On Thu, Jan 16, 2014 at 03:27:13PM -0800, Eric W. Biederman wrote: [..] > > - ELF does not tell anything whether it is self relocating or not. So we > > are forced to load it at a address it has been compiled for (In case of > > kdump). And that address is already occupied by current running kernel > > so it does not work. > > ELF does tell you if it is relocatable in the e_type field of the main > elf header. In particular ET_DYN vs ET_EXEC. ET_DYN can be loaded > anywhere, and ET_EXEC must be loaded at the specified address. It would > not surprise me if the kernel build process is using ET_EXEC in error. > > ET_DYN is also what is used for PIE executables and shared libraires. > > The rule with ET_DYN without a dynamic linker is that a constant offset > must be added to the load address of all of the program segments but > otherwise nothing changes. I thought I had support for that form in > kexec-tools. > > Perhaps not. Hi Eric, Kexec-tools supports ET_DYN. I saw code for that. Current kernel vmlinux is ET_EXEC though and expects to be loaded at the address for it has been compiled for. I think in intial version of patches I will just support ET_EXEC and then support for ET_DYN can be added later. It should really be simple as all the core structure to find a memory hole and load buffers there will already be present. And at that time one can look into converting vmlinux to a ET_DYN instead of ET_EXEC. Thanks Vivek
