Messages in this thread | | | Date | Fri, 9 Sep 2005 13:21:08 +0200 | From | Andi Kleen <> | Subject | Re: [discuss] [PATCH] allow CONFIG_FRAME_POINTER for x86-64 |
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On Fri, Sep 09, 2005 at 12:14:38PM +0100, Hugh Dickins wrote: > > Ah, right. I'm using kdb with it. (And my recollection of when > show_stack did have a framepointer version, is that it was hopelessly > broken on interrupt frames, and we're much better off without it.)
Not sure if the x86-64 kdb had code to follow them either. The i386 one has.
> > > The only reason to use them would be external debuggers, but those > > don't need them on x86-64 neither. > > Don't need them, but find them as useful on x86_64 as on i386? > > Certainly, I can go on patching in FRAME_POINTERs for x86_64 > as I have done, no problem with that. But it seems both bogus > and unhelpful to have that "&& !X86_64" in lib/Kconfig.debug - > framepointers are as helpful/useless on x86_64 as the rest.
The original reason was that they were never enabled because nobody passed -fno-omit-frame-pointer. That was apparently later fixed.
But kdb should be using a dwarf2 unwinder instead. kgdb certainly supports that, as does NLKD.
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