[PATCH][v5] mtd: rawnand: fsl_ifc: Fix eccstat array overflow for IFC ver >= 2.0.0

[PATCH][v5] mtd: rawnand: fsl_ifc: Fix eccstat array overflow for IFC ver >= 2.0.0

[Jagdish Gediya]

Number of ECC status registers i.e. (ECCSTATx) has been increased in IFC
version 2.0.0 due to increase in SRAM size. This is causing eccstat
array to over flow.

So, replace eccstat array with u32 variable to make it fail-safe and
independent of number of ECC status registers or SRAM size.

Fixes: bccb06c353af ("mtd: nand: ifc: update bufnum mask for ver >= 2.0.0")
Cc: stable@vger.kernel.org # 3.18+
Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Signed-off-by: Jagdish Gediya <jagdish.gediya@nxp.com>
---
Changes for v2: Incorporated comments from Miquel Raynal and Boris Brezillon 
        - Updated patch subject
        - Remove usage of eccstat array
        - Added Cc: stable@vger.kernel.org 

Changes for v3: Incorporated comments from Boris Brezillon
        - Added fixes tag

Changes for v4: Incorporated comments from Boris Brezillon

Changes for v5: Incorporated comments from Boris Brezillon

 drivers/mtd/nand/fsl_ifc_nand.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
index 4872a7b..f0b4ecd 100644
--- a/drivers/mtd/nand/fsl_ifc_nand.c
+++ b/drivers/mtd/nand/fsl_ifc_nand.c
@@ -173,14 +173,9 @@ static void set_addr(struct mtd_info *mtd, int column, int page_addr, int oob)
 
 /* returns nonzero if entire page is blank */
 static int check_read_ecc(struct mtd_info *mtd, struct fsl_ifc_ctrl *ctrl,
-			  u32 *eccstat, unsigned int bufnum)
+			  u32 eccstat, unsigned int bufnum)
 {
-	u32 reg = eccstat[bufnum / 4];
-	int errors;
-
-	errors = (reg >> ((3 - bufnum % 4) * 8)) & 15;
-
-	return errors;
+	return  (eccstat >> ((3 - bufnum % 4) * 8)) & 15;
 }
 
 /*
@@ -193,7 +188,7 @@ static void fsl_ifc_run_command(struct mtd_info *mtd)
 	struct fsl_ifc_ctrl *ctrl = priv->ctrl;
 	struct fsl_ifc_nand_ctrl *nctrl = ifc_nand_ctrl;
 	struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;
-	u32 eccstat[4];
+	u32 eccstat;
 	int i;
 
 	/* set the chip select for NAND Transaction */
@@ -228,8 +223,8 @@ static void fsl_ifc_run_command(struct mtd_info *mtd)
 	if (nctrl->eccread) {
 		int errors;
 		int bufnum = nctrl->page & priv->bufnum_mask;
-		int sector = bufnum * chip->ecc.steps;
-		int sector_end = sector + chip->ecc.steps - 1;
+		int sector_start = bufnum * chip->ecc.steps;
+		int sector_end = sector_start + chip->ecc.steps - 1;
 		__be32 *eccstat_regs;
 
 		if (ctrl->version >= FSL_IFC_VERSION_2_0_0)
@@ -237,10 +232,12 @@ static void fsl_ifc_run_command(struct mtd_info *mtd)
 		else
 			eccstat_regs = ifc->ifc_nand.v1_nand_eccstat;
 
-		for (i = sector / 4; i <= sector_end / 4; i++)
-			eccstat[i] = ifc_in32(&eccstat_regs[i]);
+		eccstat = ifc_in32(&eccstat_regs[sector_start / 4]);
+
+		for (i = sector_start; i <= sector_end; i++) {
+			if ((i != sector_start) && !(i % 4))
+				eccstat = ifc_in32(&eccstat_regs[i / 4]);
 
-		for (i = sector; i <= sector_end; i++) {
 			errors = check_read_ecc(mtd, ctrl, eccstat, i);
 
 			if (errors == 15) {
-- 
1.9.1

RE: [PATCH][v5] mtd: rawnand: fsl_ifc: Fix eccstat array overflow for IFC ver >= 2.0.0

[Jagdish Gediya]

