linux-kernel - [PATCH v3 2/6] coccinelle: misc: Add field

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Message-ID: <20250417-field_modify-v3-2-6f7992aafcb7@quicinc.com>
Date: Thu, 17 Apr 2025 18:47:09 +0800
From: Luo Jie <quic_luoj@...cinc.com>
To: Yury Norov <yury.norov@...il.com>,
        Rasmus Villemoes
	<linux@...musvillemoes.dk>,
        Julia Lawall <Julia.Lawall@...ia.fr>,
        "Nicolas
 Palix" <nicolas.palix@...g.fr>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>,
        Oliver Upton
	<oliver.upton@...ux.dev>,
        Joey Gouly <joey.gouly@....com>,
        Suzuki K Poulose
	<suzuki.poulose@....com>,
        Zenghui Yu <yuzenghui@...wei.com>
CC: <linux-kernel@...r.kernel.org>, <cocci@...ia.fr>,
        <linux-arm-kernel@...ts.infradead.org>, <kvmarm@...ts.linux.dev>,
        <andrew@...n.ch>, <quic_kkumarcs@...cinc.com>,
        <quic_linchen@...cinc.com>, <quic_leiwei@...cinc.com>,
        <quic_suruchia@...cinc.com>, <quic_pavir@...cinc.com>,
        Luo Jie <quic_luoj@...cinc.com>
Subject: [PATCH v3 2/6] coccinelle: misc: Add field_modify script

This script finds and suggests conversions of opencoded field
modify patterns with the wrapper FIELD_MODIFY() API defined in
include/linux/bitfield.h for better readability.

Signed-off-by: Luo Jie <quic_luoj@...cinc.com>
---
 scripts/coccinelle/misc/field_modify.cocci | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/scripts/coccinelle/misc/field_modify.cocci b/scripts/coccinelle/misc/field_modify.cocci
new file mode 100644
index 000000000000..9022c1b23291
--- /dev/null
+++ b/scripts/coccinelle/misc/field_modify.cocci
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Replaced below code with the wrapper FIELD_MODIFY(MASK, &reg, val)
+/// - reg &= ~MASK;
+/// - reg |= FIELD_PREP(MASK, val);
+//
+// Confidence: High
+// Author: Luo Jie <quic_luoj@...cinc.com>
+// Copyright (C) 2025 Qualcomm Innovation Center, Inc.
+// URL: https://coccinelle.gitlabpages.inria.fr/website
+// Keywords: FIELD_PREP, FIELD_MODIFY
+// Options: --include-headers
+
+virtual patch
+
+@...ends on patch@
+identifier reg, val;
+constant mask;
+symbol FIELD_PREP, FIELD_MODIFY;
+@@
+
+- reg &= ~mask;
+- reg |= FIELD_PREP(mask, val);
++ FIELD_MODIFY(mask, &reg, val);

-- 
2.34.1