[PATCH 4.12 31/31] mmc: tmio-mmc: fix bad pointer math

Greg Kroah-Hartman
2017-08-03T23:18:43Z

From: Chris Brandt <chris.brandt@renesas.com>

commit 9c284c41c0886f09e75c323a16278b6d353b0b4a upstream.

The existing code gives an incorrect pointer value.
The buffer pointer 'buf' was of type unsigned short *, and 'count' was a
number in bytes. A cast of buf should have been used.

However, instead of casting, just change the code to use u32 pointers.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 8185e51f358a: ("mmc: tmio-mmc: add support for 32bit data port")
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mmc/host/tmio_mmc_pio.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)

--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -404,30 +404,29 @@ static void tmio_mmc_transfer_data(struc
* Transfer the data
*/
if (host->pdata->flags & TMIO_MMC_32BIT_DATA_PORT) {
- u8 data[4] = { };
+ u32 data = 0;
+ u32 *buf32 = (u32 *)buf;

if (is_read)
- sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT, (u32 *)buf,
+ sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT, buf32,
count >> 2);
else
- sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, (u32 *)buf,
+ sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, buf32,
count >> 2);

/* if count was multiple of 4 */
if (!(count & 0x3))
return;

- buf8 = (u8 *)(buf + (count >> 2));
+ buf32 += count >> 2;
count %= 4;

if (is_read) {
- sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT,
- (u32 *)data, 1);
- memcpy(buf8, data, count);
+ sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT, &data, 1);
+ memcpy(buf32, &data, count);
} else {
- memcpy(data, buf8, count);
- sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT,
- (u32 *)data, 1);
+ memcpy(&data, buf32, count);
+ sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, &data, 1);
}

return;