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patch "usb: dwc2: Fix DMA cache alignment issues" added to usb-linus

PATCH [email protected] 1 participant 1 message Jun 8, 2019

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Stable branch USB DesignWare USB2 DRD IP driver
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This is a note to let you know that I've just added the patch titled

usb: dwc2: Fix DMA cache alignment issues

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 4a4863bf2e7932e584a3a462d3c6daf891142ddc Mon Sep 17 00:00:00 2001
From: Martin Schiller <[email protected]>
Date: Mon, 18 Feb 2019 07:37:30 +0100
Subject: usb: dwc2: Fix DMA cache alignment issues

Insert a padding between data and the stored_xfer_buffer pointer to ensure they are not on the same cache line.

Otherwise, the stored_xfer_buffer gets corrupted for IN URBs on non-cache-coherent systems. (In my case: Lantiq xRX200 MIPS)

Fixes 3bc04e28a030 ("usb: dwc2: host: Get aligned DMA in a more supported way")
Fixes 56406e017a88 ("usb: dwc2: Fix DMA alignment to start at allocated boundary")
Cc <[email protected]>
Tested-by Douglas Anderson <[email protected]>
Reviewed-by Douglas Anderson <[email protected]>
Acked-by Minas Harutyunyan <[email protected]>
Signed-off-by Martin Schiller <[email protected]>
Signed-off-by Felipe Balbi <[email protected]>
---
 drivers/usb/dwc2/hcd.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
drivers/usb/dwc2/hcd.c +7 -3
index 5c51bf5506d1..2192a2873c7c 100644
@@ -2480,8 +2480,10 @@ static void dwc2_free_dma_aligned_buffer(struct urb *urb)
 		return;
 
 	/* Restore urb->transfer_buffer from the end of the allocated area */
-	memcpy(&stored_xfer_buffer, urb->transfer_buffer +
-	       urb->transfer_buffer_length, sizeof(urb->transfer_buffer));
+	memcpy(&stored_xfer_buffer,
+	       PTR_ALIGN(urb->transfer_buffer + urb->transfer_buffer_length,
+			 dma_get_cache_alignment()),
+	       sizeof(urb->transfer_buffer));
 
 	if (usb_urb_dir_in(urb)) {
 		if (usb_pipeisoc(urb->pipe))

@@ -2513,6 +2515,7 @@ static int dwc2_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
 	 * DMA
 	 */
 	kmalloc_size = urb->transfer_buffer_length +
+		(dma_get_cache_alignment() - 1) +
 		sizeof(urb->transfer_buffer);
 
 	kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);

@@ -2523,7 +2526,8 @@ static int dwc2_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
 	 * Position value of original urb->transfer_buffer pointer to the end
 	 * of allocation for later referencing
 	 */
-	memcpy(kmalloc_ptr + urb->transfer_buffer_length,
+	memcpy(PTR_ALIGN(kmalloc_ptr + urb->transfer_buffer_length,
+			 dma_get_cache_alignment()),
 	       &urb->transfer_buffer, sizeof(urb->transfer_buffer));
 
 	if (usb_urb_dir_out(urb))
Signature · 1 line
2.21.0