From: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Date: Mon, 2 Feb 2015 10:06:56 +0000 (+0100)
Subject: spi/xilinx: Fix access invalid memory on xilinx_spi_tx
X-Git-Tag: firefly_0821_release~176^2~2405^2^2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=34093cb97abe9298a19a96b1b2f1714e28f8e67f;p=firefly-linux-kernel-4.4.55.git

spi/xilinx: Fix access invalid memory on xilinx_spi_tx

On 1 and 2 bytes per word, the transfer of the 3 last bytes will access
memory outside tx_ptr.

Although this has not trigger any error on real hardware, we should
better fix this.

Fixes: 24ba5e593f391507 (Remove rx_fn and tx_fn pointer)
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index d1901d578823..133f53a9c1d4 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -117,11 +117,26 @@ static unsigned int xspi_read32_be(void __iomem *addr)
 
 static void xilinx_spi_tx(struct xilinx_spi *xspi)
 {
+	u32 data = 0;
+
 	if (!xspi->tx_ptr) {
 		xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
 		return;
 	}
-	xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
+
+	switch (xspi->bytes_per_word) {
+	case 1:
+		data = *(u8 *)(xspi->tx_ptr);
+		break;
+	case 2:
+		data = *(u16 *)(xspi->tx_ptr);
+		break;
+	case 4:
+		data = *(u32 *)(xspi->tx_ptr);
+		break;
+	}
+
+	xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET);
 	xspi->tx_ptr += xspi->bytes_per_word;
 }