On 2017/06/22 01:48PM, Nicholas Piggin wrote: > On Thu, 22 Jun 2017 00:08:42 +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 | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S > > index d376f07153d7..49c35450f399 100644 > > --- a/arch/powerpc/kernel/entry_64.S > > +++ b/arch/powerpc/kernel/entry_64.S > > @@ -1076,6 +1076,8 @@ _GLOBAL(enter_rtas) > > rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG) > > ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI|MSR_LE > > andc r6,r0,r9 > > + > > +__enter_rtas: > > sync /* disable interrupts so SRR0/1 */ > > mtmsrd r0 /* don't get trashed */ > > Along the lines of the system call patch... For consistency, could we > put the __enter_rtas right after mtmsrd? And I wonder if we shoul
Sure. > come up with a common prefix or postfix naming convention for these > such labels used to control probing? We could, but I am not sure it will help much. On the other hand, such symbols may make backtraces pretty distracting. I'm just using '__' as a prefix to make it less distracting, though it isn't all that great either. I'm clearly hopeless with names o_O The other option is to just blacklist entire functions, but we will then lose the ability to probe in many places where we may have wanted to. > > How do opal calls avoid tracing? It doesn't yet. I'm still going through the initial few symbols and identifying what needs blacklisting. Opal is further down. Thanks, Naveen
