drivers/firmware/efi/arm-stub.c

   1 /*
   2  * EFI stub implementation that is shared by arm and arm64 architectures.
   3  * This should be #included by the EFI stub implementation files.
   4  *
   5  * Copyright (C) 2013,2014 Linaro Limited
   6  *     Roy Franz <roy.franz@linaro.org
   7  * Copyright (C) 2013 Red Hat, Inc.
   8  *     Mark Salter <msalter@redhat.com>
   9  *
  10  * This file is part of the Linux kernel, and is made available under the
  11  * terms of the GNU General Public License version 2.
  12  *
  13  */
  14
  15 static int __init efi_secureboot_enabled(efi_system_table_t *sys_table_arg)
  16 {
  17         static efi_guid_t const var_guid __initconst = EFI_GLOBAL_VARIABLE_GUID;
  18         static efi_char16_t const var_name[] __initconst = {
  19                 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
  20
  21         efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
  22         unsigned long size = sizeof(u8);
  23         efi_status_t status;
  24         u8 val;
  25
  26         status = f_getvar((efi_char16_t *)var_name, (efi_guid_t *)&var_guid,
  27                           NULL, &size, &val);
  28
  29         switch (status) {
  30         case EFI_SUCCESS:
  31                 return val;
  32         case EFI_NOT_FOUND:
  33                 return 0;
  34         default:
  35                 return 1;
  36         }
  37 }
  38
  39 static efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
  40                                     void *__image, void **__fh)
  41 {
  42         efi_file_io_interface_t *io;
  43         efi_loaded_image_t *image = __image;
  44         efi_file_handle_t *fh;
  45         efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
  46         efi_status_t status;
  47         void *handle = (void *)(unsigned long)image->device_handle;
  48
  49         status = sys_table_arg->boottime->handle_protocol(handle,
  50                                  &fs_proto, (void **)&io);
  51         if (status != EFI_SUCCESS) {
  52                 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
  53                 return status;
  54         }
  55
  56         status = io->open_volume(io, &fh);
  57         if (status != EFI_SUCCESS)
  58                 efi_printk(sys_table_arg, "Failed to open volume\n");
  59
  60         *__fh = fh;
  61         return status;
  62 }
  63 static efi_status_t efi_file_close(void *handle)
  64 {
  65         efi_file_handle_t *fh = handle;
  66
  67         return fh->close(handle);
  68 }
  69
  70 static efi_status_t
  71 efi_file_read(void *handle, unsigned long *size, void *addr)
  72 {
  73         efi_file_handle_t *fh = handle;
  74
  75         return fh->read(handle, size, addr);
  76 }
  77
  78
  79 static efi_status_t
  80 efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
  81               efi_char16_t *filename_16, void **handle, u64 *file_sz)
  82 {
  83         efi_file_handle_t *h, *fh = __fh;
  84         efi_file_info_t *info;
  85         efi_status_t status;
  86         efi_guid_t info_guid = EFI_FILE_INFO_ID;
  87         unsigned long info_sz;
  88
  89         status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
  90         if (status != EFI_SUCCESS) {
  91                 efi_printk(sys_table_arg, "Failed to open file: ");
  92                 efi_char16_printk(sys_table_arg, filename_16);
  93                 efi_printk(sys_table_arg, "\n");
  94                 return status;
  95         }
  96
  97         *handle = h;
  98
  99         info_sz = 0;
 100         status = h->get_info(h, &info_guid, &info_sz, NULL);
 101         if (status != EFI_BUFFER_TOO_SMALL) {
 102                 efi_printk(sys_table_arg, "Failed to get file info size\n");
 103                 return status;
 104         }
 105
 106 grow:
 107         status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
 108                                  info_sz, (void **)&info);
 109         if (status != EFI_SUCCESS) {
 110                 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
 111                 return status;
 112         }
 113
 114         status = h->get_info(h, &info_guid, &info_sz,
 115                                                    info);
 116         if (status == EFI_BUFFER_TOO_SMALL) {
 117                 sys_table_arg->boottime->free_pool(info);
 118                 goto grow;
 119         }
 120
 121         *file_sz = info->file_size;
 122         sys_table_arg->boottime->free_pool(info);
 123
 124         if (status != EFI_SUCCESS)
 125                 efi_printk(sys_table_arg, "Failed to get initrd info\n");
 126
 127         return status;
 128 }
 129
 130
 131
 132 static void efi_char16_printk(efi_system_table_t *sys_table_arg,
 133                               efi_char16_t *str)
 134 {
 135         struct efi_simple_text_output_protocol *out;
 136
 137         out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
 138         out->output_string(out, str);
 139 }
 140
 141
 142 /*
 143  * This function handles the architcture specific differences between arm and
 144  * arm64 regarding where the kernel image must be loaded and any memory that
 145  * must be reserved. On failure it is required to free all
 146  * all allocations it has made.
 147  */
 148 static efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
 149                                         unsigned long *image_addr,
 150                                         unsigned long *image_size,
 151                                         unsigned long *reserve_addr,
 152                                         unsigned long *reserve_size,
 153                                         unsigned long dram_base,
 154                                         efi_loaded_image_t *image);
 155 /*
 156  * EFI entry point for the arm/arm64 EFI stubs.  This is the entrypoint
 157  * that is described in the PE/COFF header.  Most of the code is the same
 158  * for both archictectures, with the arch-specific code provided in the
 159  * handle_kernel_image() function.
 160  */
 161 unsigned long __init efi_entry(void *handle, efi_system_table_t *sys_table,
 162                                unsigned long *image_addr)
 163 {
 164         efi_loaded_image_t *image;
 165         efi_status_t status;
 166         unsigned long image_size = 0;
 167         unsigned long dram_base;
 168         /* addr/point and size pairs for memory management*/
 169         unsigned long initrd_addr;
 170         u64 initrd_size = 0;
 171         unsigned long fdt_addr = 0;  /* Original DTB */
 172         u64 fdt_size = 0;  /* We don't get size from configuration table */
 173         char *cmdline_ptr = NULL;
 174         int cmdline_size = 0;
 175         unsigned long new_fdt_addr;
 176         efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
 177         unsigned long reserve_addr = 0;
 178         unsigned long reserve_size = 0;
 179
 180         /* Check if we were booted by the EFI firmware */
 181         if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 182                 goto fail;
 183
 184         pr_efi(sys_table, "Booting Linux Kernel...\n");
 185
 186         /*
 187          * Get a handle to the loaded image protocol.  This is used to get
 188          * information about the running image, such as size and the command
 189          * line.
 190          */
 191         status = sys_table->boottime->handle_protocol(handle,
 192                                         &loaded_image_proto, (void *)&image);
 193         if (status != EFI_SUCCESS) {
 194                 pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
 195                 goto fail;
 196         }
 197
 198         dram_base = get_dram_base(sys_table);
 199         if (dram_base == EFI_ERROR) {
 200                 pr_efi_err(sys_table, "Failed to find DRAM base\n");
 201                 goto fail;
 202         }
 203         status = handle_kernel_image(sys_table, image_addr, &image_size,
 204                                      &reserve_addr,
 205                                      &reserve_size,
 206                                      dram_base, image);
 207         if (status != EFI_SUCCESS) {
 208                 pr_efi_err(sys_table, "Failed to relocate kernel\n");
 209                 goto fail;
 210         }
 211
 212         /*
 213          * Get the command line from EFI, using the LOADED_IMAGE
 214          * protocol. We are going to copy the command line into the
 215          * device tree, so this can be allocated anywhere.
 216          */
 217         cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
 218         if (!cmdline_ptr) {
 219                 pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
 220                 goto fail_free_image;
 221         }
 222
 223         /*
 224          * Unauthenticated device tree data is a security hazard, so
 225          * ignore 'dtb=' unless UEFI Secure Boot is disabled.
 226          */
 227         if (efi_secureboot_enabled(sys_table)) {
 228                 pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
 229         } else {
 230                 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
 231                                               "dtb=",
 232                                               ~0UL, (unsigned long *)&fdt_addr,
 233                                               (unsigned long *)&fdt_size);
 234
 235                 if (status != EFI_SUCCESS) {
 236                         pr_efi_err(sys_table, "Failed to load device tree!\n");
 237                         goto fail_free_cmdline;
 238                 }
 239         }
 240         if (!fdt_addr)
 241                 /* Look for a device tree configuration table entry. */
 242                 fdt_addr = (uintptr_t)get_fdt(sys_table);
 243
 244         status = handle_cmdline_files(sys_table, image, cmdline_ptr,
 245                                       "initrd=", dram_base + SZ_512M,
 246                                       (unsigned long *)&initrd_addr,
 247                                       (unsigned long *)&initrd_size);
 248         if (status != EFI_SUCCESS)
 249                 pr_efi_err(sys_table, "Failed initrd from command line!\n");
 250
 251         new_fdt_addr = fdt_addr;
 252         status = allocate_new_fdt_and_exit_boot(sys_table, handle,
 253                                 &new_fdt_addr, dram_base + MAX_FDT_OFFSET,
 254                                 initrd_addr, initrd_size, cmdline_ptr,
 255                                 fdt_addr, fdt_size);
 256
 257         /*
 258          * If all went well, we need to return the FDT address to the
 259          * calling function so it can be passed to kernel as part of
 260          * the kernel boot protocol.
 261          */
 262         if (status == EFI_SUCCESS)
 263                 return new_fdt_addr;
 264
 265         pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
 266
 267         efi_free(sys_table, initrd_size, initrd_addr);
 268         efi_free(sys_table, fdt_size, fdt_addr);
 269
 270 fail_free_cmdline:
 271         efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
 272
 273 fail_free_image:
 274         efi_free(sys_table, image_size, *image_addr);
 275         efi_free(sys_table, reserve_size, reserve_addr);
 276 fail:
 277         return EFI_ERROR;
 278 }