[PATCH V2 1/2] powerpc/perf: Infrastructure to support checking of attr.config*
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STALE2034d
From: Madhavan Srinivasan <maddy@linux.ibm.com>
Date: 2021-02-26 06:51:22
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
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 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. Writing a non-zero values in these fields or writing invalid value to bit 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 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