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authorFabrice Gasnier <fabrice.gasnier@foss.st.com>2021-03-02 15:43:55 +0100
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2021-03-06 16:47:03 +0000
commite4c3e133294c0a292d21073899b05ebf530169bd (patch)
treeb1929940b125ccc62167296cd29e58c795710285 /drivers/counter
parentfae6f62e6a580b663ecf42c2120a0898deae9137 (diff)
counter: stm32-timer-cnt: fix ceiling write max value
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>
Diffstat (limited to 'drivers/counter')
-rw-r--r--drivers/counter/stm32-timer-cnt.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index cd50dc12bd02..2295be3f309a 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -32,6 +32,7 @@ struct stm32_timer_cnt {
struct regmap *regmap;
struct clk *clk;
u32 ceiling;
+ u32 max_arr;
bool enabled;
struct stm32_timer_regs bak;
};
@@ -191,6 +192,9 @@ 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);
@@ -371,6 +375,7 @@ 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;