[PATCH] perf jit: genelf makes assumptions about endian

From: Anton Blanchard
Date: Tue Mar 29 2016 - 03:00:24 EST


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 <anton@xxxxxxxxx>
---

diff --git a/tools/perf/util/genelf.h b/tools/perf/util/genelf.h
index cd67e64..2fbeb59 100644
--- a/tools/perf/util/genelf.h
+++ b/tools/perf/util/genelf.h
@@ -9,36 +9,32 @@ int jit_add_debug_info(Elf *e, uint64_t code_addr, void *debug, int nr_debug_ent

#if defined(__arm__)
#define GEN_ELF_ARCH EM_ARM
-#define GEN_ELF_ENDIAN ELFDATA2LSB
#define GEN_ELF_CLASS ELFCLASS32
#elif defined(__aarch64__)
#define GEN_ELF_ARCH EM_AARCH64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
#define GEN_ELF_CLASS ELFCLASS64
#elif defined(__x86_64__)
#define GEN_ELF_ARCH EM_X86_64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
#define GEN_ELF_CLASS ELFCLASS64
#elif defined(__i386__)
#define GEN_ELF_ARCH EM_386
-#define GEN_ELF_ENDIAN ELFDATA2LSB
#define GEN_ELF_CLASS ELFCLASS32
-#elif defined(__ppcle__)
-#define GEN_ELF_ARCH EM_PPC
-#define GEN_ELF_ENDIAN ELFDATA2LSB
-#define GEN_ELF_CLASS ELFCLASS64
-#elif defined(__powerpc__)
-#define GEN_ELF_ARCH EM_PPC64
-#define GEN_ELF_ENDIAN ELFDATA2MSB
-#define GEN_ELF_CLASS ELFCLASS64
-#elif defined(__powerpcle__)
+#elif defined(__powerpc64__)
#define GEN_ELF_ARCH EM_PPC64
-#define GEN_ELF_ENDIAN ELFDATA2LSB
#define GEN_ELF_CLASS ELFCLASS64
+#elif defined(__powerpc__)
+#define GEN_ELF_ARCH EM_PPC
+#define GEN_ELF_CLASS ELFCLASS32
#else
#error "unsupported architecture"
#endif

+#if __BYTE_ORDER == __BIG_ENDIAN
+#define GEN_ELF_ENDIAN ELFDATA2MSB
+#else
+#define GEN_ELF_ENDIAN ELFDATA2LSB
+#endif
+
#if GEN_ELF_CLASS == ELFCLASS64
#define elf_newehdr elf64_newehdr
#define elf_getshdr elf64_getshdr