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SubjectRe: [RFC] [PATCH 2/16] x86_64: Assembly safe page.h and pgtable.h
Date
Andi Kleen <ak@suse.de> writes:

>>
>> I think we need these UL suffixes. Otherwise in some cases overflow
>> can take place and compiler emits warning.
>>
>> For ex. in following definition I got rid of UL.
>>
>> #define PGDIR_SIZE (1 << PGDIR_SHIFT)
>
> Yes for the shifts it is needed, but not for the unshifted constants.
> I think. At least when they're hex the compiler should chose the right
> type on its own.

Only if the high bit is set. But it should chose a big enough type.
However there is no reason to play games and possibly out smart ourselves.
That is the point of the _AC() macro. It adds the suffix only for
C code, and drops it for assembly.

Eric
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