From nobody Tue Apr 7 05:57:29 2026 Received: from PH7PR06CU001.outbound.protection.outlook.com (mail-westus3azon11010014.outbound.protection.outlook.com [52.101.201.14]) (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 28A673DB62E; Thu, 2 Apr 2026 11:25:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.201.14 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775129112; cv=fail; b=rWDirXwqgIwg4gCMq5W+YMh70MRbjfNzH266Yv8ejzLozhukFFQDj7cH8exskdJnxw5LAVKdHK8tT2X1VuXLSURPWHBO810aIWcLk9RKg6hGsSFJPj+BFATox2XyCwgy+XMTNmBMDc6nr3BUKpDXxZncyN07/zHVicskL4Zp4aM= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775129112; c=relaxed/simple; bh=aa72g+kjmtrkaOUdelUMgIkbkvLcyaYu2EkrafpBqnk=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=I7bdIRF31Za6eZ/6x2vfSRz/7+LQlN9h041033DPNZaJVR/GEj0rROzURXg2BxYGtVa+pPXiaAVASptUjzZGPFeg+YI6NaE+o//5Dw3Sj7RmFf/PsV9h6mXMUvvSxwRa9KfE/ppJ3EZDAOBbYUmyFWEj27NPh2F3adaehiP+7Xw= 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=oAGg7lkA; arc=fail smtp.client-ip=52.101.201.14 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="oAGg7lkA" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=R2OalziUPqlOmTU4ufr2SJ6pnXmZJ97o9g+b1pVl8+/7C2znnVZwQu9HEz1qnYWt60a/dRd5KrTgDz8F05N32yIsLR7xHFyw34TI/NyIamN775jocD6zjW9aynZOERNj16apzt0CqZ123QTjDijZ/N+G2SVpfN50/He7fdK3dJwGOV0MGLrKkPZNs2qDq1+VCZCU6APARK3oGzs4U1nQ3PW32V/66T+AmxeOUFFVw5ye+ZR3ddVtsLlr5UJT+fyJLRRhVyR+jUgXcORytpUFa4Hga+lr6vSw+Ez8Cweq0FrAcvKMZzsh8pERtIVnbre2HA3MxRiAIeyBHIKd8gAiew== 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=RHSa+xo/iTViJb7JDvDPIatbIaKCf8lHcG1QohC93pA=; b=GpsN/7VPlFvjhEhooiJYcbCadHd4c0Iue+G5hXnkLiF7SHJjXuGClx6ifyxqC3uPxLQ3Kod6lQnyL6x8ffCw5ent+jswuAQNvv8lj+daJBqevSKbzXnoMt0vkQHilHIN2Q3fsaSTfQaBzriNq20F05Yo4NdGyU2MGx+bsT7/gfN9WeBaXnY6L/+2ZDgX30nAMh42V3DTvUqNlOknn2wQ0G5PBD8Kqs2FNTLBubkQwc38595J6g2zbGrPzm2/7iFND49uFqe5J/351UnqM9tMSyKLOMWu29E1KPl+9BPE9FDLlbFm/OZgMsaF/upWAOtb52GpYFT5KpmqBroOX/A4Rg== 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=RHSa+xo/iTViJb7JDvDPIatbIaKCf8lHcG1QohC93pA=; b=oAGg7lkAaeBy5aAWHPDrNT8ymzVfdkc/oRo4eYCUj9QPg7U1BHBQzRH/Kp/HBkzVcdzn5CN0FsHR5Md+6c0YeMr6z5XrmIVv8RiP84oJ82EtlzPgfqkN6ZIFuLny7QKnnlkTL3+T7TXTDcJtOjB/yT1qQsdywEf4Pb8BxWFL5AA= Received: from BY1P220CA0017.NAMP220.PROD.OUTLOOK.COM (2603:10b6:a03:5c3::6) by MW4PR12MB5602.namprd12.prod.outlook.com (2603:10b6:303:169::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.17; Thu, 2 Apr 2026 11:24:56 +0000 Received: from BY1PEPF0001AE17.namprd04.prod.outlook.com (2603:10b6:a03:5c3:cafe::c6) by BY1P220CA0017.outlook.office365.com (2603:10b6:a03:5c3::6) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9769.20 via Frontend Transport; Thu, 2 Apr 2026 11:24:56 +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 BY1PEPF0001AE17.mail.protection.outlook.com (10.167.242.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.17 via Frontend Transport; Thu, 2 Apr 2026 11:24:56 +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; Thu, 2 Apr 2026 06:24:37 -0500 From: K Prateek Nayak To: Thomas Gleixner , Ingo Molnar , "Peter Zijlstra" , Sebastian Andrzej Siewior , Paul Walmsley , Palmer Dabbelt , Albert Ou , Samuel Holland , David Laight CC: Darren Hart , Davidlohr Bueso , =?UTF-8?q?Andr=C3=A9=20Almeida?