Date: Fri, 14 Jan 2011 08:17:32 -0500 From: John Baldwin <jhb@freebsd.org> To: Warner Losh <imp@bsdimp.com> Cc: svn-src-head@freebsd.org, Matthew D Fleming <mdf@freebsd.org>, svn-src-all@freebsd.org, src-committers@freebsd.org, Bruce Evans <brde@optusnet.com.au> Subject: Re: svn commit: r217330 - head/sys/x86/x86 Message-ID: <201101140817.32393.jhb@freebsd.org> In-Reply-To: <4D2F78DF.1090106@bsdimp.com> References: <201101122108.p0CL8o3Q012038@svn.freebsd.org> <20110113104728.L1003@besplex.bde.org> <4D2F78DF.1090106@bsdimp.com>
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On Thursday, January 13, 2011 5:12:47 pm Warner Losh wrote: > 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. It doesn't work on PAE either. bus_size_t is not the same as size_t in this case. -- John Baldwin
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