On Thu, Nov 15, 2012 at 02:39:41PM +0000, Arnd Bergmann wrote: > On Thursday 15 November 2012, Rob Clark wrote: > > > I still haven't heard a conclusive argument why we need to use get_user() > > > rather than copy_from_user() in the DRM code. Is this about a fast path > > > where you want to shave off a few cycles for each call, or does this > > > simplify the code structure, or something else? > > > > well, it is mostly because it seemed like a good idea to first try to > > solve the root issue, rather than having to fix things up in each > > driver when someone from x86-world introduces a 64b get_user().. > > As pointed out by hpa earlier, x86-32 doesn't have a 64b get_user > either. I don't think we have a lot of drivers that are used only > on 64-bit x86 and on 32-bit ARM but not on 32-bit x86. Ouch. I didn't realize that x86-32 doesn't have it. All the systems where I've run the new code are 64bit so I never noticed the problem. I see there was a patch [1] posted a long time ago to implement 64bit get_user() on x86-32. I wonder what happened to it? [1] https://lkml.org/lkml/2004/4/20/96 -- Ville Syrjälä Intel OTC -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
