On Fri, Jul 25, 2008 at 7:33 AM, kenneth johansson kenneth@southpole.se wrote:
here is a patch to generate dynamic relocations in the elf file. What is the next step? objcopy -j .rela.dyn -O binary u-boot dyn_reloc_table ??
--- config.mk +++ config.mk @@ -215,7 +215,8 @@
AFLAGS := $(AFLAGS_DEBUG) -D__ASSEMBLY__ $(CPPFLAGS)
-LDFLAGS += -Bstatic -T $(LDSCRIPT) $(PLATFORM_LDFLAGS) +#LDFLAGS += -Bstatic -T $(LDSCRIPT) $(PLATFORM_LDFLAGS) +LDFLAGS += -Bstatic -shared -T $(LDSCRIPT) $(PLATFORM_LDFLAGS) ifneq ($(TEXT_BASE),) LDFLAGS += -Ttext $(TEXT_BASE) endif
Interesting, but after this step we have a file which can't be converted to a runnable binary without resolving the relocation information first, right? This is not good then, as we need something to run from reset.
I think this discussion covers much more ground than needed: certainly the problem of running the same executable at different addresses has been solved many times over, for different architectures and file formats. The thing is that unless we want the loader be part of u-boot we can not use those standard solutions. And I don't think we want, because it would be an unnecessary complication.
I still believe that my original suggestion of determining the addresses of pointers to relocate by comparing to stripped binaries is the simplest way to do it across architectures. Apparently the same could be achieved by using -mrelocatable on powerPc, this still remains to be seen.
cheers, /vb