[PATCH 0/5] powerpc: Implement masked user access
Segher Boessenkool
segher at kernel.crashing.org
Sat Jul 5 21:42:49 AEST 2025
Hi!
On Sat, Jul 05, 2025 at 12:55:06PM +0200, Christophe Leroy wrote:
> > > For book3s64, GCC only use isel with -mcpu=power9 or -mcpu=power10
> >
> > I have no idea what "book3s64" means.
>
> Well that's the name given in Linux kernel to the 64 bits power CPU
> processors.
A fantasy name. Great.
> > What is "powerpc/32"? It does not help if you use different names from
> > what everyone else does.
>
> Again, that's the way it is called in Linux kernel, refer below commits
> subjects:
And another.
> It means everything built with CONFIG_PPC32
Similar names for very dissimilar concepts, even! Woohoo!
> > > For powerpc/64 we have less constraint than on powerpc32:
> > > - Kernel memory starts at 0xc000000000000000
> > > - User memory stops at 0x0010000000000000
> >
> > That isn't true, not even if you mean some existing name. Usually
> > userspace code is mapped at 256MB (0x10000000). On powerpc64-linux
> > anyway, different default on different ABIs of course :-)
>
> 0x10000000 is below 0x0010000000000000, isn't it ? So why isn't it true ?
I understood "starts at". I read cross-eyed maybe, hehe.
Segher
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