[PATCH v2] hwmon: (xgene-hwmon) use appropriate type for the latency value

[PATCH v2] hwmon: (xgene-hwmon) use appropriate type for the latency value

[Ваторопин Андрей]

From: Andrey Vatoropin <a.vatoropin@crpt.ru>

The expression PCC_NUM_RETRIES * pcc_chan->latency is currently being
evaluated using 32-bit arithmetic.

Since a value of type 'u64' is used to store the eventual result,
and this result is later sent to the function usecs_to_jiffies with 
input parameter unsigned int, the current data type is too wide to 
store the value of ctx->usecs_lat.

Change the data type of "usecs_lat" to a more suitable (narrower) type.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Andrey Vatoropin <a.vatoropin@crpt.ru>
---
v1->v2: rework the patch by utilizing more appropriate data types for
the variables in question as Guenter Roeck noticed.
 drivers/hwmon/xgene-hwmon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
index 1e3bd129a922..72ba569dde1c 100644
--- a/drivers/hwmon/xgene-hwmon.c
+++ b/drivers/hwmon/xgene-hwmon.c
@@ -105,7 +105,7 @@ struct xgene_hwmon_dev {
 
 	phys_addr_t		comm_base_addr;
 	void			*pcc_comm_addr;
-	u64			usecs_lat;
+	unsigned int		usecs_lat;
 };
 
 /*
-- 
2.43.0

Re: [PATCH v2] hwmon: (xgene-hwmon) use appropriate type for the latency value

[Guenter Roeck]

On Tue, Feb 04, 2025 at 09:54:08AM +0000, Ваторопин Андрей wrote:
> From: Andrey Vatoropin <a.vatoropin@crpt.ru>
> 
> The expression PCC_NUM_RETRIES * pcc_chan->latency is currently being
> evaluated using 32-bit arithmetic.
> 
> Since a value of type 'u64' is used to store the eventual result,
> and this result is later sent to the function usecs_to_jiffies with 
> input parameter unsigned int, the current data type is too wide to 
> store the value of ctx->usecs_lat.
> 
> Change the data type of "usecs_lat" to a more suitable (narrower) type.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Andrey Vatoropin <a.vatoropin@crpt.ru>

Applied.

Thanks,
Guenter