[PATCH] mfd: db8500: avoid uninitialized variable reference
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From: Lee Jones <hidden>
Date: 2016-01-28 11:16:04
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On Mon, 25 Jan 2016, Arnd Bergmann wrote:
The prcmu_config_clkout() function ensures that the 'clkout' argument
can only be '0' or '1' using an appropriate BUG_ON(), so the compiler
should know that the div_mask, mask, and bits variables are always
initialized later on. However, it doesn't understand this in gcc-5.2
and produces a false positive warning instead:
drivers/mfd/db8500-prcmu.c: In function 'prcmu_config_clkout':
drivers/mfd/db8500-prcmu.c:762:10: error: 'div_mask' may be used uninitialized in this function [-Werror=maybe-uninitialized]
if (val & div_mask) {
^
drivers/mfd/db8500-prcmu.c:769:13: error: 'mask' may be used uninitialized in this function [-Werror=maybe-uninitialized]
if ((val & mask & ~div_mask) != bits) {
^
drivers/mfd/db8500-prcmu.c:757:7: error: 'bits' may be used uninitialized in this function [-Werror=maybe-uninitialized]
Replacing the switch() statement with an equivalent if() lets
gcc figure this out reliably and avoids the warnings.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/mfd/db8500-prcmu.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)Applied, thanks.
quoted hunk ↗ jump to hunk
diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c index 12099b09a9a7..c0a86aeb1733 100644 --- a/drivers/mfd/db8500-prcmu.c +++ b/drivers/mfd/db8500-prcmu.c@@ -739,20 +739,17 @@ int prcmu_config_clkout(u8 clkout, u8 source, u8 div) if (!div && !requests[clkout]) return -EINVAL; - switch (clkout) { - case 0: + if (clkout == 0) { div_mask = PRCM_CLKOCR_CLKODIV0_MASK; mask = (PRCM_CLKOCR_CLKODIV0_MASK | PRCM_CLKOCR_CLKOSEL0_MASK); bits = ((source << PRCM_CLKOCR_CLKOSEL0_SHIFT) | (div << PRCM_CLKOCR_CLKODIV0_SHIFT)); - break; - case 1: + } else { div_mask = PRCM_CLKOCR_CLKODIV1_MASK; mask = (PRCM_CLKOCR_CLKODIV1_MASK | PRCM_CLKOCR_CLKOSEL1_MASK | PRCM_CLKOCR_CLK1TYPE); bits = ((source << PRCM_CLKOCR_CLKOSEL1_SHIFT) | (div << PRCM_CLKOCR_CLKODIV1_SHIFT)); - break; } bits &= mask;
-- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog