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@xxxxxxxxxx> > Acked-by: Guo Ren <guoren@xxxxxxxxxx> > Reviewed-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> Reviewed-by: Simon Horman <horms@xxxxxxxxxx>