Messages in this thread | | | Date | Mon, 12 Nov 2012 13:58:32 -0600 | Subject | Re: [PATCH] ARM: add get_user() support for 8 byte types | From | Rob Clark <> |
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On Mon, Nov 12, 2012 at 1:27 PM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Fri, Nov 09, 2012 at 03:17:33PM -0600, Rob Clark wrote: >> From: Rob Clark <rob@ti.com> >> >> A new atomic modeset/pageflip ioctl being developed in DRM requires >> get_user() to work for 64bit types (in addition to just put_user()). > > NAK. > > (I did write a better email explaining all the ins and outs of why this > won't work and why 64-bit get_user isn't possible, but my editor crapped > out and lost all that well written message; I don't fancy typing it all > out again.) > > Nevertheless, > int test_ptr(unsigned int **v, unsigned int **p) > { > return get_user(*v, p); > } > > produces a warning, and you can't get away from that if you stick 64-bit > support into get_user().
Actually, it seems like using 'register typeof(x) __r2 asm("r2");' does avoid that warning..
I don't know if that was the only argument against 64-bit get_user(). But it will at least be inconvenient that get_user() works for 64bit on x86 but not arm..
BR, -R
> Sorry, 64-bit get_user() is a no-no. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
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