[PATCH v3 7/9] powerpc/xive: Fix xmon command "dxi"

["Cédric Le Goater" <clg@kaod.org>]

When under xmon, the "dxi" command dumps the state of the XIVE
interrupts. If an interrupt number is specified, only the state of
the associated XIVE interrupt is dumped. This form of the command
lacks an irq_data parameter which is nevertheless used by
xmon_xive_get_irq_config(), leading to an xmon crash.

Fix that by doing a lookup in the system IRQ mapping to query the IRQ
descriptor data. Invalid interrupt numbers, or not belonging to the
XIVE IRQ domain, OPAL event interrupt number for instance, should be
caught by the previous query done at the firmware level.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 97ef27507793 ("powerpc/xive: Fix xmon support on the PowerNV platform")
Tested-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 arch/powerpc/sysdev/xive/common.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
index 4c6e2e1289f5..69980b49afb7 100644
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c
@@ -253,17 +253,20 @@ notrace void xmon_xive_do_dump(int cpu)
 	xmon_printf("\n");
 }
 
+static struct irq_data *xive_get_irq_data(u32 hw_irq)
+{
+	unsigned int irq = irq_find_mapping(xive_irq_domain, hw_irq);
+
+	return irq ? irq_get_irq_data(irq) : NULL;
+}
+
 int xmon_xive_get_irq_config(u32 hw_irq, struct irq_data *d)
 {
-	struct irq_chip *chip = irq_data_get_irq_chip(d);
 	int rc;
 	u32 target;
 	u8 prio;
 	u32 lirq;
 
-	if (!is_xive_irq(chip))
-		return -EINVAL;
-
 	rc = xive_ops->get_irq_config(hw_irq, &target, &prio, &lirq);
 	if (rc) {
 		xmon_printf("IRQ 0x%08x : no config rc=%d\n", hw_irq, rc);
@@ -273,6 +276,9 @@ int xmon_xive_get_irq_config(u32 hw_irq, struct irq_data *d)
 	xmon_printf("IRQ 0x%08x : target=0x%x prio=%02x lirq=0x%x ",
 		    hw_irq, target, prio, lirq);
 
+	if (!d)
+		d = xive_get_irq_data(hw_irq);
+
 	if (d) {
 		struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
 		u64 val = xive_esb_read(xd, XIVE_ESB_GET);
-- 
2.26.3