Re: [PATCH -next v3 2/2] docs: kdump: Update the crashkernel description for riscv

Guo Ren
2023-04-07T08:34:49Z

Reviewed-by: Guo Ren <guoren@kernel.org>

On Thu, Apr 6, 2023 at 10:05 PM Chen Jiahao <chenjiahao16@huawei.com> wrote:
>
> Now "crashkernel=" parameter on riscv has been updated to support
> crashkernel=X,[high,low]. Through which we can reserve memory region
> above/within 32bit addressible DMA zone.
>
> Here update the parameter description accordingly.
>
> Signed-off-by: Chen Jiahao <chenjiahao16@huawei.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 54702bd488eb..41865aae9eaa 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -866,7 +866,7 @@
> memory region [offset, offset + size] for that kernel
> image. If '@offset' is omitted, then a suitable offset
> is selected automatically.
> - [KNL, X86-64, ARM64] Select a region under 4G first, and
> + [KNL, X86-64, ARM64, RISCV] Select a region under 4G first, and
> fall back to reserve region above 4G when '@offset'
> hasn't been specified.
> See Documentation/admin-guide/kdump/kdump.rst for further details.
> @@ -879,14 +879,14 @@
> Documentation/admin-guide/kdump/kdump.rst for an example.
>
> crashkernel=size[KMG],high
> - [KNL, X86-64, ARM64] range could be above 4G. Allow kernel
> - to allocate physical memory region from top, so could
> - be above 4G if system have more than 4G ram installed.
> - Otherwise memory region will be allocated below 4G, if
> - available.
> + [KNL, X86-64, ARM64, RISCV] range could be above 4G.
> + Allow kernel to allocate physical memory region from top,
> + so could be above 4G if system have more than 4G ram
> + installed. Otherwise memory region will be allocated
> + below 4G, if available.
> It will be ignored if crashkernel=X is specified.
> crashkernel=size[KMG],low
> - [KNL, X86-64, ARM64] range under 4G. When crashkernel=X,high
> + [KNL, X86-64, ARM64, RISCV] range under 4G. When crashkernel=X,high
> is passed, kernel could allocate physical memory region
> above 4G, that cause second kernel crash on system
> that require some amount of low memory, e.g. swiotlb
> @@ -897,6 +897,7 @@
> size is platform dependent.
> --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
> --> arm64: 128MiB
> + --> riscv: 128MiB
> This one lets the user specify own low range under 4G
> for second kernel instead.
> 0: to disable low allocation.
> --
> 2.31.1
>

--
Best Regards
Guo Ren