Messages in this thread | | | Date | Wed, 9 Mar 2016 13:27:10 -0500 | From | Benjamin LaHaise <> | Subject | Re: [PATCH] x86_32: add support for 64 bit __get_user() |
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On Wed, Mar 09, 2016 at 10:22:50AM -0800, H. Peter Anvin wrote: > On 03/09/2016 09:50 AM, Benjamin LaHaise wrote: > > On Wed, Mar 09, 2016 at 09:36:30AM -0800, H. Peter Anvin wrote: > >> On March 9, 2016 9:22:25 AM PST, Benjamin LaHaise <bcrl@kvack.org> wrote: > >>> The existing __get_user() implementation does not support fetching > >>> 64 bit values on 32 bit x86. Implement this in a way that does not > >>> generate any incorrect warnings as cautioned by Russell King. Test > >>> code available at http://www.kvack.org/~bcrl/x86_32-get_user.tar . > > ... > >> Weird. I could swear we had already fixed this a few years ago. > > > > That surprised me as well, but Russell raised the fact that the approaches > > previously tried on 32 bit architectures had caused various incorrect > > compiler warnings for certain obscure cases -- see the code in test_module.c > > in that URL that Russell provided to demonstrate the problem across all the > > corner cases. > > Oh, I see... I implemented it for put but not get... weird. You may > want to look at the __inttype() macro defined earlier in this file; it > might be useful.
Ah, interesting. I'll look at that.
> I presume you have already seen: > > >> fs/select.c:710: Error: operand type mismatch for `movq' > >> fs/select.c:714: Error: incorrect register `%cx' used with `q' suffix > fs/select.c:711: Error: operand type mismatch for `movq' > >> fs/select.c:715: Error: incorrect register `%si' used with `q' suffix > -- > fs/aio.c: Assembler messages: > >> fs/aio.c:1606: Error: operand type mismatch for `movq' > >> fs/aio.c:1610: Error: incorrect register `%si' used with `q' suffix > > ... which implies it used 16-bit registers for 64-bit operations when > compiling for 64 bits.
Yup, will respin shortly.
-ben -- "Thought is the essence of where you are now."
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