From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f41.google.com (mail-ej1-f41.google.com [209.85.218.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 24F0119C54E; Mon, 24 Feb 2025 15:24:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740410661; cv=none; b=CNXCxExf6Yjnzkm6PoKlzAWQyV78SRRlVf0CyULw8K6Zu+thFMbjH3QCv6VTvhe0bAuvBS2LJdAmIJjKS30qZZRcLriKSpUegn+Pyv0FHgdXBne3SaeuA7D2BX5XaCP26SITTf/8stNuoNdy4fgK7CgMRmdIS74VRo6ZVi5dd5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740410661; c=relaxed/simple; bh=+JH9WFIVg0ke/75TFC25dWturzu4JHdGKnJIyiQPccM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=q/you+aBKq7dJ+joVq+ka63Vta0b+TqWcsrafvCIsufliUBu9YXAJGJ/JFvGys7H2y6O//iTzYkwEmSBIxJ0TZQYrfNxI+9tXratBApyO3YHEZUwGQfD4WTiXTb54yXOCVbM6yTZxsIqJd1Y5E2mAoQlAoLsMN2BLrqgVHZLm+Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=W15ouCed; arc=none smtp.client-ip=209.85.218.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="W15ouCed" Received: by mail-ej1-f41.google.com with SMTP id a640c23a62f3a-abb81285d33so874841866b.0; Mon, 24 Feb 2025 07:24:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1740410658; x=1741015458; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=90b7JTu64HyQeEwAMfpKEcwfZyjyUK0IOy6HdZ/FyAs=; b=W15ouCedxAj7B9Oa5TVxKG8joKlxu/lhNekNMTWhqfNuN+JP/nW4gdxExLVipl0RPr sbQZej8tAM0TD0vnBz3hArfOJwztMyGnyuqcqUukykIz5uVTZnNDLP07sO4wgwqNahm+ +q0TFUpnNzGk+ObxqrpFeL745qb02VbtH5OF+6jb3TDgGnVcvFdn1hWDZ3L3TEUMPXEp M1yxX8jQJyMTN14cnrxmLhPAiuby010XsWB/RAS4hutxX4E5Z7umwryAPp5P2UpmlYi9 DYQCvxKR7HOVe49YDqj8Lfpgn1V5F3lz5k1mBfTZyNQ79tfiCmMFylyDwVZIFHa/zJIR Q92Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740410658; x=1741015458; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=90b7JTu64HyQeEwAMfpKEcwfZyjyUK0IOy6HdZ/FyAs=; b=R9BtLimFQCXkt+eEE/HB8sCIHh6ITD7J6JIjHKbNtElp7X2TZRv7CmEhzR5M3QB5PX dQPCUkf2A0ISqes9hU+eWQqWBlPFBCC9vO6mgJIF3LIFIwPiMr2e8y31x8R+C9/7p2Sa C0aDOdX5Pim0DHVQc/k8Ou6DibqZPsRe34rvkQao/ssa/p5cAjvbTopRB6o/bcifRU+K SigGrfoy/BnBAuD+i4UQZ6K4PiVgQXsqvxRxXh0xhOjpz6OJXlEjeSpdTg8GIiqp3KvY HeXQ/qG0lnfahYPOYNu1F0RaeA93v8WC2O+lNZKBSjsJc+bBJKdonPG125sbAeb60GZ5 LImg== X-Forwarded-Encrypted: i=1; AJvYcCULYRHg1mzgd9qrXrKI8NmjZtnAFyPbwoUYaLxAwjRgUQiDmcG9a8wynShtXu3dOaU/Rw0eRA8w/HEfRTxV@vger.kernel.org, AJvYcCVEuaxg5OY02XCRsjG8aXOVZdY/pK5G92n5fFJVX3YGas1l8QykNyZWt3+oIicIBYfyK13Qpvdywa0hEvRW@vger.kernel.org, AJvYcCW1KewY0vtk7QWlhjCN/aQkinmx32IXC8VTGF8XUBLKYVKAy5/FwJoaeyeanbYlVUidYDjv4BdauZ6L5oY=@vger.kernel.org, AJvYcCWUMVlEgFo9MAJdTHiBdbxArf0ffsLQNZYqUOh/Grf3rbW3Bh/LwReNnnq8HqYRvyiylWJROXKwCVtugmU=@vger.kernel.org, AJvYcCWXCaNE4z3FfBRU70v/zq5Ghf1NV8uNTswumP/CYY9tHmFilQaVzgKhhj9jC4i54gnylIeiA3S7@vger.kernel.org, AJvYcCXXhh6AatyGWOPXNTc7BqJEN694h0uWNgvL6vkiggzGpgoelWe1Ef66cOQ8cXank89mzhSsUKZARDOEidAJFWw=@vger.kernel.org, AJvYcCXyhGM6EHEGJtY/vH05kw3A4G4u6stNHN1scl3tEnxaB4gnb8A5R9JdrnkJZsbNc77CCcE=@vger.kernel.org X-Gm-Message-State: AOJu0Yw/GHpGs480zr2aVtxqVHV5ZZTsGBV8AsyzYLFK5kHcxyEvjwFd edYlEPVXr7KOpbTs3UA2yfavnNrdXBCHdkjSGgInTFsACWUP3Pmu X-Gm-Gg: ASbGncucznpWvUSFF2v5t2s03hDCiGIyhu90jbdvbzusOgUwm9Bp14x9lwA0KiG+Mj1 LuAZ0+6mM1X1lRz341+/rShWIV/AAhy0E47B3jHfhCJbufwS3/t7NzReUBQ7Eoe5uH+61y7fyWR F6EjkWe+jTvWOa+deBD4mQbNIcaeuVrr+uLY+Zw1G7DU3T8mw0oh/QMsURuxCcMyhht3gT+e7Se L69W6LqNvHwsO2snAsbQFouBRGG33s/UNXHXhjv8H0J52QD6inqTaPxvvFEj0cl3jG4Kj/bxlF6 ur7Okl1C7eG4qnKRPtc++EE2YAk= X-Google-Smtp-Source: AGHT+IFuxTp/JUjRKgHm6bk8HGglm4eMoWBRrY8PM6xIIRBJOeg9hhqPfUM+m5fxkbKuGg8YC/F0FQ== X-Received: by 2002:a17:907:c29:b0:ab7:86ae:4bb8 with SMTP id a640c23a62f3a-abc09a0bc37mr1270641566b.23.1740410658075; Mon, 24 Feb 2025 07:24:18 -0800 (PST) Received: from [192.168.1.100] ([46.248.82.114]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-abb9f8442c0sm1531734566b.150.2025.02.24.07.24.