89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2012 Intel Corporation
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* Author: Josh Triplett <josh@joshtriplett.org>
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*
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* Based on the bgrt driver:
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* Copyright 2012 Red Hat, Inc <mjg@redhat.com>
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* Author: Matthew Garrett
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/acpi.h>
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#include <linux/efi.h>
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#include <linux/efi-bgrt.h>
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struct acpi_table_bgrt bgrt_tab;
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size_t bgrt_image_size;
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struct bmp_header {
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u16 id;
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u32 size;
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} __packed;
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void __init efi_bgrt_init(struct acpi_table_header *table)
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{
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void *image;
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struct bmp_header bmp_header;
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struct acpi_table_bgrt *bgrt = &bgrt_tab;
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if (acpi_disabled)
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return;
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if (!efi_enabled(EFI_MEMMAP))
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return;
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if (table->length < sizeof(bgrt_tab)) {
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pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
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table->length, sizeof(bgrt_tab));
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return;
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}
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*bgrt = *(struct acpi_table_bgrt *)table;
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/*
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* Only version 1 is defined but some older laptops (seen on Lenovo
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* Ivy Bridge models) have a correct version 1 BGRT table with the
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* version set to 0, so we accept version 0 and 1.
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*/
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if (bgrt->version > 1) {
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pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
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bgrt->version);
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goto out;
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}
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if (bgrt->image_type != 0) {
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pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
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bgrt->image_type);
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goto out;
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}
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if (!bgrt->image_address) {
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pr_notice("Ignoring BGRT: null image address\n");
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goto out;
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}
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if (efi_mem_type(bgrt->image_address) != EFI_BOOT_SERVICES_DATA) {
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pr_notice("Ignoring BGRT: invalid image address\n");
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goto out;
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}
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image = early_memremap(bgrt->image_address, sizeof(bmp_header));
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if (!image) {
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pr_notice("Ignoring BGRT: failed to map image header memory\n");
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goto out;
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}
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memcpy(&bmp_header, image, sizeof(bmp_header));
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early_memunmap(image, sizeof(bmp_header));
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if (bmp_header.id != 0x4d42) {
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pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
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bmp_header.id);
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goto out;
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}
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bgrt_image_size = bmp_header.size;
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efi_mem_reserve(bgrt->image_address, bgrt_image_size);
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return;
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out:
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memset(bgrt, 0, sizeof(bgrt_tab));
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}
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