[PATCH 4.14 159/191] mic: vop: copy data to kernel space then write to io memory

[Greg Kroah-Hartman]

From: Sherry Sun <sherry.sun@xxxxxxx>

[ Upstream commit 675f0ad4046946e80412896436164d172cd92238 ]

Read and write io memory should address align on ARCH ARM. Change to use
memcpy_toio to avoid kernel panic caused by the address un-align issue.

Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
Link: https://lore.kernel.org/r/20200929091106.24624-5-sherry.sun@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/misc/mic/vop/vop_vringh.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/misc/mic/vop/vop_vringh.c b/drivers/misc/mic/vop/vop_vringh.c
index fed992e2c2583..99bde52a3a256 100644
--- a/drivers/misc/mic/vop/vop_vringh.c
+++ b/drivers/misc/mic/vop/vop_vringh.c
@@ -611,6 +611,7 @@ static int vop_virtio_copy_from_user(struct vop_vdev *vdev, void __user *ubuf,
 	size_t partlen;
 	bool dma = VOP_USE_DMA;
 	int err = 0;
+	size_t offset = 0;
 
 	if (daddr & (dma_alignment - 1)) {
 		vdev->tx_dst_unaligned += len;
@@ -659,13 +660,20 @@ static int vop_virtio_copy_from_user(struct vop_vdev *vdev, void __user *ubuf,
 	 * We are copying to IO below and should ideally use something
 	 * like copy_from_user_toio(..) if it existed.
 	 */
-	if (copy_from_user((void __force *)dbuf, ubuf, len)) {
-		err = -EFAULT;
-		dev_err(vop_dev(vdev), "%s %d err %d\n",
-			__func__, __LINE__, err);
-		goto err;
+	while (len) {
+		partlen = min_t(size_t, len, VOP_INT_DMA_BUF_SIZE);
+
+		if (copy_from_user(vvr->buf, ubuf + offset, partlen)) {
+			err = -EFAULT;
+			dev_err(vop_dev(vdev), "%s %d err %d\n",
+				__func__, __LINE__, err);
+			goto err;
+		}
+		memcpy_toio(dbuf + offset, vvr->buf, partlen);
+		offset += partlen;
+		vdev->out_bytes += partlen;
+		len -= partlen;
 	}
-	vdev->out_bytes += len;
 	err = 0;
 err:
 	vpdev->hw_ops->iounmap(vpdev, dbuf);
-- 
2.25.1