From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 3154E186E26; Sun, 16 Jun 2024 08:58:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718528303; cv=none; b=rvmUBgqWchP6WTCB9IYuOfXVQvgTgjMq7Y3u5lS54UCDQFhZE0bpbItoPB+dBjT5yk6/puVl2nWAbTcDTNkSJwu0RcHj14QGTMb3YBMQyPmW5ABnrk3G3g1/HRlwVIZl/AT0UFxRzHQkcOzFCuIi9OZUb0x2XjhHrkw7S1YtgpY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718528303; c=relaxed/simple; bh=ysxXEWdSdFeJRANHElWTANKfJwhXp9/aaLwfLeDh3nI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KKFpzRM1uhgeMOcP18nE4s4eLAS+FOFui+c300njQTTwJMQyUfElzj1y3ZbIpH/bOtlk01i9UL/twGUG8CbRpyHlXyw/g1OqQ2Z80frGajWkEPaVP1qtxj7KFOn8VlHneo9ODYtUTLwfe6mqmptn9o/zmD/xRzlEqi5AgadgdAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=qdCi3pKR; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="qdCi3pKR" Received: from terminus.zytor.com (terminus.zytor.com [IPv6:2607:7c80:54:3:0:0:0:136]) (authenticated bits=0) by mail.zytor.com (8.17.2/8.17.1) with ESMTPSA id 45G8viDj1100721 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sun, 16 Jun 2024 01:57:48 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 45G8viDj1100721 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2024051501; t=1718528269; bh=tORcu0KzoezwP+svxxymeaOgQSsooEptNlD6MZV7h1Q=; h=From:To:Cc:Subject:Date:From; b=qdCi3pKRGBCyGMdQv4641rh0aeln7aK5WhliHJsJRT96xGzVAtLVF6JxHsFVeYOT3 4j2SHk7L6GXRcjmwrwyn64pz3RyaU3cqI2GyHTKUAQ3yQsHzEOXiKHW/oHWiyaUqIm qr5AYgD8SBEU+8piD8gSVZa/24cJsBFL1GbOiLU6hG6CcepnR5Xk4u5F7mpcbjIVty ijE70paxJ2/9ILUjciaKBtGwzTTB/YXLDpWgrHMebYXKkx47AyQeEnLIyGFyUrQAUB TkdnPmljF/txTz90cPvAEpQ3x8Uwi7Mk/euxA+H33SSi3+F8n91PAugSgtoOsBsSOw RvG9Ij1oNcxpg== From: "Xin Li (Intel)" To: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, will@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, acme@kernel.org, namhyung@kernel.org Subject: [PATCH v2 0/3] x86/cpufeatures: Automatically generate required and disabled feature masks Date: Sun, 16 Jun 2024 01:57:40 -0700 Message-ID: <20240616085743.1100704-1-xin@zytor.com> X-Mailer: git-send-email 2.45.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The x86 build process first generates required and disabled feature masks based on current build config, and then uses these generated masks to compile the source code. When a CPU feature is not enabled in a build config, e.g., when CONFIG_X86_FRED=n, its feature disable flag, i.e., DISABLE_FRED, needs to be properly defined and added to a specific disabled CPU features mask in , as the following patch does: https://lore.kernel.org/all/20231205105030.8698-8-xin3.li@intel.com/. As a result, the FRED feature bit is surely cleared in the generated kernel binary when CONFIG_X86_FRED=n. Recently there is another case to repeat the same exercise for the AMD SEV-SNP CPU feature: https://lore.kernel.org/all/20240126041126.1927228-2-michael.roth@amd.com/. https://lore.kernel.org/all/20240126041126.1927228-23-michael.roth@amd.com/. It was one thing when there were four of CPU feature masks, but with over 20 it is going to cause mistakes, e.g., https://lore.kernel.org/lkml/aaed79d5-d683-d1bc-7ba1-b33c8d6db618@suse.com/. We want to eliminate the stupidly repeated exercise to manually assign features to CPU feature words through introducing an AWK script to automatically generate a header with required and disabled CPU feature masks based on current build config, and this patch set does that. Changes since v1: * Keep the X86_{REQUIRED,DISABLED}_FEATURE_ prefixes solely in arch/x86/Kconfig.cpufeatures (Borislav Petkov). * Explain how config option names X86_{REQUIRED,DISABLED}_FEATURE_ are formed (Borislav Petkov). * Remove code generating unused macros {REQUIRED,DISABLED}_FEATURE(x) to tell if a CPU feature, e.g., X86_FEATURE_FRED, is a required or disabled feature for this particular compile-time configuration. H. Peter Anvin (Intel) (2): x86/cpufeatures: Add {required,disabled} feature configs x86/cpufeatures: Generate a feature mask header based on build config Xin Li (Intel) (1): x86/cpufeatures: Remove {disabled,required}-features.h arch/x86/Kconfig | 4 +- arch/x86/Kconfig.cpu | 12 +- arch/x86/Kconfig.cpufeatures | 197 ++++++++++++++++++ arch/x86/Makefile | 17 +- arch/x86/boot/cpucheck.c | 3 +- arch/x86/boot/cpuflags.c | 1 - arch/x86/boot/mkcpustr.c | 3 +- arch/x86/include/asm/Kbuild | 1 + arch/x86/include/asm/asm-prototypes.h | 2 +- arch/x86/include/asm/atomic64_32.h | 2 +- arch/x86/include/asm/bitops.h | 4 +- arch/x86/include/asm/cmpxchg_32.h | 2 +- arch/x86/include/asm/cpufeature.h | 1 + arch/x86/include/asm/cpufeatures.h | 8 - arch/x86/include/asm/disabled-features.h | 161 -------------- arch/x86/include/asm/required-features.h | 105 ---------- arch/x86/kernel/verify_cpu.S | 1 + arch/x86/lib/Makefile | 2 +- arch/x86/lib/cmpxchg8b_emu.S | 2 +- arch/x86/tools/featuremasks.awk | 90 ++++++++ lib/atomic64_test.c | 2 +- tools/arch/x86/include/asm/cpufeatures.h | 8 - .../arch/x86/include/asm/disabled-features.h | 161 -------------- .../arch/x86/include/asm/required-features.h | 105 ---------- tools/perf/check-headers.sh | 2 - 25 files changed, 320 insertions(+), 576 deletions(-) create mode 100644 arch/x86/Kconfig.cpufeatures delete mode 100644 arch/x86/include/asm/disabled-features.h delete mode 100644 arch/x86/include/asm/required-features.h create mode 100755 arch/x86/tools/featuremasks.awk delete mode 100644 tools/arch/x86/include/asm/disabled-features.h delete mode 100644 tools/arch/x86/include/asm/required-features.h base-commit: 49b33979e3bf0a5424420d14f026de12f34e8b1e -- 2.45.1