[PATCH v2 4/4] powerpc/perf/vpa-pmu: Avoid loading vpa-pmu driver during dump kernel

[Madhavan Srinivasan <maddy@linux.ibm.com>]

vpa-pmu driver is used to collect latency metrics for host to guest
or guest to host context switches in a PowerVM KVM guest scenario.
These are enabled using CONFIG_VPA_PMU and when these are compiled
as built-in, add check for kdump and fadump kernel to avoids
loading them, since there are no commandline option to disable them.

Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
---
Changelog v1:
- Added more details to commmit message

 arch/powerpc/perf/vpa-pmu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/perf/vpa-pmu.c b/arch/powerpc/perf/vpa-pmu.c
index 6a5bfd2a13b5..f7f72b976c1d 100644
--- a/arch/powerpc/perf/vpa-pmu.c
+++ b/arch/powerpc/perf/vpa-pmu.c
@@ -10,6 +10,8 @@
 #include <linux/perf_event.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s_64.h>
+#include <asm/fadump.h>
+#include <asm/kexec.h>
 
 #define MODULE_VERS "1.0"
 #define MODULE_NAME "pseries_vpa_pmu"
@@ -183,6 +185,9 @@ static int __init pseries_vpa_pmu_init(void)
 	if (!firmware_has_feature(FW_FEATURE_LPAR) || is_kvm_guest())
 		return -ENODEV;
 
+	if (is_kdump_kernel() || is_fadump_active())
+		return 0;
+
 	perf_pmu_register(&vpa_pmu, vpa_pmu.name, -1);
 	pr_info("Virtual Processor Area PMU registered.\n");
 
-- 
2.47.0