| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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 | |
| 14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 15 | |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/acpi.h> |
| 19 | #include <linux/efi.h> |
| 20 | #include <linux/efi-bgrt.h> |
| 21 | |
| 22 | struct acpi_table_bgrt bgrt_tab; |
| 23 | size_t __initdata bgrt_image_size; |
| 24 | |
| 25 | struct bmp_header { |
| 26 | u16 id; |
| 27 | u32 size; |
| 28 | } __packed; |
| 29 | |
| 30 | void __init efi_bgrt_init(struct acpi_table_header *table) |
| 31 | { |
| 32 | void *image; |
| 33 | struct bmp_header bmp_header; |
| 34 | struct acpi_table_bgrt *bgrt = &bgrt_tab; |
| 35 | |
| 36 | if (acpi_disabled) |
| 37 | return; |
| 38 | |
| 39 | if (!efi_enabled(EFI_MEMMAP)) |
| 40 | return; |
| 41 | |
| 42 | if (table->length < sizeof(bgrt_tab)) { |
| 43 | pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n", |
| 44 | table->length, sizeof(bgrt_tab)); |
| 45 | return; |
| 46 | } |
| 47 | *bgrt = *(struct acpi_table_bgrt *)table; |
| 48 | if (bgrt->version != 1) { |
| 49 | pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n", |
| 50 | bgrt->version); |
| 51 | goto out; |
| 52 | } |
| 53 | if (bgrt->image_type != 0) { |
| 54 | pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n", |
| 55 | bgrt->image_type); |
| 56 | goto out; |
| 57 | } |
| 58 | if (!bgrt->image_address) { |
| 59 | pr_notice("Ignoring BGRT: null image address\n"); |
| 60 | goto out; |
| 61 | } |
| 62 | |
| 63 | if (efi_mem_type(bgrt->image_address) != EFI_BOOT_SERVICES_DATA) { |
| 64 | pr_notice("Ignoring BGRT: invalid image address\n"); |
| 65 | goto out; |
| 66 | } |
| 67 | image = early_memremap(bgrt->image_address, sizeof(bmp_header)); |
| 68 | if (!image) { |
| 69 | pr_notice("Ignoring BGRT: failed to map image header memory\n"); |
| 70 | goto out; |
| 71 | } |
| 72 | |
| 73 | memcpy(&bmp_header, image, sizeof(bmp_header)); |
| 74 | early_memunmap(image, sizeof(bmp_header)); |
| 75 | if (bmp_header.id != 0x4d42) { |
| 76 | pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n", |
| 77 | bmp_header.id); |
| 78 | goto out; |
| 79 | } |
| 80 | bgrt_image_size = bmp_header.size; |
| 81 | efi_mem_reserve(bgrt->image_address, bgrt_image_size); |
| 82 | |
| 83 | return; |
| 84 | out: |
| 85 | memset(bgrt, 0, sizeof(bgrt_tab)); |
| 86 | } |