Hi Boris,

> -----Original Message-----
> From: Jagdish Gediya
> Sent: Thursday, March 22, 2018 3:36 AM
> To: linux-mtd@lists.infradead.org
> Cc: boris.brezillon@free-electrons.com; computersforpeace@gmail.com;
> oss@buserror.net; Leo Li <leoyang.li@nxp.com>; Jagdish Gediya
> <jagdish.gediya@nxp.com>; stable@vger.kernel.org; Prabhakar Kushwaha
> <prabhakar.kushwaha@nxp.com>
> Subject: [PATCH][v5] mtd: rawnand: fsl_ifc: Fix eccstat array overflow for IFC
> ver >= 2.0.0
> 
> Number of ECC status registers i.e. (ECCSTATx) has been increased in IFC
> version 2.0.0 due to increase in SRAM size. This is causing eccstat array to over
> flow.
> 
> So, replace eccstat array with u32 variable to make it fail-safe and independent
> of number of ECC status registers or SRAM size.
> 
> Fixes: bccb06c353af ("mtd: nand: ifc: update bufnum mask for ver >= 2.0.0")
> Cc: stable@vger.kernel.org # 3.18+
> Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
> Signed-off-by: Jagdish Gediya <jagdish.gediya@nxp.com>
> ---
> Changes for v2: Incorporated comments from Miquel Raynal and Boris Brezillon
>         - Updated patch subject
>         - Remove usage of eccstat array
>         - Added Cc: stable@vger.kernel.org
> 
> Changes for v3: Incorporated comments from Boris Brezillon
>         - Added fixes tag
> 
> Changes for v4: Incorporated comments from Boris Brezillon
> 
> Changes for v5: Incorporated comments from Boris Brezillon

I am seeing this patch[v5]'s state as superseded @ https://patchwork.ozlabs.org/project/linux-mtd/list/?series=&submitter=73665&state=9&q=&archive=&delegate= , May I know the reason?
> 
>  drivers/mtd/nand/fsl_ifc_nand.c | 23 ++++++++++-------------
>  1 file changed, 10 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
> index 4872a7b..f0b4ecd 100644
> --- a/drivers/mtd/nand/fsl_ifc_nand.c
> +++ b/drivers/mtd/nand/fsl_ifc_nand.c
> @@ -173,14 +173,9 @@ static void set_addr(struct mtd_info *mtd, int
> column, int page_addr, int oob)
> 
>  /* returns nonzero if entire page is blank */  static int check_read_ecc(struct
> mtd_info *mtd, struct fsl_ifc_ctrl *ctrl,
> -			  u32 *eccstat, unsigned int bufnum)
> +			  u32 eccstat, unsigned int bufnum)
>  {
> -	u32 reg = eccstat[bufnum / 4];
> -	int errors;
> -
> -	errors = (reg >> ((3 - bufnum % 4) * 8)) & 15;
> -
> -	return errors;
> +	return  (eccstat >> ((3 - bufnum % 4) * 8)) & 15;
>  }
> 
>  /*
> @@ -193,7 +188,7 @@ static void fsl_ifc_run_command(struct mtd_info
> *mtd)
>  	struct fsl_ifc_ctrl *ctrl = priv->ctrl;
>  	struct fsl_ifc_nand_ctrl *nctrl = ifc_nand_ctrl;
>  	struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;
> -	u32 eccstat[4];
> +	u32 eccstat;
>  	int i;
> 
>  	/* set the chip select for NAND Transaction */ @@ -228,8 +223,8 @@
> static void fsl_ifc_run_command(struct mtd_info *mtd)
>  	if (nctrl->eccread) {
>  		int errors;
>  		int bufnum = nctrl->page & priv->bufnum_mask;
> -		int sector = bufnum * chip->ecc.steps;
> -		int sector_end = sector + chip->ecc.steps - 1;
> +		int sector_start = bufnum * chip->ecc.steps;
> +		int sector_end = sector_start + chip->ecc.steps - 1;
>  		__be32 *eccstat_regs;
> 
>  		if (ctrl->version >= FSL_IFC_VERSION_2_0_0) @@ -237,10
> +232,12 @@ static void fsl_ifc_run_command(struct mtd_info *mtd)
>  		else
>  			eccstat_regs = ifc->ifc_nand.v1_nand_eccstat;
> 
> -		for (i = sector / 4; i <= sector_end / 4; i++)
> -			eccstat[i] = ifc_in32(&eccstat_regs[i]);
> +		eccstat = ifc_in32(&eccstat_regs[sector_start / 4]);
> +
> +		for (i = sector_start; i <= sector_end; i++) {
> +			if ((i != sector_start) && !(i % 4))
> +				eccstat = ifc_in32(&eccstat_regs[i / 4]);
> 
> -		for (i = sector; i <= sector_end; i++) {
>  			errors = check_read_ecc(mtd, ctrl, eccstat, i);
> 
>  			if (errors == 15) {
> --
> 1.9.1

Thanks,
Jagdish

Re: [PATCH][v5] mtd: rawnand: fsl_ifc: Fix eccstat array overflow for IFC ver >= 2.0.0

[Boris Brezillon]

On Fri, 23 Mar 2018 05:04:15 +0000
Jagdish Gediya <jagdish.gediya@nxp.com> wrote:

