Date: Wed, 05 Feb 2014 15:38:34 -0500 From: John Baldwin <jhb@freebsd.org> To: Ian Lepore <ian@freebsd.org> Cc: freebsd-arch@freebsd.org Subject: Re: Malloc alignment in libstand / loader(8) Message-ID: <2263843.rxdRK42Wk4@ralph.baldwin.cx> In-Reply-To: <1391630829.1196.31.camel@revolution.hippie.lan> References: <1391576134.1196.21.camel@revolution.hippie.lan> <2882663.sRzekugaiD@ralph.baldwin.cx> <1391630829.1196.31.camel@revolution.hippie.lan>
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On Wednesday, February 05, 2014 01:07:09 PM Ian Lepore wrote: > On Wed, 2014-02-05 at 08:29 -0500, John Baldwin wrote: > > On Tuesday, February 04, 2014 09:55:34 PM Ian Lepore wrote: > > > On newer ARM chips, the device drivers used by loader(8) require that > > > I/O buffers be aligned on cache line sized boundaries. The drivers are > > > part of u-boot which serves as a sort of load-time bios. > > > > > > Attached is a patch that sets the malloc alignment in libstand to 64 > > > bytes when compiled on ARM, and leaves it at 16 bytes for all other > > > platforms. If there are no objections I'd like to commit this soon. > > > > > > I've tested this on ARM, but have no way to test it on other platforms. > > > The changes should be a no-op on other platforms. > > > > I think this looks fine, but perhaps use CTASSERT() instead of rolling > > your > > own? (I would say to use _Static_assert(), but I don't think that works > > with our old GCC) > > I wasn't sure if it's a good idea to #include <systm.h> in the libstand > environment, since it has declarations for a lot of stuff. I looked at > what's in systm.h and then hand-replicated what seemed like the most > generic of the choices. That's fair. -- John Baldwin
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