s390/oprofile: remove hardware sampler support

Remove hardware sampler support from oprofile module.

The oprofile user space utilty has been switched to use the kernel
perf interface, for which we also provide hardware sampling support.

In addition the hardware sampling support is also slightly broken: it
supports only 16 bits for the pid and therefore would generate wrong
results on machines which have a pid >64k.

Also the pt_regs structure which was passed to oprofile common code
cannot necessarily be used to generate sane backtraces, since the
task(s) in question may run while the samples are fed to oprofile.
So the result would be more or less random.

However given that the only user space tools switched to the perf
interface already four years ago the hardware sampler code seems to be
unused code, and therefore it should be reasonable to remove it.

The timer based oprofile support continues to work.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Andreas Arnez <arnez@linux.vnet.ibm.com>
Acked-by: Andreas Krebbel <krebbel@linux.vnet.ibm.com>
Acked-by: Robert Richter <rric@kernel.org>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 0 insertions, 2 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 82b42c958d1c..68b0c022861a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2788,8 +2788,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			timer: [X86] Force use of architectural NMI
 				timer mode (see also oprofile.timer
 				for generic hr timer mode)
-				[s390] Force legacy basic mode sampling
-                                (report cpu_type "timer")
 
 	oops=panic	Always panic on oopses. Default is to just kill the
 			process, but there is a small probability of