From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=17.171.2.35; helo=mail-in25.apple.com; envelope-from=afish@apple.com; receiver=edk2-devel@lists.01.org Received: from mail-in25.apple.com (mail-out25.apple.com [17.171.2.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id EE1E4207E53FE for ; Tue, 8 May 2018 08:55:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; d=apple.com; s=mailout2048s; c=relaxed/simple; q=dns/txt; i=@apple.com; t=1525794936; x=2389708536; h=From:Sender:Reply-To:Subject:Date:Message-id:To:Cc:MIME-version:Content-type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-reply-to:References:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=A/bQiRaf9Help6KQpulPX+t0hoOexOoexOrroExf3pw=; b=KjJ23ZkAPqG1XsjiVBzedeyAEa2SmigWhmZsscQjnx12qhQJ4LUvs6I3/8j6Qfht stdrMFCzgHR9ULIfCB8ffA/NYGBrtaGjaiLyezHq08QuCQlzQ+tbSAgijljDfa1X e+GgHG/KNxbcKidc3HXKZYAfmbfV4dxZ1u/jh21AZGsVJctpSL7vruw7u09FK03f KAxyC9vv5unZxEmtqy9B/Fw9s/7RsKEuclh/CIH45afnQdSvtrfqUUAZrCn1qZ20 ljPXuHdB7gl4vFIi7WRLSGQK4seiymAvde5gVx6gIZR02Lk0ZXJzOlLqcD+bwNvy oZkoRwIgLMDeUt/y9q3K6w==; Received: from relay6.apple.com (relay6.apple.com [17.128.113.90]) (using TLS with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mail-in25.apple.com (Apple Secure Mail Relay) with SMTP id DC.23.14365.878C1FA5; Tue, 8 May 2018 08:55:36 -0700 (PDT) X-AuditID: 11ab0219-e904d9e00000381d-9d-5af1c878f9fa Received: from nwk-mmpp-sz09.apple.com (nwk-mmpp-sz09.apple.com [17.128.115.80]) (using TLS with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by relay6.apple.com (Apple SCV relay) with SMTP id 72.F1.23861.878C1FA5; Tue, 8 May 2018 08:55:36 -0700 (PDT) MIME-version: 1.0 Received: from [17.234.73.163] by nwk-mmpp-sz09.apple.com (Oracle Communications Messaging Server 8.0.2.2.20180403 64bit (built Apr 3 2018)) with ESMTPSA id <0P8F00EHX2WN5M10@nwk-mmpp-sz09.apple.com>; Tue, 08 May 2018 08:55:36 -0700 (PDT) Sender: afish@apple.com From: Andrew Fish Message-id: <220B682A-EFD1-4989-A9BD-6D3DEB2E3EB4@apple.com> Date: Tue, 08 May 2018 08:55:34 -0700 In-reply-to: Cc: "edk2-devel@lists.01.org" To: Rafael Machado References: X-Mailer: Apple Mail (2.3445.6.18) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrCLMWRmVeSWpSXmKPExsUi2FAYpVtx4mOUwbR+K4s9h44yW+x8OYPd gclj56y77B7ds/+xBDBFcdmkpOZklqUW6dslcGX07L7AVnBNvuL2yTPsDYz7pLsYOTgkBEwk +q+ldzFycQgJrGGSeNp7jbGLkRMsvmH2c0aIxHomiasLprKBJHgFBCV+TL7HAmIzC4RJLPh5 gRmi6CujxPa3t9hBEsIC4hLvzmxiBrHZBJQlVsz/wA7RbCOxtmsdVI2txJVdd8FsFgFViV+9 nWA2p0CwRPO7E6wQC8wlZlz4wgRiiwiYSeydNQGsRkggQGL2hx4WiEuVJP7vOgJ2hITAHDaJ Fa8nsE1gFJqF5NhZSI6FsLUkvj9qBYpzANnyEgfPy0KENSWe3fvEDmFrSzx5d4F1ASPbKkbh 3MTMHN3MPCNTvcSCgpxUveT83E2MoGhYzSS5g/Hra8NDjAIcjEo8vAW7P0YJsSaWFVfmHmKU 5mBREuf9zPYoSkggPbEkNTs1tSC1KL6oNCe1+BAjEwenVAMjx+0Xm377Cy7uPqDFf4i52iw0 wPFiglVan766sTnft91v9bN0qxNvT2K0m7dTadKt/7yLVa1WcETUPDydrO46VXnTm6qQMFe5 Pcc4n3qwGz3q/X3Ey2ybe1gC65sbL2pOr7M+L/Gl0fkPR9D3aUHT8tm3RnRX3b/ZYKnQ9Wbh e5Wzoq1z+sOVWIozEg21mIuKEwFQpRtQZwIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrOLMWRmVeSWpSXmKPExsUi2FAcoFtx4mOUwcuJ6hZ7Dh1lttj5cga7 A5PHzll32T26Z/9jCWCK4rJJSc3JLEst0rdL4Mro2X2BreCafMXtk2fYGxj3SXcxcnJICJhI bJj9nLGLkYtDSGA9k8TVBVPZQBK8AoISPybfYwGxmQXCJBb8vMAMUfSVUWL721vsIAlhAXGJ d2c2MYPYbALKEivmf2CHaLaRWNu1DqrGVuLKrrtgNouAqsSv3k4wm1MgWKL53QlWiAXmEjMu fGECsUUEzCT2zpoAViMkECAx+0MPC8SlShL/dx1hnsDIPwvJfbOQ3Adha0l8f9QKFOcAsuUl Dp6XhQhrSjy794kdwtaWePLuAusCRrZVjAJFqTmJlWZ6iQUFOal6yfm5mxjBwVsYtYOxYbnV IUYBDkYlHl6JnR+jhFgTy4orcw8xSnAwK4nwKssChXhTEiurUovy44tKc1KLDzFKc7AoifPq 3f0QJSSQnliSmp2aWpBaBJNl4uCUamAU+vf47rzmncsPrNHX9Fv99fEy+TKVyAcLsk8mXlkc 9XaXVuGSWQcPTSrzml05S/Nbx2aXHaFfNK6uun2b2zB524TpuY51Ha03rQ7u+v7sw1Xl0K5Z xvbd3Pf+f+b8eNZTrfjiSkOGkqqHa0onP7t7yszZebMit9j6ZRqWG7t4fVvyj3rOP9pnocRS nJFoqMVcVJwIALC0cAdaAgAA X-Content-Filtered-By: Mailman/MimeDel 2.1.26 Subject: Re: Empty function at BaseCacheMaintenanceLib X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 May 2018 15:55:38 -0000 Content-Type: text/plain; CHARSET=US-ASCII Content-Transfer-Encoding: 7BIT Rafael, I seem to remember those functions are used to manage the cache on a Harvard architecture caches [1]. If you look at InvalidateInstructionCacheRange() you will notice it is used when code gets loaded into memory to keep the data and instruction caches coherent. If the instruction cache maintains coherency in hardware then there is no need for this functions to do anything. If you notice the IPF version actually does something, and that is why these functions exists. [1] https://en.wikipedia.org/wiki/Harvard_architecture Thanks, Andrew Fish > On May 8, 2018, at 6:46 AM, Rafael Machado wrote: > > Hi everyone > > I have a question. During a research I got to the BaseCacheMaintenanceLib, > and noticed that there is a function that is not implemented. > > The function InvalidateInstructionCache does not have a body, but as far as > I > could check it's used in some places. > > Is it ok to have this function empty? > > Thanks and Regards > Rafael R. Machado > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel