linux-kernel - Re: [PATCH 1/2] irqchip: renesas-intc-irqpin: Propagate wake-up settings to parent

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:	Wed, 9 Sep 2015 11:43:06 +0300
From:	Grygorii Strashko <grygorii.strashko@...com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Marc Zyngier <marc.zyngier@....com>
CC:	Geert Uytterhoeven <geert+renesas@...der.be>,
	Jason Cooper <jason@...edaemon.net>,
	Sudeep Holla <sudeep.holla@....com>,
	Magnus Damm <magnus.damm@...il.com>,
	Linux-sh list <linux-sh@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] irqchip: renesas-intc-irqpin: Propagate wake-up
 settings to parent

Hi,

On 09/08/2015 11:03 PM, Thomas Gleixner wrote:
> On Tue, 8 Sep 2015, Geert Uytterhoeven wrote:
>>>> --- a/drivers/irqchip/irq-renesas-intc-irqpin.c
>>>> +++ b/drivers/irqchip/irq-renesas-intc-irqpin.c
>>>> @@ -283,6 +283,9 @@ static int intc_irqpin_irq_set_type(struct irq_data *d, unsigned int type)
>>>>   static int intc_irqpin_irq_set_wake(struct irq_data *d, unsigned int on)
>>>>   {
>>>>        struct intc_irqpin_priv *p = irq_data_get_irq_chip_data(d);
>>>> +     int hw_irq = irqd_to_hwirq(d);
>>>> +
>>>> +     irq_set_irq_wake(p->irq[hw_irq].requested_irq, on);
>>>
>>> Are you sure that this does not make lockdep unhappy due to lock
>>> nesting?
>>
>> Actually I did see one lockdep warning, so I'm aware we're probably gonna
>> need a similar solution like commit a0a8bcf4670c2c69 ("gpiolib: irqchip:
>> use different lockdep class for each gpio irqchip")?
>>
>> To be honest, these lockdep warnings aren't helping much here: on embedded
>> we typical have several stacked interrupt controllers, so wake-up settings
>> have to propagate from the bottom to the top of the stack.
> 
> But ignoring them does not help much either, right?
>   
>> E.g. on sh73a0/kzm9g gpio-keys wake-up goes through 3 interrupt controllers:
>> pcf875x -> renesas-intc-irqpin -> gic.
> 
> So, yes a seperate locking class for that intc trainwreck is probably
> required.
> 

Just as an option, May be we can proceed with patch:
[PATCH v2 2/6] genirq: fix irqchip_set_wake_parent if IRQCHIP_SKIP_SET_WAKE
http://www.spinics.net/lists/linux-omap/msg121262.html

As result, irq_chip_set_wake_parent() can be used here and no lockdep issues.

Marc, what do you think? renesas-intc-irqpin has own .irq_set_wake()
implementation and IRQCHIP_SKIP_SET_WAKE can't be used here as W/A.


-- 
regards,
-grygorii
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/