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From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
	 Will Deacon <will@kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>,
	 Jackson Cooper-Driver <Jackson.Cooper-Driver@arm.com>,
	 linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,  Mark Brown <broonie@kernel.org>
Subject: [PATCH v2 2/2] arm64/sme: Restore SMCR_EL1.EZT0 on exit from suspend
Date: Sat, 03 Feb 2024 13:00:41 +0000	[thread overview]
Message-ID: <20240203-arm64-sme-resume-v2-2-a1fbaddc4425@kernel.org> (raw)
In-Reply-To: <20240203-arm64-sme-resume-v2-0-a1fbaddc4425@kernel.org>

The fields in SMCR_EL1 reset to an architecturally UNKNOWN value. Since we
do not otherwise manage the traps configured in this register at runtime we
need to reconfigure them after a suspend in case nothing else was kind
enough to preserve them for us. Do so for SMCR_EL1.EZT0.

Fixes: d4913eee152d (arm64/sme: Add basic enumeration for SME2)
Reported-by: Jackson Cooper-Driver <Jackson.Cooper-Driver@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/kernel/fpsimd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 8d2a5824d5d3..7a7c056f0647 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1320,6 +1320,8 @@ void sme_suspend_exit(void)
 
 	if (system_supports_fa64())
 		smcr |= SMCR_ELx_FA64;
+	if (system_supports_sme2())
+		smcr |= SMCR_ELx_EZT0;
 
 	write_sysreg_s(smcr, SYS_SMCR_EL1);
 	write_sysreg_s(0, SYS_SMPRI_EL1);

-- 
2.30.2


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      parent reply	other threads:[~2024-02-03 13:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-03 13:00 [PATCH v2 0/2] arm64/sme: Fix handling of traps on resume Mark Brown
2024-02-03 13:00 ` [PATCH v2 1/2] arm64/sme: Restore SMCR on exit from suspend Mark Brown
2024-02-09 16:46   ` Will Deacon
2024-02-09 17:25     ` Mark Brown
2024-02-03 13:00 ` Mark Brown [this message]

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