Unverified Commit 8868c03f authored by Pratyush Yadav's avatar Pratyush Yadav Committed by Mark Brown
Browse files

spi: spi-mem: check if data buffers are on stack 



The buffers passed in the data phase must be DMA-able. Programmers often
don't realise this requirement and pass in buffers that reside on the
stack. This can be hard to spot when reviewing code. Reject ops if their
data buffer is on the stack to avoid this.

Signed-off-by: default avatarPratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/20220420102022.3310970-1-p.yadav@ti.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 8c235cc2

drivers/spi/spi-mem.c

+10 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/pm_runtime.h>

#include <linux/spi/spi.h>

#include <linux/spi/spi-mem.h>

#include <linux/sched/task_stack.h>



#include "internals.h"
@@ -211,6 +212,15 @@ static int spi_mem_check_op(const struct spi_mem_op *op) 
	    !spi_mem_buswidth_is_valid(op->data.buswidth))

		return -EINVAL;



	/* Buffers must be DMA-able. */

	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_IN &&

			 object_is_on_stack(op->data.buf.in)))

		return -EINVAL;



	if (WARN_ON_ONCE(op->data.dir == SPI_MEM_DATA_OUT &&

			 object_is_on_stack(op->data.buf.out)))

		return -EINVAL;



	return 0;

}