Re: [PATCH] perf jit: genelf makes assumptions about endian

Em Wed, Mar 30, 2016 at 01:38:20PM +1100, Michael Ellerman escreveu:

On Tue, 2016-03-29 at 17:59 +1100, Anton Blanchard wrote:

quoted

Commit 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
incorrectly assumed that PowerPC is big endian only.

Simplify things by consolidating the define of GEN_ELF_ENDIAN and checking
for __BYTE_ORDER == __BIG_ENDIAN.

The PowerPC checks were also incorrect, they do not match what gcc
emits. We should first look for __powerpc64__, then __powerpc__.

Fixes: 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support")
Signed-off-by: Anton Blanchard <redacted>

The diff's a little hard to read because you're pulling the endian logic out,
if I remove that I get something like:

Yeah, I'm taking this patch, but would be better next time to break it
down in two, one doing the reorg, the other doing the actual fix...

Thanks,

- Arnaldo
 

quoted

 #elif defined(__i386__)
 #define GEN_ELF_ARCH	EM_386
 #define GEN_ELF_CLASS	ELFCLASS32
-#elif defined(__ppcle__)
-#define GEN_ELF_ARCH	EM_PPC
-#define GEN_ELF_CLASS	ELFCLASS64
-#elif defined(__powerpc__)
-#define GEN_ELF_ARCH	EM_PPC64
-#define GEN_ELF_CLASS	ELFCLASS64
-#elif defined(__powerpcle__)
+#elif defined(__powerpc64__)
 #define GEN_ELF_ARCH	EM_PPC64
 #define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__powerpc__)
+#define GEN_ELF_ARCH	EM_PPC
+#define GEN_ELF_CLASS	ELFCLASS32
 #else
 #error "unsupported architecture"
 #endif

Which looks correct to me.

And the consolidation of the endian logic is "obviously correct", so:

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers