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Date:   Tue, 13 Aug 2019 09:39:41 -0700 (PDT)
From:   Paul Walmsley <paul.walmsley@sifive.com>
To:     Logan Gunthorpe <logang@deltatee.com>
cc:     Greentime Hu <green.hu@gmail.com>, Rob Herring <robh@kernel.org>,
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Subject: Re: [PATCH v4 2/2] RISC-V: Implement sparsemem
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On Tue, 13 Aug 2019, Logan Gunthorpe wrote:

> On 2019-08-13 12:04 a.m., Greentime Hu wrote:
> 
> > Every architecture with mmu defines their own pfn_valid().
> 
> Not true. Arm64, for example just uses the generic implementation in
> mmzone.h. 

arm64 seems to define their own:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/Kconfig#n899

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/mm/init.c#n235

While there are many architectures which have their own pfn_valid(); 
oddly, almost none of them set HAVE_ARCH_PFN_VALID ?


- Paul