[PATCH v16.1 26/33] x86/kvm: Make test_cc() always inline

From: Josh Poimboeuf
Date: Fri Jan 22 2016 - 11:16:22 EST

With some configs (including allyesconfig), gcc doesn't inline
test_cc(). When that happens, test_cc() doesn't create a stack frame
before inserting the inline asm call instruction. This breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace.

Force it to always be inlined so that its containing function's stack
frame can be used.

Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
arch/x86/kvm/emulate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index aa4d726..80363eb 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -969,7 +969,7 @@ static int em_bsr_c(struct x86_emulate_ctxt *ctxt)
return fastop(ctxt, em_bsr);

-static u8 test_cc(unsigned int condition, unsigned long flags)
+static __always_inline u8 test_cc(unsigned int condition, unsigned long flags)
u8 rc;
void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf);