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[23.128.96.18]) by mx.google.com with ESMTP id d1si3047165edr.360.2020.04.15.14.47.28; Wed, 15 Apr 2020 14:47:52 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503170AbgDNSAa convert rfc822-to-8bit (ORCPT + 99 others); Tue, 14 Apr 2020 14:00:30 -0400 Received: from mga05.intel.com ([192.55.52.43]:8797 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2503161AbgDNSAY (ORCPT ); Tue, 14 Apr 2020 14:00:24 -0400 IronPort-SDR: 1X7DPwPJQiLnDsqXKS5iAizHQH4CxA/e2cg97tAXQxGk7O5jshKpvlB7wtGM2t2uxKrQWbDpqx aIc7vR4EqYKw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2020 11:00:23 -0700 IronPort-SDR: BJ8Yd0vwgZtKtR9gvTVC3zAxgOeegZUqINl7BRHh3C1dt6lIEcB2hhOSnbSevBceVDWfbh6CGp xQ1CKt1EY1+w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,383,1580803200"; d="scan'208";a="242066029" Received: from orsmsx104.amr.corp.intel.com ([10.22.225.131]) by orsmga007.jf.intel.com with ESMTP; 14 Apr 2020 11:00:23 -0700 Received: from orsmsx122.amr.corp.intel.com (10.22.225.227) by ORSMSX104.amr.corp.intel.com (10.22.225.131) with Microsoft SMTP Server (TLS) id 14.3.439.0; Tue, 14 Apr 2020 11:00:22 -0700 Received: from orsmsx115.amr.corp.intel.com ([169.254.4.102]) by ORSMSX122.amr.corp.intel.com ([169.254.11.34]) with mapi id 14.03.0439.000; Tue, 14 Apr 2020 11:00:22 -0700 From: "Luck, Tony" To: Peter Zijlstra , "Park, Kyung Min" CC: "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "gregkh@linuxfoundation.org" , "ak@linux.intel.com" , "Raj, Ashok" , "Shankar, Ravi V" , "Yu, Fenghua" Subject: RE: [PATCH v3 3/3] x86/delay: Introduce TPAUSE delay Thread-Topic: [PATCH v3 3/3] x86/delay: Introduce TPAUSE delay Thread-Index: AQHWD4/qMw0TcUxzb0+IsfW0PyjEy6h45dQAgAAGJzA= Date: Tue, 14 Apr 2020 18:00:21 +0000 Message-ID: <3908561D78D1C84285E8C5FCA982C28F7F5E3E80@ORSMSX115.amr.corp.intel.com> References: <1586561395-50914-1-git-send-email-kyung.min.park@intel.com> <1586561395-50914-4-git-send-email-kyung.min.park@intel.com> <20200414103106.GK20713@hirez.programming.kicks-ass.net> In-Reply-To: <20200414103106.GK20713@hirez.programming.kicks-ass.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.2.0.6 dlp-reaction: no-action x-originating-ip: [10.22.254.138] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> +static inline void __tpause(u32 ecx, u32 edx, u32 eax) >> +{ >> + /* "tpause %ecx, %edx, %eax;" */ >> + asm volatile(".byte 0x66, 0x0f, 0xae, 0xf1\t\n" >> + : >> + : "c"(ecx), "d"(edx), "a"(eax)); >> +} > > Can we please get a comment stating from what binutils version this > opcode has a mnemonic? That way, when we raise the minimum binutils > version we can easily grep and find such things. Or maybe use arch/x86/Kconfig.assembler to set up a CONFIG_AS_TPAUSE? Then the code can read something like (syntax may need fixing) #ifdef CONFIG_AS_TPAUSE asm volatile("tpause %ecx\n", : : "c"(ecx), "d"(edx), "a"(eax)); #else asm volatile(".byte hex gibberish ... #endif -Tony