On 2017/06/29 10:13PM, Nicholas Piggin wrote: > On Thu, 29 Jun 2017 17:24:14 +0530 > "Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> wrote: > > > On 2017/06/29 09:01PM, Nicholas Piggin wrote: > > > On Thu, 29 Jun 2017 16:11:10 +0530 > > > "Naveen N. Rao" <naveen.n....@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....@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? > > No you're right, I'm contradicting myself. Let me start again. > > I think we'd like to put the label before the mtmsrd if possible. So > in that case, should we adjust the system call code instead (then you > wouldn't have to add a comment for it). > > And then you could move this label back above the mtmsrd. Sorry for > the confusion.
Sure - I now get why you were insisting on a comment with the system_call_exit symbol. v5 enroute... Thanks, Naveen
