[ Upstream commit bc83f79bd2119230888fb8574639d5a51b38f903 ]
Generally, declaring a platform device as a static variable is
a bad idea and can cause all kinds of problems, in particular
with the DMA configuration and lifetime rules.
A specific problem we hit here is from a bug in clang that warns
about certain (otherwise valid) macros when used in static variables:
drivers/misc/mic/card/mic_x100.c:285:27: warning: shift count >= width of type [-Wshift-count-overflow]
static u64 mic_dma_mask = DMA_BIT_MASK(64);
^~~~~~~~~~~~~~~~
include/linux/dma-mapping.h:141:54: note: expanded from macro 'DMA_BIT_MASK'
#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
^ ~~~
A slightly better way here is to create the platform device dynamically
and set the dma mask in the probe function.
This avoids the warning and some other problems, but is still not ideal
because the device creation should really be separated from the driver,
and the fact that the device has no parent means we have to force
the dma mask rather than having it set up from the bus that the device
is actually on.
Fixes: dd8d8d44df64 ("misc: mic: MIC card driver specific changes to enable SCIF")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20190712092426.872625-1-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6b995f4eec34745f6cb20d66d5277611f0b3c3fa ]
In _scif_prog_signal(), the boolean variable 'x100' is used to indicate
whether the MIC Coprocessor is X100. If 'x100' is true, the status
descriptor will be used to write the value to the destination. Otherwise, a
DMA pool will be allocated for this purpose. Specifically, if the DMA pool
is allocated successfully, two memory addresses will be returned. One is
for the CPU and the other is for the device to access the DMA pool. The
former is stored to the variable 'status' and the latter is stored to the
variable 'src'. After the allocation, the address in 'src' is saved to
'status->src_dma_addr', which is actually in the DMA pool, and 'src' is
then modified.
Later on, if an error occurs, the execution flow will transfer to the label
'dma_fail', which will check 'x100' and free up the allocated DMA pool if
'x100' is false. The point here is that 'status->src_dma_addr' is used for
freeing up the DMA pool. As mentioned before, 'status->src_dma_addr' is in
the DMA pool. And thus, the device is able to modify this data. This can
potentially cause failures when freeing up the DMA pool because of the
modified device address.
This patch avoids the above issue by using the variable 'src' (with
necessary calculation) to free up the DMA pool.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
