From nobody Tue Apr 7 05:58:51 2026 Received: from PH7PR06CU001.outbound.protection.outlook.com (mail-westus3azon11010005.outbound.protection.outlook.com [52.101.201.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C2A7A33FE05; Mon, 16 Mar 2026 05:25:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.201.5 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773638747; cv=fail; b=gz+dVK0Se83WRmZSce6ekcZYm5aCPmWGP5ibNbPBYHmoDoF1lw7/cglBCGRe6+1dMiF0xGBbt1bGjzNxuVb7QirGcrJ7FRCLqUnWPmOfBK2rHkUFC8VO0qWUvy8QmEOl5yWnaLNoiB9UupeVcxT03zzPXVhNtbW9hPQHkQJXi8Y= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773638747; c=relaxed/simple; bh=/IbkdJi9QawlvCBt92m9qyaUdU9rvkyrZ+98H6MCR1w=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=e9pSsXQ2DJZMoQj3Six0i6p0eub+kKtzuAFmK7uD1QRn5NvSLEHq1A5jhgiAIDWmSdOwGJGS0PVkrlRLeRFzq3fkU5Xropqld1YRwYJ6yjTdIBa58DHiDBCy4HUFSZt3Z3xg8GQxVktXvB2wZg81old6HecBXHn/Th9uljU8pdw= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=DinIt20O; arc=fail smtp.client-ip=52.101.201.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="DinIt20O" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=jQS4JnSA6qQMDyVA4o3tr7NI9dr8b3i/lmZQ+JAUDc3X+IGLKALVlQnFE3BrKPeS2POXaSTNDwy2B5TD0ksu7ZMnQfPoUFWwDiOzOo1oDSwNfbs5K5cl4dswk5Q26LCcGtmZ9FuhsyYbtn2oQ3om58yF78+TzMV8A7/v1sLEgpA67/ZsaatMNGl8MHtU1sBESZD8Dmo2MxQ3+cZD59dbiMPanRGsjZgjYo1Pe+vkcAMmJiX5a4OaOkmkohs/SXLnYpLo16WmYmrXNBZXOHBrJxTqqpXSg8DCZOZFNxtscTJdOTys62J2Bx2wb7aJkslK+15eMDdCucWpW2GffJY9ag== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=8IInZyX9l7F/pmWJSWhAWj1hnmM3CjZxxb7Wx5P05fs=; b=EBvmT5qL1iG3yCWWPbc+5gzg9lPocAnBQHEugUo5exHzg2AZed2hCFTa2YXi6AAP5pv1R6tdob60pWK9lZphOSBocBEfnO7Vz1b7NyrAuQEp0+9aNDpNCMq4cV4XEilAoFTBp5QQlPlI4DgBZrIKLbd1nfdfRYiLIpYOLH0CckDPits957ZOW6pD95O/trnflenRrSBk83I61tszAFdm6SEtYFn9wpA3E/ZSpcsP81xF7YF9IiZFf4kIuo7P2EoLqqUAKlUC0cPMQW9ccX51sBKRLKVoA52PjwEAFugDF6JuDeT+5rd+ufZTyt8RFmNPFxfvYRY7FSU3mvb8J0mRTA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=kernel.org smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=8IInZyX9l7F/pmWJSWhAWj1hnmM3CjZxxb7Wx5P05fs=; b=DinIt20O31LNxhf64qKQtNQbFF0L6BhGeR9zeBNgnw8RKb0racQGe2RVp2hlhYcYihzrMnstlUK8d4yTJUG+asPPebsyQ2wImNCyj+kVA8j8prbj2zlL/TXAJg4k9AwzonzMPDWEAMA5ny347yygOWiCbPewKRkFFlAoQNVHpLA= Received: from DS7PR03CA0125.namprd03.prod.outlook.com (2603:10b6:5:3b4::10) by SA5PPFCAFD069B8.namprd12.prod.outlook.com (2603:10b6:80f:fc04::8e1) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.16; Mon, 16 Mar 2026 05:25:38 +0000 Received: from DS1PEPF00017096.namprd05.prod.outlook.com (2603:10b6:5:3b4:cafe::5c) by DS7PR03CA0125.outlook.office365.com (2603:10b6:5:3b4::10) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9700.25 via Frontend Transport; Mon, 16 Mar 2026 05:25:36 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by DS1PEPF00017096.mail.protection.outlook.com (10.167.18.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9700.17 via Frontend Transport; Mon, 16 Mar 2026 05:25:38 +0000 Received: from BLRKPRNAYAK.amd.com (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Mon, 16 Mar 2026 00:25:33 -0500 From: K Prateek Nayak To: Thomas Gleixner , Ingo Molnar , "Peter Zijlstra" , Sebastian Andrzej Siewior , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti CC: Darren Hart , Davidlohr Bueso , =?UTF-8?q?Andr=C3=A9=20Almeida?= , , , , , , K Prateek Nayak , Charlie Jenkins , Charles Mirabile Subject: [RFC PATCH v2 4/7] riscv/runtime-const: Introduce runtime_const_mask_32() Date: Mon, 16 Mar 2026 05:23:58 +0000 Message-ID: <20260316052401.18910-5-kprateek.nayak@amd.