mailbox: pcc: fix channel calculation in get_pcc_channel()

This patch fixes the calculation of pcc_chan for non-zero id.
After the compiler ignores the (unsigned long) cast the
pcc_mbox_channels pointer is type-cast and then the type-cast
offset is added which results in address outside of the range
leading to the kernel crashing.

We might add braces and make it:

pcc_chan = (struct mbox_chan *)
		((unsigned long) pcc_mbox_channels +
		(id * sizeof(*pcc_chan)));

but let's go with array approach here and use id as index.

Tested on Juno board.

Signed-off-by: Alexey Klimov <alexey.klimov@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 45d85aea9955404d0c4567f33863e0e3f500674f..8f779a1ec99c4b248c9721fceef19b579432539b 100644 (file)
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -81,16 +81,10 @@ static struct mbox_controller pcc_mbox_ctrl = {};
  */
 static struct mbox_chan *get_pcc_channel(int id)
 {
-       struct mbox_chan *pcc_chan;
-
        if (id < 0 || id > pcc_mbox_ctrl.num_chans)
                return ERR_PTR(-ENOENT);
 
-       pcc_chan = (struct mbox_chan *)
-               (unsigned long) pcc_mbox_channels +
-               (id * sizeof(*pcc_chan));
-
-       return pcc_chan;
+       return &pcc_mbox_channels[id];
 }
 
 /**