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Commit 5937f182 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
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staging: comedi: addi_apci_1500: Fix endian problem for command sample 



commit ac0bbf55ed3be75fde1f8907e91ecd2fd589bde3 upstream.

The digital input subdevice supports Comedi asynchronous commands that
read interrupt status information.  This uses 16-bit Comedi samples (of
which only the bottom 8 bits contain status information).  However, the
interrupt handler is calling `comedi_buf_write_samples()` with the
address of a 32-bit variable `unsigned int status`.  On a bigendian
machine, this will copy 2 bytes from the wrong end of the variable.  Fix
it by changing the type of the variable to `unsigned short`.

Fixes: a8c66b68 ("staging: comedi: addi_apci_1500: rewrite the subdevice support functions")
Cc: <stable@vger.kernel.org> #4.0+
Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-3-abbotti@mev.co.uk


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4e384bd9

drivers/staging/comedi/drivers/addi_apci_1500.c

+9 −9
Original line number Original line Diff line number Diff line
@@ -217,7 +217,7 @@ static irqreturn_t apci1500_interrupt(int irq, void *d) 
	struct comedi_device *dev = d;

	struct comedi_device *dev = d;

	struct apci1500_private *devpriv = dev->private;

	struct apci1500_private *devpriv = dev->private;

	struct comedi_subdevice *s = dev->read_subdev;

	struct comedi_subdevice *s = dev->read_subdev;

	unsigned int status = 0;

	unsigned short status = 0;

	unsigned int val;

	unsigned int val;





	val = inl(devpriv->amcc + AMCC_OP_REG_INTCSR);

	val = inl(devpriv->amcc + AMCC_OP_REG_INTCSR);
@@ -247,14 +247,14 @@ static irqreturn_t apci1500_interrupt(int irq, void *d) 
	 *

	 *

	 *    Mask     Meaning

	 *    Mask     Meaning

	 * ----------  ------------------------------------------

	 * ----------  ------------------------------------------

	 * 0x00000001  Event 1 has occurred

	 * 0b00000001  Event 1 has occurred

	 * 0x00000010  Event 2 has occurred

	 * 0b00000010  Event 2 has occurred

	 * 0x00000100  Counter/timer 1 has run down (not implemented)

	 * 0b00000100  Counter/timer 1 has run down (not implemented)

	 * 0x00001000  Counter/timer 2 has run down (not implemented)

	 * 0b00001000  Counter/timer 2 has run down (not implemented)

	 * 0x00010000  Counter 3 has run down (not implemented)

	 * 0b00010000  Counter 3 has run down (not implemented)

	 * 0x00100000  Watchdog has run down (not implemented)

	 * 0b00100000  Watchdog has run down (not implemented)

	 * 0x01000000  Voltage error

	 * 0b01000000  Voltage error

	 * 0x10000000  Short-circuit error

	 * 0b10000000  Short-circuit error

	 */

	 */

	comedi_buf_write_samples(s, &status, 1);

	comedi_buf_write_samples(s, &status, 1);

	comedi_handle_events(dev, s);

	comedi_handle_events(dev, s);