;
  25
  26         offset = fdt_path_offset(fdt, "/");
  27         /* Set the #address-cells and #size-cells values for an empty tree */
  28
  29         fdt_setprop_u32(fdt, offset, "#address-cells",
  30                         EFI_DT_ADDR_CELLS_DEFAULT);
  31
  32         fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT);
  33 }
  34
  35 static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
  36                                unsigned long orig_fdt_size,
  37                                void *fdt, int new_fdt_size, char *cmdline_ptr,
  38                                u64 initrd_addr, u64 initrd_size)
  39 {
  40         int node, num_rsv;
  41         int status;
  42         u32 fdt_val32;
  43         u64 fdt_val64;
  44
  45         /* Do some checks on provided FDT, if it exists*/
  46         if (orig_fdt) {
  47                 if (fdt_check_header(orig_fdt)) {
  48                         pr_efi_err(sys_table, "Device Tree header not valid!\n");
  49                         return EFI_LOAD_ERROR;
  50                 }
  51                 /*
  52                  * We don't get the size of the FDT if we get if from a
  53                  * configuration table.
  54                  */
  55                 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
  56                         pr_efi_err(sys_table, "Truncated device tree! foo!\n");
  57                         return EFI_LOAD_ERROR;
  58                 }
  59         }
  60
  61         if (orig_fdt) {
  62                 status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
  63         } else {
  64                 status = fdt_create_empty_tree(fdt, new_fdt_size);
  65                 if (status == 0) {
  66                         /*
  67                          * Any failure from the following function is non
  68                          * critical
  69                          */
  70                         fdt_update_cell_size(sys_table, fdt);
  71                 }
  72         }
  73
  74         if (status != 0)
  75                 goto fdt_set_fail;
  76
  77         /*
  78          * Delete all memory reserve map entries. When booting via UEFI,
  79          * kernel will use the UEFI memory map to find reserved regions.
  80          */
  81         num_rsv = fdt_num_mem_rsv(fdt);
  82         while (num_rsv-- > 0)
  83                 fdt_del_mem_rsv(fdt, num_rsv);
  84
  85         node = fdt_subnode_offset(fdt, 0, "chosen");
  86         if (node < 0) {
  87                 node = fdt_add_subnode(fdt, 0, "chosen");
  88                 if (node < 0) {
  89                         status = node; /* node is error code when negative */
  90                         goto fdt_set_fail;
  91                 }
  92         }
  93
  94         if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
  95                 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
  96                                      strlen(cmdline_ptr) + 1);
  97                 if (status)
  98                         goto fdt_set_fail;
  99         }
 100
 101         /* Set initrd address/end in device tree, if present */
 102         if (initrd_size != 0) {
 103                 u64 initrd_image_end;
 104                 u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
 105
 106                 status = fdt_setprop(fdt, node, "linux,initrd-start",
 107                                      &initrd_image_start, sizeof(u64));
 108                 if (status)
 109                         goto fdt_set_fail;
 110                 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
 111                 status = fdt_setprop(fdt, node, "linux,initrd-end",
 112                                      &initrd_image_end, sizeof(u64));
 113                 if (status)
 114                         goto fdt_set_fail;
 115         }
 116
 117         /* Add FDT entries for EFI runtime services in chosen node. */
 118         node = fdt_subnode_offset(fdt, 0, "chosen");
 119         fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
 120         status = fdt_setprop(fdt, node, "linux,uefi-system-table",
 121                              &fdt_val64, sizeof(fdt_val64));
 122         if (status)
 123                 goto fdt_set_fail;
 124
 125         fdt_val64 = U64_MAX; /* placeholder */
 126         status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
 127                              &fdt_val64,  sizeof(fdt_val64));
 128         if (status)
 129                 goto fdt_set_fail;
 130
 131         fdt_val32 = U32_MAX; /* placeholder */
 132         status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
 133                              &fdt_val32,  sizeof(fdt_val32));
 134         if (status)
 135                 goto fdt_set_fail;
 136
 137         status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
 138                              &fdt_val32, sizeof(fdt_val32));
 139         if (status)
 140                 goto fdt_set_fail;
 141
 142         status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
 143                              &fdt_val32, sizeof(fdt_val32));
 144         if (status)
 145                 goto fdt_set_fail;
 146
 147         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 148                 efi_status_t efi_status;
 149
 150                 efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64),
