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55087c5713
Some (somewhat older) laptops have a correct BGRT table, except that the version field is 0 instead of 1. This has been seen on several Ivy Bridge based Lenovo models. For now the spec. only defines version 1, so it is reasonably safe to assume that tables with a version of 0 really are version 1 too, which is what this commit does so that the BGRT table will be accepted by the kernel on laptop models with this issue. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20200131130623.33875-1-hdegoede@redhat.com Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
// 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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