Re: [PATCH] clk: divider: fix incorrect usage of container_of

From: Alexandre Belloni
Date: Fri Dec 22 2017 - 05:34:34 EST

On 21/12/2017 at 17:30:54 +0100, Jerome Brunet wrote:
> divider_recalc_rate() is an helper function used by clock divider of
> different types, so the structure containing the 'hw' pointer is not
> always a 'struct clk_divider'
>
> At the following line:
> > div = _get_div(table, val, flags, divider->width);
>
> in several cases, the value of 'divider->width' is garbage as the actual
> structure behind this memory is not a 'struct clk_divider'
>
> Fortunately, this width value is used by _get_val() only when
> CLK_DIVIDER_MAX_AT_ZERO flag is set. This has never been the case so
> far when the structure is not a 'struct clk_divider'. This is probably
> why we did not notice this bug before
>
> Fixes: afe76c8fd030 ("clk: allow a clk divider with max divisor when zero")
> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>

For RTC:
Acked-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>

> ---
> Hi Stephen, Mike,
>
> In addition to clock, this patch also touch the rtc and drm directories.
> As it is changing the API of the helper function, I have this fix in a
> single commit to avoid breaking bisect.
>
> Please let me know if you prefer to do differently.
>
> Cheers
> Jerome
>
> drivers/clk/clk-divider.c | 7 +++----
> drivers/clk/hisilicon/clkdivider-hi6220.c | 2 +-
> drivers/clk/nxp/clk-lpc32xx.c | 2 +-
> drivers/clk/qcom/clk-regmap-divider.c | 2 +-
> drivers/clk/sunxi-ng/ccu_div.c | 2 +-
> drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c | 2 +-
> drivers/rtc/rtc-ac100.c | 6 ++++--
> include/linux/clk-provider.h | 2 +-
> 8 files changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> index 4ed516cb7276..b49942b9fe50 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -118,12 +118,11 @@ static unsigned int _get_val(const struct clk_div_table *table,
> unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
> unsigned int val,
> const struct clk_div_table *table,
> - unsigned long flags)
> + unsigned long flags, unsigned long width)
> {
> - struct clk_divider *divider = to_clk_divider(hw);
> unsigned int div;
>
> - div = _get_div(table, val, flags, divider->width);
> + div = _get_div(table, val, flags, width);
> if (!div) {
> WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
> "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
> @@ -145,7 +144,7 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
> val &= div_mask(divider->width);
>
> return divider_recalc_rate(hw, parent_rate, val, divider->table,
> - divider->flags);
> + divider->flags, divider->width);
> }
>
> static bool _is_valid_table_div(const struct clk_div_table *table,
> diff --git a/drivers/clk/hisilicon/clkdivider-hi6220.c b/drivers/clk/hisilicon/clkdivider-hi6220.c
> index a1c1f684ad58..9f46cf9dcc65 100644
> --- a/drivers/clk/hisilicon/clkdivider-hi6220.c
> +++ b/drivers/clk/hisilicon/clkdivider-hi6220.c
> @@ -56,7 +56,7 @@ static unsigned long hi6220_clkdiv_recalc_rate(struct clk_hw *hw,
> val &= div_mask(dclk->width);
>
> return divider_recalc_rate(hw, parent_rate, val, dclk->table,
> - CLK_DIVIDER_ROUND_CLOSEST);
> + CLK_DIVIDER_ROUND_CLOSEST, dclk->width);
> }
>
> static long hi6220_clkdiv_round_rate(struct clk_hw *hw, unsigned long rate,
> diff --git a/drivers/clk/nxp/clk-lpc32xx.c b/drivers/clk/nxp/clk-lpc32xx.c