> Hi Boris,
> 
> > -----Original Message-----
> > From: Jagdish Gediya
> > Sent: Thursday, March 22, 2018 3:36 AM
> > To: linux-mtd@lists.infradead.org
> > Cc: boris.brezillon@free-electrons.com; computersforpeace@gmail.com;
> > oss@buserror.net; Leo Li <leoyang.li@nxp.com>; Jagdish Gediya
> > <jagdish.gediya@nxp.com>; stable@vger.kernel.org; Prabhakar Kushwaha
> > <prabhakar.kushwaha@nxp.com>
> > Subject: [PATCH][v5] mtd: rawnand: fsl_ifc: Fix eccstat array overflow for IFC
> > ver >= 2.0.0
> > 
> > Number of ECC status registers i.e. (ECCSTATx) has been increased in IFC
> > version 2.0.0 due to increase in SRAM size. This is causing eccstat array to over
> > flow.
> > 
> > So, replace eccstat array with u32 variable to make it fail-safe and independent
> > of number of ECC status registers or SRAM size.
> > 
> > Fixes: bccb06c353af ("mtd: nand: ifc: update bufnum mask for ver >= 2.0.0")
> > Cc: stable@vger.kernel.org # 3.18+
> > Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
> > Signed-off-by: Jagdish Gediya <jagdish.gediya@nxp.com>
> > ---
> > Changes for v2: Incorporated comments from Miquel Raynal and Boris Brezillon
> >         - Updated patch subject
> >         - Remove usage of eccstat array
> >         - Added Cc: stable@vger.kernel.org
> > 
> > Changes for v3: Incorporated comments from Boris Brezillon
> >         - Added fixes tag
> > 
> > Changes for v4: Incorporated comments from Boris Brezillon
> > 
> > Changes for v5: Incorporated comments from Boris Brezillon  
> 
> I am seeing this patch[v5]'s state as superseded @ https://patchwork.ozlabs.org/project/linux-mtd/list/?series=&submitter=73665&state=9&q=&archive=&delegate= , May I know the reason?

Because I applied v4 (+ the modification I suggested) before you sent
v5.

I just pushed the mtd/fixes branch [1] and I'm planning to send a fixes
PR to Linus later today.

Regards,

Boris

[1]http://git.infradead.org/linux-mtd.git/shortlog/refs/heads/master

> > 
> >  drivers/mtd/nand/fsl_ifc_nand.c | 23 ++++++++++-------------
> >  1 file changed, 10 insertions(+), 13 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
> > index 4872a7b..f0b4ecd 100644
> > --- a/drivers/mtd/nand/fsl_ifc_nand.c
> > +++ b/drivers/mtd/nand/fsl_ifc_nand.c
> > @@ -173,14 +173,9 @@ static void set_addr(struct mtd_info *mtd, int
> > column, int page_addr, int oob)
> > 
> >  /* returns nonzero if entire page is blank */  static int check_read_ecc(struct
> > mtd_info *mtd, struct fsl_ifc_ctrl *ctrl,
> > -			  u32 *eccstat, unsigned int bufnum)
> > +			  u32 eccstat, unsigned int bufnum)
> >  {
> > -	u32 reg = eccstat[bufnum / 4];
> > -	int errors;
> > -
> > -	errors = (reg >> ((3 - bufnum % 4) * 8)) & 15;
> > -
> > -	return errors;
> > +	return  (eccstat >> ((3 - bufnum % 4) * 8)) & 15;
> >  }
> > 
> >  /*
> > @@ -193,7 +188,7 @@ static void fsl_ifc_run_command(struct mtd_info
> > *mtd)
> >  	struct fsl_ifc_ctrl *ctrl = priv->ctrl;
> >  	struct fsl_ifc_nand_ctrl *nctrl = ifc_nand_ctrl;
> >  	struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;
> > -	u32 eccstat[4];
> > +	u32 eccstat;
> >  	int i;
> > 
> >  	/* set the chip select for NAND Transaction */ @@ -228,8 +223,8 @@
> > static void fsl_ifc_run_command(struct mtd_info *mtd)
> >  	if (nctrl->eccread) {
> >  		int errors;
> >  		int bufnum = nctrl->page & priv->bufnum_mask;
> > -		int sector = bufnum * chip->ecc.steps;
> > -		int sector_end = sector + chip->ecc.steps - 1;
> > +		int sector_start = bufnum * chip->ecc.steps;
> > +		int sector_end = sector_start + chip->ecc.steps - 1;
> >  		__be32 *eccstat_regs;
> > 
> >  		if (ctrl->version >= FSL_IFC_VERSION_2_0_0) @@ -237,10
> > +232,12 @@ static void fsl_ifc_run_command(struct mtd_info *mtd)
> >  		else
> >  			eccstat_regs = ifc->ifc_nand.v1_nand_eccstat;
> > 
> > -		for (i = sector / 4; i <= sector_end / 4; i++)
> > -			eccstat[i] = ifc_in32(&eccstat_regs[i]);
> > +		eccstat = ifc_in32(&eccstat_regs[sector_start / 4]);
> > +
> > +		for (i = sector_start; i <= sector_end; i++) {
> > +			if ((i != sector_start) && !(i % 4))
> > +				eccstat = ifc_in32(&eccstat_regs[i / 4]);
> > 
> > -		for (i = sector; i <= sector_end; i++) {
> >  			errors = check_read_ecc(mtd, ctrl, eccstat, i);
> > 
> >  			if (errors == 15) {
> > --
> > 1.9.1  
> 
> Thanks,
> Jagdish



-- 
Boris Brezillon, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com