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From: Peter Collingbourne <pcc@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	 Will Deacon <will@kernel.org>,
	Andrey Konovalov <andreyknvl@gmail.com>
Cc: Peter Collingbourne <pcc@google.com>,
	Evgenii Stepanov <eugenis@google.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/2] arm64: add an MTE support check to the top of mte_thread_switch()
Date: Tue, 14 Sep 2021 14:54:28 -0700	[thread overview]
Message-ID: <20210914215429.745849-1-pcc@google.com> (raw)

This lets us avoid doing unnecessary work on hardware that does
not support MTE, and will allow us to freely use MTE instructions
in the code called by mte_thread_switch().

Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I02fd000d1ef2c86c7d2952a7f099b254ec227a5d
---
 arch/arm64/kernel/mte.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index 9d314a3bad3b..8fc2d90eeb00 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c
@@ -199,6 +199,9 @@ void mte_thread_init_user(void)
 
 void mte_thread_switch(struct task_struct *next)
 {
+	if (!system_supports_mte())
+		return;
+
 	mte_update_sctlr_user(next);
 
 	/*
-- 
2.33.0.309.g3052b89438-goog


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             reply	other threads:[~2021-09-14 21:56 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-14 21:54 Peter Collingbourne [this message]
2021-09-14 21:54 ` [PATCH v2 2/2] arm64: kasan: mte: move GCR_EL1 switch to task switch when KASAN disabled Peter Collingbourne
2021-09-15 17:59 ` [PATCH v2 1/2] arm64: add an MTE support check to the top of mte_thread_switch() Catalin Marinas
2021-09-15 19:04   ` Peter Collingbourne

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