[PATCH v2 0/6] arm/efi: fix memblock reallocation crash due to persistent reservations

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

This series addresses the kexec/kdump crash on arm64 system with many CPUs
that was reported by Bhupesh.

Patch #1 fixes the actual crash, but may result in memblock_reserve() to
fail. This is fixed in patch #4, where the point that the persistent
reservations are applied is moved to after memblock_allow_resize() has
been called.

Patches #2 and #3 contain some minor preparatory changes that are
required on ARM to ensure that efi_apply_persistent_mem_reservations()
can be called at some point (i.e., when memblock resizing is already
permitted and early memremap() is still usable)

Patches #5 and #6 optimize the EFI persistent memreserve infrastructure
so that fewer memblock reservations are required.

Changes since v1:
- Russell pointed out that switching to ordinary memremap() was not
  possible this early, and so I refactored the ARM early boot code
  slightly so that we can keep using early_memremap().

Ard Biesheuvel (6):
  arm64: memblock: don't permit memblock resizing until linear mapping
    is up
  ARM: mm: permit memblock resizing right after mapping the linear
    region
  ARM: mm: permit early_memremap() to be used in paging_init()
  efi/arm: defer persistent reservations until after paging_init()
  efi: permit multiple entries in persistent memreserve data structure
  efi: reduce the amount of memblock reservations for persistent
    allocations

 arch/arm/kernel/setup.c                 |  2 -
 arch/arm/mm/init.c                      |  1 -
 arch/arm/mm/mmu.c                       |  5 ++
 arch/arm64/kernel/setup.c               |  1 +
 arch/arm64/mm/init.c                    |  2 -
 arch/arm64/mm/mmu.c                     |  2 +
 drivers/firmware/efi/efi.c              | 59 ++++++++++++++------
 drivers/firmware/efi/libstub/arm-stub.c |  2 +-
 include/linux/efi.h                     | 23 +++++++-
 9 files changed, 72 insertions(+), 25 deletions(-)

-- 
2.19.1