Patch "s390/cpumf: Handle events cycles and instructions identical" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    s390/cpumf: Handle events cycles and instructions identical

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-cpumf-handle-events-cycles-and-instructions-ide.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit fd836eb6e5423c3f843b02bd2298ea73dc4ad16a
Author: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Date:   Fri Jun 10 15:19:00 2022 +0200

    s390/cpumf: Handle events cycles and instructions identical
    
    [ Upstream commit be857b7f77d130dbbd47c91fc35198b040f35865 ]
    
    Events CPU_CYCLES and INSTRUCTIONS can be submitted with two different
    perf_event attribute::type values:
     - PERF_TYPE_HARDWARE: when invoked via perf tool predefined events name
       cycles or cpu-cycles or instructions.
     - pmu->type: when invoked via perf tool event name cpu_cf/CPU_CYLCES/ or
       cpu_cf/INSTRUCTIONS/. This invocation also selects the PMU to which
       the event belongs.
    Handle both type of invocations identical for events CPU_CYLCES and
    INSTRUCTIONS. They address the same hardware.
    The result is different when event modifier exclude_kernel is also set.
    Invocation with event modifier for user space event counting fails.
    
    Output before:
    
     # perf stat -e cpum_cf/cpu_cycles/u -- true
    
     Performance counter stats for 'true':
    
       <not supported>      cpum_cf/cpu_cycles/u
    
           0.000761033 seconds time elapsed
    
           0.000076000 seconds user
           0.000725000 seconds sys
    
     #
    
    Output after:
     # perf stat -e cpum_cf/cpu_cycles/u -- true
    
     Performance counter stats for 'true':
    
               349,613      cpum_cf/cpu_cycles/u
    
           0.000844143 seconds time elapsed
    
           0.000079000 seconds user
           0.000800000 seconds sys
     #
    
    Fixes: 6a82e23f45fe ("s390/cpumf: Adjust registration of s390 PMU device drivers")
    Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
    Acked-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
    [agordeev@xxxxxxxxxxxxx corrected commit ID of Fixes commit]
    Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index cceb8ec707e4..d2a2a18b5580 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -516,6 +516,26 @@ static int __hw_perf_event_init(struct perf_event *event, unsigned int type)
 	return err;
 }
 
+/* Events CPU_CYLCES and INSTRUCTIONS can be submitted with two different
+ * attribute::type values:
+ * - PERF_TYPE_HARDWARE:
+ * - pmu->type:
+ * Handle both type of invocations identical. They address the same hardware.
+ * The result is different when event modifiers exclude_kernel and/or
+ * exclude_user are also set.
+ */
+static int cpumf_pmu_event_type(struct perf_event *event)
+{
+	u64 ev = event->attr.config;
+
+	if (cpumf_generic_events_basic[PERF_COUNT_HW_CPU_CYCLES] == ev ||
+	    cpumf_generic_events_basic[PERF_COUNT_HW_INSTRUCTIONS] == ev ||
+	    cpumf_generic_events_user[PERF_COUNT_HW_CPU_CYCLES] == ev ||
+	    cpumf_generic_events_user[PERF_COUNT_HW_INSTRUCTIONS] == ev)
+		return PERF_TYPE_HARDWARE;
+	return PERF_TYPE_RAW;
+}
+
 static int cpumf_pmu_event_init(struct perf_event *event)
 {
 	unsigned int type = event->attr.type;
@@ -525,7 +545,7 @@ static int cpumf_pmu_event_init(struct perf_event *event)
 		err = __hw_perf_event_init(event, type);
 	else if (event->pmu->type == type)
 		/* Registered as unknown PMU */
-		err = __hw_perf_event_init(event, PERF_TYPE_RAW);
+		err = __hw_perf_event_init(event, cpumf_pmu_event_type(event));
 	else
 		return -ENOENT;