[PATCH v3 3/6] powerpc/64s: Blacklist system_call() and system_call_common() from kprobes

Nicholas Piggin npiggin at gmail.com
Thu Jun 22 13:36:40 AEST 2017


On Thu, 22 Jun 2017 00:08:39 +0530
"Naveen N. Rao" <naveen.n.rao at 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 at kernel.org>
> Signed-off-by: Naveen N. Rao <naveen.n.rao at 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 at 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


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