> However... that was supposed to be a 'clear RSB' operation, with 32 > CALLs in sequence. And Boris changed it to 16 by calling __fill_rsb() > instead of __clear_rsb():
True. That's even worse. > > - asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE > - ALTERNATIVE("jmp 910f", > - __stringify(__FILL_RETURN_BUFFER(%0, > RSB_CLEAR_LOOPS, %1)), > - X86_FEATURE_RETPOLINE) > - "910:" > - : "=r" (loops), ASM_CALL_CONSTRAINT > - : : "memory" ); > + alternative_input("", > + "call __fill_rsb", > + X86_FEATURE_RETPOLINE, > + ASM_NO_INPUT_CLOBBER(_ASM_BX, "memory")); > > I think we do need to revert that patch. And perhaps stop accepting any > more similar bikeshedding. Yes revertion would be the right way. I already regret the time I wasted trying to fix it. -Andi