From: Michael Ellerman <mpe@ellerman.id.au>
Date: Thu, 23 Apr 2015 07:27:12 +0000 (+1000)
Subject: powerpc: Reject binutils 2.24 when building little endian
X-Git-Tag: firefly_0821_release~176^2~1592^2~149
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=60e065f70bdb0b0e916389024922ad40f3270c96;hp=e79c8385c878abdf90290cba6bea08fd60058562;p=firefly-linux-kernel-4.4.55.git

powerpc: Reject binutils 2.24 when building little endian

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>
---

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 3609504b0ad2..a314cb024c8b 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -339,6 +339,14 @@ 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)