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From: Jia He <justin.he@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>,
	Mark Brown <broonie@kernel.org>,
	Sascha Bischoff <Sascha.Bischoff@arm.com>,
	Fuad Tabba <tabba@google.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Oliver Upton <oupton@kernel.org>,
	linux-kernel@vger.kernel.org, Bin Guo <guobin@linux.alibaba.com>,
	Jia He <justin.he@arm.com>
Subject: [PATCH] arm64/sysreg: Fix BWE field encoding in ID_AA64DFR2_EL1
Date: Tue, 30 Jun 2026 22:23:47 +0000	[thread overview]
Message-ID: <20260630222347.1449737-1-justin.he@arm.com> (raw)

Commit 93d7356e4b30 ("arm64: sysreg: Describe ID_AA64DFR2_EL1 fields")
encodes the FEAT_BWE2 value of the BWE field as '0b0002'. Binary
literals only accept the digits 0 and 1, so the intended value is 2,
i.e. 0b0010.

The macro generated by gen-sysreg.awk currently expands to
	#define ID_AA64DFR2_EL1_BWE_FEAT_BWE2 UL(0b0002)
is not legal C and would fail to compile if any in-tree code referenced
it. At present no caller uses this enum value, so the kernel still
builds cleanly, but the bug is latent.

Fix the typo by using the correct binary literal 0b0010.

Cc: Bin Guo <guobin@linux.alibaba.com>
Fixes: 93d7356e4b30 ("arm64: sysreg: Describe ID_AA64DFR2_EL1 fields")
Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index bc1788b1662b..7cb61aca3797 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1806,7 +1806,7 @@ Res0	15:8
 UnsignedEnum	7:4	BWE
 	0b0000	NI
 	0b0001	FEAT_BWE
-	0b0002	FEAT_BWE2
+	0b0010	FEAT_BWE2
 EndEnum
 UnsignedEnum	3:0	STEP
 	0b0000	NI
-- 
2.34.1



             reply	other threads:[~2026-06-30 22:24 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-30 22:23 Jia He [this message]
2026-07-01 14:29 ` [PATCH] arm64/sysreg: Fix BWE field encoding in ID_AA64DFR2_EL1 Marc Zyngier
2026-07-01 17:09 ` Oliver Upton
2026-07-02 12:58 ` Will Deacon

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