Re: [PATCH v6 1/5] pinctrl: mediatek: Check gpio pin number and use binary search in mtk_hw_pin_field_lookup()

[Light Hsieh]

Dear reviewers:

Patch v6 improves v5 by:

1.in mtk_pinconf_get() and mtk_pinconf_set() @pinctrl-paris.c:
  * check if pin is in range before using pin as array index of 
     hw->soc->pins[]
2.in mtk_pin_field_lookup() @pinctrl-mtk-common-v2.c:
  * declear start, end, check as signed integer instead of unsigned
    integer. Otherwise, kernel fault will occur when s_pin field of
    first entry of a mtk_pin_field_calc[] array is not 0.

On Fri, 2019-09-27 at 13:02 +0800, Light Hsieh wrote:
> 1. Check if gpio pin number is in valid range to prevent from get invalid
>    pointer 'desc' in the following code:
> 	desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
> 
> 2. Use binary search in mtk_hw_pin_field_lookup()
>    Modify mtk_hw_pin_field_lookup() to use binary search for accelerating
>    search.
> 
> ---
>  drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c | 25 +++++++++++++++++++-----
>  drivers/pinctrl/mediatek/pinctrl-paris.c         | 25 ++++++++++++++++++++++++
>  2 files changed, 45 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> index 20e1c89..8077855 100644
> --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> @@ -68,7 +68,8 @@ static int mtk_hw_pin_field_lookup(struct mtk_pinctrl *hw,
>  {
>  	const struct mtk_pin_field_calc *c, *e;
>  	const struct mtk_pin_reg_calc *rc;
> -	u32 bits;
> +	u32 bits, found = 0;
> +	int start = 0, end, check;
>  
>  	if (hw->soc->reg_cal && hw->soc->reg_cal[field].range) {
>  		rc = &hw->soc->reg_cal[field];
> @@ -79,21 +80,32 @@ static int mtk_hw_pin_field_lookup(struct mtk_pinctrl *hw,
>  		return -ENOTSUPP;
>  	}
>  
> +	end = rc->nranges - 1;
>  	c = rc->range;
>  	e = c + rc->nranges;
>  
> -	while (c < e) {
> -		if (desc->number >= c->s_pin && desc->number <= c->e_pin)
> +	while (start <= end) {
> +		check = (start + end) >> 1;
> +		if (desc->number >= rc->range[check].s_pin
> +		 && desc->number <= rc->range[check].e_pin) {
> +			found = 1;
>  			break;
> -		c++;
> +		} else if (start == end)
> +			break;
> +		else if (desc->number < rc->range[check].s_pin)
> +			end = check - 1;
> +		else
> +			start = check + 1;
>  	}
>  
> -	if (c >= e) {
> +	if (!found) {
>  		dev_dbg(hw->dev, "Not support field %d for pin = %d (%s)\n",
>  			field, desc->number, desc->name);
>  		return -ENOTSUPP;
>  	}
>  
> +	c = rc->range + check;
> +
>  	if (c->i_base > hw->nbase - 1) {
>  		dev_err(hw->dev,
>  			"Invalid base for field %d for pin = %d (%s)\n",
> @@ -182,6 +194,9 @@ int mtk_hw_set_value(struct mtk_pinctrl *hw, const struct mtk_pin_desc *desc,
>  	if (err)
>  		return err;
>  
> +	if (value < 0 || value > pf.mask)
> +		return -EINVAL;
> +
>  	if (!pf.next)
>  		mtk_rmw(hw, pf.index, pf.offset, pf.mask << pf.bitpos,
>  			(value & pf.mask) << pf.bitpos);
> diff --git a/drivers/pinctrl/mediatek/pinctrl-paris.c b/drivers/pinctrl/mediatek/pinctrl-paris.c
> index 923264d..3e13ae7 100644
> --- a/drivers/pinctrl/mediatek/pinctrl-paris.c
> +++ b/drivers/pinctrl/mediatek/pinctrl-paris.c
> @@ -81,6 +81,8 @@ static int mtk_pinconf_get(struct pinctrl_dev *pctldev,
>  	int val, val2, err, reg, ret = 1;
>  	const struct mtk_pin_desc *desc;
>  
> +	if (pin >= hw->soc->npins)
> +		return -EINVAL;
>  	desc = (const struct mtk_pin_desc *)&hw->soc->pins[pin];
>  
>  	switch (param) {
> @@ -206,6 +208,10 @@ static int mtk_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
>  	int err = 0;
>  	u32 reg;
>  
> +	if (pin >= hw->soc->npins) {
> +		err = -EINVAL;
> +		goto err;
> +	}
>  	desc = (const struct mtk_pin_desc *)&hw->soc->pins[pin];
>  
>  	switch ((u32)param) {
> @@ -693,6 +699,9 @@ static int mtk_gpio_get_direction(struct gpio_chip *chip, unsigned int gpio)
>  	const struct mtk_pin_desc *desc;
>  	int value, err;
>  
> +	if (gpio > hw->soc->npins)
> +		return -EINVAL;
> +
>  	desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
>  
>  	err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_DIR, &value);
> @@ -708,6 +717,9 @@ static int mtk_gpio_get(struct gpio_chip *chip, unsigned int gpio)
>  	const struct mtk_pin_desc *desc;
>  	int value, err;
>  
> +	if (gpio > hw->soc->npins)
> +		return -EINVAL;
> +
>  	desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
>  
>  	err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_DI, &value);
> @@ -722,6 +734,9 @@ static void mtk_gpio_set(struct gpio_chip *chip, unsigned int gpio, int value)
>  	struct mtk_pinctrl *hw = gpiochip_get_data(chip);
>  	const struct mtk_pin_desc *desc;
>  
> +	if (gpio > hw->soc->npins)
> +		return;
> +
>  	desc = (const struct mtk_pin_desc *)&hw->soc->pins[gpio];
>  
>  	mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_DO, !!value);
> @@ -729,12 +744,22 @@ static void mtk_gpio_set(struct gpio_chip *chip, unsigned int gpio, int value)
>  
>  static int mtk_gpio_direction_input(struct gpio_chip *chip, unsigned int gpio)
>  {
> +	struct mtk_pinctrl *hw = gpiochip_get_data(chip);
> +
> +	if (gpio > hw->soc->npins)
> +		return -EINVAL;
> +
>  	return pinctrl_gpio_direction_input(chip->base + gpio);
>  }
>  
>  static int mtk_gpio_direction_output(struct gpio_chip *chip, unsigned int gpio,
>  				     int value)
>  {
> +	struct mtk_pinctrl *hw = gpiochip_get_data(chip);
> +
> +	if (gpio > hw->soc->npins)
> +		return -EINVAL;
> +
>  	mtk_gpio_set(chip, gpio, value);
>  
>  	return pinctrl_gpio_direction_output(chip->base + gpio);