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From:   Anup Patel <anup@brainfault.org>
Date:   Fri, 5 Apr 2019 09:44:02 +0530
Message-ID: <CAAhSdy0Hz25LYwA6U0byRfbbmgorjiTUhyHs8sQ81=qvhPANrw@mail.gmail.com>
Subject: Re: [PATCH v8 06/20] riscv: mm: Add p?d_large() definitions
To:     Steven Price <steven.price@arm.com>
Cc:     linux-mm@kvack.org, Andy Lutomirski <luto@kernel.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>,
        James Morse <james.morse@arm.com>,
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        Peter Zijlstra <peterz@infradead.org>,
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        "Liang, Kan" <kan.liang@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Palmer Dabbelt <palmer@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
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On Wed, Apr 3, 2019 at 7:47 PM Steven Price <steven.price@arm.com> 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_large() functions/macros.
>
> For riscv a page is large when it has a read, write or execute bit
> set on it.
>
> CC: Palmer Dabbelt <palmer@sifive.com>
> CC: Albert Ou <aou@eecs.berkeley.edu>
> CC: linux-riscv@lists.infradead.org
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
>  arch/riscv/include/asm/pgtable-64.h | 7 +++++++
>  arch/riscv/include/asm/pgtable.h    | 7 +++++++
>  2 files changed, 14 insertions(+)
>
> diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
> index 7aa0ea9bd8bb..73747d9d7c66 100644
> --- a/arch/riscv/include/asm/pgtable-64.h
> +++ b/arch/riscv/include/asm/pgtable-64.h
> @@ -51,6 +51,13 @@ static inline int pud_bad(pud_t pud)
>         return !pud_present(pud);
>  }
>
> +#define pud_large      pud_large
> +static inline int pud_large(pud_t pud)
> +{
> +       return pud_present(pud)
> +               && (pud_val(pud) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC));
> +}
> +
>  static inline void set_pud(pud_t *pudp, pud_t pud)
>  {
>         *pudp = pud;
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 1141364d990e..9570883c79e7 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -111,6 +111,13 @@ static inline int pmd_bad(pmd_t pmd)
>         return !pmd_present(pmd);
>  }
>
> +#define pmd_large      pmd_large
> +static inline int pmd_large(pmd_t pmd)
> +{
> +       return pmd_present(pmd)
> +               && (pmd_val(pmd) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC));
> +}
> +
>  static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
>  {
>         *pmdp = pmd;
> --
> 2.20.1
>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup