From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48184 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388522AbeGPIKY (ORCPT ); Mon, 16 Jul 2018 04:10:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Borislav Petkov , Josh Triplett , Thomas Gleixner , "Srivatsa S. Bhat" , "Matt Helsley (VMware)" , Alexey Makhalov , Bo Gan Subject: [PATCH 4.4 18/43] x86/cpu: Provide a config option to disable static_cpu_has Date: Mon, 16 Jul 2018 09:36:23 +0200 Message-Id: <20180716073513.830018745@linuxfoundation.org> In-Reply-To: <20180716073511.796555857@linuxfoundation.org> References: <20180716073511.796555857@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Borislav Petkov commit 6e1315fe82308cd29e7550eab967262e8bbc71a3 upstream This brings .text savings of about ~1.6K when building a tinyconfig. It is off by default so nothing changes for the default. Kconfig help text from Josh. Signed-off-by: Borislav Petkov Reviewed-by: Josh Triplett Link: http://lkml.kernel.org/r/1449481182-27541-5-git-send-email-bp@alien8.de Signed-off-by: Thomas Gleixner Signed-off-by: Srivatsa S. Bhat Reviewed-by: Matt Helsley (VMware) Reviewed-by: Alexey Makhalov Reviewed-by: Bo Gan Signed-off-by: Greg Kroah-Hartman --- arch/x86/Kconfig | 11 +++++++++++ arch/x86/include/asm/cpufeature.h | 2 +- 2 files changed, 12 insertions(+), 1 deletion(-) --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -346,6 +346,17 @@ config X86_FEATURE_NAMES If in doubt, say Y. +config X86_FAST_FEATURE_TESTS + bool "Fast CPU feature tests" if EMBEDDED + default y + ---help--- + Some fast-paths in the kernel depend on the capabilities of the CPU. + Say Y here for the kernel to patch in the appropriate code at runtime + based on the capabilities of the CPU. The infrastructure for patching + code at runtime takes up some additional space; space-constrained + embedded systems may wish to say N here to produce smaller, slightly + slower code. + config X86_X2APIC bool "Support x2apic" depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -422,7 +422,7 @@ extern const char * const x86_bug_flags[ * fast paths and boot_cpu_has() otherwise! */ -#if __GNUC__ >= 4 +#if __GNUC__ >= 4 && defined(CONFIG_X86_FAST_FEATURE_TESTS) extern void warn_pre_alternatives(void); extern bool __static_cpu_has_safe(u16 bit);