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[v2,1/3] usb: cdns3: gadget: suspicious implicit sign extension

Message ID 20201022005505.24167-2-peter.chen@nxp.com
State New
Headers show
Series usb: cdns3: three bug fixes for v5.10 | expand

Commit Message

Peter Chen Oct. 22, 2020, 12:55 a.m. UTC 
The code:
trb->length = cpu_to_le32(TRB_BURST_LEN(priv_ep->trb_burst_size)
	       	| TRB_LEN(length));

TRB_BURST_LEN(priv_ep->trb_burst_size) may be overflow for int 32 if
priv_ep->trb_burst_size is equal or larger than 0x80;

Below is the Coverity warning:
sign_extension: Suspicious implicit sign extension: priv_ep->trb_burst_size
with type u8 (8 bits, unsigned) is promoted in priv_ep->trb_burst_size << 24
to type int (32 bits, signed), then sign-extended to type unsigned long
(64 bits, unsigned). If priv_ep->trb_burst_size << 24 is greater than 0x7FFFFFFF,
the upper bits of the result will all be 1.

To fix it, it needs to add an explicit cast to unsigned int type for ((p) << 24).

Reviewed-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
---
Changes for v2:
- Move position of explicit cast to unsigned int before ((p) << 24) [Patch 1/3]

 drivers/usb/cdns3/gadget.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/usb/cdns3/gadget.h b/drivers/usb/cdns3/gadget.h
index 1ccecd237530..737377913788 100644
--- a/drivers/usb/cdns3/gadget.h
+++ b/drivers/usb/cdns3/gadget.h
@@ -1072,7 +1072,7 @@  struct cdns3_trb {
 #define TRB_TDL_SS_SIZE_GET(p)	(((p) & GENMASK(23, 17)) >> 17)
 
 /* transfer_len bitmasks - bits 31:24 */
-#define TRB_BURST_LEN(p)	(((p) << 24) & GENMASK(31, 24))
+#define TRB_BURST_LEN(p)	((unsigned int)((p) << 24) & GENMASK(31, 24))
 #define TRB_BURST_LEN_GET(p)	(((p) & GENMASK(31, 24)) >> 24)
 
 /* Data buffer pointer bitmasks*/