From b58064da046243f0c988afd939997e9317dc6d48 Mon Sep 17 00:00:00 2001
From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Date: Sun, 4 Mar 2018 17:26:26 +0530
Subject: [PATCH] powerpc/perf: Infrastructure to support addition of
 blacklisted events

References: bsc#1056686
Patch-mainline: v4.17-rc1
Git-commit: b58064da046243f0c988afd939997e9317dc6d48

Introduce code to support addition of blacklisted events for a
processor version. Blacklisted events are events that are known to not
count correctly on that CPU revision, and so should be prevented from
being counted so as to avoid user confusion.

A 'pointer' and 'int' variable to hold the number of events are added
to 'struct power_pmu', along with a generic function to loop through
the list to validate the given event. Generic function
'is_event_blacklisted' is called in power_pmu_event_init() to detect
and reject early.

Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/include/asm/perf_event_server.h |  2 ++
 arch/powerpc/perf/core-book3s.c              | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/arch/powerpc/include/asm/perf_event_server.h b/arch/powerpc/include/asm/perf_event_server.h
index 723bf48e7494..67a8a9585d50 100644
--- a/arch/powerpc/include/asm/perf_event_server.h
+++ b/arch/powerpc/include/asm/perf_event_server.h
@@ -53,6 +53,8 @@ struct power_pmu {
 			       [PERF_COUNT_HW_CACHE_OP_MAX]
 			       [PERF_COUNT_HW_CACHE_RESULT_MAX];
 
+	int		n_blacklist_ev;
+	int 		*blacklist_ev;
 	/* BHRB entries in the PMU */
 	int		bhrb_nr;
 };
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index a00b364fb9d7..e032aeff3d6b 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1839,6 +1839,18 @@ static int hw_perf_cache_event(u64 config, u64 *eventp)
 	return 0;
 }
 
+static bool is_event_blacklisted(u64 ev)
+{
+	int i;
+
+	for (i=0; i < ppmu->n_blacklist_ev; i++) {
+		if (ppmu->blacklist_ev[i] == ev)
+			return true;
+	}
+
+	return false;
+}
+
 static int power_pmu_event_init(struct perf_event *event)
 {
 	u64 ev;
@@ -1864,15 +1876,24 @@ static int power_pmu_event_init(struct perf_event *event)
 		ev = event->attr.config;
 		if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0)
 			return -EOPNOTSUPP;
+
+		if (ppmu->blacklist_ev && is_event_blacklisted(ev))
+			return -EINVAL;
 		ev = ppmu->generic_events[ev];
 		break;
 	case PERF_TYPE_HW_CACHE:
 		err = hw_perf_cache_event(event->attr.config, &ev);
 		if (err)
 			return err;
+
+		if (ppmu->blacklist_ev && is_event_blacklisted(ev))
+			return -EINVAL;
 		break;
 	case PERF_TYPE_RAW:
 		ev = event->attr.config;
+
+		if (ppmu->blacklist_ev && is_event_blacklisted(ev))
+			return -EINVAL;
 		break;
 	default:
 		return -ENOENT;
-- 
2.13.6