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Date: Mon, 1 Sep 2025 17:53:55 +0100
From: Catalin Marinas <catalin.marinas@arm.com>
To: Yeoreum Yun <yeoreum.yun@arm.com>
Cc: ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com,
	dvyukov@google.com, vincenzo.frascino@arm.com, corbet@lwn.net,
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Subject: Re: [PATCH v6 1/2] kasan/hw-tags: introduce kasan.write_only option
Message-ID: <aLXPownoCikoHvZP@arm.com>
References: <20250901104623.402172-1-yeoreum.yun@arm.com>
 <20250901104623.402172-2-yeoreum.yun@arm.com>
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In-Reply-To: <20250901104623.402172-2-yeoreum.yun@arm.com>

On Mon, Sep 01, 2025 at 11:46:22AM +0100, Yeoreum Yun wrote:
> Since Armv8.9, FEATURE_MTE_STORE_ONLY feature is introduced to restrict
> raise of tag check fault on store operation only.
> Introcude KASAN write only mode based on this feature.
> 
> KASAN write only mode restricts KASAN checks operation for write only and
> omits the checks for fetch/read operations when accessing memory.
> So it might be used not only debugging enviroment but also normal
> enviroment to check memory safty.
> 
> This features can be controlled with "kasan.write_only" arguments.
> When "kasan.write_only=on", KASAN checks write operation only otherwise
> KASAN checks all operations.
> 
> This changes the MTE_STORE_ONLY feature as BOOT_CPU_FEATURE like
> ARM64_MTE_ASYMM so that makes it initialise in kasan_init_hw_tags()
> with other function together.
> 
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>