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