linux-kernel - [PATCH] arm64: perf: Count EL2 events if either of kernel and hyp are not excluded

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Date:   Tue,  4 Apr 2017 16:10:55 +0530
From:   Ganapatrao Kulkarni <ganapatrao.kulkarni@...ium.com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     Will.Deacon@....com, catalin.marinas@....com, mark.rutland@....com,
        marc.zyngier@....com, jnair@...iumnetworks.com,
        gpkulkarni@...il.com
Subject: [PATCH] arm64: perf: Count EL2 events if either of kernel and hyp are not excluded

commit d98ecda (arm64: perf: Count EL2 events if the kernel is running in HYP)
is returning error for perf syscall with mixed attribute set for exclude_kernel
and exlude_hv.

This change is breaking some applications (observed with hhvm) when
ran with VHE enabled. Adding change to enable EL2 event counting,
if either of or both of exclude_kernel and exlude_hv are not set.

Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@...ium.com>
---
 arch/arm64/kernel/perf_event.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index daf95919..ea5848a 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -871,15 +871,20 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
 
 	if (attr->exclude_idle)
 		return -EPERM;
-	if (is_kernel_in_hyp_mode() &&
-	    attr->exclude_kernel != attr->exclude_hv)
-		return -EINVAL;
+	if (is_kernel_in_hyp_mode()) {
+		/* include EL2 events, if either of not excluded */
+		if ((attr->exclude_kernel != attr->exclude_hv) ||
+				!attr->exclude_kernel ||
+				!attr->exclude_hv)
+			config_base |= ARMV8_PMU_INCLUDE_EL2;
+	} else {
+		if (attr->exclude_kernel)
+			config_base |= ARMV8_PMU_EXCLUDE_EL1;
+		if (!attr->exclude_hv)
+			config_base |= ARMV8_PMU_INCLUDE_EL2;
+	}
 	if (attr->exclude_user)
 		config_base |= ARMV8_PMU_EXCLUDE_EL0;
-	if (!is_kernel_in_hyp_mode() && attr->exclude_kernel)
-		config_base |= ARMV8_PMU_EXCLUDE_EL1;
-	if (!attr->exclude_hv)
-		config_base |= ARMV8_PMU_INCLUDE_EL2;
 
 	/*
 	 * Install the filter into config_base as this is used to
-- 
1.8.1.4