On Thu, Apr 14, 2016 at 11:10 AM, Dmitry Safonov <[email protected]> wrote: > We can use user_64bit_mode(regs) here instead of thread flag > because we have full register frame. > > Signed-off-by: Dmitry Safonov <[email protected]> > --- > arch/x86/events/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c > index 041e442a3e28..91d101a9a6e9 100644 > --- a/arch/x86/events/core.c > +++ b/arch/x86/events/core.c > @@ -2269,7 +2269,7 @@ perf_callchain_user32(struct pt_regs *regs, struct > perf_callchain_entry *entry) > struct stack_frame_ia32 frame; > const void __user *fp; > > - if (!test_thread_flag(TIF_IA32)) > + if (user_64bit_mode(regs)) > return 0;
Peter, I got lost in the code that calls this. Are regs coming from the overflow interrupt's regs, current_pt_regs(), or perf_get_regs_user? If it's the perf_get_regs_user, then this should be okay, but passing in the ABI field directly would be even nicer. If they're coming from the overflow interrupt's regs or current_pt_regs(), could we change that? It might also be nice to make sure that we call perf_get_regs_user exactly once per overflow interrupt -- i.e. we could push it into the main code rather than the regs sampling code. > > cs_base = get_segment_base(regs->cs); > -- > 2.8.0 > -- Andy Lutomirski AMA Capital Management, LLC
