From: Greg Kroah-Hartman <gre...@linuxfoundation.org>
From: Ian Abbott <abbo...@mev.co.uk>
commit 25317f428a78fde71b2bf3f24d05850f08a73a52 upstream.
The Change-Of-State (COS) subdevice supports Comedi asynchronous
commands to read 16-bit change-of-state values. However, the interrupt
handler is calling `comedi_buf_write_samples()` with the address of a
32-bit integer `&s->state`. On bigendian architectures, it will copy 2
bytes from the wrong end of the 32-bit integer. Fix it by transferring
the value via a 16-bit integer.
Fixes: 6bb45f2b0c86 ("staging: comedi: addi_apci_1032: use
comedi_buf_write_samples()")
Cc: <sta...@vger.kernel.org> # 3.19+
Signed-off-by: Ian Abbott <abbo...@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-2-abbo...@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/addi_apci_1032.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/staging/comedi/drivers/addi_apci_1032.c
+++ b/drivers/staging/comedi/drivers/addi_apci_1032.c
@@ -269,6 +269,7 @@ static irqreturn_t apci1032_interrupt(in
struct apci1032_private *devpriv = dev->private;
struct comedi_subdevice *s = dev->read_subdev;
unsigned int ctrl;
+ unsigned short val;
/* check interrupt is from this device */
if ((inl(devpriv->amcc_iobase + AMCC_OP_REG_INTCSR) &
@@ -284,7 +285,8 @@ static irqreturn_t apci1032_interrupt(in
outl(ctrl & ~APCI1032_CTRL_INT_ENA, dev->iobase + APCI1032_CTRL_REG);
s->state = inl(dev->iobase + APCI1032_STATUS_REG) & 0xffff;
- comedi_buf_write_samples(s, &s->state, 1);
+ val = s->state;
+ comedi_buf_write_samples(s, &val, 1);
comedi_handle_events(dev, s);
/* enable the interrupt */
