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 6CD6A179AB; Sat, 22 Jun 2024 17:35:19 +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=1719077720; cv=none; b=M+fg9Fkjm0lrS6PFvf6VLU9hnurDGWEm4JNlzwkgM4zK66LsL+9muVbz8xq/osSUnEmIOvb3kFWLdW/mArgeW8V+7ivkk8WEgrBPdNWLJBfRHrRn/q39fkgcotHiOirBZe5Mhom6yqxUCVGsHqHtVXsY2LkrDUG2eCm4NIOy2NQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719077720; c=relaxed/simple; bh=sPHz6h3ONEZA1wUzi09j0Pxmu7pkzK0jwBvpM3zlYiE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HGXqyCAW9VxIdeKVVeIW03ibQUcbXQGpyvxNkT4JzpUhjTvCHZqnFFzvetzVLIwtGPwd53mFB5W6LflEhbaGh+6z1Byam3DECsKbsp4jdooamWMX7YBh/jz7KCDuhz0Fg+3IZfUlnGyyrxO6J9R9ZYZlnKFwSDoVaBnGyAcl1ic= 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=PAvE3mIi; 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="PAvE3mIi" Received: from [192.168.7.205] ([71.202.166.45]) (authenticated bits=0) by mail.zytor.com (8.17.2/8.17.1) with ESMTPSA id 45MHYoEZ3730912 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Sat, 22 Jun 2024 10:34:51 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 45MHYoEZ3730912 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2024061501; t=1719077691; bh=VU7cbOAcW7s0UMUSdQaeZqdsO6AZuRqP2b3P0uFLK18=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=PAvE3mIiyW+8hgXGohzkIZx1QKtXmwcoK/M3BcUHTEVVijYM6f8uJ5wEQa6TlaxqP egRhMM7QeJ7SXHhf/mvznJf1yentMOr5dKcAA6Wodel/6F5z2E7IqGlcSVELVQGK3/ Jia2vwPD5mUDk4SVcLC2P7ay3VfZQ0ZwDZKO3WFT7MUr7k4R3mF5NKzdX72/n2d9fq K1kaHv4unL+rePLDr+lWknZ4/EA5TUb9Qd2HOEAKWRm/tmY2mjOGFqoYHC1uTKiPdg sQZDSo4b8ckUL+REUW12CTxSEtH6w+yBClH+U+Ygc1dyL3HSqHHZCCtuox0VY3xOkv kh+FljZaRVdog== Message-ID: <78436d01-2e91-44ad-ac99-145ddbd5e857@zytor.com> Date: Sat, 22 Jun 2024 10:34:49 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RESEND v1 2/3] x86/cpufeatures: Generate a feature mask header based on build config To: "H. Peter Anvin" , 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, will@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, acme@kernel.org, namhyung@kernel.org References: <20240509205340.275568-1-xin@zytor.com> <20240509205340.275568-3-xin@zytor.com> <99208d95-d3de-44d0-8b08-f508759aabca@zytor.com> <8F9E89A4-B05B-493C-8BED-52AC6777D915@zytor.com> Content-Language: en-US From: Xin Li Autocrypt: addr=xin@zytor.com; keydata= xsDNBGUPz1cBDACS/9yOJGojBFPxFt0OfTWuMl0uSgpwk37uRrFPTTLw4BaxhlFL0bjs6q+0 2OfG34R+a0ZCuj5c9vggUMoOLdDyA7yPVAJU0OX6lqpg6z/kyQg3t4jvajG6aCgwSDx5Kzg5 Rj3AXl8k2wb0jdqRB4RvaOPFiHNGgXCs5Pkux/qr0laeFIpzMKMootGa4kfURgPhRzUaM1vy bsMsL8vpJtGUmitrSqe5dVNBH00whLtPFM7IbzKURPUOkRRiusFAsw0a1ztCgoFczq6VfAVu raTye0L/VXwZd+aGi401V2tLsAHxxckRi9p3mc0jExPc60joK+aZPy6amwSCy5kAJ/AboYtY VmKIGKx1yx8POy6m+1lZ8C0q9b8eJ8kWPAR78PgT37FQWKYS1uAroG2wLdK7FiIEpPhCD+zH wlslo2ETbdKjrLIPNehQCOWrT32k8vFNEMLP5G/mmjfNj5sEf3IOKgMTMVl9AFjsINLHcxEQ 6T8nGbX/n3msP6A36FDfdSEAEQEAAc0WWGluIExpIDx4aW5Aenl0b3IuY29tPsLBDQQTAQgA NxYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89XBQkFo5qAAhsDBAsJCAcFFQgJCgsFFgID AQAACgkQa70OVx2uN1HUpgv/cM2fsFCQodLArMTX5nt9yqAWgA5t1srri6EgS8W3F+3Kitge tYTBKu6j5BXuXaX3vyfCm+zajDJN77JHuYnpcKKr13VcZi1Swv6Jx1u0II8DOmoDYLb1Q2ZW v83W55fOWJ2g72x/UjVJBQ0sVjAngazU3ckc0TeNQlkcpSVGa/qBIHLfZraWtdrNAQT4A1fa sWGuJrChBFhtKbYXbUCu9AoYmmbQnsx2EWoJy3h7OjtfFapJbPZql+no5AJ3Mk9eE5oWyLH+ QWqtOeJM7kKvn/dBudokFSNhDUw06e7EoVPSJyUIMbYtUO7g2+Atu44G/EPP0yV0J4lRO6EA wYRXff7+I1jIWEHpj5EFVYO6SmBg7zF2illHEW31JAPtdDLDHYcZDfS41caEKOQIPsdzQkaQ oW2hchcjcMPAfyhhRzUpVHLPxLCetP8vrVhTvnaZUo0xaVYb3+wjP+D5j/3+hwblu2agPsaE vgVbZ8Fx3TUxUPCAdr/p73DGg57oHjgezsDNBGUPz1gBDAD4Mg7hMFRQqlzotcNSxatlAQNL MadLfUTFz8wUUa21LPLrHBkUwm8RujehJrzcVbPYwPXIO0uyL/F///CogMNx7Iwo6by43KOy g89wVFhyy237EY76j1lVfLzcMYmjBoTH95fJC/lVb5Whxil6KjSN/R/y3jfG1dPXfwAuZ/4N cMoOslWkfZKJeEut5aZTRepKKF54T5r49H9F7OFLyxrC/uI9UDttWqMxcWyCkHh0v1Di8176 jjYRNTrGEfYfGxSp+3jYL3PoNceIMkqM9haXjjGl0W1B4BidK1LVYBNov0rTEzyr0a1riUrp Qk+6z/LHxCM9lFFXnqH7KWeToTOPQebD2B/Ah5CZlft41i8L6LOF/LCuDBuYlu/fI2nuCc8d m4wwtkou1Y/kIwbEsE/6RQwRXUZhzO6llfoN96Fczr/RwvPIK5SVMixqWq4QGFAyK0m/1ap4 bhIRrdCLVQcgU4glo17vqfEaRcTW5SgX+pGs4KIPPBE5J/ABD6pBnUUAEQEAAcLA/AQYAQgA JhYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89ZBQkFo5qAAhsMAAoJEGu9DlcdrjdR4C0L /RcjolEjoZW8VsyxWtXazQPnaRvzZ4vhmGOsCPr2BPtMlSwDzTlri8BBG1/3t/DNK4JLuwEj OAIE3fkkm+UG4Kjud6aNeraDI52DRVCSx6xff3bjmJsJJMb12mWglN6LjdF6K+PE+OTJUh2F dOhslN5C2kgl0dvUuevwMgQF3IljLmi/6APKYJHjkJpu1E6luZec/lRbetHuNFtbh3xgFIJx 2RpgVDP4xB3f8r0I+y6ua+p7fgOjDLyoFjubRGed0Be45JJQEn7A3CSb6Xu7NYobnxfkwAGZ Q81a2XtvNS7Aj6NWVoOQB5KbM4yosO5+Me1V1SkX2jlnn26JPEvbV3KRFcwV5RnDxm4OQTSk PYbAkjBbm+tuJ/Sm+5Yp5T/BnKz21FoCS8uvTiziHj2H7Cuekn6F8EYhegONm+RVg3vikOpn gao85i4HwQTK9/D1wgJIQkdwWXVMZ6q/OALaBp82vQ2U9sjTyFXgDjglgh00VRAHP7u1Rcu4 l75w1xInsg== In-Reply-To: <8F9E89A4-B05B-493C-8BED-52AC6777D915@zytor.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/17/2024 6:46 AM, H. Peter Anvin wrote: > On June 16, 2024 12:26:48 AM PDT, Xin Li wrote: >> On 5/9/2024 1:53 PM, Xin Li (Intel) wrote: >>> From: "H. Peter Anvin (Intel)" >>> >>> Introduce an AWK script to auto-generate a header with required and >>> disabled feature masks based on and current build >>> config. Thus for any CPU feature with a build config, e.g., X86_FRED, >>> simply add >> >> ... >> >>> + >>> + printf "\n#define %s_MASKS ", s; >>> + pfx = "{"; >>> + for (i = 0; i < ncapints; i++) { >>> + printf "%s \\\n\t%s_MASK_%d", pfx, s, i; >>> + pfx = ","; >>> + } >>> + printf " \\\n}\n\n"; >>> + >>> + printf "#define %s_FEATURE(x) \\\n", s; >>> + printf "\t((( "; >>> + for (i = 0; i < ncapints; i++) { >>> + if (masks[i]) { >>> + printf "\\\n\t\t((x) >> 5) == %2d ? %s_MASK%-3d : ", i, s, i; >>> + } >>> + } >>> + printf "0 \\\n"; >>> + printf "\t) >> ((x) & 31)) & 1)\n\n"; >> >> This code generates 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. >> >> But they are NOT currently used, so I prefer to remove them for now. >> >> Thanks! >> Xin > > The goal with these is that it can eliminate the handwritten code that tests a long list of masks. Again, automation. > This piece of code is added back in the last patch of v3: https://lore.kernel.org/lkml/20240622171435.3725548-5-xin@zytor.com/ The generated macros {REQUIRED|DISABLED}_MASK_BIT_SET are way shorter than that in the original form: #define REQUIRED_FEATURE(x) \ (( \ ((x) >> 5) == 0 ? REQUIRED_MASK0 : \ ((x) >> 5) == 1 ? REQUIRED_MASK1 : \ ((x) >> 5) == 3 ? REQUIRED_MASK3 : 0 \ ) & (1 << ((x) & 31))) #define REQUIRED_MASK_BIT_SET(x) \ (REQUIRED_FEATURE(x) || BUILD_BUG_ON_ZERO(NCAPINTS != 22)) Thanks! Xin