Staging: vt6655: Fix sparse warning. Restricted cast.

[PATCH] Staging: vt6655: Fix sparse warning. Restricted cast.

Posted by SilverPlate3 1 year, 11 months ago

Running 'make M=drivers/staging/vt6655 C=2'
causes sparse to generate few warnings.
This patch fixes the following warnings by ensuring le64_to_cpu
handles only __le64 values, thus dismissing chances of bad endianness.
* drivers/staging/vt6655/card.c:302:45: warning: cast to restricted __le64
* drivers/staging/vt6655/card.c:336:23: warning: cast to restricted __le64
* drivers/staging/vt6655/card.c:804:23: warning: cast to restricted __le64
* drivers/staging/vt6655/card.c:831:18: warning: cast to restricted __le64

Signed-off-by: Ariel Silver <arielsilver77@gmail.com>
---
 drivers/staging/vt6655/card.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vt6655/card.c b/drivers/staging/vt6655/card.c
index 350ab8f3778a..5dc2200466b7 100644
--- a/drivers/staging/vt6655/card.c
+++ b/drivers/staging/vt6655/card.c
@@ -292,6 +292,7 @@ bool card_update_tsf(struct vnt_private *priv, unsigned char rx_rate,
 {
 	u64 local_tsf;
 	u64 qwTSFOffset = 0;
+	__le64 le_qwTSFOffset = 0;
 
 	local_tsf = vt6655_get_current_tsf(priv);
 
@@ -299,7 +300,8 @@ bool card_update_tsf(struct vnt_private *priv, unsigned char rx_rate,
 		qwTSFOffset = CARDqGetTSFOffset(rx_rate, qwBSSTimestamp,
 						local_tsf);
 		/* adjust TSF, HW's TSF add TSF Offset reg */
-		qwTSFOffset =  le64_to_cpu(qwTSFOffset);
+		le_qwTSFOffset = cpu_to_le64(qwTSFOffset);
+		qwTSFOffset = le64_to_cpu(le_qwTSFOffset);
 		iowrite32((u32)qwTSFOffset, priv->port_offset + MAC_REG_TSFOFST);
 		iowrite32((u32)(qwTSFOffset >> 32), priv->port_offset + MAC_REG_TSFOFST + 4);
 		vt6655_mac_reg_bits_on(priv->port_offset, MAC_REG_TFTCTL, TFTCTL_TSFSYNCEN);
@@ -324,6 +326,7 @@ bool CARDbSetBeaconPeriod(struct vnt_private *priv,
 			  unsigned short wBeaconInterval)
 {
 	u64 qwNextTBTT;
+	__le64 le_qwNextTBTT = 0;
 
 	qwNextTBTT = vt6655_get_current_tsf(priv); /* Get Local TSF counter */
 
@@ -333,7 +336,8 @@ bool CARDbSetBeaconPeriod(struct vnt_private *priv,
 	iowrite16(wBeaconInterval, priv->port_offset + MAC_REG_BI);
 	priv->wBeaconInterval = wBeaconInterval;
 	/* Set NextTBTT */
-	qwNextTBTT =  le64_to_cpu(qwNextTBTT);
+	le_qwNextTBTT = cpu_to_le64(qwNextTBTT);
+	qwNextTBTT = le64_to_cpu(le_qwNextTBTT);
 	iowrite32((u32)qwNextTBTT, priv->port_offset + MAC_REG_NEXTTBTT);
 	iowrite32((u32)(qwNextTBTT >> 32), priv->port_offset + MAC_REG_NEXTTBTT + 4);
 	vt6655_mac_reg_bits_on(priv->port_offset, MAC_REG_TFTCTL, TFTCTL_TBTTSYNCEN);
@@ -796,12 +800,14 @@ void CARDvSetFirstNextTBTT(struct vnt_private *priv,
 {
 	void __iomem *iobase = priv->port_offset;
 	u64 qwNextTBTT;
+	__le64 le_qwNextTBTT = 0;
 
 	qwNextTBTT = vt6655_get_current_tsf(priv); /* Get Local TSF counter */
 
 	qwNextTBTT = CARDqGetNextTBTT(qwNextTBTT, wBeaconInterval);
 	/* Set NextTBTT */
-	qwNextTBTT =  le64_to_cpu(qwNextTBTT);
+	le_qwNextTBTT = cpu_to_le64(qwNextTBTT);
+	qwNextTBTT = le64_to_cpu(le_qwNextTBTT);
 	iowrite32((u32)qwNextTBTT, iobase + MAC_REG_NEXTTBTT);
 	iowrite32((u32)(qwNextTBTT >> 32), iobase + MAC_REG_NEXTTBTT + 4);
 	vt6655_mac_reg_bits_on(iobase, MAC_REG_TFTCTL, TFTCTL_TBTTSYNCEN);
@@ -825,10 +831,12 @@ void CARDvUpdateNextTBTT(struct vnt_private *priv, u64 qwTSF,
 			 unsigned short wBeaconInterval)
 {
 	void __iomem *iobase = priv->port_offset;
+	__le64 le_qwTSF = 0;
 
 	qwTSF = CARDqGetNextTBTT(qwTSF, wBeaconInterval);
 	/* Set NextTBTT */
-	qwTSF =  le64_to_cpu(qwTSF);
+	le_qwTSF = cpu_to_le64(qwTSF);
+	qwTSF = le64_to_cpu(le_qwTSF);
 	iowrite32((u32)qwTSF, iobase + MAC_REG_NEXTTBTT);
 	iowrite32((u32)(qwTSF >> 32), iobase + MAC_REG_NEXTTBTT + 4);
 	vt6655_mac_reg_bits_on(iobase, MAC_REG_TFTCTL, TFTCTL_TBTTSYNCEN);
-- 
2.25.1

Re: [PATCH] Staging: vt6655: Fix sparse warning. Restricted cast.

