diff options
| author | Stephen Warren <swarren@nvidia.com> | 2013-05-30 09:59:39 -0600 |
|---|---|---|
| committer | Jason Liu <r64343@freescale.com> | 2013-10-30 09:56:07 +0800 |
| commit | 42f079b7610d6dc1c13923579f3cce8ac077b1f6 (patch) | |
| tree | d8dc1a74c9560086390c1c67456b08a262782000 /include | |
| parent | 06958bcd9afe78bd920d142724e76c9f535aebbd (diff) | |
spi: fix undefined behaviour in SPI_BPW_RANGE_MASK
The parameters to SPI_BPW_RANGE_MASK() are in the range 1..32. If 32 is
used as a parameter, part of the expression is "1 << 32". Since 32 is >=
the size of the type in use, such a shift is undefined behaviour. Add
macro SPI_BIT_MASK to Implement a special case and thus avoid undefined
behaviour. Use this new macro rather than BIT() when implementing
SPI_BPW_RANGE_MASK().
This fixes build warnings such as:
drivers/spi/spi-gpio.c:446:2: warning: left shift count >= width of type [enabled by default]
SPI_BPW_MASK() already avoids this, since its parameter is also in range
1..32, yet it only shifts by up to one less than the input parameter.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Huang Shijie <b32955@freescale.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/spi/spi.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 173725622252..3e9479134d9d 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -309,7 +309,8 @@ struct spi_master { /* bitmask of supported bits_per_word for transfers */ u32 bits_per_word_mask; #define SPI_BPW_MASK(bits) BIT((bits) - 1) -#define SPI_BPW_RANGE_MASK(min, max) ((BIT(max) - 1) - (BIT(min) - 1)) +#define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0UL : (BIT(bits) - 1)) +#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min)) /* other constraints relevant to this driver */ u16 flags; |