> index b669a5c10fee..f5d815f577e0 100644
> --- a/drivers/clk/nxp/clk-lpc32xx.c
> +++ b/drivers/clk/nxp/clk-lpc32xx.c
> @@ -956,7 +956,7 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
> val &= div_mask(divider->width);
>
> return divider_recalc_rate(hw, parent_rate, val, divider->table,
> - divider->flags);
> + divider->flags, divider->width);
> }
>
> static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
> diff --git a/drivers/clk/qcom/clk-regmap-divider.c b/drivers/clk/qcom/clk-regmap-divider.c
> index 53484912301e..928fcc16ee27 100644
> --- a/drivers/clk/qcom/clk-regmap-divider.c
> +++ b/drivers/clk/qcom/clk-regmap-divider.c
> @@ -59,7 +59,7 @@ static unsigned long div_recalc_rate(struct clk_hw *hw,
> div &= BIT(divider->width) - 1;
>
> return divider_recalc_rate(hw, parent_rate, div, NULL,
> - CLK_DIVIDER_ROUND_CLOSEST);
> + CLK_DIVIDER_ROUND_CLOSEST, divider->width);
> }
>
> const struct clk_ops clk_regmap_div_ops = {
> diff --git a/drivers/clk/sunxi-ng/ccu_div.c b/drivers/clk/sunxi-ng/ccu_div.c
> index baa3cf96507b..302a18efd39f 100644
> --- a/drivers/clk/sunxi-ng/ccu_div.c
> +++ b/drivers/clk/sunxi-ng/ccu_div.c
> @@ -71,7 +71,7 @@ static unsigned long ccu_div_recalc_rate(struct clk_hw *hw,
> parent_rate);
>
> val = divider_recalc_rate(hw, parent_rate, val, cd->div.table,
> - cd->div.flags);
> + cd->div.flags, cd->div.width);
>
> if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV)
> val /= cd->fixed_post_div;
> diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c
> index fe15aa64086f..71fe60e5f01f 100644
> --- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c
> +++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c
> @@ -698,7 +698,7 @@ static unsigned long dsi_pll_14nm_postdiv_recalc_rate(struct clk_hw *hw,
> val &= div_mask(width);
>
> return divider_recalc_rate(hw, parent_rate, val, NULL,
> - postdiv->flags);
> + postdiv->flags, width);
> }
>
> static long dsi_pll_14nm_postdiv_round_rate(struct clk_hw *hw,
> diff --git a/drivers/rtc/rtc-ac100.c b/drivers/rtc/rtc-ac100.c
> index 9e336184491c..0282ccc6181c 100644
> --- a/drivers/rtc/rtc-ac100.c
> +++ b/drivers/rtc/rtc-ac100.c
> @@ -137,13 +137,15 @@ static unsigned long ac100_clkout_recalc_rate(struct clk_hw *hw,
> div = (reg >> AC100_CLKOUT_PRE_DIV_SHIFT) &
> ((1 << AC100_CLKOUT_PRE_DIV_WIDTH) - 1);
> prate = divider_recalc_rate(hw, prate, div,
> - ac100_clkout_prediv, 0);
> + ac100_clkout_prediv, 0,
> + AC100_CLKOUT_PRE_DIV_WIDTH);
> }
>
> div = (reg >> AC100_CLKOUT_DIV_SHIFT) &
> (BIT(AC100_CLKOUT_DIV_WIDTH) - 1);
> return divider_recalc_rate(hw, prate, div, NULL,
> - CLK_DIVIDER_POWER_OF_TWO);
> + CLK_DIVIDER_POWER_OF_TWO,
> + AC100_CLKOUT_DIV_WIDTH);
> }
>
> static long ac100_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 73ac87f34df9..4c4001086447 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -412,7 +412,7 @@ extern const struct clk_ops clk_divider_ro_ops;
>
> unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
> unsigned int val, const struct clk_div_table *table,
> - unsigned long flags);
> + unsigned long flags, unsigned long width);
> long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
> unsigned long rate, unsigned long *prate,
> const struct clk_div_table *table,
> --
> 2.14.3
>

--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com