linux-kernel - [PATCH AUTOSEL for 4.14 095/135] powerpc/xmon: Check before calling xive functions

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Message-ID: <20171207154513.4154-95-alexander.levin@verizon.com>
Date:   Thu, 7 Dec 2017 15:45:53 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Breno Leitao <leitao@...ian.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.14 095/135] powerpc/xmon: Check before calling
 xive functions

From: Breno Leitao <leitao@...ian.org>

[ 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@...ux.vnet.ibm.com>
Signed-off-by: Breno Leitao <leitao@...ian.org>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 arch/powerpc/xmon/xmon.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 33351c6704b1..c008083fbc4f 100644
--- 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();
-- 
2.11.0