From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: ** X-Spam-Status: No, score=2.4 required=3.0 tests=BAYES_40,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5951EC07E96 for ; Sun, 11 Jul 2021 15:34:25 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 784606115A for ; Sun, 11 Jul 2021 15:34:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 784606115A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=etri.re.kr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.94.2) (envelope-from ) id 1m2bSu-00083t-Af; Sun, 11 Jul 2021 11:33:56 -0400 Received: from mscreen.etri.re.kr ([129.254.9.16]) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (Exim 4.94.2) (envelope-from ) id 1m2bSr-00083n-PX for kernelnewbies@kernelnewbies.org; Sun, 11 Jul 2021 11:33:55 -0400 Received: from unknown (HELO send002-relay.gov-dooray.com) (211.180.235.153) by 129.254.9.16 with ESMTP; 12 Jul 2021 00:33:46 +0900 X-Original-SENDERIP: 211.180.235.153 X-Original-MAILFROM: ckim@etri.re.kr X-Original-RCPTTO: kernelnewbies@kernelnewbies.org Received: from [10.162.225.112] (HELO smtp002-imp.gov-dooray.com) ([10.162.225.112]) by send002-relay.gov-dooray.com with SMTP id b4273b1e60eb0f59; Mon, 12 Jul 2021 00:33:45 +0900 DKIM-Signature: a=rsa-sha256; b=uYKzgu9mD8e8OIdVC0qpVJzEW8WKVAVOvFiOkaPXjM3ggGFE/FANGrNI+iesJI13dnSiCjuNtZ 0VwOH5Ov7Y4Xh2IWlnYeyhHnOH4YO6rmmJYUTdyaXj/E0c8pn2BPlAN1Yzaj8EjYa+CWI9GNmNn+ z7n42vXrlmxy+hDGOO5em4Qwx5h5BLj+iIzhAZJpaX4xhdR5yyXDXUM/pcmpkSpNEqQiIuXexUIO pT3R+VypigA3FVqkvJMJI7ozYXRyNvUjYC2cXkqHNsf5zgcd19G2xQmnSnq8fGdz2Kxazolo6dmO Ng+2Pm7PxmzHQYrjmGQguzi0sTG3vyVK7TaxujzQ==; c=relaxed/relaxed; s=selector; d=dooray.com; v=1; bh=54HRStO6XP7DRSMiDcRyv803gaKxViFalUMlLsgbeeY=; h=From:To:Subject:Message-ID; Received: from [129.254.132.39] (HELO CHANKIMPC) ([129.254.132.39]) by smtp002-imp.gov-dooray.com with SMTP id 5f544b3060eb0f59; Mon, 12 Jul 2021 00:33:45 +0900 From: To: Subject: ioremap and page table Date: Mon, 12 Jul 2021 00:33:43 +0900 Message-ID: <012001d7766a$21c7eb80$6557c280$@etri.re.kr> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 16.0 Thread-Index: Add2acI1evFv8HjTSSW398EIc6dL1w== Content-Language: ko X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============9143040176554914326==" Errors-To: kernelnewbies-bounces@kernelnewbies.org This is a multipart message in MIME format. --===============9143040176554914326== Content-Type: multipart/alternative; boundary="----=_NextPart_000_0121_01D776B5.91B008B0" Content-Language: ko This is a multipart message in MIME format. ------=_NextPart_000_0121_01D776B5.91B008B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hello all, I'm almost sure but want to check if my understanding is correct. To use a memory mapped IO, we use functions like request_mem_region and ioremap, iounmap functions. I guess when we call ioremap function, the kernel sets up page table for the region so that the region becomes non-cacheable, and I don't also have to worry about reordering problem. Is my understanding correct? Thanks! Chan Kim ------=_NextPart_000_0121_01D776B5.91B008B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hello all,

I’m almost sure but want to = check if my understanding is correct.

To use a memory mapped IO, we use = functions like request_mem_region and ioremap, iounmap functions. =

I guess = when we call ioremap function, the kernel sets up page table for the = region so that the region becomes non-cacheable, and I don’t also = have  to worry about reordering problem.

Is my understanding = correct?

Thanks!

Chan Kim

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