linux-kernel - R: R: [PATCH 1/3] watchdog: qcom-wdt: add option to skip pretimeout

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 4 Feb 2020 18:30:40 +0100
From:   <ansuelsmth@...il.com>
To:     "'Guenter Roeck'" <linux@...ck-us.net>
Cc:     "'Andy Gross'" <agross@...nel.org>,
        "'Bjorn Andersson'" <bjorn.andersson@...aro.org>,
        "'Wim Van Sebroeck'" <wim@...ux-watchdog.org>,
        "'Rob Herring'" <robh+dt@...nel.org>,
        "'Mark Rutland'" <mark.rutland@....com>,
        <linux-arm-msm@...r.kernel.org>, <linux-watchdog@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: R: R: [PATCH 1/3] watchdog: qcom-wdt: add option to skip pretimeout

> On Tue, Feb 04, 2020 at 05:16:34PM +0100, ansuelsmth@...il.com wrote:
> > If something like this is used, msm-timer require interrupts. Without
this
> > configuration, the device is unbootable as the system froze on system
> > bootup.
> >
> > timer@...a000 {
> > 			compatible = "qcom,kpss-timer", "qcom,msm-timer";
> > 			interrupts = <GIC_PPI 1 (GIC_CPU_MASK_SIMPLE(2) |
> > 						 IRQ_TYPE_EDGE_RISING)>,
> > 				     <GIC_PPI 2 (GIC_CPU_MASK_SIMPLE(2) |
> > 						 IRQ_TYPE_EDGE_RISING)>,
> > 				     <GIC_PPI 3 (GIC_CPU_MASK_SIMPLE(2) |
> > 						 IRQ_TYPE_EDGE_RISING)>,
> > 				     <GIC_PPI 4 (GIC_CPU_MASK_SIMPLE(2) |
> > 						 IRQ_TYPE_EDGE_RISING)>,
> > 				     <GIC_PPI 5 (GIC_CPU_MASK_SIMPLE(2) |
> > 						 IRQ_TYPE_EDGE_RISING)>;
> > 			no-pretimeout;
> > 			reg = <0x0200a000 0x100>;
> > 			clock-frequency = <25000000>,
> > 					  <32768>;
> > 			clocks = <&sleep_clk>;
> > 			clock-names = "sleep";
> > 			cpu-offset = <0x80000>;
> > 		};
> >
> 
> I think this is all wrong; the new property shows up in a node which
> is completely unrelated to a watchdog. Maybe it wasn't such a good idea
> to tie the watchdog to the timer node. At the very least, the situation
> should be handled in the driver via of_table flags. If the situation can't
> be handled that way, something is even more wrong. In that case it might
> be better to revert commit 36375491a439 until that is sorted out properly.
> 
> Guenter
> 

So pretimeout should be enabled only for kpss-wdt and disabled with a flag 
in the of_table of the driver?

> > > On Tue, Feb 04, 2020 at 04:21:01PM +0100, Ansuel Smith wrote:
> > > > Some platform like ipq806x doesn't support pretimeout.
> > > > As the driver check if there are available interrupts and ipq806x
> > > > use msm-timer that require interrupts, the watchdog fail to probe
> > > > as request_irq tries to use a ppi interrupt. Add an option to skip
> > > > pretimeout setup and use the normal watchdog probe.
> > > >
> > > > Signed-off-by: Ansuel Smith <ansuelsmth@...il.com>
> > > > ---
> > > >  drivers/watchdog/qcom-wdt.c | 5 ++++-
> > > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/watchdog/qcom-wdt.c
b/drivers/watchdog/qcom-wdt.c
> > > > index a494543d3ae1..e689e97e883e 100644
> > > > --- a/drivers/watchdog/qcom-wdt.c
> > > > +++ b/drivers/watchdog/qcom-wdt.c
> > > > @@ -189,6 +189,7 @@ static int qcom_wdt_probe(struct platform_device
> > > *pdev)
> > > >  	u32 percpu_offset;
> > > >  	int irq, ret;
> > > >  	struct clk *clk;
> > > > +	bool nopretimeout;
> > > >
> > > >  	regs = of_device_get_match_data(dev);
> > > >  	if (!regs) {
> > > > @@ -204,6 +205,8 @@ static int qcom_wdt_probe(struct platform_device
> > > *pdev)
> > > >  	if (!res)
> > > >  		return -ENOMEM;
> > > >
> > > > +	nopretimeout = of_property_read_bool(np, "no-pretimeout");
> > > > +
> > > >  	/* We use CPU0's DGT for the watchdog */
> > > >  	if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
> > > >  		percpu_offset = 0;
> > > > @@ -247,7 +250,7 @@ static int qcom_wdt_probe(struct platform_device
> > > *pdev)
> > > >
> > > >  	/* check if there is pretimeout support */
> > > >  	irq = platform_get_irq(pdev, 0);
> > > > -	if (irq > 0) {
> > > > +	if (!nopretimeout && irq > 0) {
> > >
> > > That is unnecessary; such platforms should simply not provide an
> > interrupt.
> > > Or, in other words, what is the point of assigning an interrupt to be
used
> > > for pretimeout if the platform doesn't support it ? And then to add
yet
> > > another attribute to tell the driver not to use it ?
> > >
> > > Guenter
> > >
> > > >  		ret = devm_request_irq(dev, irq, qcom_wdt_isr,
> > > >  				       IRQF_TRIGGER_RISING,
> > > >  				       "wdt_bark", &wdt->wdd);
> > > > --
> > > > 2.24.0
> > > >
> >