[PATCH] powerpc: Reject binutils 2.24 when building little endian

[Michael Ellerman <mpe@ellerman.id.au>]

There is a bug in binutils 2.24 which causes miscompilation if we're
building little endian and using weak symbols (which the kernel does).

It is fixed in binutils commit 57fa7b8c7e59 "Correct elf_merge_st_other
arguments for weak symbols", which is in binutils 2.25 and has been
backported to the binutils 2.24 branch and has been picked up by most
distros it seems.

However if we're running stock 2.24 (no extra version) then the bug is
present, so check for that and bail.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 07a480861f78..f1ed279e3ea6 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -336,6 +336,14 @@ checkbin:
 		echo 'disable kernel modules' ; \
 		false ; \
 	fi
+	@if test "x${CONFIG_CPU_LITTLE_ENDIAN}" = "xy" \
+	    && $(LD) --version | head -1 | grep ' 2\.24$$' >/dev/null ; then \
+		echo -n '*** binutils 2.24 miscompiles weak symbols ' ; \
+		echo 'in some circumstances.' ; \
+		echo -n '*** Please use a different binutils version.' ; \
+		false ; \
+	fi
+
 
 CLEAN_FILES += $(TOUT)
 
-- 
2.1.0