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40 Commits (a80313ff91abda67641dc33bed97f6bcc5e9f6a4)

Author SHA1 Message Date
Thomas Richter 46a984ffb8 s390/cpum_cf: Add support for CPU-MF SVN 6
Add support for the CPU-Measurement Facility counter
second version number 6. This number is used to detect some
more counters in the crypto counter set and the extended
counter set.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-03-29 07:23:50 +01:00
Thomas Richter 47b7478583 s390/cpum_cf: Handle EBUSY return code from CPU counter facility reservation
Rservation of the CPU Measurement Counter facility may fail if
it is already in use by the cf_diag device driver.
This is indicated by a non zero return code (-EBUSY).
However this return code is ignored and the counter facility
may be used in parallel by different device drivers.

Handle the failing reservation and return an error to the
caller.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:58 +01:00
Hendrik Brueckner 7f5ac1a022 s390/cpum_cf: move common functions into a separate file
Move common functions of the couter facility support into a separate
file.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:55 +01:00
Hendrik Brueckner 869f4f98fa s390/cpum_cf: introduce kernel_cpumcf_avail() function
A preparation to move out common CPU-MF counter facility support
functions, first introduce a function that indicates whether the
support is ready to use.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:54 +01:00
Hendrik Brueckner 26b8317f51 s390/cpum_cf: introduce kernel_cpumcf_alert() to obtain measurement alerts
During a __kernel_cpumcf_begin()/end() session, save measurement alerts
for the counter facility in the per-CPU cpu_cf_events variable.
Users can obtain and, optionally, clear the alerts by calling
kernel_cpumcf_alert() to specifically handle alerts.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:50 +01:00
Hendrik Brueckner f944bcdf5b s390/cpu_mf: move struct cpu_cf_events and per-CPU variable to header file
Make the struct cpu_cf_events and the respective per-CPU variable available
to in-kernel users.  Access to this per-CPU variable shall be done between
the calls to __kernel_cpumcf_begin() and __kernel_cpumcf_end().

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:49 +01:00
Hendrik Brueckner f1c0b83173 s390/cpum_cf: rename per-CPU counter facility structure and variables
Rename the struct cpu_hw_events to cpu_cf_events and also the respective
per-CPU variable to make its name more clear.  No functional changes.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:48 +01:00
Hendrik Brueckner 3d33345aa3 s390/cpum_cf: prepare for in-kernel counter measurements
Prepare the counter facility support to be used by other in-kernel
users.  The first step introduces the __kernel_cpumcf_begin() and
__kernel_cpumcf_end() functions to reserve the counter facility
for doing measurements and to release after the measurements are
done.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:47 +01:00
Hendrik Brueckner 30e145f811 s390/cpum_cf: move counter set controls to a new header file
Move counter set specific controls and functions to the asm/cpu_mcf.h
header file containg all counter facility support definitions.  Also
adapt few variable names and header file includes.  No functional changes.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-22 09:19:46 +01:00
Thomas Richter 613a41b0d1 s390/cpum_cf: Reject request for sampling in event initialization
On s390 command perf top fails
[root@s35lp76 perf] # ./perf top -F100000  --stdio
   Error:
   cycles: PMU Hardware doesn't support sampling/overflow-interrupts.
   	Try 'perf stat'
[root@s35lp76 perf] #

Using event -e rb0000 works as designed.  Event rb0000 is the event
number of the sampling facility for basic sampling.

During system start up the following PMUs are installed in the kernel's
PMU list (from head to tail):
   cpum_cf --> s390 PMU counter facility device driver
   cpum_sf --> s390 PMU sampling facility device driver
   uprobe
   kprobe
   tracepoint
   task_clock
   cpu_clock

Perf top executes following functions and calls perf_event_open(2) system
call with different parameters many times:

cmd_top
--> __cmd_top
    --> perf_evlist__add_default
        --> __perf_evlist__add_default
            --> perf_evlist__new_cycles (creates event type:0 (HW)
			    		config 0 (CPU_CYCLES)
	        --> perf_event_attr__set_max_precise_ip
		    Uses perf_event_open(2) to detect correct
		    precise_ip level. Fails 3 times on s390 which is ok.

