On Mon, Apr 14, 2025 at 01:11:43PM +0200, Peter Zijlstra wrote: > Since there is only a single fastop() function, convert the FASTOP > stuff from CALL_NOSPEC+RET to JMP_NOSPEC+JMP, avoiding the return > thunks and all that jazz. > > Specifically FASTOPs rely on the return thunk to preserve EFLAGS, > which not all of them can trivially do (call depth tracing suffers > here). > > Objtool strenuously complains about things, therefore fix up the > various problems: > > - indirect call without a .rodata, fails to determine JUMP_TABLE, > add an annotation for this. > - fastop functions fall through, create an exception for this case > - unreachable instruction after fastop_return, save/restore I think this breaks unwinding. Each of the individual fastops inherits fastop()'s stack but the ORC doesn't reflect that. Should they just be moved to a proper .S file? -- Josh