Posted by Dan Carpenter 1 year, 11 months ago

On Tue, Jan 09, 2024 at 09:27:04AM +0200, SilverPlate3 wrote:
> Running 'make M=drivers/staging/vt6655 C=2'
> causes sparse to generate few warnings.
> This patch fixes the following warnings by ensuring le64_to_cpu
> handles only __le64 values, thus dismissing chances of bad endianness.
> * drivers/staging/vt6655/card.c:302:45: warning: cast to restricted __le64
> * drivers/staging/vt6655/card.c:336:23: warning: cast to restricted __le64
> * drivers/staging/vt6655/card.c:804:23: warning: cast to restricted __le64
> * drivers/staging/vt6655/card.c:831:18: warning: cast to restricted __le64
> 
> Signed-off-by: Ariel Silver <arielsilver77@gmail.com>
> ---
>  drivers/staging/vt6655/card.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/vt6655/card.c b/drivers/staging/vt6655/card.c
> index 350ab8f3778a..5dc2200466b7 100644
> --- a/drivers/staging/vt6655/card.c
> +++ b/drivers/staging/vt6655/card.c
> @@ -292,6 +292,7 @@ bool card_update_tsf(struct vnt_private *priv, unsigned char rx_rate,
>  {
>  	u64 local_tsf;
>  	u64 qwTSFOffset = 0;
> +	__le64 le_qwTSFOffset = 0;
>  
>  	local_tsf = vt6655_get_current_tsf(priv);
>  
> @@ -299,7 +300,8 @@ bool card_update_tsf(struct vnt_private *priv, unsigned char rx_rate,
>  		qwTSFOffset = CARDqGetTSFOffset(rx_rate, qwBSSTimestamp,
>  						local_tsf);
>  		/* adjust TSF, HW's TSF add TSF Offset reg */
> -		qwTSFOffset =  le64_to_cpu(qwTSFOffset);
> +		le_qwTSFOffset = cpu_to_le64(qwTSFOffset);
> +		qwTSFOffset = le64_to_cpu(le_qwTSFOffset);


This isn't right at all.  You've just to convert it and then convert it
back.  (In other words do nothing but in a very complicated way).

This isn't a bug, it's just an issue of annotations.  The code is
re-using a single variable to hold both cpu and little endian data.  So
the way to write the annotations is to create two variables, one that's
cpu endian and one that's little endian.

regards,
dan carpenter

Re: [PATCH] Staging: vt6655: Fix sparse warning. Restricted cast.

Posted by Greg KH 1 year, 11 months ago

On Tue, Jan 09, 2024 at 09:27:04AM +0200, SilverPlate3 wrote:
> Running 'make M=drivers/staging/vt6655 C=2'
> causes sparse to generate few warnings.
> This patch fixes the following warnings by ensuring le64_to_cpu
> handles only __le64 values, thus dismissing chances of bad endianness.
> * drivers/staging/vt6655/card.c:302:45: warning: cast to restricted __le64
> * drivers/staging/vt6655/card.c:336:23: warning: cast to restricted __le64
> * drivers/staging/vt6655/card.c:804:23: warning: cast to restricted __le64
> * drivers/staging/vt6655/card.c:831:18: warning: cast to restricted __le64
> 
> Signed-off-by: Ariel Silver <arielsilver77@gmail.com>

 From: line doesn't match the signed-off-by line :(

> ---
>  drivers/staging/vt6655/card.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/vt6655/card.c b/drivers/staging/vt6655/card.c
> index 350ab8f3778a..5dc2200466b7 100644
> --- a/drivers/staging/vt6655/card.c
> +++ b/drivers/staging/vt6655/card.c
> @@ -292,6 +292,7 @@ bool card_update_tsf(struct vnt_private *priv, unsigned char rx_rate,
>  {
>  	u64 local_tsf;
>  	u64 qwTSFOffset = 0;
> +	__le64 le_qwTSFOffset = 0;
>  
>  	local_tsf = vt6655_get_current_tsf(priv);
>  
> @@ -299,7 +300,8 @@ bool card_update_tsf(struct vnt_private *priv, unsigned char rx_rate,
>  		qwTSFOffset = CARDqGetTSFOffset(rx_rate, qwBSSTimestamp,
>  						local_tsf);
>  		/* adjust TSF, HW's TSF add TSF Offset reg */
> -		qwTSFOffset =  le64_to_cpu(qwTSFOffset);
> +		le_qwTSFOffset = cpu_to_le64(qwTSFOffset);
> +		qwTSFOffset = le64_to_cpu(le_qwTSFOffset);

Are you sure about this?  Please verify just what you are doing here
please...

thanks,

greg k-h