linux_dsm_epyc7002/arch/x86/platform/efi/efi-bgrt.c
Matt Fleming 4bc9f92e64 x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data
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>
2016-09-09 16:08:38 +01:00

94 lines
2.3 KiB
C

/*
* Copyright 2012 Intel Corporation
* Author: Josh Triplett <josh@joshtriplett.org>
*
* Based on the bgrt driver:
* Copyright 2012 Red Hat, Inc <mjg@redhat.com>
* Author: Matthew Garrett
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/efi.h>
#include <linux/efi-bgrt.h>
struct acpi_table_bgrt *bgrt_tab;
void *__initdata bgrt_image;
size_t __initdata bgrt_image_size;
struct bmp_header {
u16 id;
u32 size;
} __packed;
void __init efi_bgrt_init(void)
{
acpi_status status;
void *image;
struct bmp_header bmp_header;
if (acpi_disabled)
return;
status = acpi_get_table("BGRT", 0,
(struct acpi_table_header **)&bgrt_tab);
if (ACPI_FAILURE(status))
return;
if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
bgrt_tab->header.length, sizeof(*bgrt_tab));
return;
}
if (bgrt_tab->version != 1) {
pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
bgrt_tab->version);
return;
}
if (bgrt_tab->status & 0xfe) {
pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
bgrt_tab->status);
return;
}
if (bgrt_tab->image_type != 0) {
pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
bgrt_tab->image_type);
return;
}
if (!bgrt_tab->image_address) {
pr_notice("Ignoring BGRT: null image address\n");
return;
}
image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
if (!image) {
pr_notice("Ignoring BGRT: failed to map image header memory\n");
return;
}
memcpy(&bmp_header, image, sizeof(bmp_header));
memunmap(image);
if (bmp_header.id != 0x4d42) {
pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
bmp_header.id);
return;
}
bgrt_image_size = bmp_header.size;
bgrt_image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
if (!bgrt_image) {
pr_notice("Ignoring BGRT: failed to map image memory\n");
bgrt_image = NULL;
return;
}
efi_mem_reserve(bgrt_tab->image_address, bgrt_image_size);
}