drivers/firmware/efi/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 static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
  14                                unsigned long orig_fdt_size,
  15                                void *fdt, int new_fdt_size, char *cmdline_ptr,
  16                                u64 initrd_addr, u64 initrd_size,
  17                                efi_memory_desc_t *memory_map,
  18                                unsigned long map_size, unsigned long desc_size,
  19                                u32 desc_ver)
  20 {
  21         int node, prev;
  22         int status;
  23         u32 fdt_val32;
  24         u64 fdt_val64;
  25
  26         /* Do some checks on provided FDT, if it exists*/
  27         if (orig_fdt) {
  28                 if (fdt_check_header(orig_fdt)) {
  29                         pr_efi_err(sys_table, "Device Tree header not valid!\n");
  30                         return EFI_LOAD_ERROR;
  31                 }
  32                 /*
  33                  * We don't get the size of the FDT if we get if from a
  34                  * configuration table.
  35                  */
  36                 if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
  37                         pr_efi_err(sys_table, "Truncated device tree! foo!\n");
  38                         return EFI_LOAD_ERROR;
  39                 }
  40         }
  41
  42         if (orig_fdt)
  43                 status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
  44         else
  45                 status = fdt_create_empty_tree(fdt, new_fdt_size);
  46
  47         if (status != 0)
  48                 goto fdt_set_fail;
  49
  50         /*
  51          * Delete any memory nodes present. We must delete nodes which
  52          * early_init_dt_scan_memory may try to use.
  53          */
  54         prev = 0;
  55         for (;;) {
  56                 const char *type;
  57                 int len;
  58
  59                 node = fdt_next_node(fdt, prev, NULL);
  60                 if (node < 0)
  61                         break;
  62
  63                 type = fdt_getprop(fdt, node, "device_type", &len);
  64                 if (type && strncmp(type, "memory", len) == 0) {
  65                         fdt_del_node(fdt, node);
  66                         continue;
  67                 }
  68
  69                 prev = node;
  70         }
  71
  72         node = fdt_subnode_offset(fdt, 0, "chosen");
  73         if (node < 0) {
  74                 node = fdt_add_subnode(fdt, 0, "chosen");
  75                 if (node < 0) {
  76                         status = node; /* node is error code when negative */
  77                         goto fdt_set_fail;
  78                 }
  79         }
  80
  81         if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
  82                 status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
  83                                      strlen(cmdline_ptr) + 1);
  84                 if (status)
  85                         goto fdt_set_fail;
  86         }
  87
  88         /* Set initrd address/end in device tree, if present */
  89         if (initrd_size != 0) {
  90                 u64 initrd_image_end;
  91                 u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
  92
  93                 status = fdt_setprop(fdt, node, "linux,initrd-start",
  94                                      &initrd_image_start, sizeof(u64));
  95                 if (status)
  96                         goto fdt_set_fail;
  97                 initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
  98                 status = fdt_setprop(fdt, node, "linux,initrd-end",
  99                                      &initrd_image_end, sizeof(u64));
 100                 if (status)
 101                         goto fdt_set_fail;
 102         }
 103
 104         /* Add FDT entries for EFI runtime services in chosen node. */
 105         node = fdt_subnode_offset(fdt, 0, "chosen");
 106         fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
 107         status = fdt_setprop(fdt, node, "linux,uefi-system-table",
 108                              &fdt_val64, sizeof(fdt_val64));
 109         if (status)
 110                 goto fdt_set_fail;
 111
 112         fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map);
 113         status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
 114                              &fdt_val64,  sizeof(fdt_val64));
 115         if (status)
 116                 goto fdt_set_fail;
 117
 118         fdt_val32 = cpu_to_fdt32(map_size);
 119         status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
 120                              &fdt_val32,  sizeof(fdt_val32));
 121         if (status)
 122                 goto fdt_set_fail;
 123
 124         fdt_val32 = cpu_to_fdt32(desc_size);
 125         status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
 126                              &fdt_val32, sizeof(fdt_val32));
 127         if (status)
 128                 goto fdt_set_fail;
 129
 130         fdt_val32 = cpu_to_fdt32(desc_ver);
 131         status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
 132                              &fdt_val32, sizeof(fdt_val32));
 133         if (status)
 134                 goto fdt_set_fail;
 135
 136         /*
 137          * Add kernel version banner so stub/kernel match can be
 138          * verified.
