linux-kernel - Re: [PATCH v2 2/3] watchdog: hpwdt: Check source of NMI

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Date:   Mon, 23 Oct 2017 20:18:59 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Jerry Hoemann <jerry.hoemann@....com>, wim@...ana.be
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/3] watchdog: hpwdt: Check source of NMI

On 10/23/2017 03:46 PM, Jerry Hoemann wrote:
> 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>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>   drivers/watchdog/hpwdt.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
> index 9fd869f..e616583 100644
> --- a/drivers/watchdog/hpwdt.c
> +++ b/drivers/watchdog/hpwdt.c
> @@ -52,6 +52,7 @@
>   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;
>   
>