7425826f4f
Sabrina Dubroca reported an early panic: BUG: unable to handle kernel paging request at ffffffffff240001 IP: efi_bgrt_init+0xdc/0x134 [...] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ... which was introduced by:7b0a911478("efi/x86: Move the EFI BGRT init code to early init code") The cause is that on this machine the firmware provides the EFI ACPI BGRT table even on legacy non-EFI bootups - which table should be EFI only. The garbage BGRT data causes the efi_bgrt_init() panic. Add a check to skip efi_bgrt_init() in case non-EFI bootup to work around this firmware bug. Tested-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Dave Young <dyoung@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: <stable@vger.kernel.org> # v4.11+ Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Fixes:7b0a911478("efi/x86: Move the EFI BGRT init code to early init code") Link: http://lkml.kernel.org/r/20170526113652.21339-6-matt@codeblueprint.co.uk [ Rewrote the changelog to be more readable. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
88 lines
2.1 KiB
C
88 lines
2.1 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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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(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_BOOT))
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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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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->status & 0xfe) {
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pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
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bgrt->status);
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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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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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