[PATCH] Remove divide from _ELF_DYNAMIC_DO_RELOC

[Joseph S. Myers]

On Thu, 17 Jul 2014, Chung-Lin Tang wrote:

> > As for the rest, is there rough consensus in the Linux kernel community on 
> > the kernel/userspace ABI for Nios II (in particular, the size of time_t, 
> > but also other issues such as whether renameat will need implementing in 
> > userspace in terms of the renameat2 syscall)?  That's needed for it to be 
> > safe to add the port to glibc.
> 
> I don't see either of those patches in 3.16-rc5 at the moment, so I
> guess it won't be an issue for 3.16.
> 
> I'm not sure about the time_t/timespec changes, but renameat2 should be

Well, that ABI needs sorting out - you need to get kernel community 
consensus about time_t for Nios II - before it's safe to include the port.

> pretty straightforward, just a new __ASSUME_RENAMEAT2 in
> kernel-features.h for 3.16 (if it gets in later), and maybe adding
> renameat2() as an API function.

That's the wrong way round.  There's no need for __ASSUME_RENAMEAT2 unless 
either (a) it's added as an API function (regarding which, see 
<https://sourceware.org/ml/libc-alpha/2014-06/msg00421.html>) and you want 
a fallback version of that API function for older kernels, or (b) some 
interface can be implemented with renameat2, or in a more complicated way 
for kernels not supporting renameat2.  There's no apparent value in 
implementing the rename and renameat APIs using renameat2 on existing 
architectures, so no need for __ASSUME_RENAMEAT2 (rather, if Nios II gets 
only the renameat2 syscall but not the renameat syscall, it and any 
other asm-generic architectures added to the kernel in future would use 
the renameat2 syscall to implement the rename and renameat APIs, while 
AArch64, Tile and any other asm-generic architectures already supported in 
the kernel but not glibc would continue to use the existing code 
implementing those functions with the renameat syscall).

I suppose you might have a new __ASSUME_RENAMEAT_SYSCALL to be defined by 
the subset of asm-generic architectures that have such a syscall (if the 
direction is that new architectures don't have that syscall).

-- 
Joseph S. Myers
joseph@codesourcery.com