On Fri, Mar 25, 2011 at 11:35 AM, Albert ARIBAUD <albert.arib...@free.fr> wrote: > Le 25/03/2011 17:12, Aneesh V a écrit : > >> Another problem I have with relocation is that it makes debugging with >> JTAG debugers more difficult. The addresses of symbols in the ELF >> target are no longer valid. Of course, you can load the symbols at an >> offset from the original location. But one has to first enable debug >> prints, find the relocation offset, use it while loading the symbols >> before you can do source level debugging. > > Actually you don't need recompiling: simply set a breakpoint at the > entry of relocate_code and once you hit the bp, look up r2: it contains > the destination. If you want the offset rather than the absolute > address, set the breakpoint right after the 'sub r9, r6, r0' round line > 222: r9 will then give you the offset. Unload the current symbols, > reload the symbols with the relevant offset, and there you go.
I would like to revisit this thread. I'm not sure how other people do development in U-Boot but I like to use an ICE and a source-level debugger for any significant effort. I think it should be possible to use a JTAG debugging just by loading the u-boot ELF file and running. With this patch (or something similar) this is possible. Without it, it is painful. To be clear, we are not talking here about creating a platform that doesn't use relocation, just that for development purposes it is convenient to be able to disable it. Looking at the December thread http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/88067/focus=88262 Aneesh: > > Shouldn't we provide a CONFIG option by which users can disable > > Elf relocation? Wolfgang: > Why should we? It would just make the code even more complicated, and > require a lot of additional test cases. >From what I can see this is a new CONFIG option, two ifdefs in the board.c file, and optionally disabling the -pie position-independent executable option to reduce size. It is pretty trivial: arch/arm/config.mk | 2 ++ arch/arm/lib/board.c | 5 +++++ 2 files changed, 7 insertions(+), 0 deletions(-) Regards, Simon > > Amicalement, > -- > Albert. > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
