Messages in this thread | | | Date | Tue, 26 Jun 2007 15:29:01 -0400 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH] cross-architecture ELF clean up |
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Roman Zippel wrote: >> This patch cleans up the ELF headers and their users. It does several >> related things: >> >> 1. split linux/elf.h into pieces >> >> This splits linux/elf.h into several pieces: >> linux/elf.h - still the common elf header, >> functionally unchanged >> linux/elf-const.h - ELF constants, includable by asm code >> > > We have the __ASSEMBLY__ define for this, so just for asm code we don't > need a separate header. >
Hm. The number of __ASSEMBLY__s end up being pretty large, and it just seemed cleaner to put them in separate headers.
>> linux/elf-decl.h - ELF type declarations, without definitions >> linux/elf-defn.h - ELF type definitions >> > > What's the point in splitting these two? >
Because there are other headers which just need some type forward-declarations, and don't need the whole set of ELF types defined. In particular, linux/module.h - which is included all over the place in the kernel - needs a couple of ELF types declared, and including it all over the place is just a waste. Also, there were some nasty cyclic header dependency problems around linux/elf.h, linux/module.h, linux/bug.h and asm/bug.h which ended up leading to some awkward hacks; I need to remind myself what the problems were and see if this elf cleanup helps (pretty sure it should).
> After this patch <linux/elf.h> seems to be pretty much empty, I'd rather > suggest to move the function declarations to elfcore.h and leave the basic > elf definitions in elf.h. Many small header files have the disadvantage > that it takes longer to find the needed information. > linux/elf.h ends up pulling in a really surprising amount of stuff, mostly because it ends up including asm/elf.h. asm/elf.h, in turn, depending on the architecture, pulls in a wide variety of other headers. When I cleaned this up, I found quite a few buggy .c files which ended up relying on implicit includes via this chain.
Given that there's been a general push to try and cut down on the number of header dependency entanglements, I thought I could contribute while solving my own immediate problems.
linux/elfcore.h is specifically related to ELF core files, so the two corefile notes-related headers could be moved there.
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