Messages in this thread | | | Date | Mon, 22 Sep 2014 14:26:42 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 2/2] MIPS: mcount: Fix selfpc address for static trace |
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On Mon, 22 Sep 2014 14:32:59 +0100 Markos Chandras <markos.chandras@imgtec.com> wrote:
> According to Documentation/trace/ftrace-design.txt, the selfpc > should be the return address minus the mcount overhead (8 bytes). > This brings static trace in line with the dynamic trace regarding > the selfpc argument to the tracing function. > > This also removes the magic number '8' with the proper > MCOUNT_INSN_SIZE.
I could also update the generic code to handle delay slots.
-- Steve
> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> > --- > arch/mips/kernel/mcount.S | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S > index 2f7c734771f4..3af48b7c7a47 100644 > --- a/arch/mips/kernel/mcount.S > +++ b/arch/mips/kernel/mcount.S > @@ -79,7 +79,7 @@ _mcount: > PTR_S MCOUNT_RA_ADDRESS_REG, PT_R12(sp) > #endif > > - PTR_SUBU a0, ra, 8 /* arg1: self address */ > + PTR_SUBU a0, ra, MCOUNT_INSN_SIZE /* arg1: self address */ > PTR_LA t1, _stext > sltu t2, a0, t1 /* t2 = (a0 < _stext) */ > PTR_LA t1, _etext > @@ -138,7 +138,7 @@ NESTED(_mcount, PT_SIZE, ra) > static_trace: > MCOUNT_SAVE_REGS > > - move a0, ra /* arg1: self return address */ > + PTR_SUBU a0, ra, MCOUNT_INSN_SIZE /* arg1: self address */ > jalr t2 /* (1) call *ftrace_trace_function */ > move a1, AT /* arg2: parent's return address */ >
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