linux-kernel - Re: [PATCH v10 05/22] mips: mm: Add p?d

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190731183553.klqcwrvannde5vd7@pburton-laptop>
Date:   Wed, 31 Jul 2019 18:35:54 +0000
From:   Paul Burton <paul.burton@...s.com>
To:     Steven Price <steven.price@....com>
CC:     "linux-mm@...ck.org" <linux-mm@...ck.org>,
        Andy Lutomirski <luto@...nel.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...en8.de>,
        Catalin Marinas <catalin.marinas@....com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        James Morse <james.morse@....com>,
        Jérôme Glisse <jglisse@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Will Deacon <will@...nel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Mark Rutland <Mark.Rutland@....com>,
        "Liang, Kan" <kan.liang@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        James Hogan <jhogan@...nel.org>,
        "linux-mips@...r.kernel.org" <linux-mips@...r.kernel.org>
Subject: Re: [PATCH v10 05/22] mips: mm: Add p?d_leaf() definitions

Hi Steven,

On Wed, Jul 31, 2019 at 04:45:46PM +0100, 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.
> 
> If _PAGE_HUGE is defined we can simply look for it. When not defined we
> can be confident that there are no leaf pages in existence and fall back
> on the generic implementation (added in a later patch) which returns 0.
> 
> CC: Ralf Baechle <ralf@...ux-mips.org>
> CC: Paul Burton <paul.burton@...s.com>
> CC: James Hogan <jhogan@...nel.org>
> CC: linux-mips@...r.kernel.org
> Signed-off-by: Steven Price <steven.price@....com>

Acked-by: Paul Burton <paul.burton@...s.com>

Thanks,
    Paul

> ---
>  arch/mips/include/asm/pgtable.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index 7d27194e3b45..238ca243ad31 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -627,6 +627,11 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
>  
>  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>  
> +#ifdef _PAGE_HUGE
> +#define pmd_leaf(pmd)	((pmd_val(pmd) & _PAGE_HUGE) != 0)
> +#define pud_leaf(pud)	((pud_val(pud) & _PAGE_HUGE) != 0)
> +#endif
> +
>  #define gup_fast_permitted(start, end)	(!cpu_has_dc_aliases)
>  
>  #include <asm-generic/pgtable.h>
> -- 
> 2.20.1
>