[PATCH 4.14 140/178] powerpc/xmon: Check before calling xive functions

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Breno Leitao <leitao@xxxxxxxxxx>


[ Upstream commit 402e172a2ce76210f2fe921cf419d12103851344 ]

Currently xmon could call XIVE functions from OPAL even if the XIVE is
disabled or does not exist in the system, as in POWER8 machines. This
causes the following exception:

 1:mon> dx
 cpu 0x1: Vector: 700 (Program Check) at [c000000423c93450]
     pc: c00000000009cfa4: opal_xive_dump+0x50/0x68
     lr: c0000000000997b8: opal_return+0x0/0x50

This patch simply checks if XIVE is enabled before calling XIVE
functions.

Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller")
Suggested-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/powerpc/xmon/xmon.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -2475,6 +2475,11 @@ static void dump_xives(void)
 	unsigned long num;
 	int c;
 
+	if (!xive_enabled()) {
+		printf("Xive disabled on this system\n");
+		return;
+	}
+
 	c = inchar();
 	if (c == 'a') {
 		dump_all_xives();