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From: Marc Zyngier <maz@kernel.org>
To: <yee.lee@mediatek.com>
Cc: <linux-kernel@vger.kernel.org>, <nicholas.Tang@mediatek.com>,
	<Kuan-Ying.lee@mediatek.com>, <chinwen.chang@mediatek.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	David Brazdil <dbrazdil@google.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ionela Voinescu <ionela.voinescu@arm.com>,
	Amit Daniel Kachhap <amit.kachhap@arm.com>,
	Quentin Perret <qperret@google.com>,
	Andrew Scull <ascull@google.com>,
	James Morse <james.morse@arm.com>, Fuad Tabba <tabba@google.com>,
	"moderated list:ARM64\ PORT (AARCH64 ARCHITECTURE)"
	<linux-arm-kernel@lists.infradead.org>,
	"moderated list:ARM/Mediatek SoC support"
	<linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH 1/1] arm64/cpufeature: Add option to disable mte support
Date: Wed, 28 Jul 2021 11:04:53 +0100	[thread overview]
Message-ID: <871r7ieou2.wl-maz@kernel.org> (raw)
In-Reply-To: <20210728094302.9949-2-yee.lee@mediatek.com>

On Wed, 28 Jul 2021 10:42:58 +0100,
<yee.lee@mediatek.com> wrote:
> 
> From: Yee Lee <yee.lee@mediatek.com>
> 
> Add a static key to exapnd the logic of system_supports_mte().
> This function controls mte enablement in both EL1 and EL0.
> 
> The static key, "arm64_mte_support" is default true and can
> be disabled via the early_param.
> 
> Signed-off-by: Yee Lee <yee.lee@mediatek.com>
> ---
>  arch/arm64/include/asm/cpufeature.h |  4 +++-
>  arch/arm64/kernel/cpufeature.c      | 13 +++++++++++++
>  arch/arm64/kernel/image-vars.h      |  3 +++
>  3 files changed, 19 insertions(+), 1 deletion(-)

This seems terribly complicated. How about this instead ("arm64.nomte"
on the command line)?

Thanks,

	M.

diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 53a381a7f65d..eaf17beb2420 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -54,6 +54,7 @@ static const struct ftr_set_desc pfr1 __initconst = {
 	.override	= &id_aa64pfr1_override,
 	.fields		= {
 	        { "bt", ID_AA64PFR1_BT_SHIFT },
+	        { "mte", ID_AA64PFR1_MTE_SHIFT },
 		{}
 	},
 };
@@ -100,6 +101,7 @@ static const struct {
 	{ "arm64.nopauth",
 	  "id_aa64isar1.gpi=0 id_aa64isar1.gpa=0 "
 	  "id_aa64isar1.api=0 id_aa64isar1.apa=0"	   },
+	{ "arm64.nomte",		"id_aa64pfr1.mte=0" },
 	{ "nokaslr",			"kaslr.disabled=1" },
 };
 

-- 
Without deviation from the norm, progress is not possible.

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      parent reply	other threads:[~2021-07-28 10:07 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-28  9:42 [PATCH 0/1] arm64/cpufeature: Add an option for mte support yee.lee
2021-07-28  9:42 ` [PATCH 1/1] arm64/cpufeature: Add option to disable " yee.lee
2021-07-28  9:59   ` Suzuki K Poulose
2021-07-28 10:05     ` Marc Zyngier
2021-07-28 10:04   ` Marc Zyngier [this message]

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