1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright 2012 Intel Corporation
 4 * Author: Josh Triplett <josh@joshtriplett.org>
 5 *
 6 * Based on the bgrt driver:
 7 * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
 8 * Author: Matthew Garrett
 9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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
19struct acpi_table_bgrt bgrt_tab;
20size_t bgrt_image_size;
21
22struct bmp_header {
23	u16 id;
24	u32 size;
25} __packed;
26
27void __init efi_bgrt_init(struct acpi_table_header *table)
28{
29	void *image;
30	struct bmp_header bmp_header;
31	struct acpi_table_bgrt *bgrt = &bgrt_tab;
32
33	if (acpi_disabled)
34		return;
35
36	if (!efi_enabled(EFI_MEMMAP))
37		return;
38
39	if (table->length < sizeof(bgrt_tab)) {
40		pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
41		       table->length, sizeof(bgrt_tab));
42		return;
43	}
44	*bgrt = *(struct acpi_table_bgrt *)table;
45	/*
46	 * Only version 1 is defined but some older laptops (seen on Lenovo
47	 * Ivy Bridge models) have a correct version 1 BGRT table with the
48	 * version set to 0, so we accept version 0 and 1.
49	 */
50	if (bgrt->version > 1) {
51		pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
52		       bgrt->version);
53		goto out;
54	}
55	if (bgrt->image_type != 0) {
56		pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
57		       bgrt->image_type);
58		goto out;
59	}
60	if (!bgrt->image_address) {
61		pr_notice("Ignoring BGRT: null image address\n");
62		goto out;
63	}
64
65	if (efi_mem_type(bgrt->image_address) != EFI_BOOT_SERVICES_DATA) {
66		pr_notice("Ignoring BGRT: invalid image address\n");
67		goto out;
68	}
69	image = early_memremap(bgrt->image_address, sizeof(bmp_header));
70	if (!image) {
71		pr_notice("Ignoring BGRT: failed to map image header memory\n");
72		goto out;
73	}
74
75	memcpy(&bmp_header, image, sizeof(bmp_header));
76	early_memunmap(image, sizeof(bmp_header));
77	if (bmp_header.id != 0x4d42) {
78		pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
79			bmp_header.id);
80		goto out;
81	}
82	bgrt_image_size = bmp_header.size;
83	efi_mem_reserve(bgrt->image_address, bgrt_image_size);
84
85	return;
86out:
87	memset(bgrt, 0, sizeof(bgrt_tab));
88}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright 2012 Intel Corporation
 4 * Author: Josh Triplett <josh@joshtriplett.org>
 5 *
 6 * Based on the bgrt driver:
 7 * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
 8 * Author: Matthew Garrett
 9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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
19struct acpi_table_bgrt bgrt_tab;
20size_t bgrt_image_size;
21
22struct bmp_header {
23	u16 id;
24	u32 size;
25} __packed;
26
27void __init efi_bgrt_init(struct acpi_table_header *table)
28{
29	void *image;
30	struct bmp_header bmp_header;
31	struct acpi_table_bgrt *bgrt = &bgrt_tab;
32
33	if (acpi_disabled)
34		return;
35
36	if (!efi_enabled(EFI_MEMMAP))
37		return;
38
39	if (table->length < sizeof(bgrt_tab)) {
40		pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
41		       table->length, sizeof(bgrt_tab));
42		return;
43	}
44	*bgrt = *(struct acpi_table_bgrt *)table;
45	/*
46	 * Only version 1 is defined but some older laptops (seen on Lenovo
47	 * Ivy Bridge models) have a correct version 1 BGRT table with the
48	 * version set to 0, so we accept version 0 and 1.
49	 */
50	if (bgrt->version > 1) {
51		pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
52		       bgrt->version);
53		goto out;
54	}
55	if (bgrt->image_type != 0) {
56		pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
57		       bgrt->image_type);
58		goto out;
59	}
60	if (!bgrt->image_address) {
61		pr_notice("Ignoring BGRT: null image address\n");
62		goto out;
63	}
64
65	if (efi_mem_type(bgrt->image_address) != EFI_BOOT_SERVICES_DATA) {
66		pr_notice("Ignoring BGRT: invalid image address\n");
67		goto out;
68	}
69	image = early_memremap(bgrt->image_address, sizeof(bmp_header));
70	if (!image) {
71		pr_notice("Ignoring BGRT: failed to map image header memory\n");
72		goto out;
73	}
74
75	memcpy(&bmp_header, image, sizeof(bmp_header));
76	early_memunmap(image, sizeof(bmp_header));
77	if (bmp_header.id != 0x4d42) {
78		pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
79			bmp_header.id);
80		goto out;
81	}
82	bgrt_image_size = bmp_header.size;
83	efi_mem_reserve(bgrt->image_address, bgrt_image_size);
84
85	return;
86out:
87	memset(bgrt, 0, sizeof(bgrt_tab));
88}