From: Logan Gunthorpe <logang@deltatee.com>
To: Greentime Hu <green.hu@gmail.com>
Cc: Rob Herring <robh@kernel.org>, Albert Ou <aou@eecs.berkeley.edu>,
Andrew Waterman <andrew@sifive.com>,
Palmer Dabbelt <palmer@sifive.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Stephen Bates <sbates@raithlin.com>,
linux-mm@vger.kernel.org,
Paul Walmsley <paul.walmsley@sifive.com>,
Olof Johansson <olof@lixom.net>,
greentime.hu@sifive.com, linux-riscv@lists.infradead.org,
Michael Clark <michaeljclark@mac.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v4 2/2] RISC-V: Implement sparsemem
Date: Wed, 14 Aug 2019 10:56:35 -0600 [thread overview]
Message-ID: <0d81412d-73fc-fa56-6f84-dedda72b9cc6@deltatee.com> (raw)
In-Reply-To: <CAEbi=3f+JDywuHYspfYKuC8z2wm8inRenBz+3DYbKK3ixFjU_g@mail.gmail.com>
On 2019-08-14 7:35 a.m., Greentime Hu wrote:
> Logan Gunthorpe <logang@deltatee.com> 於 2019年8月14日 週三 上午12:50寫道:
>>
>> On 2019-08-13 10:39 a.m., Paul Walmsley wrote:
>>> 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
>>
>> Oh, yup. My mistake.
>>
>>> 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 ?
>>
>> Yes, much of this is super confusing. Seems HAVE_ARCH_PFN_VALID only
>> matters if SPARSEMEM is set. So risc-v probably doesn't need to set it
>> and we just need a #ifdef !CONFIG_FLATMEM around the pfn_valid
>> definition like other arches.
>>
>
> Maybe this commit explains why it used HAVE_ARCH_PFN_VALID instead of SPARSEMEM.
> https://github.com/torvalds/linux/commit/7b7bf499f79de3f6c85a340c8453a78789523f85
>
> BTW, I found another issue here.
> #define FIXADDR_TOP (VMALLOC_START)
> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
> #define VMEMMAP_END (VMALLOC_START - 1)
> #define VMEMMAP_START (VMALLOC_START - VMEMMAP_SIZE)
> These 2 regions are overlapped.
>
> How about this fix? Not sure if it is good for everyone.
Yes, this looks good to me. I can fold these changes into my patch and
send a v5 to the list.
Thanks!
Logan
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 3f12b069af1d..3c4d394679d0 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -115,9 +115,6 @@ config PGTABLE_LEVELS
> default 3 if 64BIT
> default 2
>
> -config HAVE_ARCH_PFN_VALID
> - def_bool y
> -
> menu "Platform type"
>
> choice
> diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
> index c207f6634b91..72e106b60bc5 100644
> --- a/arch/riscv/include/asm/fixmap.h
> +++ b/arch/riscv/include/asm/fixmap.h
> @@ -26,7 +26,7 @@ enum fixed_addresses {
> };
>
> #define FIXADDR_SIZE (__end_of_fixed_addresses * PAGE_SIZE)
> -#define FIXADDR_TOP (VMALLOC_START)
> +#define FIXADDR_TOP (VMEMMAP_START)
> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
>
> #define FIXMAP_PAGE_IO PAGE_KERNEL
> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> index 8ddb6c7fedac..83830997dce6 100644
> --- a/arch/riscv/include/asm/page.h
> +++ b/arch/riscv/include/asm/page.h
> @@ -100,8 +100,10 @@ extern unsigned long min_low_pfn;
> #define page_to_bus(page) (page_to_phys(page))
> #define phys_to_page(paddr) (pfn_to_page(phys_to_pfn(paddr)))
>
> +#if defined(CONFIG_FLATMEM)
> #define pfn_valid(pfn) \
> (((pfn) >= pfn_base) && (((pfn)-pfn_base) < max_mapnr))
> +#endif
>
> #define ARCH_PFN_OFFSET (pfn_base)
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next prev parent reply other threads:[~2019-08-14 16:56 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 20:39 [PATCH v4 0/2] [PATCH v2 0/6] sparsemem support for RISC-V Logan Gunthorpe
2019-01-09 20:39 ` [PATCH v4 1/2] sh: mm: make use of new memblocks_present() helper Logan Gunthorpe
2019-01-15 13:58 ` Christoph Hellwig
2019-01-15 17:30 ` Logan Gunthorpe
2019-01-09 20:39 ` [PATCH v4 2/2] RISC-V: Implement sparsemem Logan Gunthorpe
2019-01-15 13:58 ` Christoph Hellwig
2019-07-31 6:30 ` Greentime Hu
2019-07-31 17:07 ` Logan Gunthorpe
2019-08-01 3:34 ` Greentime Hu
[not found] ` <CAEbi=3eZcgWevpX9VO9ohgxVDFVprk_t52Xbs3-TdtZ+js3NVA@mail.gmail.com>
2019-08-09 15:46 ` Logan Gunthorpe
2019-08-09 17:01 ` Greentime Hu
2019-08-09 19:03 ` Logan Gunthorpe
2019-08-12 4:01 ` Greentime Hu
2019-08-12 15:51 ` Logan Gunthorpe
2019-08-13 6:04 ` Greentime Hu
2019-08-13 16:14 ` Logan Gunthorpe
2019-08-13 16:39 ` Paul Walmsley
2019-08-13 16:48 ` Paul Walmsley
2019-08-13 16:49 ` Logan Gunthorpe
2019-08-14 13:35 ` Greentime Hu
2019-08-14 16:56 ` Logan Gunthorpe [this message]
2019-08-14 17:40 ` Paul Walmsley
2019-08-14 17:46 ` Logan Gunthorpe
2019-08-14 20:09 ` Paul Walmsley
2019-08-14 22:21 ` Logan Gunthorpe
2019-08-15 9:31 ` Greentime Hu
2019-08-15 16:20 ` Logan Gunthorpe
2019-08-16 2:07 ` Greentime Hu
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