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