watchdog/hpwdt: Refine hpwdt message for UV platform

The watchdog hardware the hpwdt driver uses was added to the UV
platform for UV_5, but the logging mentioned by this driver was not
added to the BIOS.  When the watchdog fires, the printed message had
the administrators and developers looking for non-existent log files,
and confused about whether a watchdog actually tripped.

Change the message that prints on UV platforms so it doesn't send the
user looking for non-existent logs.

To aid in any future debugging, include all 8 bits of the NMISTAT
register in the output, not just the two bits being used to determine
this was "mynmi".  And provide names to the bits in NMISTAT so the
code is easier to understand.

Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20260318155005.90271-1-steve.wahl@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
index 2a848c35c14d2d5536bd2bd717b02e0c08caf5e0..8af1fad2de0bd35aae80f24ca11fd9ef39c62eb2 100644 (file)
--- a/drivers/watchdog/hpwdt.c
+++ b/drivers/watchdog/hpwdt.c
@@ -23,6 +23,7 @@
 #include <linux/watchdog.h>
 #ifdef CONFIG_HPWDT_NMI_DECODING
 #include <asm/nmi.h>
+#include <asm/uv/uv.h>
 #endif
 #include <linux/crash_dump.h>
 
@@ -159,24 +160,31 @@ static int hpwdt_set_pretimeout(struct watchdog_device *wdd, unsigned int req)
        return 0;
 }
 
-static int hpwdt_my_nmi(void)
-{
-       return ioread8(hpwdt_nmistat) & 0x6;
-}
+#define NMISTAT_EASR   BIT(0)
+#define NMISTAT_EWDOG  BIT(1)
+#define NMISTAT_RTRAP  BIT(2)
+#define NMISTAT_DBELL  BIT(3)
+#define NMISTAT_EMSWDG BIT(4)
+#define NMISTAT_GPI    BIT(5)
+#define NMISTAT_NMIOUT BIT(7)
 
 /*
  *     NMI Handler
  */
 static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
 {
-       unsigned int mynmi = hpwdt_my_nmi();
-       static char panic_msg[] =
+       u8 nmistat = ioread8(hpwdt_nmistat);
+       bool mynmi = (nmistat & (NMISTAT_EWDOG | NMISTAT_RTRAP)) != 0;
+       static char panic_msg_default[] =
                "00: An NMI occurred. Depending on your system the reason "
                "for the NMI is logged in any one of the following resources:\n"
                "1. Integrated Management Log (IML)\n"
                "2. OA Syslog\n"
                "3. OA Forward Progress Log\n"
                "4. iLO Event Log";
+       static char panic_msg_uv[] =
+               "00: A watchdog NMI occurred.";
+       char *panic_msg = is_uv_system() ? panic_msg_uv : panic_msg_default;
 
        if (ulReason == NMI_UNKNOWN && !mynmi)
                return NMI_DONE;
@@ -190,7 +198,7 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
                hpwdt_ping_ticks(SECS_TO_TICKS(val));
        }
 
-       hex_byte_pack(panic_msg, mynmi);
+       hex_byte_pack(panic_msg, nmistat);
        nmi_panic(regs, panic_msg);
 
        return NMI_HANDLED;