RE: [RFC PATCH] powerpc: Convert ____flush_dcache_icache_phys() to C

"Alastair D'Silva" [off-list ref] writes:

On Wed, 2019-08-21 at 22:27 +0200, Christophe Leroy wrote:

quoted

Le 20/08/2019 à 06:36, Alastair D'Silva a écrit :

quoted

On Fri, 2019-08-16 at 15:52 +0000, Christophe Leroy wrote:

[...]

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Thanks Christophe,

I'm trying a somewhat different approach that requires less
knowledge
of assembler. Handling of CPU_FTR_COHERENT_ICACHE is outside this
function. The code below is not a patch as my tree is a bit messy,
sorry:

Can we be 100% sure that GCC won't add any code accessing some
global data or stack while the Data MMU is OFF ?

+mpe

I'm not sure how we would go about making such a guarantee, but I've
tied every variable used to a register and addr is passed in a
register, so there is no stack usage, and every call in there only
operates on it's operands.

That's not safe, I can believe it happens to work but the compiler
people will laugh at us if it ever breaks.

Let's leave it in asm.

cheers