On Monday 09 May 2016 19:34:53 Michael Ellerman wrote: > On Mon, 2016-05-09 at 16:33 +1000, Stephen Rothwell wrote: > > On Mon, 9 May 2016 10:59:27 +1000 Stephen Rothwell <s...@canb.auug.org.au> > > wrote: > > > On Fri, 6 May 2016 09:22:25 -0500 Josh Poimboeuf <jpoim...@redhat.com> > > > wrote: > > > > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h > > > > index eeae401..3d5202e 100644 > > > > --- a/include/linux/compiler-gcc.h > > > > +++ b/include/linux/compiler-gcc.h > > > > @@ -246,7 +246,7 @@ > > > > #define __HAVE_BUILTIN_BSWAP32__ > > > > #define __HAVE_BUILTIN_BSWAP64__ > > > > #endif > > > > -#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= > > > > 40600) > > > > +#if GCC_VERSION >= 40800 > > > > #define __HAVE_BUILTIN_BSWAP16__ > > > > #endif > > > > #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ > > > > Tested-by: Stephen Rothwell <s...@canb.auug.org.au>
Acked-by: Arnd Bergmann <a...@arndb.de> > > Michael, do you want to pass the fix patch on, or will I submit it > > directly to Linus? > > I'm happy for you to send it, I haven't actually hit the bug myself. I found the commit in gcc-4.8 that replaced the powerpc-specific implementation of __builtin_bswap16 with an architecture-independent one. Apparently the powerpc version (gcc-4.6 and 4.7) just mapped to the lhbrx/sthbrx instructions, so it ended up not being a constant, though the intent of the patch was mainly to add support for the builtin to x86. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52624 has the patch that went into gcc-4.8 and more information. Arnd