 151                                                   (u8 *)&fdt_val64);
 152                 if (efi_status == EFI_SUCCESS) {
 153                         status = fdt_setprop(fdt, node, "kaslr-seed",
 154                                              &fdt_val64, sizeof(fdt_val64));
 155                         if (status)
 156                                 goto fdt_set_fail;
 157                 } else if (efi_status != EFI_NOT_FOUND) {
 158                         return efi_status;
 159                 }
 160         }
 161
 162         /* shrink the FDT back to its minimum size */
 163         fdt_pack(fdt);
 164
 165         return EFI_SUCCESS;
 166
 167 fdt_set_fail:
 168         if (status == -FDT_ERR_NOSPACE)
 169                 return EFI_BUFFER_TOO_SMALL;
 170
 171         return EFI_LOAD_ERROR;
 172 }
 173
 174 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
 175 {
 176         int node = fdt_path_offset(fdt, "/chosen");
 177         u64 fdt_val64;
 178         u32 fdt_val32;
 179         int err;
 180
 181         if (node < 0)
 182                 return EFI_LOAD_ERROR;
 183
 184         fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
 185         err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
 186                                   &fdt_val64, sizeof(fdt_val64));
 187         if (err)
 188                 return EFI_LOAD_ERROR;
 189
 190         fdt_val32 = cpu_to_fdt32(*map->map_size);
 191         err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
 192                                   &fdt_val32, sizeof(fdt_val32));
 193         if (err)
 194                 return EFI_LOAD_ERROR;
 195
 196         fdt_val32 = cpu_to_fdt32(*map->desc_size);
 197         err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-size",
 198                                   &fdt_val32, sizeof(fdt_val32));
 199         if (err)
 200                 return EFI_LOAD_ERROR;
 201
 202         fdt_val32 = cpu_to_fdt32(*map->desc_ver);
 203         err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-ver",
 204                                   &fdt_val32, sizeof(fdt_val32));
 205         if (err)
 206                 return EFI_LOAD_ERROR;
 207
 208         return EFI_SUCCESS;
 209 }
 210
 211 #ifndef EFI_FDT_ALIGN
 212 #define EFI_FDT_ALIGN EFI_PAGE_SIZE
 213 #endif
 214
 215 struct exit_boot_struct {
 216         efi_memory_desc_t *runtime_map;
 217         int *runtime_entry_count;
 218         void *new_fdt_addr;
 219 };
 220
 221 static efi_status_t exit_boot_func(efi_system_table_t *sys_table_arg,
 222                                    struct efi_boot_memmap *map,
 223                                    void *priv)
 224 {
 225         struct exit_boot_struct *p = priv;
 226         /*
 227          * Update the memory map with virtual addresses. The function will also
 228          * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
 229          * entries so that we can pass it straight to SetVirtualAddressMap()
 230          */
 231         efi_get_virtmap(*map->map, *map->map_size, *map->desc_size,
 232                         p->runtime_map, p->runtime_entry_count);
 233
 234         return update_fdt_memmap(p->new_fdt_addr, map);
 235 }
 236
 237 #ifndef MAX_FDT_SIZE
 238 #define MAX_FDT_SIZE    SZ_2M
 239 #endif
 240
 241 /*
 242  * Allocate memory for a new FDT, then add EFI, commandline, and
 243  * initrd related fields to the FDT.  This routine increases the
 244  * FDT allocation size until the allocated memory is large
 245  * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
 246  * which are fixed at 4K bytes, so in most cases the first
 247  * allocation should succeed.
 248  * EFI boot services are exited at the end of this function.
 249  * There must be no allocations between the get_memory_map()
 250  * call and the exit_boot_services() call, so the exiting of
 251  * boot services is very tightly tied to the creation of the FDT
 252  * with the final memory map in it.
 253  */
 254
 255 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
 256                                             void *handle,
 257                                             unsigned long *new_fdt_addr,
 258                                             unsigned long max_addr,
 259                                             u64 initrd_addr, u64 initrd_size,
 260                                             char *cmdline_ptr,
 261                                             unsigned long fdt_addr,
 262                                             unsigned long fdt_size)
 263 {
 264         unsigned long map_size, desc_size, buff_size;
 265         u32 desc_ver;
 266         unsigned long mmap_key;
 267         efi_memory_desc_t *memory_map, *runtime_map;
 268         efi_status_t status;
 269         int runtime_entry_count = 0;
 270         struct efi_boot_memmap map;
 271         struct exit_boot_struct priv;
 272
 273         map.map =       &runtime_map;
 274         map.map_size =  &map_size;
 275         map.desc_size = &desc_size;
 276         map.desc_ver =  &desc_ver;
 277         map.key_ptr =   &mmap_key;
 278         map.buff_size = &buff_size;
 279
 280         /*
 281          * Get a copy of the current memory map that we will use to prepare
 282          * the input for SetVirtualAddressMap(). We don't have to worry about
 283          * subsequent allocations adding entries, since they could not affect
 284          * the number of EFI_MEMORY_RUNTIME regions.
