Messages in this thread | | | Date | Wed, 25 Mar 2009 14:41:16 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: Anyone working on ftrace function graph support on ARM? |
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On Wed, 25 Mar 2009, Tim Bird wrote:
> Russell King - ARM Linux wrote: > > On Wed, Mar 25, 2009 at 06:05:33PM +0100, Uwe Kleine-K???nig wrote: > >> On Wed, Mar 25, 2009 at 09:34:07AM -0700, Tim Bird wrote: > >>> Russell King - ARM Linux wrote: > >>>> As pointed out in my previous mail, identifying where on the stack the > >>>> return address is stored is only possible for OABI with frame pointers. > >>>> > >>>> EABI will probably be possible with the stack unwinding code, but it > >>>> probably won't be cheap. The EABI unwinder is scheduled for merging > >>>> during the present now-open merge window. > >> EABI with frame pointers should work, too, shouldn't it? > > > > Yes, as I said at the top of my reply dated Wed, 25 Mar 2009 09:57:51 +0000 > > It turns out you can't use -pg and -fomit-frame-pointers at the same time. > At least, my gcc complains about this: > $ make > arm-sony-linux-gnueabi-dev-gcc -g -pg -fomit-frame-pointer -o hello hello.c > arm-sony-linux-gnueabi-dev-gcc: -pg and -fomit-frame-pointer are incompatible > make: *** [hello] Error 1
Correct, that is because mcount requires (as Russell earlier pointed out) the use of frame pointers.
-- Steve
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