linux-kernel - Re: [PATCH v11 07/22] riscv: mm: Add p?d_leaf() definitions

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Date:   Wed, 9 Oct 2019 11:55:43 +0100
From:   Steven Price <steven.price@....com>
To:     Paul Walmsley <paul.walmsley@...ive.com>, alex@...ti.fr
Cc:     Mark Rutland <Mark.Rutland@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, linux-mm@...ck.org,
        Albert Ou <aou@...s.berkeley.edu>,
        "H. Peter Anvin" <hpa@...or.com>, linux-riscv@...ts.infradead.org,
        Will Deacon <will@...nel.org>,
        "Liang, Kan" <kan.liang@...ux.intel.com>, x86@...nel.org,
        Ingo Molnar <mingo@...hat.com>,
        Palmer Dabbelt <palmer@...ive.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jérôme Glisse <jglisse@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-arm-kernel@...ts.infradead.org,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        linux-kernel@...r.kernel.org, James Morse <james.morse@....com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v11 07/22] riscv: mm: Add p?d_leaf() definitions

On 08/10/2019 22:33, Paul Walmsley wrote:
> On Mon, 7 Oct 2019, Steven Price wrote:
> 
>> walk_page_range() is going to be allowed to walk page tables other than
>> those of user space. For this it needs to know when it has reached a
>> 'leaf' entry in the page tables. This information is provided by the
>> p?d_leaf() functions/macros.
>>
>> For riscv a page is a leaf page when it has a read, write or execute bit
>> set on it.
>>
>> CC: Palmer Dabbelt <palmer@...ive.com>
>> CC: Albert Ou <aou@...s.berkeley.edu>
>> CC: linux-riscv@...ts.infradead.org
>> Signed-off-by: Steven Price <steven.price@....com>
> 
> Acked-by: Paul Walmsley <paul.walmsley@...ive.com> # for arch/riscv  
> 
> Alex has a good point, but probably the right thing to do is to replace 
> the contents of the arch/riscv/mm/hugetlbpage.c p{u,m}d_huge() functions 
> with calls to Steven's new static inline functions.

The intention is to create new functions that are not dependent on
hugepage support in user space. hugetlbpage.c is only built if
CONFIG_HUGETLB_PAGE is defined.

As you say - the p{u,m}d_huge() functions can be reimplemented using the
new static inline functions if desired.

Thanks for the review.

Steve

> 
> - Paul
> 
> _______________________________________________
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> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

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