[PATCH v4 7/7] powerpc/64s: Blacklist rtas entry/exit from kprobes

[Naveen N. Rao]

On 2017/06/29 09:01PM, Nicholas Piggin wrote:
> On Thu, 29 Jun 2017 16:11:10 +0530
> "Naveen N. Rao" <naveen.n.rao at linux.vnet.ibm.com> wrote:
> 
> > We can't take traps with relocation off, so blacklist enter_rtas() and
> > rtas_return_loc(). However, instead of blacklisting all of enter_rtas(),
> > introduce a new symbol __enter_rtas from where on we can't take a trap
> > and blacklist that.
> > 
> > Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
> > ---
> >  arch/powerpc/kernel/entry_64.S | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
> > index 0c27084800b6..16f4c4a1a294 100644
> > --- a/arch/powerpc/kernel/entry_64.S
> > +++ b/arch/powerpc/kernel/entry_64.S
> > @@ -1082,6 +1082,7 @@ _GLOBAL(enter_rtas)
> >  	sync				/* disable interrupts so SRR0/1 */
> >  	mtmsrd	r0			/* don't get trashed */
> >  
> > +__enter_rtas:
> 
> Hmm, am I missing something, or is there a reason to put these labels
> after the mtmsr? Even if kprobes does the right thing, I think it's
> easier to read the code if you cover the mtmsr as well.

I thought you asked for this, per your previous review comment:
https://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg119667.html

Or, did I get that wrong?

Thanks,
Naveen