 285          */
 286         status = efi_get_memory_map(sys_table, &map);
 287         if (status != EFI_SUCCESS) {
 288                 pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
 289                 return status;
 290         }
 291
 292         pr_efi(sys_table,
 293                "Exiting boot services and installing virtual address map...\n");
 294
 295         map.map = &memory_map;
 296         status = efi_high_alloc(sys_table, MAX_FDT_SIZE, EFI_FDT_ALIGN,
 297                                 new_fdt_addr, max_addr);
 298         if (status != EFI_SUCCESS) {
 299                 pr_efi_err(sys_table,
 300                            "Unable to allocate memory for new device tree.\n");
 301                 goto fail;
 302         }
 303
 304         /*
 305          * Now that we have done our final memory allocation (and free)
 306          * we can get the memory map key needed for exit_boot_services().
 307          */
 308         status = efi_get_memory_map(sys_table, &map);
 309         if (status != EFI_SUCCESS)
 310                 goto fail_free_new_fdt;
 311
 312         status = update_fdt(sys_table, (void *)fdt_addr, fdt_size,
 313                             (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,
 314                             initrd_addr, initrd_size);
 315
 316         if (status != EFI_SUCCESS) {
 317                 pr_efi_err(sys_table, "Unable to construct new device tree.\n");
 318                 goto fail_free_new_fdt;
 319         }
 320
 321         priv.runtime_map = runtime_map;
 322         priv.runtime_entry_count = &runtime_entry_count;
 323         priv.new_fdt_addr = (void *)*new_fdt_addr;
 324         status = efi_exit_boot_services(sys_table, handle, &map, &priv,
 325                                         exit_boot_func);
 326
 327         if (status == EFI_SUCCESS) {
 328                 efi_set_virtual_address_map_t *svam;
 329
 330                 /* Install the new virtual address map */
 331                 svam = sys_table->runtime->set_virtual_address_map;
 332                 status = svam(runtime_entry_count * desc_size, desc_size,
 333                               desc_ver, runtime_map);
 334
 335                 /*
 336                  * We are beyond the point of no return here, so if the call to
 337                  * SetVirtualAddressMap() failed, we need to signal that to the
 338                  * incoming kernel but proceed normally otherwise.
 339                  */
 340                 if (status != EFI_SUCCESS) {
 341                         int l;
 342
 343                         /*
 344                          * Set the virtual address field of all
 345                          * EFI_MEMORY_RUNTIME entries to 0. This will signal
 346                          * the incoming kernel that no virtual translation has
 347                          * been installed.
 348                          */
 349                         for (l = 0; l < map_size; l += desc_size) {
 350                                 efi_memory_desc_t *p = (void *)memory_map + l;
 351
 352                                 if (p->attribute & EFI_MEMORY_RUNTIME)
 353                                         p->virt_addr = 0;
 354                         }
 355                 }
 356                 return EFI_SUCCESS;
 357         }
 358
 359         pr_efi_err(sys_table, "Exit boot services failed.\n");
 360
 361 fail_free_new_fdt:
 362         efi_free(sys_table, MAX_FDT_SIZE, *new_fdt_addr);
 363
 364 fail:
 365         sys_table->boottime->free_pool(runtime_map);
 366         return EFI_LOAD_ERROR;
 367 }
 368
 369 void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
 370 {
 371         efi_guid_t fdt_guid = DEVICE_TREE_GUID;
 372         efi_config_table_t *tables;
 373         void *fdt;
 374         int i;
 375
 376         tables = (efi_config_table_t *) sys_table->tables;
 377         fdt = NULL;
 378
 379         for (i = 0; i < sys_table->nr_tables; i++)
 380                 if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
 381                         fdt = (void *) tables[i].table;
 382                         if (fdt_check_header(fdt) != 0) {
 383                                 pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
 384                                 return NULL;
 385                         }
 386                         *fdt_size = fdt_totalsize(fdt);
 387                         break;
 388          }
 389
 390         return fdt;
 391 }