[PATCH v12 00/15] arm64/riscv: Add support for crashkernel CMA reservation

Jinjie Ruan
2026-04-02T07:25:54Z

The crash memory allocation, and the exclude of crashk_res, crashk_low_res
and crashk_cma memory are almost identical across different architectures,
This patch set handle them in crash core in a general way, which eliminate
a lot of duplication code.

And add support for crashkernel CMA reservation for arm64 and riscv.

Rebased on v7.0-rc1.

Basic second kernel boot test were performed on QEMU platforms for x86,
ARM64, and RISC-V architectures with the following parameters:

"cma=256M crashkernel=256M crashkernel=64M,cma"

Changes in v12:
- Remove the unused "nr_mem_ranges" for x86.
- Add "Fix crashk_low_res not exclude bug" test log.
- Provide a separate patch for each architecture for using
crash_prepare_headers(), which will make the review more convenient.
- Add Reviewed-by and Tested-by.
- Link to v11: https://lore.kernel.org/all/20260328074013.3589544-1-ruanjinjie@huawei.com/

Changes in v11:
- Avoid silently drop crash memory if the crash kernel is built without
CONFIG_CMA.
- Remove unnecessary "cmem->nr_ranges = 0" for arch_crash_populate_cmem()
as we use kvzalloc().
- Provide a separate patch for each architecture to fix the existing
buffer overflow issue.
- Add Acked-bys for arm64.

Changes in v10:
- Fix crashk_low_res not excluded bug in the existing
RISC-V code.
- Fix an existing memory leak issue in the existing PowerPC code.
- Fix the ordering issue of adding CMA ranges to
"linux,usable-memory-range".
- Fix an existing concurrency issue. A Concurrent memory hotplug may occur
between reading memblock and attempting to fill cmem during kexec_load()
for almost all existing architectures.
- Link to v9: https://lore.kernel.org/all/20260323072745.2481719-1-ruanjinjie@huawei.com/

Changes in v9:
- Collect Reviewed-by and Acked-by, and prepare for Sashiko AI review.
- Link to v8: https://lore.kernel.org/all/20260302035315.3892241-1-ruanjinjie@huawei.com/

Changes in v8:
- Fix the build issues reported by kernel test robot and Sourabh.
- Link to v7: https://lore.kernel.org/all/20260226130437.1867658-1-ruanjinjie@huawei.com/

Changes in v7:
- Correct the inclusion of CMA-reserved ranges for kdump kernel in of/kexec
for arm64 and riscv.
- Add Acked-by.
- Link to v6: https://lore.kernel.org/all/20260224085342.387996-1-ruanjinjie@huawei.com/

Changes in v6:
- Update the crash core exclude code as Mike suggested.
- Rebased on v7.0-rc1.
- Add acked-by.
- Link to v5: https://lore.kernel.org/all/20260212101001.343158-1-ruanjinjie@huawei.com/

Jinjie Ruan (14):
riscv: kexec_file: Fix crashk_low_res not exclude bug
powerpc/crash: Fix possible memory leak in update_crash_elfcorehdr()
x86/kexec: Fix potential buffer overflow in prepare_elf_headers()
arm64: kexec_file: Fix potential buffer overflow in
prepare_elf_headers()
riscv: kexec_file: Fix potential buffer overflow in
prepare_elf_headers()
LoongArch: kexec: Fix potential buffer overflow in
prepare_elf_headers()
crash: Add crash_prepare_headers() to exclude crash kernel memory
arm64: kexec_file: Use crash_prepare_headers() helper to simplify code
x86/kexec: Use crash_prepare_headers() helper to simplify code
riscv: kexec_file: Use crash_prepare_headers() helper to simplify code
LoongArch: kexec: Use crash_prepare_headers() helper to simplify code
crash: Use crash_exclude_core_ranges() on powerpc
arm64: kexec: Add support for crashkernel CMA reservation
riscv: kexec: Add support for crashkernel CMA reservation

Sourabh Jain (1):
powerpc/crash: sort crash memory ranges before preparing elfcorehdr

.../admin-guide/kernel-parameters.txt | 16 +--
arch/arm64/kernel/machine_kexec_file.c | 43 +++-----
arch/arm64/mm/init.c | 5 +-
arch/loongarch/kernel/machine_kexec_file.c | 43 +++-----
arch/powerpc/include/asm/kexec_ranges.h | 1 -
arch/powerpc/kexec/crash.c | 7 +-
arch/powerpc/kexec/ranges.c | 101 +-----------------
arch/riscv/kernel/machine_kexec_file.c | 42 +++-----
arch/riscv/mm/init.c | 5 +-
arch/x86/kernel/crash.c | 92 +++-------------
drivers/of/fdt.c | 9 +-
drivers/of/kexec.c | 9 ++
include/linux/crash_core.h | 9 ++
include/linux/crash_reserve.h | 4 +-
kernel/crash_core.c | 89 ++++++++++++++-
15 files changed, 193 insertions(+), 282 deletions(-)

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2.34.1