On 05/05/2018 19:22, Nadav Amit wrote: > Paolo Bonzini <[email protected]> wrote: > >> -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 <[email protected]> >> Cc: Michal Marek <[email protected]> >> Cc: [email protected] >> Cc: [email protected] >> Reported-by: Linda Walsh <[email protected]> >> Signed-off-by: Paolo Bonzini <[email protected]> >> --- >> include/linux/compiler-gcc.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h >> index 22ab246feed3..eeae401a2412 100644 >> --- a/include/linux/compiler-gcc.h >> +++ b/include/linux/compiler-gcc.h >> @@ -199,7 +199,7 @@ >> #define unreachable() __builtin_unreachable() >> >> /* Mark a function definition as prohibited from being cloned. */ >> -#define __noclone __attribute__((__noclone__)) >> +#define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) > > [ Bringing the thread back from the dead for context ] > > Setting different optimization attributes to certain functions apparently > prevents gcc from inlining functions with different “optimizations”. This > results in poor compilation - most notably of vmx_vcpu_run() - and causes > short functions such as to_vmx() not to be inlined.
Hmm, I suppose we need to disable -fno-tracer globally... Has this changed in recent versions of GCC? Paolo
