On Mon, 23 Nov 2015, Nicolas Pitre wrote:
> On Mon, 23 Nov 2015, Arnd Bergmann wrote:
>
> > On Sunday 22 November 2015 17:28:33 Nicolas Pitre wrote:
> > > On Sun, 22 Nov 2015, Arnd Bergmann wrote:
> > > > On Monday 16 November 2015 20:20:38 you wrote:
> > > > I'm now getting a build regressing with the attached randconfig configuration,
> > > > when compiling drivers/net/wireless/iwlegacy/common.o:
> > > >
> > > > drivers/built-in.o: In function `il_send_rxon_timing':
> > > > :(.text+0xbbac80): undefined reference to `__aeabi_uldivmod'
> > > > :(.text+0xbbac9c): undefined reference to `__aeabi_uldivmod'
> > > > :(.text+0xbbacdc): undefined reference to `__aeabi_uldivmod'
> > > > :(.text+0xbbadc8): undefined reference to `__aeabi_uldivmod'
> > > > :(.text+0xbbadf8): undefined reference to `__aeabi_uldivmod'
> > > > :(.text+0xbbae3c): more undefined references to `__aeabi_uldivmod' follow
> > > > drivers/built-in.o: In function `il_send_rxon_timing':
> > > > :(.text+0xbbb11c): undefined reference to `____ilog2_NaN'
> > >
>
> I'm able to reproduce it, and I am in the process of reintroducing the
> last patch piece by piece to see what breaks. The presence of
> ____ilog2_NaN is particularly intriguing as this would mean 0 is passed
> to ilog2() somewhere.
OK... I'm able to "fix" the build with:
diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
index 163f77999e..d246c4c801 100644
--- a/include/asm-generic/div64.h
+++ b/include/asm-generic/div64.h
@@ -206,7 +206,7 @@ extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
uint32_t __rem; \
(void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
if (__builtin_constant_p(__base) && \
- is_power_of_2(__base)) { \
+ is_power_of_2(__base) && __base != 0) { \
__rem = (n) & (__base - 1); \
(n) >>= ilog2(__base); \
} else if (__div64_const32_is_OK && \
What doesn't make sense to me is the fact that is_power_of_2() is
defined as:
static inline __attribute__((const))
bool is_power_of_2(unsigned long n)
{
return (n != 0 && ((n & (n - 1)) == 0));
}
So the test for zero is already in there.
And adding BUILD_BUG_ON(__builtin_constant_p(__base) && __base == 0)
before the if doesn't trig either.
Confused.
Nicolas
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