Re: (regression) kernel/timeconst.h bugs with HZ=128

[H. Peter Anvin]

Andrew Morton wrote:
> On Tue, 26 Feb 2008 10:32:24 -0800 David Brownell <david-b@xxxxxxxxxxx> 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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