Messages in this thread | | | Date | Mon, 17 Oct 2011 20:03:51 +0200 | From | "Hans J. Koch" <> | Subject | Re: [PATCH] uio: Support 36-bit physical addresses on 32-bit systems |
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On Mon, Oct 17, 2011 at 07:18:59PM +0200, Hans J. Koch wrote: > On Mon, Oct 17, 2011 at 11:00:55AM -0500, Kumar Gala wrote: > > > > On Oct 14, 2011, at 1:31 PM, Hans J. Koch wrote: > > > > > On Thu, Oct 13, 2011 at 10:50:58AM -0500, Kumar Gala wrote: > > >> From: Kai Jiang <Kai.Jiang@freescale.com> > > >> > > >> To support >32-bit physical addresses for UIO_MEM_PHYS type we need to > > >> extend the width of 'addr' in struct uio_mem. Numerous platforms like > > >> embedded PPC, ARM, and X86 have support for systems with larger physical > > >> address than logical. > > >> > > >> Since 'addr' may contain a physical, logical, or virtual address the > > >> easiest solution is to just change the type to 'phys_addr_t' which > > >> should always be greater than or equal to the sizeof(void *) such that > > >> it can properly hold any of the address types. > > >> > > >> For physical address we can support up to a 44-bit physical address on a > > >> typical 32-bit system as we utilize remap_pfn_range() for the mapping of > > >> the memory region and pfn's are represnted by shifting the address by > > >> the page size (typically 4k). > > >> > > >> Signed-off-by: Kai Jiang <Kai.Jiang@freescale.com> > > >> Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com> > > >> Signed-off-by: Kumar Gala <galak@kernel.crashing.org> > > > > > > Signed-off-by: "Hans J. Koch" <hjk@hansjkoch.de> > > > > > > That looks good to me. There's an unnecessary cast (see below), but I fixed that > > > on the way. > > > > > > Greg, please pull this from branch uio-for-gregkh from > > > > > > git://hansjkoch.de/git/linux-hjk > > > > > > Thanks, > > > Hans > > > > I think removing that cast is wrong: > > > > drivers/uio/uio.c: In function 'uio_vma_fault': > > drivers/uio/uio.c:637:26: warning: cast to pointer from integer of different size > > Hmm, on what platform did you see this? I tested on 32bit-x86 and didn't get > any warnings.
OK, you're right. I turned on CONFIG_HIGHMEM64G and got that warning. Damned x86...
Greg, can you fix it, or should I send the patch again?
Thanks, Hans
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