Messages in this thread | | | Date | Tue, 26 Feb 2008 16:34:04 -0800 | From | "H. Peter Anvin" <> | Subject | Re: (regression) kernel/timeconst.h bugs with HZ=128 |
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Andrew Morton wrote: > On Tue, 26 Feb 2008 10:32:24 -0800 David Brownell <david-b@pacbell.net> wrote: > >> I see these warnings on 32 bit ARM systems: >> >> CC kernel/time.o >> kernel/time.c: In function 'msecs_to_jiffies': >> kernel/time.c:472: warning: integer constant is too large for 'long' type >> kernel/time.c: In function 'usecs_to_jiffies': >> kernel/time.c:487: warning: integer constant is too large for 'long' type >> >> Line 472: >> return ((u64)MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) >> line 487: >> return ((u64)USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32) >> >> The problem seems to be that these constants from kernel/timeconst.h >> have too many digits: >> >> #define ONLY_THIRTYTWO_BITS 0x01234567 >> >> #define MSEC_TO_HZ_ADJ32 0x3f7ced916 >> #define USEC_TO_HZ_ADJ32 0xfffbce4217d >> >> Those *_ADJ32 constants should have "ULL" suffixes, yes? >> Adding that by hand resolves the problem, but only until >> the next time that header file gets regenerated. >> >> Someone with observable Perl-fu should fix this ... >> >
<barf>
The real issue is that we don't have any equivalent to the UINTxx_C() creation macros in Linux, and even though we're using a cast -- which is totally correct -- makes gcc issue a (spurious) warning.
The right thing would be to create _C() macros and use those in the C code, i.e. UINT64_C(MSEC_TO_HZ_MUL32).
I'll write up a patch, but probably not today.
-hpa
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