Hi Wolfgang, <snip>
> Well, please keep in mind that all this code is working find on > PowerPC, which has been using relocation right from the beginning. > > It is my understanding that we don't suffer from this issue any more > on PPC - Peter Tyser posted relocation fixup patches for PPC about a > year ago or so. > > I have to admit that I cannot remeber the final result of this > discussion (there were tool chain dependencies?), but IIRC this has > been solved for PPC. > > We should do the same for AMR now. > > > Peter, could you please fill in the details of that old story? I haven't been following the ARM relocation thread very closely, but a summary of the PPC relocation is: - Prior to commit 858290178f222d998b6425d85cf06822467918f3 PPC supported basic relocation, but didn't relocate static pointers, eg pointers in a structure, such as the strings in the cmd_pca953x[] table. So we had to use the hokey "struct->field += gd->reloc_off" fixups that we still have for some arches. - Adding "-mrelocatable" to the gcc's flags would add additional relocation info into the ".fixup" section that allowed us to properly fixup static pointers and get rid of the "+= gd->reloc_off" fixups. The additional fixup code was relatively small, in the 1-2% ballpark I think. - Unfortunately "-mrelocatable" is PPC specific. I remember dabbling with other, more general relocation flags like -fPIC, pie, etc, but went with -mrelocatable mainly because it was a smaller, easier change. We could share the already-used relocation fixup code in many PPC arch's start.S, so it wasn't too hard to get working unlike the other relocation schemes. - Graeme Russ was working on relocation for x86 near the same time. He started this thread which may provide useful info: http://www.mail-archive.com/u-boot@lists.denx.de/msg23347.html He discusses the impact of other compile flags, most of which were generic so could apply to this ARM discussion hopefully. Regards, Peter _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
