[PATCH 0/5] x86/efi: Re-enable memory attributes table for kexec

[Ard Biesheuvel]

From: Ard Biesheuvel <ardb@xxxxxxxxxx>

The EFI memory attributes table augments the EFI memory map, and
provides permission attributes for all runtime code and data regions
that are otherwise mapped read-write-execute in their entirety.

Currently, this table is disregarded when doing kexec boot on x86, for
two reasons:
- the boot services data region that holds the table is not reserved
  correctly, and may contain garbage at kexec time
- a misguided sanity check on the size of the table is likely to trigger
  on kexec, as the EFI memory map has been trimmed down by that time.

Fix both issues, so that the EFI memory attributes table can be taken
into account again at kexec time. Note that this requires that the call
to efi_memattr_init() is moved to a later point for x86.

Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Gregory Price <gourry@xxxxxxxxxx>
Cc: Usama Arif <usamaarif642@xxxxxxxxx>
Cc: Jiri Slaby <jirislaby@xxxxxxxxxx>
Cc: Breno Leitao <leitao@xxxxxxxxxx>

Ard Biesheuvel (5):
  efi/memattr: Fix thinko in table size sanity check
  x86/efi: Gather initial memory reservation and table handling logic
  x86/efi: Defer the call to efi_memattr_init()
  efi: Use efi_mem_reserve() to reserve the memory attribute table
  x86/efi: Drop kexec quirk for the EFI memory attributes table

 arch/x86/include/asm/efi.h     |  5 ++---
 arch/x86/kernel/setup.c        | 11 ++---------
 arch/x86/platform/efi/efi.c    | 15 +++++++++++++++
 arch/x86/platform/efi/quirks.c |  4 ----
 drivers/firmware/efi/efi.c     |  2 +-
 drivers/firmware/efi/memattr.c | 17 ++++++++++-------
 6 files changed, 30 insertions(+), 24 deletions(-)


base-commit: 217c0a5c177a3d4f7c8497950cbf5c36756e8bbb
-- 
2.53.0.1018.g2bb0e51243-goog