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Date: Thu, 22 Jun 2017 13:36:40 +1000
From: Nicholas Piggin <npiggin@gmail.com>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>, Ananth N Mavinakayanahalli
 <ananth@linux.vnet.ibm.com>, Masami Hiramatsu <mhiramat@kernel.org>,
 linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 3/6] powerpc/64s: Blacklist system_call() and
 system_call_common() from kprobes
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On Thu, 22 Jun 2017 00:08:39 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:

> Convert some of the symbols into private symbols and blacklist
> system_call_common() and system_call() from kprobes. We can't take a
> trap at parts of these functions as either MSR_RI is unset or the kernel
> stack pointer is not yet setup.
> 
> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>

I don't have a problem with this bunch of system call labels
going private. They've never added much for me in profiles.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

Semi-related question, why is system_call: where it is? Should we
move it up to right after the mtmsrd / wrteei instruction?
(obviously for another patch). It's pretty common to get PMU
interrupts coming in right after mtmsr and this makes profiles split
the syscall into two which is annoying.

Thanks,
Nick