Then functions cmd_top
--> __cmd_top
    --> perf_top__start_counters
        -->perf_evlist__config
	   --> perf_can_comm_exec
               --> perf_probe_api
	           This functions test support for the following events:
		   "cycles:u", "instructions:u", "cpu-clock:u" using
		   --> perf_do_probe_api
		       --> perf_event_open_cloexec
		           Test the close on exec flag support with
			   perf_event_open(2).
	               perf_do_probe_api returns true if the event is
		       supported.
		       The function returns true because event cpu-clock is
		       supported by the PMU cpu_clock.
	               This is achieved by many calls to perf_event_open(2).

Function perf_top__start_counters now calls perf_evsel__open() for every
event, which is the default event cpu_cycles (config:0) and type HARDWARE
(type:0) which a predfined frequence of 4000.

Given the above order of the PMU list, the PMU cpum_cf gets called first
and returns 0, which indicates support for this sampling. The event is
fully allocated in the function perf_event_open (file kernel/event/core.c
near line 10521 and the following check fails:

        event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
		                 NULL, NULL, cgroup_fd);
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err_cred;
	}

        if (is_sampling_event(event)) {
		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
			err = -EOPNOTSUPP;
			goto err_alloc;
		}
	}

The check for the interrupt capabilities fails and the system call
perf_event_open() returns -EOPNOTSUPP (-95).

Add a check to return -ENODEV when sampling is requested in PMU cpum_cf.
This allows common kernel code in the perf_event_open() system call to
test the next PMU in above list.

Fixes: 97b1198fec (" "s390, perf: Use common PMU interrupt disabled code")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-11-14 13:44:55 +01:00
Thomas Richter 0bb2ae1b26 s390/perf: Change CPUM_CF return code in event init function
The function perf_init_event() creates a new event and
assignes it to a PMU. This a done in a loop over all existing
PMUs. For each listed PMU the event init function is called
and if this function does return any other error than -ENOENT,
the loop is terminated the creation of the event fails.

If the event is invalid, return -ENOENT to try other PMUs.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-11-08 07:58:16 +01:00
Greg Kroah-Hartman 53634237e7 s390: kernel: Remove redundant license text
Now that the SPDX tag is in all arch/s390/kernel/ files, that identifies
the license in a specific and legally-defined manner.  So the extra GPL
text wording can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-24 15:37:20 +01:00
Greg Kroah-Hartman a17ae4c3a6 s390: kernel: add SPDX identifiers to the remaining files
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the arch/s390/kernel/ files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-24 15:37:12 +01:00
Hendrik Brueckner 485527ba57 s390/cpum_cf: make hw_perf_event_update() a void function
The return code of hw_perf_event_update() is not evaluated by
its callers.  Hence, simplify the function by removing the
return code.

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-03-31 07:53:35 +02:00
Hendrik Brueckner ee699f329a s390/cpum_cf: add support for the MT-diagnostic counter set (z13)
Complete the IBM z13 support and support counters from the
MT-diagnostic counter set.  Note that this counter set is
available only if SMT is enabled.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-03-31 07:53:30 +02:00
Hendrik Brueckner db17160dce s390/cpum_cf: cleanup event/counter validation
The validate_event() function just checked for reserved counters
in particular CPU-MF counter sets.  Because the number of counters
in counter sets vary among different hardware models, remove the
explicit check to tolerate new models.

Reserved counters are not accounted and, thus, will return zero.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-03-31 07:53:29 +02:00
Hendrik Brueckner 20ba46da36 s390/cpum_cf: update counter numbers to ecctr limits
Use the highest counter number that can be specified for the
ecctr (extract CPU counter) instruction for perf.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-03-31 07:53:26 +02:00
Thomas Gleixner 73c1b41e63 cpu/hotplug: Cleanup state names
When the state names got added a script was used to add the extra argument
to the calls. The script basically converted the state constant to a
string, but the cleanup to convert these strings into meaningful ones did
not happen.

