[v4,00/10] Add generic support for kdump DT properties

Hi all,

This patch series adds generic support for parsing DT properties related
to crash dump kernels ("linux,elfcorehdr" and "linux,elfcorehdr" under
the "/chosen" node), makes use of it on arm64, arm32, and (partially)
riscv, and performs a few cleanups.  It is an evolution of the
combination of [1] and [2].

The series consists of 5 parts:
  1. Patches 1-2 prepare (the visibility of) variables used to hold
     information retrieved from the DT properties.
  2. Patches 3-5 add support to the FDT core for parsing the properties.
     This can co-exist safely with architecture-specific parsing, until
     the latter has been removed.
  3. Patch 6 removes the non-standard handling of "linux,elfcorehdr" on
     riscv.
     I think this can be applied independently, as the non-standard
     handling is in v5.13, but upstream riscv kdump support is still
     incomplete.
  4. Patches 7-9 convert arm64 to use the generic handling instead of
     its own implementation.
  5. Patch 10 adds support for kdump properties to arm32.
     The corresponding patch for kexec-tools is "[PATCH] arm: kdump: Add
     DT properties to crash dump kernel's DTB"[3], which is still valid.

Changes compared to the previous versions:
  - Make elfcorehdr_{addr,size} always visible,
  - Add variables for usable memory limitation,
  - Use IS_ENABLED() instead of #ifdef (incl. initrd and arm64),
  - Clarify what architecture-specific code is still responsible for,
  - Add generic support for parsing linux,usable-memory-range,
  - Remove custom linux,usable-memory-range parsing on arm64,
  - Use generic handling on ARM.
  
This has been tested on arm32 and arm64, and compile-tested on riscv64.

Thanks for your comments!

[1] "[PATCH v3] ARM: Parse kdump DT properties"
    https://lore.kernel.org/r/20210317113130.2554368-1-geert+renesas@glider.be/
[2] "[PATCH 0/3] Add generic-support for linux,elfcorehdr and fix riscv"
    https://lore.kernel.org/r/cover.1623780059.git.geert+renesas@glider.be/
[3] "[PATCH] arm: kdump: Add DT properties to crash dump kernel's DTB"
    https://lore.kernel.org/linux-arm-kernel/20200902154129.6358-1-geert+renesas@glider.be/


Geert Uytterhoeven (10):
  crash_dump: Make elfcorehdr_{addr,size} always visible
  memblock: Add variables for usable memory limitation
  of: fdt: Add generic support for parsing elf core headers property
  of: fdt: Add generic support for parsing usable memory range property
  of: fdt: Use IS_ENABLED(CONFIG_BLK_DEV_INITRD) instead of #ifdef
  riscv: Remove non-standard linux,elfcorehdr handling
  arm64: kdump: Remove custom linux,elfcorehdr parsing
  arm64: kdump: Remove custom linux,usable-memory-range parsing
  arm64: kdump: Use IS_ENABLED(CONFIG_CRASH_DUMP) instead of #ifdef
  ARM: Parse kdump DT properties

 Documentation/devicetree/bindings/chosen.txt  | 12 ++--
 .../arm/boot/compressed/fdt_check_mem_start.c | 48 ++++++++++++--
 arch/arm/mm/init.c                            | 30 +++++++++
 arch/arm64/mm/init.c                          | 63 +------------------
 arch/riscv/mm/init.c                          | 20 ------
 drivers/of/fdt.c                              | 63 ++++++++++++++++---
 include/linux/crash_dump.h                    |  7 ++-
 include/linux/memblock.h                      |  6 ++
 mm/memblock.c                                 |  2 +
 9 files changed, 148 insertions(+), 103 deletions(-)