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Date:   Mon, 18 Feb 2019 12:29:22 +0100
From:   Peter Zijlstra <peterz@infradead.org>
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>,
        =?iso-8859-1?B?Suly9G1l?= Glisse <jglisse@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <will.deacon@arm.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/13] arm64: mm: Add p?d_large() definitions
Message-ID: <20190218112922.GT32477@hirez.programming.kicks-ass.net>
References: <20190215170235.23360-1-steven.price@arm.com>
 <20190215170235.23360-2-steven.price@arm.com>
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On Fri, Feb 15, 2019 at 05:02:22PM +0000, Steven Price wrote:

> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index de70c1eabf33..09d308921625 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -428,6 +428,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
>  				 PMD_TYPE_TABLE)
>  #define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
>  				 PMD_TYPE_SECT)
> +#define pmd_large(x)		pmd_sect(x)
>  
>  #if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3
>  #define pud_sect(pud)		(0)
> @@ -435,6 +436,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
>  #else
>  #define pud_sect(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \
>  				 PUD_TYPE_SECT)
> +#define pud_large(x)		pud_sect(x)
>  #define pud_table(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \
>  				 PUD_TYPE_TABLE)
>  #endif

So on x86 p*d_large() also matches p*d_huge() and thp, But it is not
clear to me this p*d_sect() thing does so, given your definitions.

See here why I care:

  http://lkml.kernel.org/r/20190201124741.GE31552@hirez.programming.kicks-ass.net