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 v3 1/2] powerpc/perf: Infrastructure to support checking of attr.config*
Date: Thu, 25 Mar 2021 17:23:25 +0530 [thread overview]
Message-ID: <20210325115326.143151-1-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.
"check_attr_config" is valid only for raw event type.
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
---
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 | 14 ++++++++++++++
2 files changed, 20 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 6817331e22ff..c6eeb4fdc5fd 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1958,6 +1958,20 @@ static int power_pmu_event_init(struct perf_event *event)
if (ppmu->blacklist_ev && is_event_blacklisted(ev))
return -EINVAL;
+ /*
+ * PMU config registers have fields that are
+ * reserved and specific value to bit field as reserved.
+ * For ex., MMCRA[61:62] is Randome Sampling Mode (SM)
+ * and value of 0b11 to this field is reserved.
+ *
+ * This check is needed only for raw event type,
+ * since tools like fuzzer use raw event type to
+ * provide randomized event code values for test.
+ *
+ */
+ if (ppmu->check_attr_config &&
+ ppmu->check_attr_config(event))
+ return -EINVAL;
break;
default:
return -ENOENT;
--
2.26.2
next reply other threads:[~2021-03-25 11:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 11:53 Madhavan Srinivasan [this message]
2021-03-25 11:53 ` [PATCH v3 2/2] powerpc/perf: Add platform specific check_attr_config Madhavan Srinivasan
2021-04-01 16:00 ` [PATCH v3 1/2] powerpc/perf: Infrastructure to support checking of attr.config* Athira Rajeev
2021-04-07 11:38 ` Michael Ellerman
2021-04-08 2:38 ` Madhavan Srinivasan
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