[PATCH V4 0/3] mm: Add generic copy from early unmapped RAM

[Mark Salter]

When booting an arm64 kernel w/initrd using UEFI/grub, use of mem= will likely
cut off part or all of the initrd. This leaves it outside the kernel linear
map which leads to failure when unpacking. The x86 code has a similar need to
relocate an initrd outside of mapped memory in some cases.

The current x86 code uses early_memremap() to copy the original initrd from
unmapped to mapped RAM. This patchset creates a generic copy_from_early_mem()
utility based on that x86 code and has arm64 and x86 share it in their
respective initrd relocation code.

Changes from V3:

  * Fixed arm64 build error with !CONFIG_BLK_DEV_INITRD case

  * Fixed nonsensical comment in arm64 relocate_initrd()

Changes from V2:

  * Fixed sparse warning in copy_from_early_mem()

  * Removed unneeded MAX_MAP_CHUNK from x86 setup.c

  * Moved #ifdef outside arm64 relocate_initrd() definition.
  
Changes from V1:

  * Change cover letter subject to highlight the added generic code

  * Add patch for x86 to use common copy_from_early_mem()


Mark Salter (3):
  mm: add utility for early copy from unmapped ram
  arm64: support initrd outside kernel linear map
  x86: use generic early mem copy

 arch/arm64/kernel/setup.c           | 62 +++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/setup.c             | 22 +------------
 include/asm-generic/early_ioremap.h |  6 ++++
 mm/early_ioremap.c                  | 22 +++++++++++++
 4 files changed, 91 insertions(+), 21 deletions(-)

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2.4.3