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

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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: Pratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/20220420102022.3310970-1-p.yadav@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Pratyush Yadav 2022-04-20 15:50:22 +05:30 committed by Mark Brown
parent 8c235cc250
commit 8868c03f3c
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1 changed files with 10 additions and 0 deletions
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10
drivers/spi/spi-mem.c
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@ -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;
}