 139          */
 140         status = fdt_setprop_string(fdt, node, "linux,uefi-stub-kern-ver",
 141                              linux_banner);
 142         if (status)
 143                 goto fdt_set_fail;
 144
 145         return EFI_SUCCESS;
 146
 147 fdt_set_fail:
 148         if (status == -FDT_ERR_NOSPACE)
 149                 return EFI_BUFFER_TOO_SMALL;
 150
 151         return EFI_LOAD_ERROR;
 152 }
 153
 154 #ifndef EFI_FDT_ALIGN
 155 #define EFI_FDT_ALIGN EFI_PAGE_SIZE
 156 #endif
 157
 158 /*
 159  * Allocate memory for a new FDT, then add EFI, commandline, and
 160  * initrd related fields to the FDT.  This routine increases the
 161  * FDT allocation size until the allocated memory is large
 162  * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
 163  * which are fixed at 4K bytes, so in most cases the first
 164  * allocation should succeed.
 165  * EFI boot services are exited at the end of this function.
 166  * There must be no allocations between the get_memory_map()
 167  * call and the exit_boot_services() call, so the exiting of
 168  * boot services is very tightly tied to the creation of the FDT
 169  * with the final memory map in it.
 170  */
 171
 172 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
 173                                             void *handle,
 174                                             unsigned long *new_fdt_addr,
 175                                             unsigned long max_addr,
 176                                             u64 initrd_addr, u64 initrd_size,
 177                                             char *cmdline_ptr,
 178                                             unsigned long fdt_addr,
 179                                             unsigned long fdt_size)
 180 {
 181         unsigned long map_size, desc_size;
 182         u32 desc_ver;
 183         unsigned long mmap_key;
 184         efi_memory_desc_t *memory_map;
 185         unsigned long new_fdt_size;
 186         efi_status_t status;
 187
 188         /*
 189          * Estimate size of new FDT, and allocate memory for it. We
 190          * will allocate a bigger buffer if this ends up being too
 191          * small, so a rough guess is OK here.
 192          */
 193         new_fdt_size = fdt_size + EFI_PAGE_SIZE;
 194         while (1) {
 195                 status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,
 196                                         new_fdt_addr, max_addr);
 197                 if (status != EFI_SUCCESS) {
 198                         pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
 199                         goto fail;
 200                 }
 201
 202                 /*
 203                  * Now that we have done our final memory allocation (and free)
 204                  * we can get the memory map key  needed for
 205                  * exit_boot_services().
 206                  */
 207                 status = efi_get_memory_map(sys_table, &memory_map, &map_size,
 208                                             &desc_size, &desc_ver, &mmap_key);
 209                 if (status != EFI_SUCCESS)
 210                         goto fail_free_new_fdt;
 211
 212                 status = update_fdt(sys_table,
 213                                     (void *)fdt_addr, fdt_size,
 214                                     (void *)*new_fdt_addr, new_fdt_size,
 215                                     cmdline_ptr, initrd_addr, initrd_size,
 216                                     memory_map, map_size, desc_size, desc_ver);
 217
 218                 /* Succeeding the first time is the expected case. */
 219                 if (status == EFI_SUCCESS)
 220                         break;
 221
 222                 if (status == EFI_BUFFER_TOO_SMALL) {
 223                         /*
 224                          * We need to allocate more space for the new
 225                          * device tree, so free existing buffer that is
 226                          * too small.  Also free memory map, as we will need
 227                          * to get new one that reflects the free/alloc we do
 228                          * on the device tree buffer.
 229                          */
 230                         efi_free(sys_table, new_fdt_size, *new_fdt_addr);
 231                         sys_table->boottime->free_pool(memory_map);
 232                         new_fdt_size += EFI_PAGE_SIZE;
 233                 } else {
 234                         pr_efi_err(sys_table, "Unable to constuct new device tree.\n");
 235                         goto fail_free_mmap;
 236                 }
 237         }
 238
 239         /* Now we are ready to exit_boot_services.*/
 240         status = sys_table->boottime->exit_boot_services(handle, mmap_key);
 241
 242
 243         if (status == EFI_SUCCESS)
 244                 return status;
 245
 246         pr_efi_err(sys_table, "Exit boot services failed.\n");
 247
 248 fail_free_mmap:
 249         sys_table->boottime->free_pool(memory_map);
 250
 251 fail_free_new_fdt:
 252         efi_free(sys_table, new_fdt_size, *new_fdt_addr);
 253
 254 fail:
 255         return EFI_LOAD_ERROR;
 256 }
 257
 258 static void *get_fdt(efi_system_table_t *sys_table)
 259 {
 260         efi_guid_t fdt_guid = DEVICE_TREE_GUID;
 261         efi_config_table_t *tables;
 262         void *fdt;
 263         int i;
 264
 265         tables = (efi_config_table_t *) sys_table->tables;
 266         fdt = NULL;
 267
 268         for (i = 0; i < sys_table->nr_tables; i++)
 269                 if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
 270                         fdt = (void *) tables[i].table;
 271                         break;
 272          }
 273
 274         return fdt;
 275 }