s390_runtime_instr.2: document signum argument behavior change
PATCH v2 2/4 s390_runtime_instr.2: document signum argument behavior change
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 <[email protected]>
Signed-off-by Heiko Carstens <[email protected]>
Signed-off-by Eugene Syromyatnikov <[email protected]>
--- man2/s390_runtime_instr.2 | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)
man2/s390_runtime_instr.2 +20 -4
@@ -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)
Signature · 1 line
2.1.4
Hello Heiko, Eugene,
Quoted 7 lines · Heiko Carstens
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 <[email protected]>Signed-off-by Heiko Carstens <[email protected]>Signed-off-by Eugene Syromyatnikov <[email protected]>
Thanks. Patch (at last) applied.
Cheers,
Michael
Quoted 56 lines
--- man2/s390_runtime_instr.2 | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)man2/s390_runtime_instr.2 +20
-4@@ -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)
Signature · 3 lines
Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/