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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2021-01-29 15:00:29 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-29 14:16:50 +0100 |
| commit | 0353810a047ef0101af01665f60597d7f5cc6b02 (patch) | |
| tree | 57dfb5e32ef43466986f38c12ed6598a13c5a0fa /drivers | |
| parent | 55f6153d8cc8eff0852d108f80087fdf41dc2169 (diff) | |
| download | linux-0353810a047ef0101af01665f60597d7f5cc6b02.tar.gz linux-0353810a047ef0101af01665f60597d7f5cc6b02.tar.bz2 linux-0353810a047ef0101af01665f60597d7f5cc6b02.zip | |
xhci: avoid DMA double fetch when reading event trb type.
Instead of re-reading, masking and endianness correcting the same trb
several times to get the trb type from an event, just do it once and
store it in a local variable.
Also pass the trb_type directly to the vendor specific event handler,
avoiding one more similar read.
In addition to the security benefit this also cleans up the code
and helps readability.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-13-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/host/xhci-ring.c | 27 | ||||
| -rw-r--r-- | drivers/usb/host/xhci.h | 2 |
2 files changed, 13 insertions, 16 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 372a3c98db97..a078f465770f 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1564,11 +1564,8 @@ event_handled: } static void handle_vendor_event(struct xhci_hcd *xhci, - union xhci_trb *event) + union xhci_trb *event, u32 trb_type) { - u32 trb_type; - - trb_type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->generic.field[3])); xhci_dbg(xhci, "Vendor specific event TRB type = %u\n", trb_type); if (trb_type == TRB_NEC_CMD_COMP && (xhci->quirks & XHCI_NEC_HOST)) handle_cmd_completion(xhci, &event->event_cmd); @@ -2733,6 +2730,7 @@ static int xhci_handle_event(struct xhci_hcd *xhci) { union xhci_trb *event; int update_ptrs = 1; + u32 trb_type; int ret; /* Event ring hasn't been allocated yet. */ @@ -2754,31 +2752,30 @@ static int xhci_handle_event(struct xhci_hcd *xhci) * speculative reads of the event's flags/data below. */ rmb(); + trb_type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags)); /* FIXME: Handle more event types. */ - switch (le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK) { - case TRB_TYPE(TRB_COMPLETION): + + switch (trb_type) { + case TRB_COMPLETION: handle_cmd_completion(xhci, &event->event_cmd); break; - case TRB_TYPE(TRB_PORT_STATUS): + case TRB_PORT_STATUS: handle_port_status(xhci, event); update_ptrs = 0; break; - case TRB_TYPE(TRB_TRANSFER): + case TRB_TRANSFER: ret = handle_tx_event(xhci, &event->trans_event); if (ret >= 0) update_ptrs = 0; break; - case TRB_TYPE(TRB_DEV_NOTE): + case TRB_DEV_NOTE: handle_device_notification(xhci, event); break; default: - if ((le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK) >= - TRB_TYPE(48)) - handle_vendor_event(xhci, event); + if (trb_type >= TRB_VENDOR_DEFINED_LOW) + handle_vendor_event(xhci, event, trb_type); else - xhci_warn(xhci, "ERROR unknown event type %d\n", - TRB_FIELD_TO_TYPE( - le32_to_cpu(event->event_cmd.flags))); + xhci_warn(xhci, "ERROR unknown event type %d\n", trb_type); } /* Any of the above functions may drop and re-acquire the lock, so check * to make sure a watchdog timer didn't mark the host as non-responsive. diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index b28a2d9fe35e..87af91447985 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1419,7 +1419,7 @@ union xhci_trb { /* MFINDEX Wrap Event - microframe counter wrapped */ #define TRB_MFINDEX_WRAP 39 /* TRB IDs 40-47 reserved, 48-63 is vendor-defined */ - +#define TRB_VENDOR_DEFINED_LOW 48 /* Nec vendor-specific command completion event. */ #define TRB_NEC_CMD_COMP 48 /* Get NEC firmware revision. */ |