Re: [Qemu-devel] [PATCH 05/35] tcg-s390: Icache flush is a no-op.

[Richard Henderson]

On 06/09/2010 03:55 PM, Aurelien Jarno wrote:
> On Fri, Jun 04, 2010 at 12:14:13PM -0700, Richard Henderson wrote:
>> Before gcc 4.2, __builtin___clear_cache doesn't exist, and
>> afterward the gcc s390 backend implements it as nothing.
> 
> Does it means that instruction and data caches are coherent on s390?

Yes.

Principles of Operation, 2.1 Main storage:
# Main storage may include a faster-access buffer storage, sometimes called a 
cache.
# Each CPU may have an associated cache. The effects, except on  performance, of
# the physical construction and the use of distinct storage media are not 
observable
# by the program.

This architecture pre-dates caches, I think.  ;-)


r~