[PATCH v4 03/10] arm64: cpufeature: Correctly display signed override values

From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	James Morse <james.morse@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Zenghui Yu <yuzenghui@huawei.com>
Subject: [PATCH v4 03/10] arm64: cpufeature: Correctly display signed override values
Date: Mon, 22 Jan 2024 18:13:37 +0000	[thread overview]
Message-ID: <20240122181344.258974-4-maz@kernel.org> (raw)
In-Reply-To: <20240122181344.258974-1-maz@kernel.org>

When a field gets overriden, the kernel indicates the result of
the override in dmesg. This works well with unsigned fields, but
results in a pretty ugly output when the field is signed.

Truncate the field to its width before displaying it.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kernel/cpufeature.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 92b1546f2622..bae5d0655262 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -949,7 +949,8 @@ static void init_cpu_ftr_reg(u32 sys_reg, u64 new)
 				pr_warn("%s[%d:%d]: %s to %llx\n",
 					reg->name,
 					ftrp->shift + ftrp->width - 1,
-					ftrp->shift, str, tmp);
+					ftrp->shift, str,
+					tmp & (BIT(ftrp->width) - 1));
 		} else if ((ftr_mask & reg->override->val) == ftr_mask) {
 			reg->override->val &= ~ftr_mask;
 			pr_warn("%s[%d:%d]: impossible override, ignored\n",
-- 
2.39.2

