Re: [PATCH] Disable dlmzb on the PowerPC 405 due to the AMCC 405EP

["Yann E. MORIN" <yann dot morin dot 1998 at free dot fr>]

BjÃrn, All,

On Friday 09 November 2012 Herwig, BjÃrn wrote:
> It is generally assumed, that all PowerPC 405 cores support the dlmzb instruction.
> Sadly, the AMCC 405EP core is an exception to that rule. And while this must be known
> to the Linux kernel people, GCC and GLIBC default to use dlmzb on all 405s.
> 
> This adds a patch to crosstool-ng, which removes the optimized assembler
> implementations using dlmzb from eglibc-ports-2_16 and also killing memset.S
> due to an already known problem with cache sizes on the 405, which also affects
> the 405EP [1].
> 
> [1] http://sourceware.org/bugzilla/show_bug.cgi?id=14595
> 
> The second patch added modifies GCC 4.7.2 to never emit dlmzb for all 405s.
> 
> With these two patches in place, it is possible to use GCC 4.7.2 and EGLIBC 2.16
> for a perfectly running Linux rootfs on the AMCC 405EP.

These patches are too intrusive to be added to crosstool-NG. It should be
fixed upstream (ie. eglibc/glib and gcc) instead.

Regards,
Yann E. MORIN.

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