On Thu, Oct 10, 2013 at 10:24:30AM +0200, Ingo Molnar wrote: > Something like the patch below? (Totally untested and all that.) > > Notes: > > - If the bug is fixed in 4.8.3 then the version check can be sharpened > from 99999 to 40803.
The bug is likely going to be fixed already for 4.8.2 (to be released next week or so). > - I'd really prefer this quirk versus having to add the extra barrier to > the label, as it makes the actual usage sites a lot less painful. Please check how much it bloats the generated code. Also, for the bitops patch, you probably want an asm_volatile_goto variant. > --- a/include/linux/compiler-gcc4.h > +++ b/include/linux/compiler-gcc4.h > @@ -65,6 +65,19 @@ > #define __visible __attribute__((externally_visible)) > #endif > > +/* > + * GCC 'asm goto' miscompiles certain code sequences: > + * > + * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 > + * > + * Work it around via quirk suggested by Jakub Jelinek. > + * Not yet fixed, so use the quirk on all compiler versions: > + */ > +#if GCC_VERSION <= 99999 > +# define asm_goto(x...) do { asm goto(x); asm (""); } while (0) > +#else > +# define asm_goto(x...) do { asm goto(x); } while (0) > +#endif > > #ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP > #if GCC_VERSION >= 40400 Jakub -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
