On 5/9/16, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote: > Hi Josh, > > On Fri, 6 May 2016 09:22:25 -0500 Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > wrote: >> >> I've also seen no problems on powerpc with 4.4 and 4.8. I suspect it's >> specific to gcc 4.6. Stephen, can you confirm this patch fixes it? > > That will obviously fix the problem for us (since it will effectively > restore the code to what it was before the other commit for our gcc > 4.6.3 builds and we have not seen it in other builds). I will add this > patch to linux-next today. > > And since "byteswap: try to avoid __builtin_constant_p gcc bug" is not > in Linus' tree, hopefully we can have this fix applied soon. > FYI, this patch is in Linus tree (v4.6-rc7 has it). - Sedat - [1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7322dd755e7dd34bc5359aa27abeed1687e0f628 >> From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> >> Subject: [PATCH] compiler-gcc: require gcc 4.8 for powerpc >> __builtin_bswap16() >> >> gcc support for __builtin_bswap16() was supposedly added for powerpc in >> gcc 4.6, and was then later added for other architectures in gcc 4.8. >> >> However, Stephen Rothwell reported that attempting to use it on powerpc >> in gcc 4.6 fails with: >> >> lib/vsprintf.c:160:2: error: initializer element is not constant >> lib/vsprintf.c:160:2: error: (near initialization for 'decpair[0]') >> lib/vsprintf.c:160:2: error: initializer element is not constant >> lib/vsprintf.c:160:2: error: (near initialization for 'decpair[1]') >> lib/vsprintf.c:160:2: error: initializer element is not constant >> lib/vsprintf.c:160:2: error: (near initialization for 'decpair[2]') >> lib/vsprintf.c:160:2: error: initializer element is not constant >> lib/vsprintf.c:160:2: error: (near initialization for 'decpair[3]') >> lib/vsprintf.c:160:2: error: initializer element is not constant >> >> I'm not entirely sure what those errors mean, but I don't see them on >> gcc 4.8. So let's consider gcc 4.8 to be the official starting point >> for __builtin_bswap16(). >> >> Fixes: 7322dd755e7d ("byteswap: try to avoid __builtin_constant_p gcc >> bug") >> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> >> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> >> --- >> include/linux/compiler-gcc.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> 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 */ >> -- >> 2.4.11 > > -- > Cheers, > Stephen Rothwell > -- > To unsubscribe from this list: send the line "unsubscribe linux-next" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
