arch/arm64/kernel/efi-stub.c

   1 /*
   2  * Copyright (C) 2013, 2014 Linaro Ltd;  <roy.franz@linaro.org>
   3  *
   4  * This file implements the EFI boot stub for the arm64 kernel.
   5  * Adapted from ARM version by Mark Salter <msalter@redhat.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12 #include <linux/efi.h>
  13 #include <asm/efi.h>
  14 #include <asm/sections.h>
  15
  16 efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
  17                                         unsigned long *image_addr,
  18                                         unsigned long *image_size,
  19                                         unsigned long *reserve_addr,
  20                                         unsigned long *reserve_size,
  21                                         unsigned long dram_base,
  22                                         efi_loaded_image_t *image)
  23 {
  24         efi_status_t status;
  25         unsigned long kernel_size, kernel_memsize = 0;
  26         unsigned long nr_pages;
  27         void *old_image_addr = (void *)*image_addr;
  28
  29         /* Relocate the image, if required. */
  30         kernel_size = _edata - _text;
  31         if (*image_addr != (dram_base + TEXT_OFFSET)) {
  32                 kernel_memsize = kernel_size + (_end - _edata);
  33
  34                 /*
  35                  * First, try a straight allocation at the preferred offset.
  36                  * This will work around the issue where, if dram_base == 0x0,
  37                  * efi_low_alloc() refuses to allocate at 0x0 (to prevent the
  38                  * address of the allocation to be mistaken for a FAIL return
  39                  * value or a NULL pointer). It will also ensure that, on
  40                  * platforms where the [dram_base, dram_base + TEXT_OFFSET)
  41                  * interval is partially occupied by the firmware (like on APM
  42                  * Mustang), we can still place the kernel at the address
  43                  * 'dram_base + TEXT_OFFSET'.
  44                  */
  45                 *image_addr = *reserve_addr = dram_base + TEXT_OFFSET;
  46                 nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
  47                            EFI_PAGE_SIZE;
  48                 status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
  49                                         EFI_LOADER_DATA, nr_pages,
  50                                         (efi_physical_addr_t *)reserve_addr);
  51                 if (status != EFI_SUCCESS) {
  52                         kernel_memsize += TEXT_OFFSET;
  53                         status = efi_low_alloc(sys_table_arg, kernel_memsize,
  54                                                SZ_2M, reserve_addr);
  55
  56                         if (status != EFI_SUCCESS) {
  57                                 pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
  58                                 return status;
  59                         }
  60                         *image_addr = *reserve_addr + TEXT_OFFSET;
  61                 }
  62                 memcpy((void *)*image_addr, old_image_addr, kernel_size);
  63                 *reserve_size = kernel_memsize;
  64         }
  65
  66
  67         return EFI_SUCCESS;
  68 }