[PATCH] x86_64: Pass -32 to the assembler when compiling the 32bit vsyscall pages

This quietens warnings and actually fixes a bug.  The unwind tables would
come out wrong without -32, causing pthread cancellation during them to
crash in the gcc runtime.

The problem seems to only happen with newer binutils (it doesn't happen
with 2.16.91.0.2 but happens wit 2.16.91.0.5)

Thanks to David Altobelli <david.altobelli@hp.com> and Brian Baker
<Brian.B@hp.com> for test case and initial analysis.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/x86_64/ia32/Makefile b/arch/x86_64/ia32/Makefile
index 929e6b0771f803bb410e37d63188dba10b63fd4f..e9263b4975e0c4fec437c134ae45bebac2d501af 100644 (file)
--- a/arch/x86_64/ia32/Makefile
+++ b/arch/x86_64/ia32/Makefile
@@ -27,5 +27,5 @@ $(obj)/vsyscall-sysenter.so $(obj)/vsyscall-syscall.so: \
 $(obj)/vsyscall-%.so: $(src)/vsyscall.lds $(obj)/vsyscall-%.o FORCE
        $(call if_changed,syscall)
 
-AFLAGS_vsyscall-sysenter.o = -m32
-AFLAGS_vsyscall-syscall.o = -m32
+AFLAGS_vsyscall-sysenter.o = -m32 -Wa,-32
+AFLAGS_vsyscall-syscall.o = -m32 -Wa,-32