[PATCH RFC 0/3] riscv: Add DMA_COHERENT support
guoren at kernel.org
Tue May 18 22:48:23 PDT 2021
On Wed, May 19, 2021 at 1:20 PM Christoph Hellwig <hch at lst.de> wrote:
> On Wed, May 19, 2021 at 05:04:13AM +0000, guoren at kernel.org wrote:
> > From: Guo Ren <guoren at linux.alibaba.com>
> > The RISC-V ISA doesn't yet specify how to query or modify PMAs, so let
> > vendors define the custom properties of memory regions in PTE.
> Err, hell no. The ISA needs to gets this fixed first. Then we can
> talk about alternatives patching things in or trapping in the SBI.
> But if the RISC-V ISA can't get these basic done after years we can't
> support it in Linux at all.
The patchset just leaves a configuration chance for vendors. Before
RISC-V ISA fixes it, we should give the chance to let vendor solve
their real chip issues.
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