Vivek Goyal <vgoyal at redhat.com> writes: > 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. Sounds good. Eric
