On Wed, May 08, 2019 at 05:39:07PM +0200, Peter Zijlstra wrote: > On Wed, May 08, 2019 at 07:42:48AM -0500, Josh Poimboeuf wrote: > > On Wed, May 08, 2019 at 02:04:16PM +0200, Peter Zijlstra wrote: > > > > Do the x86_64 variants also want some ORC annotation? > > > > Maybe so. Though it looks like regs->ip isn't saved. The saved > > registers might need to be tweaked. I'll need to look into it. > > What all these sites do (and maybe we should look at unifying them > somehow) is turn a CALL frame (aka RET-IP) into an exception frame (aka > pt_regs). > > So regs->ip will be the return address (which is fixed up to be the CALL > address in the handler). But from what I can tell, trampoline_handler() hard-codes regs->ip to point to kretprobe_trampoline(), and the original return address is placed in regs->sp. Masami, is there a reason why regs->ip doesn't have the original return address and regs->sp doesn't have the original SP? I think that would help the unwinder understand things. -- Josh