Replace all the useless strings with 'subsys/xxx/yyy:state' strings which
are used in all the other places already.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/20161221192112.085444152@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-25 10:47:44 +01:00
Thomas Gleixner 4f0f8217e6 s390/perf: Convert the hotplug notifier to state machine callbacks (Counter)
Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153334.436370635@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-14 09:34:37 +02:00
Hendrik Brueckner 9254e70c4e s390/cpum_cf: use perf software context for hardware counters
On s390, there are two different hardware PMUs for counting and
sampling.  Previously, both PMUs have shared the perf_hw_context
which is not correct and, recently, results in this warning:

    ------------[ cut here ]------------
    WARNING: CPU: 5 PID: 1 at kernel/events/core.c:8485 perf_pmu_register+0x420/0x428
    Modules linked in:
    CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.7.0-rc1+ #2
    task: 00000009c5240000 ti: 00000009c5234000 task.ti: 00000009c5234000
    Krnl PSW : 0704c00180000000 0000000000220c50 (perf_pmu_register+0x420/0x428)
               R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
    Krnl GPRS: ffffffffffffffff 0000000000b15ac6 0000000000000000 00000009cb440000
               000000000022087a 0000000000000000 0000000000b78fa0 0000000000000000
               0000000000a9aa90 0000000000000084 0000000000000005 000000000088a97a
               0000000000000004 0000000000749dd0 000000000022087a 00000009c5237cc0
    Krnl Code: 0000000000220c44: a7f4ff54            brc     15,220aec
               0000000000220c48: 92011000           mvi     0(%r1),1
              #0000000000220c4c: a7f40001           brc     15,220c4e
              >0000000000220c50: a7f4ff12           brc     15,220a74
               0000000000220c54: 0707               bcr     0,%r7
               0000000000220c56: 0707               bcr     0,%r7
               0000000000220c58: ebdff0800024       stmg    %r13,%r15,128(%r15)
               0000000000220c5e: a7f13fe0           tmll    %r15,16352
    Call Trace:
    ([<000000000022087a>] perf_pmu_register+0x4a/0x428)
    ([<0000000000b2c25c>] init_cpum_sampling_pmu+0x14c/0x1f8)
    ([<0000000000100248>] do_one_initcall+0x48/0x140)
    ([<0000000000b25d26>] kernel_init_freeable+0x1e6/0x2a0)
    ([<000000000072bda4>] kernel_init+0x24/0x138)
    ([<000000000073495e>] kernel_thread_starter+0x6/0xc)
    ([<0000000000734958>] kernel_thread_starter+0x0/0xc)
    Last Breaking-Event-Address:
     [<0000000000220c4c>] perf_pmu_register+0x41c/0x428
    ---[ end trace 0c6ef9f5b771ad97 ]---

Using the perf_sw_context is an option because the cpum_cf PMU does
not use interrupts.  To make this more clear, initialize the
capabilities in the PMU structure.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-06-16 12:08:49 +02:00
Anna-Maria Gleixner 5bc7353901 s390/cpum_cf: Remove superfluous SMP function call
Since commit 3b9d6da67e ("cpu/hotplug: Fix rollback during error-out
in __cpu_disable()") it is ensured that callbacks of CPU_ONLINE and
CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP
function calls are no longer required.

Replace smp_call_function_single() with a direct call of
setup_pmc_cpu(). To keep the calling convention, interrupts are
explicitly disabled around the call.

Cc: linux-s390@vger.kernel.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-05-03 09:25:44 +02:00
Anna-Maria Gleixner a987884295 s390/cpum_cf: Fix missing cpu hotplug notifier transition
The cpumf_pmu_notfier() hotplug callback lacks handling of the
CPU_DOWN_FAILED case. That means, if CPU_DOWN_PREPARE failes, the PMC
of the CPU is not setup again.

