Messages in this thread | | | Date | Mon, 2 Sep 2019 06:11:05 -0500 | From | Segher Boessenkool <> | Subject | Re: [RFC PATCH] powerpc: Convert ____flush_dcache_icache_phys() to C |
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On Mon, Sep 02, 2019 at 11:48:59AM +1000, Michael Ellerman wrote: > "Alastair D'Silva" <alastair@au1.ibm.com> writes: > > On Wed, 2019-08-21 at 22:27 +0200, Christophe Leroy wrote: > >> 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.
Yes. Sorry.
> Let's leave it in asm.
+1
The asm is simpler, more readable, more maintainable, and perhaps more performant even. Plus the being-laughed-at issue.
Segher
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