Re: [PATCH] PAGE_SIZE definition for MIPS XLP

["Joseph S. Myers" <joseph@codesourcery.com>]

On Mon, 18 Nov 2013, Andrew Stubbs wrote:

> The attached patch makes the definition conditional, rather than removing it
> completely. It's not clear to me whether the HOST_* definitions are similarly
> affected, but other platforms that do not define PAGE_SIZE also choose not to
> define those, so I've extended the ifndef similarly.
> 
> I this OK to commit? Should it be solved a different way?

This should be raised on libc-alpha, not libc-ports, as it's a generic 
issue regarding what the glibc API is for PAGE_SIZE being provided or not 
provided in sys/user.h.

It's definitely wrong to test _MIPS_ARCH_XLP like that - glibc built for 
generic MIPS should work on all MIPS variants supporting all the 
instructions used in that glibc binary, so the fact that MIPS has variable 
page sizes means it's always wrong for MIPS glibc to embed a page size 
assumption in the binaries.  The question is whether PAGE_SIZE must only 
be defined when it is the kernel page size, or whether it should also be 
defined in some cases when it's some form of ABI page size even when that 
differs from the kernel page size.  I also see no rationale given for 
making any of the other macros conditional.

At least MicroBlaze also has variable kernel page size but defines 
PAGE_SIZE in sys/user.h.

-- 
Joseph S. Myers
joseph@codesourcery.com