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https://github.com/torvalds/linux
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4bc9f92e64
efi_mem_reserve() allows us to permanently mark EFI boot services regions as reserved, which means we no longer need to copy the image data out and into a separate buffer. Leaving the data in the original boot services region has the added benefit that BGRT images can now be passed across kexec reboot. Reviewed-by: Josh Triplett <josh@joshtriplett.org> Tested-by: Dave Young <dyoung@redhat.com> [kexec/kdump] Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> [arm] Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Peter Jones <pjones@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Josh Boyer <jwboyer@fedoraproject.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Môshe van der Sterre <me@moshe.nl> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
94 lines
2.3 KiB
C
94 lines
2.3 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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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void *__initdata bgrt_image;
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size_t __initdata 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(void)
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{
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acpi_status status;
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void *image;
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struct bmp_header bmp_header;
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if (acpi_disabled)
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return;
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status = acpi_get_table("BGRT", 0,
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(struct acpi_table_header **)&bgrt_tab);
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if (ACPI_FAILURE(status))
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return;
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if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
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pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
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bgrt_tab->header.length, sizeof(*bgrt_tab));
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return;
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}
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if (bgrt_tab->version != 1) {
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pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
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bgrt_tab->version);
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return;
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}
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if (bgrt_tab->status & 0xfe) {
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pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
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bgrt_tab->status);
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return;
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}
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if (bgrt_tab->image_type != 0) {
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pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
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bgrt_tab->image_type);
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return;
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}
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if (!bgrt_tab->image_address) {
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pr_notice("Ignoring BGRT: null image address\n");
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return;
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}
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image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
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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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return;
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}
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memcpy(&bmp_header, image, sizeof(bmp_header));
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memunmap(image);
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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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return;
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}
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bgrt_image_size = bmp_header.size;
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bgrt_image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
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if (!bgrt_image) {
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pr_notice("Ignoring BGRT: failed to map image memory\n");
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bgrt_image = NULL;
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return;
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}
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efi_mem_reserve(bgrt_tab->image_address, bgrt_image_size);
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}
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