From owner-svn-src-all@freebsd.org Wed Jul 8 14:47:43 2015 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D86569968FC; Wed, 8 Jul 2015 14:47:43 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-ie0-x22a.google.com (mail-ie0-x22a.google.com [IPv6:2607:f8b0:4001:c03::22a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A2CED1EA2; Wed, 8 Jul 2015 14:47:43 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: by iecuq6 with SMTP id uq6so157005932iec.2; Wed, 08 Jul 2015 07:47:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=rs4c+09tGdhfcnZsKSfnWU/MsA5Sot2oh72DeMOuTrk=; b=Ud1E7AoqdEJIQ1V15Njm2BLHuIMpUuFwHsE5d2ORxmfbU1D/FTZ4Kbp0WWA146qCUT XQG8er2voEuMDeetjvQeuJcNjh2nx0RstV0S4OMDKVsXjw9gNLH3N8Oo2dB9v/gwGIm6 Lxw5wiaNEsZlWhhQLuVvS8Xc3+Ku1zbBHfqc06zT0yPyRCfLJ5fyiTtbtem9rT8wpz/o iJuvwsRVx56kIt5LuNSdAwNiuzXi52tf5a0tzcZMVdL9qChKpnRwqlaYjvK2CN9kfEKE 1LMCjeQaDVimrz06tKgukvvCm/eplh8i+2R6qJUadVfg/GJd3SA4Cj+cCn0MucsU/sVe PpzA== MIME-Version: 1.0 X-Received: by 10.50.171.232 with SMTP id ax8mr20074529igc.32.1436366862850; Wed, 08 Jul 2015 07:47:42 -0700 (PDT) Received: by 10.36.38.133 with HTTP; Wed, 8 Jul 2015 07:47:42 -0700 (PDT) In-Reply-To: <1436366547.1334.81.camel@freebsd.org> References: <201507081353.t68Dr0up028388@repo.freebsd.org> <1436366547.1334.81.camel@freebsd.org> Date: Wed, 8 Jul 2015 07:47:42 -0700 Message-ID: Subject: Re: svn commit: r285270 - head/sys/sys From: Adrian Chadd To: Ian Lepore Cc: Zbigniew Bodek , "src-committers@freebsd.org" , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Jul 2015 14:47:44 -0000 On 8 July 2015 at 07:42, Ian Lepore wrote: > On Wed, 2015-07-08 at 07:30 -0700, Adrian Chadd wrote: >> Why is this implemented in sys/sys/bus_dma.h, rather than in a machdep header? >> >> > > Indeed, this stuff is a mess that really needs to be cleaned up. The > pre-existing assumption that MI functions don't need to be called, just > because one of the parameters of that function has some value that has a > special meaning on one platform, is purely x86-MD code in an MI header > file. This change just complicates the existing mess. +1 (So who's going to do it? I'm already taken.) -a >> -a >> >> >> On 8 July 2015 at 06:53, Zbigniew Bodek wrote: >> > Author: zbb >> > Date: Wed Jul 8 13:52:59 2015 >> > New Revision: 285270 >> > URL: https://svnweb.freebsd.org/changeset/base/285270 >> > >> > Log: >> > Add memory barrier to bus_dmamap_sync() >> > >> > On platforms which are fully IO-coherent, the map might be null. >> > We need to guarantee that all data is observable after the >> > sync operation is called. Add a memory barrier to ensure that on ARM. >> > >> > Reviewed by: andrew, kib >> > Obtained from: Semihalf >> > Sponsored by: The FreeBSD Foundation >> > Differential Revision: https://reviews.freebsd.org/D3012 >> > >> > Modified: >> > head/sys/sys/bus_dma.h >> > >> > Modified: head/sys/sys/bus_dma.h >> > ============================================================================== >> > --- head/sys/sys/bus_dma.h Wed Jul 8 13:19:13 2015 (r285269) >> > +++ head/sys/sys/bus_dma.h Wed Jul 8 13:52:59 2015 (r285270) >> > @@ -282,13 +282,25 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat, >> > void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map); >> > >> > /* >> > - * Perform a synchronization operation on the given map. >> > + * Perform a synchronization operation on the given map. If the map >> > + * is NULL we have a fully IO-coherent system. On every ARM architecture >> > + * there must be a memory barrier placed to ensure that all data >> > + * accesses are visible before going any further. >> > */ >> > void _bus_dmamap_sync(bus_dma_tag_t, bus_dmamap_t, bus_dmasync_op_t); >> > +#if defined(__arm__) >> > + #define __BUS_DMAMAP_SYNC_DEFAULT mb(); >> > +#elif defined(__aarch64__) >> > + #define __BUS_DMAMAP_SYNC_DEFAULT dmb(sy); >> > +#else >> > + #define __BUS_DMAMAP_SYNC_DEFAULT {} >> > +#endif >> > #define bus_dmamap_sync(dmat, dmamap, op) \ >> > do { \ >> > if ((dmamap) != NULL) \ >> > _bus_dmamap_sync(dmat, dmamap, op); \ >> > + else \ >> > + __BUS_DMAMAP_SYNC_DEFAULT \ >> > } while (0) >> > >> > /* >> > >> > >