payloads/libpayload/arch/x86/boot_media.c

   1 /* SPDX-License-Identifier: BSD-3-Clause */
   2
   3 #include <libpayload.h>
   4 #include <boot_device.h>
   5
   6 __attribute__((weak)) ssize_t boot_device_read(void *buf, size_t offset, size_t size)
   7 {
   8         /* Memory-mapping usually only works for the top 16MB. */
   9         if (!lib_sysinfo.boot_media_size || lib_sysinfo.boot_media_size - offset > 16 * MiB)
  10                 return CB_ERR_ARG;
  11         const void *const ptr = phys_to_virt(0 - lib_sysinfo.boot_media_size + offset);
  12         memcpy(buf, ptr, size);
  13         return size;
  14 }