Date: Thu, 13 Jan 2011 15:12:47 -0700 From: Warner Losh <imp@bsdimp.com> To: Bruce Evans <brde@optusnet.com.au> Cc: svn-src-head@FreeBSD.org, Matthew D Fleming <mdf@FreeBSD.org>, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, John Baldwin <jhb@FreeBSD.org> Subject: Re: svn commit: r217330 - head/sys/x86/x86 Message-ID: <4D2F78DF.1090106@bsdimp.com> In-Reply-To: <20110113104728.L1003@besplex.bde.org> References: <201101122108.p0CL8o3Q012038@svn.freebsd.org> <201101121621.30371.jhb@freebsd.org> <20110113104728.L1003@besplex.bde.org>
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On 01/12/2011 17:06, Bruce Evans wrote: > On Wed, 12 Jan 2011, John Baldwin wrote: > >>> Log: >>> Fix a brain fart. Since this file is shared between i386 and >>> amd64, a >>> bus_size_t may be 32 or 64 bits. Change the bounce_zone alignment >>> field >>> to explicitly be 32 bits, as I can't really imagine a DMA device that >>> needs anything close to 2GB alignment of data. >> >> Hmm, we do have devices with 4GB boundaries though. I think I'd >> prefer it if >> you instead if you did this: >> >> #if defined(amd64) || defined(PAE) >> #define SYSCTL_ADD_BUS_SIZE_T SYSCTL_ADD_UQUAD >> #else >> #define SYSCTL_ADD_BUS_SIZE_T SYSCTL_ADD_UINT >> #endif >> >> and then just used SYSCTL_ADD_BUS_SIZE_T() in the code so we could >> let the >> members in the bounce zone retain the same types passed to >> bus_dma_tag_create(). > > U_LONG should work on all arches. malloc(9) still uses u_long instead > of size_t. This works for scalars even on the recently removed i386's > with 32-bit longs where u_long is larger than size_t, since larger is > a fail-safe direction. This fails for pointers. Newer parts of malloc() > and uma are broken unless u_long is the same as uintptr_t, since they > cast pointers to u_long. This direction is fail-safe too, but gcc warns > about it. u_long doesn't work for N32. There, the pointers may only be 32-bit, but PAs ar 64-bit. Longs are only 32-bits. Warner > > uquad_t should never be used, like unsigned long long. Similarly for > signed types. Perhaps it could be removed in sysctl interfaces first. > > Bruce > > >
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