Messages in this thread | | | Date | Sun, 24 Aug 2008 09:59:15 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH 1 of 3] add phys_addr_t for holding physical addresses |
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Benjamin Herrenschmidt wrote: > .../... > > >> diff --git a/include/asm-x86/page_32.h b/include/asm-x86/page_32.h >> --- a/include/asm-x86/page_32.h >> +++ b/include/asm-x86/page_32.h >> @@ -33,7 +33,6 @@ >> typedef u64 pudval_t; >> typedef u64 pgdval_t; >> typedef u64 pgprotval_t; >> -typedef u64 phys_addr_t; >> > > .../... > > Might sound a stupid question, but why have a CONFIG_ option and > a global definition based on it rather than each arch defining it > as part of the base types ? I don't have a firm preference for one > or the other at this point, I can see pro and cons to both approach, > so I'm curious to see what others think about it.
My thinking is that:
There's only two possible types it can have: u32 and u64. If we leave it to per-arch definitions, they'll come up with a variety of different ways of spelling those types (like u64 itself, but I gather that's being fixed).
Furthermore, with only a couple of exceptions, the size is the same as the bitness of the architecture, so there's no need to set a config in most cases.
So, avoiding lots of duplication, basically.
J
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