Hello Heiko, Eugene, On 4/14/18 6:43 PM, Heiko Carstens wrote: > Document that the signum argument is ignored in newer kernels, but > that user space should pass a valid real-time signal number for > backwards compatibility. > > Co-Authored-by: Eugene Syromyatnikov <evgsyr@xxxxxxxxx> > Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> > Signed-off-by: Eugene Syromyatnikov <evgsyr@xxxxxxxxx> Thanks. Patch (at last) applied. Cheers, Michael > --- > man2/s390_runtime_instr.2 | 24 ++++++++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) > > diff --git a/man2/s390_runtime_instr.2 b/man2/s390_runtime_instr.2 > index 9ef293f..17665b7 100644 > --- a/man2/s390_runtime_instr.2 > +++ b/man2/s390_runtime_instr.2 > @@ -48,9 +48,11 @@ argument controls whether run-time instrumentation is started > The > .IR signum > argument specifies the number of a real-time signal. > -The real-time signal is sent to the thread if the run-time instrumentation > -buffer is full or if the run-time-instrumentation-halted interrupt > -occurred. > +This argument was used to specify a signal number that should be delivered > +to the thread if the run-time instrumentation buffer was full or if > +the run-time-instrumentation-halted interrupt had occurred. > +It has no effect beginning with Linux 4.4, since support for signalling > +was never used and kernel support was removed. > .SH RETURN VALUE > On success, > .BR s390_runtime_instr () > @@ -67,9 +69,16 @@ is set to one of the error codes listed below. > .B EINVAL > The value specified in > .IR command > -is not a valid command or the value specified in > +is not a valid command. > +.TP > +.B EINVAL > +The value specified in > .IR signum > is not a real-time signal number. > +From Linux 4.4 onwards, the > +.IR signum > +argument has no effect, so that an invalid signal number will not result in an > +error. > .TP > .B ENOMEM > Allocating memory for the run-time instrumentation control block failed. > @@ -89,6 +98,13 @@ to call it. > The header > .B asm/runtime_instr.h > is available since Linux 4.16. > +.PP > +Support for signalling was removed with Linux 4.4. > +With Linux 4.4 also the check whether > +.IR signum > +is a valid real-time signal was removed. > +For backwards compatibility with old kernels it is recommended to pass a valid > +real-time signal number and install a handler for it. > .SH SEE ALSO > .BR syscall (2), > .BR signal (7) > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
