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Date:   Fri, 18 Sep 2020 15:00:37 +0200
From:   Marco Elver <elver@google.com>
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        kasan-dev@googlegroups.com,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Elena Petrova <lenaptr@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 23/37] arm64: kasan: Add arch layer for memory tagging
 helpers
Message-ID: <20200918130037.GE2384246@elver.google.com>
References: <cover.1600204505.git.andreyknvl@google.com>
 <b52bdc9fc7fd11bf3e0003c96855bb4c191cc4fa.1600204505.git.andreyknvl@google.com>
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On Tue, Sep 15, 2020 at 11:16PM +0200, 'Andrey Konovalov' via kasan-dev wrote:
> This patch add a set of arch_*() memory tagging helpers currently only
> defined for arm64 when hardware tag-based KASAN is enabled. These helpers
> will be used by KASAN runtime to implement the hardware tag-based mode.
> 
> The arch-level indirection level is introduced to simplify adding hardware
> tag-based KASAN support for other architectures in the future by defining
> the appropriate arch_*() macros.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> ---
> Change-Id: I42b0795a28067872f8308e00c6f0195bca435c2a
> ---
>  arch/arm64/include/asm/memory.h |  8 ++++++++
>  mm/kasan/kasan.h                | 19 +++++++++++++++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index e424fc3a68cb..268a3b6cebd2 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -231,6 +231,14 @@ static inline const void *__tag_set(const void *addr, u8 tag)
>  	return (const void *)(__addr | __tag_shifted(tag));
>  }
>  
> +#ifdef CONFIG_KASAN_HW_TAGS
> +#define arch_init_tags(max_tag)			mte_init_tags(max_tag)
> +#define arch_get_random_tag()			mte_get_random_tag()
> +#define arch_get_mem_tag(addr)			mte_get_mem_tag(addr)
> +#define arch_set_mem_tag_range(addr, size, tag)	\
> +			mte_set_mem_tag_range((addr), (size), (tag))

Suggested edit below, assuming you're fine with checkpatch.pl's new
100col limit:

-#define set_mem_tag_range(addr, size, tag)	\
-				arch_set_mem_tag_range((addr), (size), (tag))
+#define set_mem_tag_range(addr, size, tag)	arch_set_mem_tag_range((addr), (size), (tag))