Re: Illegal use of reserved word in system.h

From: Maciej W. Rozycki
Date: Fri May 20 2005 - 07:25:54 EST


On Thu, 19 May 2005, Steven Rostedt wrote:

> Well, they probably are the same, but then what's the reason for the
> lines in binfmt_elf.c:
>
> #if ELF_EXEC_PAGESIZE > PAGE_SIZE
> # define ELF_MIN_ALIGN ELF_EXEC_PAGESIZE
> #else
> # define ELF_MIN_ALIGN PAGE_SIZE
> #endif
>
>
> This looks to me that ELF_EXEC_PAGESIZE and PAGE_SIZE may not be the
> same. And what's passed to AT_PAGESZ is ELF_EXEC_PAGESIZE. In mips (as
> your email address shows you are interested in) ELF_EXEC_PAGESIZE is
> simply defined as PAGE_SIZE. But in intel i386, it is defined as 4096,

And for MIPS PAGE_SIZE is also variable (currently one of: 4k, 16k, 64k).

> which coincidentally is the same as PAGE_SIZE but there's no guarantee
> that this will be the same, unless who ever changes PAGE_SIZE also
> remembers to change ELF_EXEC_PAGESIZE.

That's the maintainer's problem.

> In arm26 the PAGE_SIZE is configurable (16k or 32k) but the
> ELF_EXEC_PAGESIZE stays as 32k. So is this a bug?

I guess so. Unless these smaller pages are always handled in pairs by
Linux. That would be a legitimate case of ELF_EXEC_PAGESIZE != PAGE_SIZE.

Maciej
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