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260316052401.18910-1-kprateek.nayak@amd.com> References: <20260316052401.18910-1-kprateek.nayak@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS1PEPF00017096:EE_|SA5PPFCAFD069B8:EE_ X-MS-Office365-Filtering-Correlation-Id: 1d7e1b82-faae-4dcc-05a7-08de831c758f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|36860700016|7416014|82310400026|1800799024|22082099003|56012099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(376014)(36860700016)(7416014)(82310400026)(1800799024)(22082099003)(56012099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 1DYWVfhOo+e288MSLDszrtZ2THH2KdmD+OdoxJ5H8QP+uftVa1q2jSZV5dxIS3LSPVVMk+DFCK4rU4ETReiXcSkBQVsFcow15QxOfK8k1LjgYwhACuNQtVMs91OzF2tKyQ4lNjVgc6/9ExQqhA+FND7fPq4gkBoDUmHCjeA0VMEZyhxZ+Co/9w4mFEGJbRaEsGVFCWuOob19VngGcpCZvsNnePEX9FVIAOVwJQUuYB2u1wOhkag0iezEtsujPfL5dUbJWqet0qzZFXpMS7teyiFe0tfBe5V5DVcG203tebfO8JZ8QlZuxAPXmt7XmmwnqHBAucB51cxoa5VeqkQHITOZn+4A4uvubq6A76veArefT2W1yf0l0bkW9Ptk3ri14PUdnTiRwTnTR9kWustc8hvYvxircEwdONJpcQzRtZbAg7m5Oi0sO89bezMWQzgb X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Mar 2026 05:25:38.7028 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 1d7e1b82-faae-4dcc-05a7-08de831c758f X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS1PEPF00017096.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA5PPFCAFD069B8 Content-Type: text/plain; charset="utf-8" Futex hash computation requires a mask operation with read-only after init data that will be converted to a runtime constant in the subsequent commit. Introduce runtime_const_mask_32 to further optimize the mask operation in the futex hash computation hot path. GCC generates a: lui a0, 0x12346 # upper; +0x800 then >>12 for correct rounding addi a0, a0, 0x678 # lower 12 bits and a1, a1, a0 # a1 =3D a1 & a0 pattern to tackle arbitrary 32-bit masks and the same was also suggested by Claude which is implemented here. __runtime_fixup_ptr() already patches a "lui + addi" sequence which has been reused to patch the same sequence for __runtime_fixup_mask(). Assisted-by: Claude:claude-sonnet-4-5 Signed-off-by: K Prateek Nayak --- arch/riscv/include/asm/runtime-const.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/arch/riscv/include/asm/runtime-const.h b/arch/riscv/include/as= m/runtime-const.h index d766e2b9e6df..f54289a7ddeb 100644 --- a/arch/riscv/include/asm/runtime-const.h +++ b/arch/riscv/include/asm/runtime-const.h @@ -153,6 +153,24 @@ __ret; \ }) =20 +#define runtime_const_mask_32(val, sym) \ +({ \ + u32 __ret; \ + asm_inline(".option push\n\t" \ + ".option norvc\n\t" \ + "1:\t" \ + "lui %[__ret],0x89abd\n\t" \ + "addi %[__ret],%[__ret],-0x211\n\t" \ + "and %[__ret],%[__ret],%[__val]\n\t" \ + ".option pop\n\t" \ + ".pushsection runtime_mask_" #sym ",\"a\"\n\t" \ + ".long 1b - .\n\t" \ + ".popsection" \ + : [__ret] "=3D&r" (__ret) \ + : [__val] "r" (val)); \ + __ret; \ +}) + #define runtime_const_init(type, sym) do { \ extern s32 __start_runtime_##type##_##sym[]; \ extern s32 __stop_runtime_##type##_##sym[]; \ @@ -256,6 +274,12 @@ static inline void __runtime_fixup_shift(void *where, = unsigned long val) mutex_unlock(&text_mutex); } =20 +static inline void __runtime_fixup_mask(void *where, unsigned long val) +{ + __runtime_fixup_32(where, where + 4, val); + __runtime_fixup_caches(where, 2); +} + static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), unsigned long val, s32 *start, s32 *end) { --=20 2.43.0