On Wed, 29 Jan 2014 16:09:24 -0500
John David Anglin <dave.anglin@bell.net> wrote:

> On 1/29/2014 3:44 PM, Helge Deller wrote:
> > Can you try
> > BL ftrace_return_to_handler, %r0
> > (I'm not good in hppa assembly - as you can see if you take a look
> > at this assembly code section :-)).
> >
> BL might not reach on PA 1.1.  The PA 2.0 b,l instruction is only
> "long" when the link
> register is %rp and it is used for the return_trampoline.
> 
> I would say replace "b" with the following as it will always reach
> target: load32  ftrace_return_to_handler, %r20
>          bv      %r0(%r20)
> 
> %r1 is another register alternative.


Thanks, however, I later found out that this part of the code isn't
used if you set CONFIG_FUNCTION_GRAPH_TRACER=n.


In my config, I've enabled only this :
CONFIG_FTRACE=y
CONFIG_FUNCTION_TRACER=y

Full config can be found here : http://bpaste.net/show/178555/


So far I came up with the attached patch to try to get a booting kernel
but I don't even have the first line being printed, the box HPMC and
reboot.


As far as I understand, compiling with -pg will make each function jump
to _mcount before being actually executed. This is why I tried to make
the _mcount function simply jump back to %rp but this doesn't seem to
be helpful.


What am I missing here ?

  GUy