Re: [PATCH] mfd: 88pm80x: refine irq bit operation

[Lee Jones <lee.jones@linaro.org>]

On Fri, 15 May 2015, Qiao Zhou wrote:

> Set_bit/clear_bit for wu_flag may be corrupted if irq > 5(or 6 for
> aarch64). The maximum irq number from 88pm80x chip series is 24.
> Here we refine the code to protect the potential memory corruption.
> 
> Also change wu_flag to wakeup_flag for easier understanding.
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Qiao Zhou <zhouqiao@marvell.com>
> ---
>  drivers/mfd/88pm80x.c       |    4 ++--
>  include/linux/mfd/88pm80x.h |   19 ++++++++++++++++---
>  2 files changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mfd/88pm80x.c b/drivers/mfd/88pm80x.c
> index 5e72f65..e1d803a 100644
> --- a/drivers/mfd/88pm80x.c
> +++ b/drivers/mfd/88pm80x.c
> @@ -136,7 +136,7 @@ static int pm80x_suspend(struct device *dev)
>  	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
>  	struct pm80x_chip *chip = i2c_get_clientdata(client);
>  
> -	if (chip && chip->wu_flag)
> +	if (chip && chip->wakeup_flag)
>  		if (device_may_wakeup(chip->dev))
>  			enable_irq_wake(chip->irq);
>  
> @@ -148,7 +148,7 @@ static int pm80x_resume(struct device *dev)
>  	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
>  	struct pm80x_chip *chip = i2c_get_clientdata(client);
>  
> -	if (chip && chip->wu_flag)
> +	if (chip && chip->wakeup_flag)
>  		if (device_may_wakeup(chip->dev))
>  			disable_irq_wake(chip->irq);
>  
> diff --git a/include/linux/mfd/88pm80x.h b/include/linux/mfd/88pm80x.h
> index 97cb283..1bca7eb 100644
> --- a/include/linux/mfd/88pm80x.h
> +++ b/include/linux/mfd/88pm80x.h
> @@ -276,6 +276,9 @@ enum {
>  #define PM805_EARPHONE_SETTING			(0x29)
>  #define PM805_AUTO_SEQ_SETTING			(0x2A)
>  
> +/* supported 24 sub-irq */
> +#define PM80x_MAX_IRQ			24

s/x/X/

>  struct pm80x_rtc_pdata {
>  	int		vrtc;
>  	int		rtc_wakeup;
> @@ -301,7 +304,7 @@ struct pm80x_chip {
>  	int type;
>  	int irq;
>  	int irq_mode;
> -	unsigned long wu_flag;
> +	unsigned long wakeup_flag;
>  	spinlock_t lock;
>  };
>  
> @@ -348,8 +351,13 @@ static inline int pm80x_dev_suspend(struct device *dev)
>  	struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
>  	int irq = platform_get_irq(pdev, 0);
>  
> +	if (irq < 0 || irq >= PM80x_MAX_IRQ) {
> +		dev_err(dev, "Invalid irq %d\n", irq);

s/irq/IRQ/

> +		return 0;
> +	}
> +
>  	if (device_may_wakeup(dev))
> -		set_bit((1 << irq), &chip->wu_flag);
> +		set_bit(irq, &chip->wakeup_flag);
>  
>  	return 0;
>  }
> @@ -360,8 +368,13 @@ static inline int pm80x_dev_resume(struct device *dev)
>  	struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
>  	int irq = platform_get_irq(pdev, 0);
>  
> +	if (irq < 0 || irq >= PM80x_MAX_IRQ) {
> +		dev_err(dev, "Invalid irq %d\n", irq);
> +		return 0;
> +	}

Why would this have changed over a suspend/resume?

>  	if (device_may_wakeup(dev))
> -		clear_bit((1 << irq), &chip->wu_flag);
> +		clear_bit(irq, &chip->wakeup_flag);
>  
>  	return 0;
>  }

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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