From: Madhavan Srinivasan <maddy@linux.ibm.com>
To: mpe@ellerman.id.au
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v4 1/2] powerpc/perf: Infrastructure to support checking of attr.config*
Date: Thu, 8 Apr 2021 13:15:03 +0530 [thread overview]
Message-ID: <20210408074504.248211-1-maddy@linux.ibm.com> (raw)
Introduce code to support the checking of attr.config* for
values which are reserved for a given platform.
Performance Monitoring Unit (PMU) configuration registers
have fields that are reserved and some specific values for
bit fields are reserved. For ex., MMCRA[61:62] is
Random Sampling Mode (SM) and value of 0b11 for this field
is reserved.
Writing non-zero or invalid values in these fields will
have unknown behaviours.
Patch adds a generic call-back function "check_attr_config"
in "struct power_pmu", to be called in event_init to
check for attr.config* values for a given platform.
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
---
Changelog v3:
-Made the check_attr_config() to be called for all event type of instead
only for raw event type.
Changelog v2:
-Fixed commit message
Changelog v1:
-Fixed commit message and in-code comments
arch/powerpc/include/asm/perf_event_server.h | 6 ++++++
arch/powerpc/perf/core-book3s.c | 11 +++++++++++
2 files changed, 17 insertions(+)
diff --git a/arch/powerpc/include/asm/perf_event_server.h b/arch/powerpc/include/asm/perf_event_server.h
index 00e7e671bb4b..dde97d7d9253 100644
--- a/arch/powerpc/include/asm/perf_event_server.h
+++ b/arch/powerpc/include/asm/perf_event_server.h
@@ -67,6 +67,12 @@ struct power_pmu {
* the pmu supports extended perf regs capability
*/
int capabilities;
+ /*
+ * Function to check event code for values which are
+ * reserved. Function takes struct perf_event as input,
+ * since event code could be spread in attr.config*
+ */
+ int (*check_attr_config)(struct perf_event *ev);
};
/*
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 766f064f00fb..b17358e8dc12 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1963,6 +1963,17 @@ static int power_pmu_event_init(struct perf_event *event)
return -ENOENT;
}
+ /*
+ * PMU config registers have fields that are
+ * reserved and some specific values for bit fields are reserved.
+ * For ex., MMCRA[61:62] is Randome Sampling Mode (SM)
+ * and value of 0b11 to this field is reserved.
+ * Check for invalid values in attr.config.
+ */
+ if (ppmu->check_attr_config &&
+ ppmu->check_attr_config(event))
+ return -EINVAL;
+
event->hw.config_base = ev;
event->hw.idx = 0;
--
2.26.2
next reply other threads:[~2021-04-08 7:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 7:45 Madhavan Srinivasan [this message]
2021-04-08 7:45 ` [PATCH 2/2] powerpc/perf: Add platform specific check_attr_config Madhavan Srinivasan
2021-04-21 13:08 ` Michael Ellerman
2021-04-19 4:00 ` [PATCH v4 1/2] powerpc/perf: Infrastructure to support checking of attr.config* Michael Ellerman
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