The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 000412276370a9bcfec73b3752ceefd9a927f1db Mon Sep 17 00:00:00 2001

From: Ahmad Fatoum a.fatoum@pengutronix.de Date: Fri, 21 Sep 2018 11:32:53 +0200 Subject: [PATCH] mtd: spi-nor: fsl-quadspi: Don't let -EINVAL on the bus

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.

Fixes: e46ecda764dc ("mtd: spi-nor: Add Freescale QuadSPI driver") Cc: stable@vger.kernel.org Signed-off-by: Ahmad Fatoum a.fatoum@pengutronix.de Signed-off-by: Boris Brezillon boris.brezillon@bootlin.com

diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c index 7d9620c7ff6c..d1ace310e7c1 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 +699,13 @@ 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 +813,7 @@ 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[] = {