Peter Zijlstra <[email protected]> writes:
> On Sat, May 16, 2020 at 01:45:51AM +0200, Thomas Gleixner wrote:
>> --- a/arch/x86/kernel/nmi.c
>> +++ b/arch/x86/kernel/nmi.c
>> @@ -334,6 +334,7 @@ static noinstr void default_do_nmi(struc
>> __this_cpu_write(last_nmi_rip, regs->ip);
>>
>> instrumentation_begin();
>> + ftrace_nmi_handler_enter();
>>
>> handled = nmi_handle(NMI_LOCAL, regs);
>> __this_cpu_add(nmi_stats.normal, handled);
>> @@ -420,6 +421,7 @@ static noinstr void default_do_nmi(struc
>> unknown_nmi_error(reason, regs);
>>
>> out:
>> + ftrace_nmi_handler_exit();
>> instrumentation_end();
>> }
>
> Yeah, so I'm confused about this and the previous patch too. Why not
> do just this? Remove that ftrace_nmi_handler.* crud from
> nmi_{enter,exit}() and stick it here? Why do we needs the
> nmi_{enter,exit}_notrace() thing?
Because you then have to fixup _all_ architectures which use
nmi_enter/exit().
Thanks,
tglx
