Date: Tue, 27 Aug 2013 16:40:55 +0100 From: Andrew Turner <andrew@fubar.geek.nz> To: Warner Losh <imp@bsdimp.com> Cc: freebsd-arm <freebsd-arm@FreeBSD.org>, Andre Oppermann <andre@freebsd.org> Subject: Re: ARM network trouble after recent mbuf changes Message-ID: <20130827164055.4a757a13@bender> In-Reply-To: <DD3D1045-535F-4593-A3B4-E33CFECF0818@bsdimp.com> References: <1377550636.1111.156.camel@revolution.hippie.lan> <521BC472.7040804@freebsd.org> <521BD531.4090104@sbcglobal.net> <521C4CD9.4050308@freebsd.org> <20130827102810.37e2dfc7@bender> <DD3D1045-535F-4593-A3B4-E33CFECF0818@bsdimp.com>
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On Tue, 27 Aug 2013 07:26:03 -0600 Warner Losh <imp@bsdimp.com> wrote: > > On Aug 27, 2013, at 3:28 AM, Andrew Turner wrote: > > > On Tue, 27 Aug 2013 08:53:13 +0200 > > Andre Oppermann <andre@freebsd.org> wrote: > >> Please try the patch below to confirm. If it fixes your problem > >> for now I'm going to commit as an immediate fix while searching > >> for a better long term stable solution. > >> > > > > I tried this with a CTASSERT to check if struct m_hdr is the correct > > length. In this test the size is incorrect. It appears __ILP32__ is > > not defined on ARM. > > > > I have tested a fix suggested by Hans Petter Selasky where we mark > > m_hdr with __aligned(8). With this change I can netboot a > > PandaBoard. > > Isn't that a bug with our arm compiler then? No, on ARM EABI the definition of the size of a struct is to be the smallest multiple of its alignment. As we are increasing the alignment to 8-byte and the struct without this alignment is not a multiple of 8-bytes adding this alignment will pad to struct to use the unused 4 bytes between this and the next struct. Andrew > > Warner > >
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