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 24 Feb 2025 07:24:17 -0800 (PST) Message-ID: Date: Mon, 24 Feb 2025 16:24:14 +0100 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH 03/17] x86: Replace open-coded parity calculation with parity8() To: Kuan-Wei Chiu , tglx@linutronix.de, Ingo Molnar , bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, jk@ozlabs.org, joel@jms.id.au, eajames@linux.ibm.com, andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, dmitry.torokhov@gmail.com, mchehab@kernel.org, awalls@md.metrocast.net, hverkuil@xs4all.nl, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, louis.peens@corigine.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, parthiban.veerasooran@microchip.com, arend.vanspriel@broadcom.com, johannes@sipsolutions.net, gregkh@linuxfoundation.org, jirislaby@kernel.org, yury.norov@gmail.com, akpm@linux-foundation.org, mingo@kernel.org Cc: hpa@zytor.com, alistair@popple.id.au, linux@rasmusvillemoes.dk, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-fsi@lists.ozlabs.org, dri-devel@lists.freedesktop.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, linux-mtd@lists.infradead.org, oss-drivers@corigine.com, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, brcm80211@lists.linux.dev, brcm80211-dev-list.pdl@broadcom.com, linux-serial@vger.kernel.org, bpf@vger.kernel.org, jserv@ccns.ncku.edu.tw, Yu-Chun Lin References: <20250223164217.2139331-1-visitorckw@gmail.com> <20250223164217.2139331-4-visitorckw@gmail.com> Content-Language: en-US From: Uros Bizjak In-Reply-To: <20250223164217.2139331-4-visitorckw@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 23. 02. 25 17:42, Kuan-Wei Chiu wrote: > Refactor parity calculations to use the standard parity8() helper. This > change eliminates redundant implementations and improves code > efficiency. The patch improves parity assembly code in bootflag.o from: 58: 89 de mov %ebx,%esi 5a: b9 08 00 00 00 mov $0x8,%ecx 5f: 31 d2 xor %edx,%edx 61: 89 f0 mov %esi,%eax 63: 89 d7 mov %edx,%edi 65: 40 d0 ee shr %sil 68: 83 e0 01 and $0x1,%eax 6b: 31 c2 xor %eax,%edx 6d: 83 e9 01 sub $0x1,%ecx 70: 75 ef jne 61 72: 39 c7 cmp %eax,%edi 74: 74 7f je f5 76: to: 54: 89 d8 mov %ebx,%eax 56: ba 96 69 00 00 mov $0x6996,%edx 5b: c0 e8 04 shr $0x4,%al 5e: 31 d8 xor %ebx,%eax 60: 83 e0 0f and $0xf,%eax 63: 0f a3 c2 bt %eax,%edx 66: 73 64 jae cc 68: which is faster and smaller (-10 bytes) code. Reviewed-by: Uros Bizjak Thanks, Uros. > > Co-developed-by: Yu-Chun Lin > Signed-off-by: Yu-Chun Lin > Signed-off-by: Kuan-Wei Chiu > --- > arch/x86/kernel/bootflag.c | 18 +++--------------- > 1 file changed, 3 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/kernel/bootflag.c b/arch/x86/kernel/bootflag.c > index 3fed7ae58b60..314ff0e84900 100644 > --- a/arch/x86/kernel/bootflag.c > +++ b/arch/x86/kernel/bootflag.c > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > #include > > #include > @@ -20,26 +21,13 @@ > > int sbf_port __initdata = -1; /* set via acpi_boot_init() */ > > -static int __init parity(u8 v) > -{ > - int x = 0; > - int i; > - > - for (i = 0; i < 8; i++) { > - x ^= (v & 1); > - v >>= 1; > - } > - > - return x; > -} > - > static void __init sbf_write(u8 v) > { > unsigned long flags; > > if (sbf_port != -1) { > v &= ~SBF_PARITY; > - if (!parity(v)) > + if (!parity8(v)) > v |= SBF_PARITY; > > printk(KERN_INFO "Simple Boot Flag at 0x%x set to 0x%x\n", > @@ -70,7 +58,7 @@ static int __init sbf_value_valid(u8 v) > { > if (v & SBF_RESERVED) /* Reserved bits */ > return 0; > - if (!parity(v)) > + if (!parity8(v)) > return 0; > > return 1;