compiler-gcc: disable -ftracer for __noclone functions

commit 95272c29378ee7dc15f43fa2758cb28a5913a06d upstream.

-ftracer can duplicate asm blocks causing compilation to fail in
noclone functions.  For example, KVM declares a global variable
in an asm like

    asm("2: ... \n
         .pushsection data \n
         .global vmx_return \n
         vmx_return: .long 2b");

and -ftracer causes a double declaration.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: kvm@vger.kernel.org
Reported-by: Linda Walsh <lkml@tlinx.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.16: apply to compiler-gcc{4,5}.h]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index 2507fd2a1eb4f9d4971b9de5344e8f250570c012..cc7da99ad58d70a636e096198cfb38cada5419c6 100644 (file)
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -54,7 +54,7 @@
 #define unreachable() __builtin_unreachable()
 
 /* Mark a function definition as prohibited from being cloned. */
-#define __noclone      __attribute__((__noclone__))
+#define __noclone      __attribute__((__noclone__, __optimize__("no-tracer")))
 
 #endif /* GCC_VERSION >= 40500 */
 

diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
index cdd1cc202d51ef2c33654630023022284977ea8d..be39624de8b5363ad727eac1b41133bd90186217 100644 (file)
--- a/include/linux/compiler-gcc5.h
+++ b/include/linux/compiler-gcc5.h
@@ -40,7 +40,7 @@
 #define unreachable() __builtin_unreachable()
 
 /* Mark a function definition as prohibited from being cloned. */
-#define __noclone      __attribute__((__noclone__))
+#define __noclone      __attribute__((__noclone__, __optimize__("no-tracer")))
 
 /*
  * Tell the optimizer that something else uses this function or variable.