diff options
| author | Fabrice Gasnier <fabrice.gasnier@foss.st.com> | 2021-03-02 15:43:55 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-24 11:26:43 +0100 |
| commit | 796fc331c3cf1391bffbf97e590f8026963ff057 (patch) | |
| tree | 4712c314dcb27c574dc3199f678ec7428c4a27f7 /drivers/counter | |
| parent | 850ca1c0130af6611afc236457ff919c3d858ed6 (diff) | |
counter: stm32-timer-cnt: fix ceiling write max value
commit e4c3e133294c0a292d21073899b05ebf530169bd upstream.
The ceiling value isn't checked before writing it into registers. The user
could write a value higher than the counter resolution (e.g. 16 or 32 bits
indicated by max_arr). This makes most significant bits to be truncated.
Fix it by checking the max_arr to report a range error [1] to the user.
[1] https://lkml.org/lkml/2021/2/12/358
Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1614696235-24088-1-git-send-email-fabrice.gasnier@foss.st.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/counter')
| -rw-r--r-- | drivers/counter/stm32-timer-cnt.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c index c680c7abdd26..75e08a98d09b 100644 --- a/drivers/counter/stm32-timer-cnt.c +++ b/drivers/counter/stm32-timer-cnt.c @@ -25,6 +25,7 @@ struct stm32_timer_cnt { struct regmap *regmap; struct clk *clk; u32 ceiling; + u32 max_arr; }; /** @@ -189,6 +190,9 @@ static ssize_t stm32_count_ceiling_write(struct counter_device *counter, if (ret) return ret; + if (ceiling > priv->max_arr) + return -ERANGE; + /* TIMx_ARR register shouldn't be buffered (ARPE=0) */ regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0); regmap_write(priv->regmap, TIM_ARR, ceiling); @@ -366,6 +370,7 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev) priv->regmap = ddata->regmap; priv->clk = ddata->clk; priv->ceiling = ddata->max_arr; + priv->max_arr = ddata->max_arr; priv->counter.name = dev_name(dev); priv->counter.parent = dev; |