diff mbox series

[5.4,29/37] usb: mtu3: add memory barrier before set GPDs HWO

Message ID 20220103142052.771639311@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH Jan. 3, 2022, 2:24 p.m. UTC 
From: Chunfeng Yun <chunfeng.yun@mediatek.com>

commit a7aae769ca626819a7f9f078ebdc69a8a1b00c81 upstream.

There is a seldom issue that the controller access invalid address
and trigger devapc or emimpu violation. That is due to memory access
is out of order and cause gpd data is not correct.
Add mb() to prohibit compiler or cpu from reordering to make sure GPD
is fully written before setting its HWO.

Fixes: 48e0d3735aa5 ("usb: mtu3: supports new QMU format")
Cc: stable@vger.kernel.org
Reported-by: Eddie Hung <eddie.hung@mediatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20211218095749.6250-2-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/mtu3/mtu3_qmu.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/usb/mtu3/mtu3_qmu.c
+++ b/drivers/usb/mtu3/mtu3_qmu.c
@@ -273,6 +273,8 @@  static int mtu3_prepare_tx_gpd(struct mt
 			gpd->dw3_info |= cpu_to_le32(GPD_EXT_FLAG_ZLP);
 	}
 
+	/* prevent reorder, make sure GPD's HWO is set last */
+	mb();
 	gpd->dw0_info |= cpu_to_le32(GPD_FLAGS_IOC | GPD_FLAGS_HWO);
 
 	mreq->gpd = gpd;
@@ -306,6 +308,8 @@  static int mtu3_prepare_rx_gpd(struct mt
 	gpd->next_gpd = cpu_to_le32(lower_32_bits(enq_dma));
 	ext_addr |= GPD_EXT_NGP(mtu, upper_32_bits(enq_dma));
 	gpd->dw3_info = cpu_to_le32(ext_addr);
+	/* prevent reorder, make sure GPD's HWO is set last */
+	mb();
 	gpd->dw0_info |= cpu_to_le32(GPD_FLAGS_IOC | GPD_FLAGS_HWO);
 
 	mreq->gpd = gpd;
@@ -445,7 +449,8 @@  static void qmu_tx_zlp_error_handler(str
 		return;
 	}
 	mtu3_setbits(mbase, MU3D_EP_TXCR0(mep->epnum), TX_TXPKTRDY);
-
+	/* prevent reorder, make sure GPD's HWO is set last */
+	mb();
 	/* by pass the current GDP */
 	gpd_current->dw0_info |= cpu_to_le32(GPD_FLAGS_BPS | GPD_FLAGS_HWO);