linux-kernel - Re: [PATCH v2 15/16] gpio: tegra: Use banked GPIO infrastructure

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, 10 Oct 2017 14:31:15 -0500
From:   Grygorii Strashko <grygorii.strashko@...com>
To:     Thierry Reding <thierry.reding@...il.com>
CC:     Linus Walleij <linus.walleij@...aro.org>,
        Jonathan Hunter <jonathanh@...dia.com>,
        <linux-gpio@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 15/16] gpio: tegra: Use banked GPIO infrastructure



On 10/10/2017 05:27 AM, Thierry Reding wrote:
> On Mon, Oct 09, 2017 at 04:22:29PM -0500, Grygorii Strashko wrote:
>>
>>
>> On 09/28/2017 04:56 AM, Thierry Reding wrote:
>>> From: Thierry Reding <treding@...dia.com>
>>>
>>> Convert the Tegra GPIO driver to use the banked GPIO infrastructure,
>>> which simplifies some parts of the driver.
>>>
>>> Signed-off-by: Thierry Reding <treding@...dia.com>
>>> ---
>>>    drivers/gpio/Kconfig      |   1 +
>>>    drivers/gpio/gpio-tegra.c | 203 ++++++++++++++++++++++------------------------
>>>    2 files changed, 98 insertions(+), 106 deletions(-)
>>>
>>> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
>>> index db3e446ad9b3..458157d6d491 100644
>>> --- a/drivers/gpio/Kconfig
>>> +++ b/drivers/gpio/Kconfig
>>> @@ -439,6 +439,7 @@ config GPIO_TEGRA
>>>    	default ARCH_TEGRA
>>>    	depends on ARCH_TEGRA || COMPILE_TEST
>>
>> ...
>>
>>> @@ -616,76 +617,66 @@ static int tegra_gpio_probe(struct platform_device *pdev)
>>>    	tgi->ic.irq_set_wake		= tegra_gpio_irq_set_wake;
>>>    #endif
>>>    
>>> +	irq = &tgi->gc.irq;
>>> +	irq->chip = &tgi->ic;
>>> +	irq->handler = handle_simple_irq;
>>> +	irq->lock_key = &tegra_gpio_lock_class;
>>
>> As per current gpiolib design lockdep lock_class_key is assigned
>> automatically and hidden from gpiolib users.
>> Why do you need to do the same manually?
> 
> Can you elaborate? I don't see the lock class key getting set anywhere.
> gpiolib does set if for interrupts, but only if the drivers assigned it
> before adding the chip.
> 

include/linux/gpio/driver.h

#ifdef CONFIG_LOCKDEP

/*
 * Lockdep requires that each irqchip instance be created with a
 * unique key so as to avoid unnecessary warnings. This upfront
 * boilerplate static inlines provides such a key for each
 * unique instance.
 */
static inline int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
				       struct irq_chip *irqchip,
				       unsigned int first_irq,
				       irq_flow_handler_t handler,
				       unsigned int type)
{
	static struct lock_class_key key;
^^^

	return gpiochip_irqchip_add_key(gpiochip, irqchip, first_irq,
					handler, type, false, &key);
}
 

-- 
regards,
-grygorii