linux/arch/x86/platform/efi
Matt Fleming 09503379dc x86/efi: Check status field to validate BGRT header
Madper reported seeing the following crash,

  BUG: unable to handle kernel paging request at ffffffffff340003
  IP: [<ffffffff81d85ba4>] efi_bgrt_init+0x9d/0x133
  Call Trace:
   [<ffffffff81d8525d>] efi_late_init+0x9/0xb
   [<ffffffff81d68f59>] start_kernel+0x436/0x450
   [<ffffffff81d6892c>] ? repair_env_string+0x5c/0x5c
   [<ffffffff81d68120>] ? early_idt_handlers+0x120/0x120
   [<ffffffff81d685de>] x86_64_start_reservations+0x2a/0x2c
   [<ffffffff81d6871e>] x86_64_start_kernel+0x13e/0x14d

This is caused because the layout of the ACPI BGRT header on this system
doesn't match the definition from the ACPI spec, and so we get a bogus
physical address when dereferencing ->image_address in efi_bgrt_init().

Luckily the status field in the BGRT header clearly marks it as invalid,
so we can check that field and skip BGRT initialisation.

Reported-by: Madper Xie <cxie@redhat.com>
Suggested-by: Toshi Kani <toshi.kani@hp.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2014-02-14 10:07:15 +00:00
..
Makefile x86/efi: Add EFI framebuffer earlyprintk support 2013-10-28 18:09:58 +00:00
early_printk.c x86/efi: Fix earlyprintk off-by-one bug 2013-11-28 20:16:56 +00:00
efi-bgrt.c x86/efi: Check status field to validate BGRT header 2014-02-14 10:07:15 +00:00
efi.c x86/efi: Fix 32-bit fallout 2014-02-14 09:30:19 +00:00
efi_32.c x86/efi: Fix 32-bit fallout 2014-02-14 09:30:19 +00:00
efi_64.c x86/efi: Fix 32-bit fallout 2014-02-14 09:30:19 +00:00
efi_stub_32.S x86: Move efi to platform 2010-10-27 14:30:01 +02:00
efi_stub_64.S x86/efi: Runtime services virtual mapping 2013-11-02 11:09:36 +00:00