[lowrisc-dev] Re: [sw-dev] Is a de facto standard memory map helpful or harmful?

Alex Bradbury asb at asbradbury.org
Wed Jul 13 15:03:59 BST 2016


On 13 July 2016 at 14:38, Arnd Bergmann <arnd at arndb.de> wrote:
> The main problem for operating systems is to have the kernel run at
> a nonconstant physical address. On ARM Linux, we work around this by
> patching every call to phys_to_virt() and virt_to_phys() at early
> boot time as soon as we have detected the start of RAM.
>
> This works fine for the most part, but there are a couple of downsides:
>
> (snip)

Thanks for sharing your experience here Arnd - I'm glad someone with
considerable kernel experience has chimed in. Would having a CSR
(RISC-V control register) that contains the base physical address be
an effective solution to avoid the need for function patching?

Alex



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