powerpc/xmon: Check before calling xive functions

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@linux.vnet.ibm.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 4679aeb84767cdd74c0ce094b12745656d6c92ff..2e2320edb96b9b5aa4c9e52ebefe2afc967dcd27 100644 (file)
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -2508,6 +2508,11 @@ 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();