diff options
| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2021-04-20 19:44:25 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2021-04-21 15:49:54 +0100 |
| commit | f60d7270c8a3d2beb1c23ae0da42497afa3584c2 (patch) | |
| tree | 546b47407e4e4b72205acb74be341a2c9b518887 /drivers/spi/spi.c | |
| parent | dbaca8e56ea3f23fa215f48c2d46dd03ede06e02 (diff) | |
spi: Avoid undefined behaviour when counting unused native CSs
ffz(), that has been used to count unused native CSs,
might cause undefined behaviour when called against ~0U.
To fix that, open code it with ffs(~value) - 1.
Fixes: 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164425.40287-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 2e5dca20c8d0..6fe2a9509675 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2611,7 +2611,7 @@ static int spi_get_gpio_descs(struct spi_controller *ctlr) native_cs_mask |= BIT(i); } - ctlr->unused_native_cs = ffz(native_cs_mask); + ctlr->unused_native_cs = ffs(~native_cs_mask) - 1; if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios && ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) { |