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