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Subject: Re: [PATCH 22/35] arm64: mte: Enable in-kernel MTE
To:     Catalin Marinas <catalin.marinas@arm.com>,
        Andrey Konovalov <andreyknvl@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>, kasan-dev@googlegroups.com,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@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
References: <cover.1597425745.git.andreyknvl@google.com>
 <6a83a47d9954935d37a654978e96c951cc56a2f6.1597425745.git.andreyknvl@google.com>
 <20200827100155.GD29264@gaia>
From:   Vincenzo Frascino <vincenzo.frascino@arm.com>
Message-ID: <a9ca504c-70cb-2fea-77dc-c02ba9dd3a7e@arm.com>
Date:   Thu, 27 Aug 2020 11:46:07 +0100
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On 8/27/20 11:01 AM, Catalin Marinas wrote:
> On Fri, Aug 14, 2020 at 07:27:04PM +0200, Andrey Konovalov wrote:
>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>> index 4d3abb51f7d4..4d94af19d8f6 100644
>> --- a/arch/arm64/kernel/cpufeature.c
>> +++ b/arch/arm64/kernel/cpufeature.c
>> @@ -1670,6 +1670,9 @@ static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap)
>>  	write_sysreg_s(0, SYS_TFSR_EL1);
>>  	write_sysreg_s(0, SYS_TFSRE0_EL1);
>>  
>> +	/* Enable Match-All at EL1 */
>> +	sysreg_clear_set(tcr_el1, 0, SYS_TCR_EL1_TCMA1);
>> +
>>  	/*
>>  	 * CnP must be enabled only after the MAIR_EL1 register has been set
>>  	 * up. Inconsistent MAIR_EL1 between CPUs sharing the same TLB may
>> @@ -1687,6 +1690,9 @@ static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap)
>>  	mair &= ~MAIR_ATTRIDX(MAIR_ATTR_MASK, MT_NORMAL_TAGGED);
>>  	mair |= MAIR_ATTRIDX(MAIR_ATTR_NORMAL_TAGGED, MT_NORMAL_TAGGED);
>>  	write_sysreg_s(mair, SYS_MAIR_EL1);
>> +
>> +	/* Enable MTE Sync Mode for EL1 */
>> +	sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC);
> 
> In the 8th incarnation of the user MTE patches, this initialisation
> moved to proc.S before the MMU is initialised. When rebasing, please
> take this into account.
> 

Thank you for the heads up.

-- 
Regards,
Vincenzo