[PATCH] mtd: spi-nor: fsl-quadspi: Don't let -EINVAL on the bus

[PATCH] mtd: spi-nor: fsl-quadspi: Don't let -EINVAL on the bus

[Ahmad Fatoum]

fsl_qspi_get_seqid() may return -EINVAL, but fsl_qspi_init_ahb_read()
doesn't check for error codes with the result that -EINVAL could find
itself signalled over the bus.

In conjunction with the LS1046A SoC's A-009283 errata
("Illegal accesses to SPI flash memory can result in a system hang")
this illegal access to SPI flash memory results in a system hang
if userspace attempts reading later on.

Avoid this by always checking fsl_qspi_get_seqid()'s return value
and bail out otherwise.

Cc: stable@vger.kernel.org
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/mtd/spi-nor/fsl-quadspi.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c
index 7d9620c7ff6c..1bb42e40c38b 100644
--- a/drivers/mtd/spi-nor/fsl-quadspi.c
+++ b/drivers/mtd/spi-nor/fsl-quadspi.c
@@ -543,6 +543,9 @@ fsl_qspi_runcmd(struct fsl_qspi *q, u8 cmd, unsigned int addr, int len)
 
 	/* trigger the LUT now */
 	seqid = fsl_qspi_get_seqid(q, cmd);
+	if (seqid < 0)
+		return seqid;
+
 	qspi_writel(q, (seqid << QUADSPI_IPCR_SEQID_SHIFT) | len,
 			base + QUADSPI_IPCR);
 
@@ -671,7 +674,7 @@ static void fsl_qspi_set_map_addr(struct fsl_qspi *q)
  * causes the controller to clear the buffer, and use the sequence pointed
  * by the QUADSPI_BFGENCR[SEQID] to initiate a read from the flash.
  */
-static void fsl_qspi_init_ahb_read(struct fsl_qspi *q)
+static int fsl_qspi_init_ahb_read(struct fsl_qspi *q)
 {
 	void __iomem *base = q->iobase;
 	int seqid;
@@ -696,8 +699,12 @@ static void fsl_qspi_init_ahb_read(struct fsl_qspi *q)
 
 	/* Set the default lut sequence for AHB Read. */
 	seqid = fsl_qspi_get_seqid(q, q->nor[0].read_opcode);
+	if (seqid < 0)
+		return seqid;
+
 	qspi_writel(q, seqid << QUADSPI_BFGENCR_SEQID_SHIFT,
 		q->iobase + QUADSPI_BFGENCR);
+	return 0;
 }
 
 /* This function was used to prepare and enable QSPI clock */
@@ -805,9 +812,7 @@ static int fsl_qspi_nor_setup_last(struct fsl_qspi *q)
 	fsl_qspi_init_lut(q);
 
 	/* Init for AHB read */
-	fsl_qspi_init_ahb_read(q);
-
-	return 0;
+	return fsl_qspi_init_ahb_read(q);
 }
 
 static const struct of_device_id fsl_qspi_dt_ids[] = {
-- 
2.19.0

Re: [PATCH] mtd: spi-nor: fsl-quadspi: Don't let -EINVAL on the bus

[Boris Brezillon]

On Fri, 21 Sep 2018 11:32:53 +0200
Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:

> fsl_qspi_get_seqid() may return -EINVAL, but fsl_qspi_init_ahb_read()
> doesn't check for error codes with the result that -EINVAL could find
> itself signalled over the bus.
> 
> In conjunction with the LS1046A SoC's A-009283 errata
> ("Illegal accesses to SPI flash memory can result in a system hang")
> this illegal access to SPI flash memory results in a system hang
> if userspace attempts reading later on.
> 
> Avoid this by always checking fsl_qspi_get_seqid()'s return value
> and bail out otherwise.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

Added

Fixes: e46ecda764dc ("mtd: spi-nor: Add Freescale QuadSPI driver")

and queued it to spi-nor/next.

Thanks,

Boris

> ---
>  drivers/mtd/spi-nor/fsl-quadspi.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c
> index 7d9620c7ff6c..1bb42e40c38b 100644
> --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> @@ -543,6 +543,9 @@ fsl_qspi_runcmd(struct fsl_qspi *q, u8 cmd, unsigned int addr, int len)
>  
>  	/* trigger the LUT now */
>  	seqid = fsl_qspi_get_seqid(q, cmd);
> +	if (seqid < 0)
> +		return seqid;
> +
>  	qspi_writel(q, (seqid << QUADSPI_IPCR_SEQID_SHIFT) | len,
>  			base + QUADSPI_IPCR);
>  
> @@ -671,7 +674,7 @@ static void fsl_qspi_set_map_addr(struct fsl_qspi *q)
>   * causes the controller to clear the buffer, and use the sequence pointed
>   * by the QUADSPI_BFGENCR[SEQID] to initiate a read from the flash.
>   */
> -static void fsl_qspi_init_ahb_read(struct fsl_qspi *q)
> +static int fsl_qspi_init_ahb_read(struct fsl_qspi *q)
>  {
>  	void __iomem *base = q->iobase;
>  	int seqid;
> @@ -696,8 +699,12 @@ static void fsl_qspi_init_ahb_read(struct fsl_qspi *q)
>  
>  	/* Set the default lut sequence for AHB Read. */
>  	seqid = fsl_qspi_get_seqid(q, q->nor[0].read_opcode);
> +	if (seqid < 0)
> +		return seqid;
> +
>  	qspi_writel(q, seqid << QUADSPI_BFGENCR_SEQID_SHIFT,
>  		q->iobase + QUADSPI_BFGENCR);
> +	return 0;
>  }
>  
>  /* This function was used to prepare and enable QSPI clock */
> @@ -805,9 +812,7 @@ static int fsl_qspi_nor_setup_last(struct fsl_qspi *q)
>  	fsl_qspi_init_lut(q);
>  
>  	/* Init for AHB read */
> -	fsl_qspi_init_ahb_read(q);
> -
> -	return 0;
> +	return fsl_qspi_init_ahb_read(q);
>  }
>  
>  static const struct of_device_id fsl_qspi_dt_ids[] = {