On Fri, 2008-07-25 at 13:02 -0400, Jerry Van Baren wrote:
kenneth johansson wrote:
On Fri, 2008-07-25 at 17:23 +0200, Haavard Skinnemoen wrote:
[snip]
There will obviously be a fair amount of arch-specific code required to make the actual relocation work though.
So the gain of using dynamic relocation is that we have fever relocation types to implement and objcopy is not going to strip away the relocation section as it do for non dynamic relocs.
still the code to actually do the relocation is architecture dependent and non existing. At least for powerpc we have a much easier option of having gcc generate a fixup table.
EVERYTHING *already* exists, we just aren't using it right. That is what the elf loader does in a "normal" system. Grant did it on the PowerPC architecture - look at the archives, he didn't write new code for this, it's already in there.
I know exactly what Grant did. But he is not using the elf relocation information as that is simply not included in the data that is the u-boot.bin file.
Also this discussion is more about doing it in a way that is not powerpc specific and documented, we already have as you mentioned code for the powerpc specific way but it's not using elf relocation information.
I was afraid that what was needed was more or less a complete linker but it looks like if one generate the dynamic reloc table a much simpler linker(relocation function) is needed. Still probably a lot more complex than the GOT and fixup code that is just a loop over a table. We may need a case also ;-)