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Subject: Re: [PATCH v14 5/8] arm64: mte: Enable TCO in functions that can read
 beyond buffer limits
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kasan-dev@googlegroups.com,
        Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
References: <20210308161434.33424-1-vincenzo.frascino@arm.com>
 <20210308161434.33424-6-vincenzo.frascino@arm.com>
 <20210308180910.GB17002@C02TD0UTHF1T.local>
From:   Vincenzo Frascino <vincenzo.frascino@arm.com>
Message-ID: <42b39ecc-4f97-63bf-cdab-2ba4817b8610@arm.com>
Date:   Tue, 9 Mar 2021 10:26:54 +0000
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On 3/8/21 6:09 PM, Mark Rutland wrote:
>> +DECLARE_STATIC_KEY_FALSE(mte_async_mode);
> Can we please hide this behind something like:
> 
> static inline bool system_uses_mte_async_mode(void)
> {
> 	return IS_ENABLED(CONFIG_KASAN_HW_TAGS) &&
> 		static_branch_unlikely(&mte_async_mode);
> }
> 
> ... like we do for system_uses_ttbr0_pan()?
>

I agree, it is a cleaner solution. I will add it to v15.

> That way the callers are easier to read, and kernels built without
> CONFIG_KASAN_HW_TAGS don't have the static branch at all. I reckon you
> can put that in one of hte mte headers and include it where needed.

-- 
Regards,
Vincenzo