[PATCH v5 0/9] Add generic support for kdump DT properties

From: Geert Uytterhoeven
Date: Wed Aug 11 2021 - 04:51:45 EST

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 arm32, and performs a few
cleanups. It is an evolution of the combination of [1] and [2].

The series consists of 6 parts:
1. Patch 1 prepares architecture-specific code (needed for MIPS only)
to avoid duplicating elf core header reservation later.
2. Patch 2 prepares the visibility of variables used to hold
information retrieved from the DT properties.
3. Patches 3-5 add support to the FDT core for handling the
This can co-exist safely with architecture-specific handling, until
the latter has been removed.
4. Patch 6 removes the non-standard handling of "linux,elfcorehdr" on
5. Patches 7-8 convert arm64 to use the generic handling instead of
its own implementation.
6. Patch 9 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 v4[4]:
- New patch "[PATCH v5 1/9] MIPS: Avoid future duplicate elf core
header reservation",
- Drop "memblock: Add variables for usable memory limitation", as this
is now handled in FDT core code,
- Make ELFCORE_ADDR_{MAX,ERR} visible, too,
- Handle the actual elf core header reservation and memory capping in
FDT core code,
- Add Reviewed-by, Acked-by,
- Remove all architecture-specific handling on arm64,
- Drop "arm64: kdump: Use IS_ENABLED(CONFIG_CRASH_DUMP) instead of
#ifdef", as the affected code is gone,
- Remove the addition of "linux,elfcorehdr" and
"linux,usable-memory-range" handling to arch/arm/mm/init.c.

Changes compared to older 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 with kexec/kdump on arm32 and arm64, and
boot-tested on riscv64 and DT-less MIPS.


[1] "[PATCH v3] ARM: Parse kdump DT properties"
[2] "[PATCH 0/3] Add generic-support for linux,elfcorehdr and fix riscv"
[3] "[PATCH] arm: kdump: Add DT properties to crash dump kernel's DTB"
[4] "[PATCH v4 00/10] Add generic support for kdump DT properties"

Geert Uytterhoeven (9):
MIPS: Avoid future duplicate elf core header reservation
crash_dump: Make elfcorehdr address/size symbols always visible
of: fdt: Add generic support for handling elf core headers property
of: fdt: Add generic support for handling 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 handling
arm64: kdump: Remove custom linux,usable-memory-range handling
ARM: uncompress: Parse "linux,usable-memory-range" DT property

Documentation/devicetree/bindings/chosen.txt | 12 +--
.../arm/boot/compressed/fdt_check_mem_start.c | 48 ++++++++--
arch/arm64/mm/init.c | 88 -----------------
arch/mips/kernel/setup.c | 3 +-
arch/riscv/mm/init.c | 20 ----
drivers/of/fdt.c | 94 +++++++++++++++++--
include/linux/crash_dump.h | 3 +-
7 files changed, 139 insertions(+), 129 deletions(-)




Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds