arch/x86/platform/efi/efi-bgrt.c

   1 /*
   2  * Copyright 2012 Intel Corporation
   3  * Author: Josh Triplett <josh@joshtriplett.org>
   4  *
   5  * Based on the bgrt driver:
   6  * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
   7  * Author: Matthew Garrett
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/acpi.h>
  16 #include <linux/efi.h>
  17 #include <linux/efi-bgrt.h>
  18
  19 struct acpi_table_bgrt *bgrt_tab;
  20 void *__initdata bgrt_image;
  21 size_t __initdata bgrt_image_size;
  22
  23 struct bmp_header {
  24         u16 id;
  25         u32 size;
  26 } __packed;
  27
  28 void __init efi_bgrt_init(void)
  29 {
  30         acpi_status status;
  31         void __iomem *image;
  32         bool ioremapped = false;
  33         struct bmp_header bmp_header;
  34
  35         if (acpi_disabled)
  36                 return;
  37
  38         status = acpi_get_table("BGRT", 0,
  39                                 (struct acpi_table_header **)&bgrt_tab);
  40         if (ACPI_FAILURE(status))
  41                 return;
  42
  43         if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
  44                 pr_err("Ignoring BGRT: invalid length %u (expected %zu)\n",
  45                        bgrt_tab->header.length, sizeof(*bgrt_tab));
  46                 return;
  47         }
  48         if (bgrt_tab->version != 1) {
  49                 pr_err("Ignoring BGRT: invalid version %u (expected 1)\n",
  50                        bgrt_tab->version);
  51                 return;
  52         }
  53         if (bgrt_tab->status & 0xfe) {
  54                 pr_err("Ignoring BGRT: reserved status bits are non-zero %u\n",
  55                        bgrt_tab->status);
  56                 return;
  57         }
  58         if (bgrt_tab->status != 1) {
  59                 pr_debug("Ignoring BGRT: invalid status %u (expected 1)\n",
  60                          bgrt_tab->status);
  61                 return;
  62         }
  63         if (bgrt_tab->image_type != 0) {
  64                 pr_err("Ignoring BGRT: invalid image type %u (expected 0)\n",
  65                        bgrt_tab->image_type);
  66                 return;
  67         }
  68         if (!bgrt_tab->image_address) {
  69                 pr_err("Ignoring BGRT: null image address\n");
  70                 return;
  71         }
  72
  73         image = efi_lookup_mapped_addr(bgrt_tab->image_address);
  74         if (!image) {
  75                 image = early_ioremap(bgrt_tab->image_address,
  76                                        sizeof(bmp_header));
  77                 ioremapped = true;
  78                 if (!image) {
  79                         pr_err("Ignoring BGRT: failed to map image header memory\n");
  80                         return;
  81                 }
  82         }
  83
  84         memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
  85         if (ioremapped)
  86                 early_iounmap(image, sizeof(bmp_header));
  87         bgrt_image_size = bmp_header.size;
  88
  89         bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
  90         if (!bgrt_image) {
  91                 pr_err("Ignoring BGRT: failed to allocate memory for image (wanted %zu bytes)\n",
  92                        bgrt_image_size);
  93                 return;
  94         }
  95
  96         if (ioremapped) {
  97                 image = early_ioremap(bgrt_tab->image_address,
  98                                        bmp_header.size);
  99                 if (!image) {
 100                         pr_err("Ignoring BGRT: failed to map image memory\n");
 101                         kfree(bgrt_image);
 102                         bgrt_image = NULL;
 103                         return;
 104                 }
 105         }
 106
 107         memcpy_fromio(bgrt_image, image, bgrt_image_size);
 108         if (ioremapped)
 109                 early_iounmap(image, bmp_header.size);
 110 }