Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 12 Aug 2010 13:26:37 -0700 | Subject | Re: Problem with commit deda2e81961e96be4f2c09328baca4710a2fd1a0 |
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On Thu, Aug 12, 2010 at 1:18 PM, Larry Finger <Larry.Finger@lwfinger.net> wrote: > > With the above commit, building an i386 version of the kernel results in the > following from the build: > > kernel/built-in.o: In function `logarithmic_accumulation': > /home/finger/linux-realtek/kernel/time/timekeeping.c:715: undefined reference to > `__umoddi3' > /home/finger/linux-realtek/kernel/time/timekeeping.c:715: undefined reference to > `__udivdi3' > make: *** [.tmp_vmlinux1] Error 1 > > Reverting the patch allows the system to build correctly.
Damn. It's your compiler turning a while-loop into a divide. Which likely isn't even an optimization, but whatever.
John: I think that while-loop needs to be something like
if (raw_nsecs >= NSEC_PER_SEC) { u64 raw_secs = raw_nsecs; raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); raw_time.tv_sec += taw_secs; } raw_time.tc_nsec = raw_nsecs;
which is sad and overly complicated, but the simple thing seems to get messed up by the compiler.
Untested. Maybe I got the complex do_div() semantics wrong. Somebody needs to check.
Linus
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