The kbuild test robot reported this objtool warning [1]:
arch/x86/kvm/emulate.o: warning: objtool: fastop()+0x69: call without frame pointer save/setup
The issue seems to be caused by CONFIG_PROFILE_ALL_BRANCHES. With that
option, for some reason gcc decides not to create a stack frame in
fastop() before doing the inline asm call, which can result in a bad
stack trace.
Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
listing the stack pointer as an output operand for the inline asm
statement.
This change has no effect for !CONFIG_PROFILE_ALL_BRANCHES.
[1] https://lists.01.org/pipermail/kbuild-all/2016-March/018249.html
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
4548f63e65