Messages in this thread | | | Date | Wed, 27 Nov 2013 14:20:50 +0000 | From | "Jan Beulich" <> | Subject | Re: [PATCH] x86: override __compiletime_object_size() |
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>>> On 27.11.13 at 15:03, Ingo Molnar <mingo@kernel.org> wrote:
> * Jan Beulich <JBeulich@suse.com> wrote: > >> As discussed in the context of commits 3df7b41a ("x86: Unify >> copy_from_user() size checking") and 7a3d9b0f ("x86: Unify >> copy_to_user() and add size checking to it"), we want to leverage >> __builtin_object_size() also on newer gcc versions, but with other >> architectures still using another model of copy_*_user() verification >> we can't replace the global definition. Do it in the (only) header >> needing the construct for now. >> >> Signed-off-by: Jan Beulich <jbeulich@suse.com> >> Cc: Arjan van de Ven <arjan@linux.intel.com> >> Cc: Guenter Roeck <linux@roeck-us.net> >> --- >> arch/x86/include/asm/uaccess.h | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> --- 3.13-rc1/arch/x86/include/asm/uaccess.h >> +++ 3.13-rc1-x86-compiletime-object-size/arch/x86/include/asm/uaccess.h >> @@ -584,6 +584,12 @@ __copy_from_user_overflow(int size, unsi >> >> #endif >> >> +/* linux/compiler-gcc4.h restricts this to gcc < 4.6, which doesn't suit us. */ >> +#if defined(__GNUC__) && GCC_VERSION >= 40100 >> +# undef __compiletime_object_size >> +# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) >> +#endif >> + > > Would be nice to have a more verbose changelog that explains what > benefits this brings us.
That makes no sense to me - the benefits of this construct should have been explained with its introduction; the change here just makes it being used under wider range of compilers (and the code comment already says exactly that).
Jan
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