Messages in this thread | | | Date | Mon, 19 Jun 2017 04:11:05 +0300 | From | Yury Norov <> | Subject | Re: [PATCH v3 2/4] asm-generic: Provide a fncpy() implementation |
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> > +/* > > + * Minimum alignment requirement for the source and destination addresses > > + * for function copying. > > + */ > > +#define FNCPY_ALIGN 8 > > >From now this is not arm-only, and it's possible that some architectures > might want to redefine it in their arch/xxx/include/asm/fncpy.h files. > So it will be easier for them if you'll wrap FNCPY_ALIGN here with #ifdef > guards. > > By the way, compiler already has an information on the proper alignment. > Maybe it's better to use it as the default value here instead of the > hardcoded value? > > #ifndef FNCPY_ALIGN > #define FNCPY_ALIGN ({void foo(); __alignof__(&foo);}) > #endif
Ah sorry, at first it should be like this: #define FNCPY_ALIGN ({void foo(); __alignof__(foo);})
And at second, the correct version returns 1 always.
Even if I pass falign-functions=4096 to gcc, and I see that functions are aligned accordingly in elf file, the macro returns 1 anyway. So if it doesn't work, the hardcoded '8' is the only option.
Yury
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