riscv: kexec_file: Add support for crashkernel CMA reservation

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Commit 35c18f2933 ("Add a new optional ",cma" suffix to the
crashkernel= command line option") and commit ab475510e0 ("kdump:
implement reserve_crashkernel_cma") added CMA support for kdump
crashkernel reservation. This allows the kernel to dynamically allocate
contiguous memory for crash dumping when needed, rather than permanently
reserving a fixed region at boot time.

So extend crashkernel CMA reservation support to riscv. The following
changes are made to enable CMA reservation:

- Parse and obtain the CMA reservation size along with other crashkernel
  parameters.
- Call reserve_crashkernel_cma() to allocate the CMA region for kdump.
- Include the CMA-reserved ranges for kdump kernel to use, which was
  already done in of_kexec_alloc_and_setup_fdt().
- Exclude the CMA-reserved ranges from the crash kernel memory to
  prevent them from being exported through /proc/vmcore, which was
  already done in the crash core.

Update kernel-parameters.txt to document CMA support for crashkernel on
riscv architecture.

Cc: Paul Walmsley <pjw@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Paul Walmsley <pjw@kernel.org> # arch/riscv
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20260629094746.191843-11-ruanjinjie@huawei.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

...

This commit is contained in:

Jinjie Ruan 2026-06-29 17:47:46 +08:00 • committed by Mike Rapoport (Microsoft)

parent c12c63d05d

commit a037fe3c58

3 changed files with 12 additions and 11 deletions

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16

Documentation/admin-guide/kernel-parameters.txt

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2

arch/riscv/kernel/machine_kexec_file.c

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5

arch/riscv/mm/init.c

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