[PATCH v2] powerpc32: memcpy/memset: only use dcbz once cache is enabled
christophe.leroy at c-s.fr
Sat Sep 12 19:57:21 AEST 2015
Le 11/09/2015 03:24, Michael Ellerman a écrit :
> On Thu, 2015-09-10 at 17:05 -0500, Scott Wood wrote:
>> I don't think this duplication is what Michael meant by "the normal cpu
>> feature sections". What else is going to use this very specific
> Yeah, sorry, I was hoping you could do it with the existing cpu feature
> It looks like the timing doesn't work, ie. you need to patch this stuff in
> machine_init(), which is later than the regular patching which gets done in
> This is one of the festering differences we have between the 32 and 64-bit
> initialisation code, ie. on 64-bit we do the patching much later.
I've just thought about maybe another alternative.
Is there any issue with calling do_feature_fixups() twice for the same
If not, we could define a MMU_CACHE_NOW_ON dummy MMU feature, then
call again do_feature_fixups() in machine_init() to patch memcpy/memset
stuff, something like:
+#define MMU_CACHE_NOW_ON ASM_CONST(0x00008000)
In arch/powerpc/kernel/setup_32.c: @machine_init()
+ spec = identify_cpu(0, mfspr(SPRN_PVR));
+ do_feature_fixups(spec->mmu_features | MMU_CACHE_NOW_ON,
/* Do some early initialization based on the flat device tree */
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