From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754454AbcBPH5A (ORCPT ); Tue, 16 Feb 2016 02:57:00 -0500 Received: from terminus.zytor.com ([198.137.202.10]:40759 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754356AbcBPH46 (ORCPT ); Tue, 16 Feb 2016 02:56:58 -0500 Date: Mon, 15 Feb 2016 23:56:20 -0800 From: tip-bot for Borislav Petkov Message-ID: Cc: peterz@infradead.org, bp@suse.de, joro@8bytes.org, mingo@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, torvalds@linux-foundation.org, tglx@linutronix.de Reply-To: joro@8bytes.org, peterz@infradead.org, bp@suse.de, tglx@linutronix.de, torvalds@linux-foundation.org, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org In-Reply-To: <1455578358-28347-1-git-send-email-bp@alien8.de> References: <1455578358-28347-1-git-send-email-bp@alien8.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/cpufeature: Speed up cpu_feature_enabled() Git-Commit-ID: f2cc8e0791c70833758101d9756609a08dd601ec X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f2cc8e0791c70833758101d9756609a08dd601ec Gitweb: http://git.kernel.org/tip/f2cc8e0791c70833758101d9756609a08dd601ec Author: Borislav Petkov AuthorDate: Tue, 16 Feb 2016 00:19:18 +0100 Committer: Ingo Molnar CommitDate: Tue, 16 Feb 2016 08:45:15 +0100 x86/cpufeature: Speed up cpu_feature_enabled() When GCC cannot do constant folding for this macro, it falls back to cpu_has(). But static_cpu_has() is optimal and it works at all times now. So use it and speedup the fallback case. Before we had this: mov 0x99d674(%rip),%rdx # ffffffff81b0d9f4 shr $0x2e,%rdx and $0x1,%edx jne ffffffff811704e9 After alternatives patching, it turns into: jmp 0xffffffff81170390 nopl (%rax) ... callq ffffffff81056e00 ffffffff81170390: mov 0x170(%r12),%rdi Signed-off-by: Borislav Petkov Cc: Joerg Roedel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1455578358-28347-1-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/include/asm/cpufeature.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 9fba7a5..68e4e82 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -88,8 +88,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32]; * is not relevant. */ #define cpu_feature_enabled(bit) \ - (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : \ - cpu_has(&boot_cpu_data, bit)) + (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit)) #define boot_cpu_has(bit) cpu_has(&boot_cpu_data, bit)