Re: [PATCH 4.9 00/92] 4.9.81-stable review

[Guenter Roeck]

On 02/17/2018 05:45 AM, Greg Kroah-Hartman wrote:
> On Sat, Feb 17, 2018 at 02:31:53PM +0100, Yves-Alexis Perez wrote:
> > On Tue, 2018-02-13 at 16:29 +0100, Greg Kroah-Hartman wrote:
> > > > arch/powerpc/kernel/entry_64.S: Assembler messages:
> > > > arch/powerpc/kernel/entry_64.S:260: Error: unrecognized opcode: `rfi_to_user'
> > > > arch/powerpc/kernel/entry_64.S:270: Error: unrecognized opcode: `rfi_to_kernel'
> > > > arch/powerpc/kernel/entry_64.S:885: Error: unrecognized opcode: `rfi_to_user'
> > > > arch/powerpc/kernel/entry_64.S:900: Error: unrecognized opcode: `rfi_to_kernel'
> > > >
> > > > Looks like 222f20f140623 ("powerpc/64s: Simple RFI macro conversions") is missing,
> > > > or at least part of it. Unfortunately it doesn't apply cleanly.
> > >
> > > Ugh.  Let's see if the ppc developers care about this or not :)
> >
> > Hi,
> >
> > in Debian we extracted the following hunk from 222f20f140623 to fix build on
> > powerpc/ppc64el. Only compile tested against Debian builds though.
> >
> > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
> > index 3320bcac7192..e68faa4d1b13 100644
> > --- a/arch/powerpc/kernel/entry_64.S
> > +++ b/arch/powerpc/kernel/entry_64.S
> > @@ -37,6 +37,11 @@
> >   #include <asm/tm.h>
> >   #include <asm/ppc-opcode.h>
> >   #include <asm/export.h>
> > +#ifdef CONFIG_PPC_BOOK3S
> > +#include <asm/exception-64s.h>
> > +#else
> > +#include <asm/exception-64e.h>
> > +#endif
> >   
>
> Ah, thanks!  I've now queued up this portion of the patch.

Hmm, that chunk really doesn't do what the original patch is supposed to do,
meaning it won't provide the vulnerability protection it is supposed to provide
(AFAICS that is Meltdown). Just a note in case anyone is concerned about
actually providing that protection.

Guenter