[PATCH v2 1/5] powerpc/powernv: Re-enable imc trace-mode in kernel

[Anju T Sudhakar <anju@linux.vnet.ibm.com>]

commit <249fad734a25> ""powerpc/perf: Disable trace_imc pmu"
disables IMC(In-Memory Collection) trace-mode in kernel, since frequent
mode switching between accumulation mode and trace mode via the spr LDBAR
in the hardware can trigger a checkstop(system crash).

Patch to re-enable imc-trace mode in kernel.

The following patch in this series will address the mode switching issue
by implementing a global lock, and will restrict the usage of
accumulation and trace-mode at a time.

Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/powernv/opal-imc.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
index 000b350d4060..3b4518f4b643 100644
--- a/arch/powerpc/platforms/powernv/opal-imc.c
+++ b/arch/powerpc/platforms/powernv/opal-imc.c
@@ -278,14 +278,7 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
 			domain = IMC_DOMAIN_THREAD;
 			break;
 		case IMC_TYPE_TRACE:
-			/*
-			 * FIXME. Using trace_imc events to monitor application
-			 * or KVM thread performance can cause a checkstop
-			 * (system crash).
-			 * Disable it for now.
-			 */
-			pr_info_once("IMC: disabling trace_imc PMU\n");
-			domain = -1;
+			domain = IMC_DOMAIN_TRACE;
 			break;
 		default:
 			pr_warn("IMC Unknown Device type \n");
-- 
2.20.1