Add handling for CPU_DOWN_FAILED transition to setup the PMC of the
CPU.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-03-17 13:18:24 +01:00
Adam Buchbinder 7eb792bf7c s390: Fix misspellings in comments
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-03-08 15:00:17 +01:00
Ingo Molnar 6afc0c269c Merge branch 'linus' into perf/core, to pick up fixes before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-28 08:06:57 +02:00
Hendrik Brueckner 58f8e9da33 s390/cpum_cf: Corrected return code for unauthorized counter sets
Previously, the cpum_cf PMU returned -EPERM if a counter is requested and
the counter set to which the counter belongs is not authorized.  According
to the perf_event_open() system call manual, an error code of EPERM indicates
an unsupported exclude setting or CAP_SYS_ADMIN is missing.

Use ENOENT to indicate that particular counters are not available when the
counter set which contains the counter is not authorized.  For generic events,
this might trigger a fall back, for example, to a software event.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-09-17 13:43:42 +02:00
Sukadev Bhattiprolu 8f3e5684d3 perf/core: Drop PERF_EVENT_TXN
We currently use PERF_EVENT_TXN flag to determine if we are in the middle
of a transaction. If in a transaction, we defer the schedulability checks
from pmu->add() operation to the pmu->commit() operation.

Now that we have "transaction types" (PERF_PMU_TXN_ADD, PERF_PMU_TXN_READ)
we can use the type to determine if we are in a transaction and drop the
PERF_EVENT_TXN flag.

When PERF_EVENT_TXN is dropped, the cpuhw->group_flag on some architectures
becomes unused, so drop that field as well.

This is an extension of the Powerpc patch from Peter Zijlstra to s390,
Sparc and x86 architectures.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-11-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13 11:27:30 +02:00
Sukadev Bhattiprolu fbbe070115 perf/core: Add a 'flags' parameter to the PMU transactional interfaces
Currently, the PMU interface allows reading only one counter at a time.
But some PMUs like the 24x7 counters in Power, support reading several
counters at once. To leveage this functionality, extend the transaction
interface to support a "transaction type".

The first type, PERF_PMU_TXN_ADD, refers to the existing transactions,
i.e. used to _schedule_ all the events on the PMU as a group. A second
transaction type, PERF_PMU_TXN_READ, will be used in a follow-on patch,
by the 24x7 counters to read several counters at once.

Extend the transaction interfaces to the PMU to accept a 'txn_flags'
parameter and use this parameter to ignore any transactions that are
not of type PERF_PMU_TXN_ADD.

Thanks to Peter Zijlstra for his input.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
[peterz: s390 compile fix]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-3-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13 11:27:25 +02:00
Christoph Lameter eb7e7d7663 s390: Replace __get_cpu_var uses
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	this_cpu_inc(y)

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
CC: linux390@de.ibm.com
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-26 13:45:52 -04:00
Vince Weaver 97b1198fec s390, perf: Use common PMU interrupt disabled code
Transition to using the new generic PERF_PMU_CAP_NO_INTERRUPT method for
failing a sampling event when no PMU interrupt is available.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Thomas Huth <thuth@linux.vnet.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1406150204290.16738@vincent-weaver-1.umelst.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-19 19:37:50 +02:00
Thomas Huth 1dad093b66 s390/irq: Use defines for external interruption codes
Use the new defines for external interruption codes to get rid
of "magic" numbers in the s390 source code. And while we're at it,
also rename the (un-)register_external_interrupt function to
something shorter so that this patch does not exceed the 80
columns all over the place.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-04-03 14:30:52 +02:00
Hendrik Brueckner c716832513 s390/cpum_cf: Export event names in sysfs
Provide PMU event attributes for supported counters and export their symbolic
names to the sysfs "events" directory.

