[PATCH AUTOSEL 4.19 022/244] powerpc/perf: Return accordingly on invalid chip-id in

[Sasha Levin]

From: Anju T Sudhakar <anju at linux.vnet.ibm.com>

[ Upstream commit a913e5e8b43be1d3897a141ce61c1ec071cad89c ]

Nest hardware counter memory resides in a per-chip reserve-memory.
During nest_imc_event_init(), chip-id of the event-cpu is considered to
calculate the base memory addresss for that cpu. Return, proper error
condition if the chip_id calculated is invalid.

Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
Fixes: 885dcd709ba91 ("powerpc/perf: Add nest IMC PMU support")
Reviewed-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
Signed-off-by: Anju T Sudhakar <anju at linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 arch/powerpc/perf/imc-pmu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 1fafc32b12a0f..3cebfdf362116 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -496,6 +496,11 @@ static int nest_imc_event_init(struct perf_event *event)
 	 * Get the base memory addresss for this cpu.
 	 */
 	chip_id = cpu_to_chip_id(event->cpu);
+
+	/* Return, if chip_id is not valid */
+	if (chip_id < 0)
+		return -ENODEV;
+
 	pcni = pmu->mem_info;
 	do {
 		if (pcni->id == chip_id) {
-- 
2.20.1