On Wed, Jun 05, 2019 at 03:08:06PM +0200, Peter Zijlstra wrote: > --- a/arch/x86/include/asm/static_call.h > +++ b/arch/x86/include/asm/static_call.h > @@ -2,6 +2,20 @@ > #ifndef _ASM_STATIC_CALL_H > #define _ASM_STATIC_CALL_H > > +#include <asm/asm-offsets.h> > + > +#ifdef CONFIG_HAVE_STATIC_CALL_INLINE > + > +/* > + * This trampoline is only used during boot / module init, so it's safe to > use > + * the indirect branch without a retpoline. > + */ > +#define __ARCH_STATIC_CALL_TRAMP_JMP(key, func) > \ > + ANNOTATE_RETPOLINE_SAFE \ > + "jmpq *" __stringify(key) "+" __stringify(SC_KEY_func) "(%rip) \n" > + > +#else /* !CONFIG_HAVE_STATIC_CALL_INLINE */
I wonder if we can simplify this (and drop the indirect branch) by getting rid of the above cruft, and instead just use the out-of-line trampoline as the default for inline as well. Then the inline case could fall back to the out-of-line implementation (by patching the trampoline's jmp dest) before static_call_initialized is set. -- Josh
