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> --- 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) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
