[PATCH -next v4 1/2] riscv: kdump: Implement crashkernel=X,[high,low]

[Simon Horman]

On Mon, Apr 10, 2023 at 09:05:52PM +0800, Chen Jiahao wrote:
> On riscv, the current crash kernel allocation logic is trying to
> allocate within 32bit addressible memory region by default, if
> failed, try to allocate without 4G restriction.
> 
> In need of saving DMA zone memory while allocating a relatively large
> crash kernel region, allocating the reserved memory top down in
> high memory, without overlapping the DMA zone, is a mature solution.
> Here introduce the parameter option crashkernel=X,[high,low].
> 
> One can reserve the crash kernel from high memory above DMA zone range
> by explicitly passing "crashkernel=X,high"; or reserve a memory range
> below 4G with "crashkernel=X,low".
> 
> Signed-off-by: Chen Jiahao <chenjiahao16 at huawei.com>
> Acked-by: Guo Ren <guoren at kernel.org>
> Reviewed-by: Zhen Lei <thunder.leizhen at huawei.com>

Reviewed-by: Simon Horman <horms at kernel.org>