watchdog: hpwdt: Check source of NMI

Do not claim the NMI (i.e. return NMI_DONE) if the source of
the NMI isn't the iLO watchdog or debug.
Signed-off-by: NJerry Hoemann <jerry.hoemann@hpe.com>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

drivers/watchdog/hpwdt.c

@@ -52,6 +52,7 @@ static char expect_release;
 static unsigned long hpwdt_is_open;
 
 static void __iomem *pci_mem_addr;		/* the PCI-memory address */
+static unsigned long __iomem *hpwdt_nmistat;
 static unsigned long __iomem *hpwdt_timer_reg;
 static unsigned long __iomem *hpwdt_timer_con;
 
@@ -474,6 +475,11 @@ static int hpwdt_time_left(void)
 	return TICKS_TO_SECS(ioread16(hpwdt_timer_reg));
 }
 
+static int hpwdt_my_nmi(void)
+{
+	return ioread8(hpwdt_nmistat) & 0x6;
+}
+
 #ifdef CONFIG_HPWDT_NMI_DECODING
 /*
  *	NMI Handler
@@ -486,6 +492,9 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
 	if (!hpwdt_nmi_decoding)
 		return NMI_DONE;
 
+	if ((ulReason == NMI_UNKNOWN) && !hpwdt_my_nmi())
+		return NMI_DONE;
+
 	spin_lock_irqsave(&rom_lock, rom_pl);
 	if (!die_nmi_called && !is_icru && !is_uefi)
 		asminline_call(&cmn_regs, cru_rom_addr);
@@ -842,6 +851,7 @@ static int hpwdt_init_one(struct pci_dev *dev,
 		retval = -ENOMEM;
 		goto error_pci_iomap;
 	}
+	hpwdt_nmistat	= pci_mem_addr + 0x6e;
 	hpwdt_timer_reg = pci_mem_addr + 0x70;
 	hpwdt_timer_con = pci_mem_addr + 0x72;