See the /sys/devices/cpum_cf/events/ directory for a list of available counters.
Note that you might require counter set authorizations for the LPAR to use them.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-12-16 14:37:50 +01:00
Heiko Carstens 82003c3e60 s390/irq: rework irq subclass handling
Let's not add a function for every external interrupt subclass for
which we need reference counting. Just have two register/unregister
functions which have a subclass parameter:

void irq_subclass_register(enum irq_subclass subclass);
void irq_subclass_unregister(enum irq_subclass subclass);

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2013-09-04 17:19:13 +02:00
Paul Gortmaker e2741f1758 s390: delete __cpuinit usage from all s390 files
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/s390 uses of the __cpuinit macros from
all C files.  Currently s390 does not have any __CPUINIT used in
assembly files.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-14 19:36:53 -04:00
Hendrik Brueckner 151a0eb6c8 s390/perf: cpum_cf: fallback to software sampling events
The CPU-measurement counter facility does not support sampling events
and returns -EINVAL in that case.  This return code lets the perf tool
fail.  To fall back to software sampling events, return -ENOENT instead.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-14 15:55:15 +01:00
Heiko Carstens 420f42ecf4 s390/irq: remove split irq fields from /proc/stat
Now that irq sum accounting for /proc/stat's "intr" line works again we
have the oddity that the sum field (first field) contains only the sum
of the second (external irqs) and third field (I/O interrupts).
The reason for that is that these two fields are already sums of all other
fields. So if we would sum up everything we would count every interrupt
twice.
This is broken since the split interrupt accounting was merged two years
ago: 052ff461c8 "[S390] irq: have detailed
statistics for interrupt types".
To fix this remove the split interrupt fields from /proc/stat's "intr"
line again and only have them in /proc/interrupts.

This restores the old behaviour, seems to be the only sane fix and mimics
a behaviour from other architectures where /proc/interrupts also contains
more than /proc/stat's "intr" line does.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-01-08 10:57:07 +01:00
Hendrik Brueckner f47586b24c perf_cpum_cf: Add support for counters available with IBM zEC12
Increase the maximum number of available counters and check if
the hardware supports the counter.  Support is indicated by the
version of the CPU-measurement counter facility.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-10-18 17:50:09 +02:00
Hendrik Brueckner 02456169e0 s390/irq: split irq stats for cpu-measurement alert facilities
CPU-measurement alerts are generated for different CPU-measurement
facilities, for example, the sampling and counter facilities.
Split the irq stats according to available facilities.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-05-23 17:06:52 +02:00
Heiko Carstens af0ee94e54 [S390] cpum_cf: get rid of compile warnings
Fix these:

arch/s390/kernel/perf_cpum_cf.c:180:3: warning: format '%lx'
   expects argument of type 'long unsigned int',
   but argument 2 has type 'int' [-Wformat]
arch/s390/kernel/perf_cpum_cf.c: In function 'cpumf_pmu_disable':
arch/s390/kernel/perf_cpum_cf.c:205:3: warning: format '%lx'
   expects argument of type 'long unsigned int',
   but argument 2 has type 'int' [-Wformat]

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-04-11 14:28:25 +02:00
Heiko Carstens 1e3cab2f2f [S390] Fix build errors (fallout from system.h disintegration)
Signed-off-by: Heiko Carstens <h.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-03-30 09:41:12 +02:00
Hendrik Brueckner 212188a596 [S390] perf: add support for s390x CPU counters
Add a perf PMU to access the CPU-measurement counter facility CPUM CF.
CPUM CF provides multiple counter sets for measuring generic,
problem-state, and crypto activaties.  Also an extended counter set for
the IBM System z10 and IBM z196 mainframes is available.

Counters from the basic and problem-state counter set are mapped to
generic perf hardware events.  Other counters are accessible through
raw events.

For a list of available counter sets and counters, see:

  - The Load-Program-Parameter and the CPU-Measurement Facilities (SA23-2260)
  - The CPU-Measurement Facility Extended Counters Definition for
    z10 and z196 (SA23-2261)

Reviewed-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-03-23 11:13:25 +01:00