linux-kernel - [PATCH 3/3] watchdog: hpwdt: Check source of NMI

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Message-Id: <8d4ef9a3b816c9a54310c0411f45cd097f04c2fb.1508539271.git.jerry.hoemann@hpe.com>
Date:   Fri, 20 Oct 2017 16:54:50 -0600
From:   Jerry Hoemann <jerry.hoemann@....com>
To:     wim@...ana.be, linux@...ck-us.net
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jerry Hoemann <jerry.hoemann@....com>
Subject: [PATCH 3/3] 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: Jerry Hoemann <jerry.hoemann@....com>
---
 drivers/watchdog/hpwdt.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
index 4c011e8..b64ce43 100644
--- a/drivers/watchdog/hpwdt.c
+++ b/drivers/watchdog/hpwdt.c
@@ -53,6 +53,7 @@
 static const int pretimeout = 9;
 
 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;
 
@@ -475,6 +476,11 @@ 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
@@ -487,6 +493,9 @@ 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);
@@ -849,6 +858,7 @@ 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;
 
-- 
1.8.3.1