linux-kernel - Re: [PATCH] swiotlb: swiotlb_{alloc,free}_buffer should depend on CONFIG_DMA_DIRECT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20180326134259.GA15387@lst.de>
Date:   Mon, 26 Mar 2018 15:42:59 +0200
From:   Christoph Hellwig <hch@....de>
To:     Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:     Christoph Hellwig <hch@....de>, tglx@...utronix.de, mingo@...e.hu,
        linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org
Subject: Re: [PATCH] swiotlb: swiotlb_{alloc,free}_buffer should depend on
        CONFIG_DMA_DIRECT_OPS

On Sat, Mar 24, 2018 at 04:05:45PM -0400, Konrad Rzeszutek Wilk wrote:
> > > > Otherwise we might get unused symbol warnings for configs that built
> > > > swiotlb.c only for use by xen-swiotlb.c and that don't otherwise select
> > > > CONFIG_DMA_DIRECT_OPS, which is possible on arm.
> > > > 
> > > > Fixes: 16e73adbca76 ("dma/swiotlb: Remove swiotlb_{alloc,free}_coherent()")
> > > > Reported-by: Stephen Rothwell <sfr@...b.auug.org.au>
> > > > Signed-off-by: Christoph Hellwig <hch@....de>
> > > 
> > > 
> > > Alternatively could we set the Kconfig to slect DMA_DIRECT_OPS?
> > 
> > 
> > IFF we build swiotlb.c only for xen-swiotlb we don't need DMA_DIRECT_OPS.
> 
> I don't think there is ever an case where you want a Xen specific build.

arm never uses swiotlb directly, so any swiotlb.c build on arm is purely
for xen-swiotlb.c