From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7AD88C34022 for ; Thu, 27 Feb 2020 13:40:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 532FC24692 for ; Thu, 27 Feb 2020 13:40:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582810818; bh=7FgmVAvrtnM/nr8UJUSPDq0BSCewXoaDW9k0WBFW4Nw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IjU7DM2djeBG6A5G5KPXDTSb8FdAC3dgkLXOFztbHxSU7NO/nLsIWXa0cIjy0HJea JL4O1FpzTMXT3L92tcSm1ybbzBhASmEu7Xf/CuFrOiBHmjWcQAo5PXRjZXdrdmpHye FlEDhIgAjwnGjlMWENasPfwx3Azrqny4vzJe65Qw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729171AbgB0NkR (ORCPT ); Thu, 27 Feb 2020 08:40:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:34486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729030AbgB0NkR (ORCPT ); Thu, 27 Feb 2020 08:40:17 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0336424656; Thu, 27 Feb 2020 13:40:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582810816; bh=7FgmVAvrtnM/nr8UJUSPDq0BSCewXoaDW9k0WBFW4Nw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kbo4m9uOHocsBE9Bn6ot2QmEu4nUvreKafBllzXwx2umv6zC9Rs5h1XIMiGfZy4Ul sAJ3RACn1Cc7wqjOp8/weSf7iu+9OLU8ptaT/j+RhubgjOSXTE6jbSDrVD3NF/5YPK Dq9qwD8/1q1+/aJ9hs/MqGfDI9DOX8cbtYqJ7688= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Megha Dey , Andy Lutomirski , Borislav Petkov , Brian Gerst , Denys Vlasenko , "H. Peter Anvin" , Josh Poimboeuf , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.4 001/113] x86/vdso: Use RDPID in preference to LSL when available Date: Thu, 27 Feb 2020 14:35:17 +0100 Message-Id: <20200227132212.078257488@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132211.791484803@linuxfoundation.org> References: <20200227132211.791484803@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Lutomirski commit a582c540ac1b10f0a7d37415e04c4af42409fd08 upstream. RDPID is a new instruction that reads MSR_TSC_AUX quickly. This should be considerably faster than reading the GDT. Add a cpufeature for it and use it from __vdso_getcpu() when available. Tested-by: Megha Dey Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/4f6c3a22012d10f1c65b9ca15800e01b42c7d39d.1479320367.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/vgtod.h | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -301,6 +301,7 @@ /* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx), word 16 */ #define X86_FEATURE_PKU (16*32+ 3) /* Protection Keys for Userspace */ #define X86_FEATURE_OSPKE (16*32+ 4) /* OS Protection Keys Enable */ +#define X86_FEATURE_RDPID (16*32+ 22) /* RDPID instruction */ /* AMD-defined CPU features, CPUID level 0x80000007 (ebx), word 17 */ #define X86_FEATURE_OVERFLOW_RECOV (17*32+0) /* MCA overflow recovery support */ --- a/arch/x86/include/asm/vgtod.h +++ b/arch/x86/include/asm/vgtod.h @@ -83,8 +83,13 @@ static inline unsigned int __getcpu(void * works on all CPUs. This is volatile so that it orders * correctly wrt barrier() and to keep gcc from cleverly * hoisting it out of the calling function. + * + * If RDPID is available, use it. */ - asm volatile ("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG)); + alternative_io ("lsl %[p],%[seg]", + ".byte 0xf3,0x0f,0xc7,0xf8", /* RDPID %eax/rax */ + X86_FEATURE_RDPID, + [p] "=a" (p), [seg] "r" (__PER_CPU_SEG)); return p; }