xhci: fix even more unsafe memory usage in xhci tracing

Removes static char buffer usage in the following decode functions:
	xhci_decode_ctrl_ctx()
	xhci_decode_slot_context()
	xhci_decode_usbsts()
	xhci_decode_doorbell()
	xhci_decode_ep_context()

Caller must provide a buffer to use.
In tracing use __get_str() as recommended to pass buffer.

Minor changes are needed in other xhci code as these functions are also
used elsewhere

Cc: <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210820123503.2605901-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 13 deletions

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 99ae9994f5eb..dca6181c33fd 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -2460,10 +2460,9 @@ static inline const char *xhci_decode_trb(char *str, size_t size,
 	return str;
 }
 
-static inline const char *xhci_decode_ctrl_ctx(unsigned long drop,
-					       unsigned long add)
+static inline const char *xhci_decode_ctrl_ctx(char *str,
+		unsigned long drop, unsigned long add)
 {
-	static char	str[1024];
 	unsigned int	bit;
 	int		ret = 0;
 
@@ -2489,10 +2488,9 @@ static inline const char *xhci_decode_ctrl_ctx(unsigned long drop,
 	return str;
 }
 
-static inline const char *xhci_decode_slot_context(u32 info, u32 info2,
-		u32 tt_info, u32 state)
+static inline const char *xhci_decode_slot_context(char *str,
+		u32 info, u32 info2, u32 tt_info, u32 state)
 {
-	static char str[1024];
 	u32 speed;
 	u32 hub;
 	u32 mtt;
@@ -2621,9 +2619,8 @@ static inline const char *xhci_decode_portsc(char *str, u32 portsc)
 	return str;
 }
 
-static inline const char *xhci_decode_usbsts(u32 usbsts)
+static inline const char *xhci_decode_usbsts(char *str, u32 usbsts)
 {
-	static char str[256];
 	int ret = 0;
 
 	if (usbsts == ~(u32)0)
@@ -2650,9 +2647,8 @@ static inline const char *xhci_decode_usbsts(u32 usbsts)
 	return str;
 }
 
-static inline const char *xhci_decode_doorbell(u32 slot, u32 doorbell)
+static inline const char *xhci_decode_doorbell(char *str, u32 slot, u32 doorbell)
 {
-	static char str[256];
 	u8 ep;
 	u16 stream;
 	int ret;
@@ -2719,10 +2715,9 @@ static inline const char *xhci_ep_type_string(u8 type)
 	}
 }
 
-static inline const char *xhci_decode_ep_context(u32 info, u32 info2, u64 deq,
-		u32 tx_info)
+static inline const char *xhci_decode_ep_context(char *str, u32 info,
+		u32 info2, u64 deq, u32 tx_info)
 {
-	static char str[1024];
 	int ret;
 
 	u32 esit;