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Date:      Tue, 15 Apr 2014 23:15:58 -0300
From:      carlos antonio neira bustos <cneirabustos@gmail.com>
To:        Mark Johnston <markj@freebsd.org>
Cc:        "freebsd-dtrace@freebsd.org" <freebsd-dtrace@freebsd.org>
Subject:   Re: uaddr and friends
Message-ID:  <CACiB22hQ-9bBeFcFNeEfcrRu2MK0VxAUP1taHFCxJoW0eypxcg@mail.gmail.com>
In-Reply-To: <CAMw1wOxWUpCtrYhkp-NUfigPZUewpyesYzTYG2s=uHLmMXhQwg@mail.gmail.com>
References:  <CACiB22g4JHWhj9ZPWmKKg1FAF376J3TBcrOtgOFrs4JHkFvkOw@mail.gmail.com> <CAMw1wOxWUpCtrYhkp-NUfigPZUewpyesYzTYG2s=uHLmMXhQwg@mail.gmail.com>

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Hi Mark,

I was looking at this document
https://wikis.oracle.com/display/DTrace/Actions+and+Subroutines#ActionsandSubroutines-%7B%7Busym%7D%7D
currently looking at the code uaddr is the same as usym, but according to
this document

usym will print the symbol for a specified address. This is analogous to
how uaddr works, but without the hexadecimal offsets.

        uaddr:          date`clock_val+0x1
        usym:           date`clock_val


here are my outputs from usym and uaddr :

root@bsd:/home/cneira # dtrace -n 'pid$target::main:{usym(uregs[R_PC])}' -c
./test
dtrace: description 'pid$target::main:' matched 2 probes
abCPU     ID                    FUNCTION:NAME
  0  56282                       main:entry   test`main
  0  56281                      main:return   test`main
dtrace: pid 10588 has exited

root@bsd:/home/cneira # dtrace -n 'pid$target::main:{uaddr(uregs[R_PC])}'
-c ./test
dtrace: description 'pid$target::main:' matched 2 probes
abCPU     ID                    FUNCTION:NAME
  0  56282                       main:entry
              test`main+0x1

  0  56281                      main:return
              test`main+0x23

dtrace: pid 10591 has exited

As current is only using dt_print_usym for uaddr the output should not have
the  hexadecimal offset specified in that documentation.
So I'm somewhat lost about which is the correct behavior , Do you have a
uaddr and usym  output  example in current to check this?, all my changes
were done in 10 prod release.

Bests







On Tue, Apr 15, 2014 at 10:09 PM, Mark Johnston <markj@freebsd.org> wrote:

> On Tue, Apr 15, 2014 at 8:35 PM, carlos antonio neira bustos
> <cneirabustos@gmail.com> wrote:
> > Hi All,
> >
> > I was looking at Dtrace todo list from
> https://wiki.freebsd.org/DTraceTODO
> > and started to work on : Get uaddr(), ufunc(), umod(), and usym() action
> > funtions working.
> > I have  the  data recording action (uaddr)  working  now, here is an
> > example:
>
> Hi!
>
> Hm, these should have been (at least mostly) working since r258902:
> http://svnweb.freebsd.org/base?view=revision&revision=258902
>
> >
> > root@bsd:/home/cneira # dtrace -n
> 'pid$target::main:{uaddr(uregs[R_PC])}'
> > -c ./test
> > dtrace: description 'pid$target::main:' matched 2 probes
> > abCPU     ID                    FUNCTION:NAME
> >   0  56282                       main:entry
> >               test`main+0x1
> >
> >   0  56281                      main:return
> >               test`main+0x23
> >
> > dtrace: pid 9687 has exited
> >
> > Here is the output of nm from the test binary I have used to check this
> > change.
> >
> >         U _init_tls@@FBSD_1.0
> > 08048380 T _start
> > 080483a0 t _start1
> > 0804814c r abitag
> >          U atexit@@FBSD_1.0
> > 08048164 r crt_noinit_tag
> > 080485c0 T dosomething
> > 08049764 B environ
> >          U exit@@FBSD_1.0
> > 080484f0 t finalizer
> > 08048560 t frame_dummy
> > 08048590 T main
> >          U putchar@@FBSD_1.0
> >
> >
> > root@bsd:/home/cneira # dtrace -c ./test -n 'pid$target::main:entry{
> > uaddr(0x080485c0); }'
> > dtrace: description 'pid$target::main:entry' matched 1 probe
> > abCPU     ID                    FUNCTION:NAME
> >   0  56281                       main:entry
> >               test`dosomething
> >
> > dtrace: pid 9736 has exited
> >
> > I'll continue working on the rest, how do I submit  a patch with these
> > changes ?
>
> Pasting it inline is generally fine if it's not too large. It's also
> ok to put it in a public directory somewhere and post a link to it.
>
> -Mark
>



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