= , , , , , , K Prateek Nayak , Alexandre Ghiti , Charlie Jenkins , Charles Mirabile Subject: [PATCH v3 4/7] riscv/runtime-const: Introduce runtime_const_mask_32() Date: Thu, 2 Apr 2026 11:22:47 +0000 Message-ID: <20260402112250.2138-5-kprateek.nayak@amd.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260402112250.2138-1-kprateek.nayak@amd.com> References: <20260402112250.2138-1-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: satlexmb08.amd.com (10.181.42.217) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BY1PEPF0001AE17:EE_|MW4PR12MB5602:EE_ X-MS-Office365-Filtering-Correlation-Id: 9b0bab9c-1928-4b5f-9d81-08de90aa780a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700016|376014|1800799024|82310400026|7416014|56012099003|22082099003|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)(36860700016)(376014)(1800799024)(82310400026)(7416014)(56012099003)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: aKLCGsXlrPY0ulIXhwYdqgSAbafUs5KqMVtton1feddH2iliF6orIzjQRlx9+wM3G7fMOvQebn3qY8ocgEphomQRmKUFdxYqx/sJGZb2i4XoLAf2AqQit3ZYk1RV2+eYZ0PsszWd3RlmLmik839jiEg/yB0Ht9j8N0yld28ItOgPX/qqfaKZhcZCVS98WoeA0HdXOI6SXrB7fjm0RqKVAwptyfs9Up3svwsszgyuB+8Do6CzlGVk86n8wbH2NWRXGoGJcTn2RhWvs543zS8icTux4oTip6LfI4bhUdYoGywxyIGWT39u6nvyoz9cWiezEddf4XLQz+fF0PbC7/J4WGK0LbFDuzzQ++uvXBOVCS4Yl1f7gwMYlaZ/LzGEZrw+J4Om+Ux3D0l++17hKOYNyFrZfdRESLrhHOVkp7E+/YKPwHpXb14HHtTW3iTFjMS2 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Apr 2026 11:24:56.4585 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 9b0bab9c-1928-4b5f-9d81-08de90aa780a 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: BY1PEPF0001AE17.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB5602 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. The (__mask & val) operation is intentionally placed outside of asm block to allow compilers to further optimize it if possible. __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 --- Changelog v2..v3: o Moved the "&" operation outside the inline asm block to allow for compilers to further optimize it if possible. (Based on David's comment on ARM64 bits). --- arch/riscv/include/asm/runtime-const.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/arch/riscv/include/asm/runtime-const.h b/arch/riscv/include/as= m/runtime-const.h index d766e2b9e6df..85efba8ecf12 100644 --- a/arch/riscv/include/asm/runtime-const.h +++ b/arch/riscv/include/asm/runtime-const.h @@ -153,6 +153,22 @@ __ret; \ }) =20 +#define runtime_const_mask_32(val, sym) \ +({ \ + u32 __mask; \ + asm_inline(".option push\n\t" \ + ".option norvc\n\t" \ + "1:\t" \ + "lui %[__mask],0x89abd\n\t" \ + "addi %[__mask],%[__mask],-0x211\n\t" \ + ".option pop\n\t" \ + ".pushsection runtime_mask_" #sym ",\"a\"\n\t" \ + ".long 1b - .\n\t" \ + ".popsection" \ + : [__mask] "=3Dr" (__mask)); \ + (__mask & val); \ +}) + #define runtime_const_init(type, sym) do { \ extern s32 __start_runtime_##type##_##sym[]; \ extern s32 __stop_runtime_##type##_##sym[]; \ @@ -256,6 +272,12 @@ 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 2.34.1