Hari Bathini <hbathini@xxxxxxxxxxxxx> writes: > Right now purgatory implementation is only minimal. But if purgatory > code is to be enhanced to copy memory to the backup region and verify Can't the memcpy be done in asm? We have arch/powerpc/lib/memcpy_64.S for example, perhaps it could be linked in with the purgatory? > sha256 digest, relocations may have to be applied to the purgatory. Do we want to do the sha256 verification? My original patch series for kexec_file_load() had a purgatory in C from kexec-tools which did the sha256 verification but Michael Ellerman thought it was unnecessary and decided to use the simpler purgatory in asm from kexec-lite. As a result, this relocation processing became unnecessary. > So, add support to relocate purgatory in kexec_file_load system call > by setting up TOC pointer and applying RELA relocations as needed. If we do want to use a C purgatory, Michael Ellerman had suggested building it as a Position Independent Executable, which greatly reduces the number and types of relocations that are needed. See patches 4 and 9 here: https://lore.kernel.org/linuxppc-dev/1478748449-3894-1-git-send-email-bauerman@xxxxxxxxxxxxxxxxxx/ In the series above I hadn't converted x86 to PIE. If I had done that, possibly Dave Young's opinion would have been different. :-) If that's still not desirable, he suggested in that discussion lifting some code from x86 to generic code, which I implemented and would simplify this patch as well: https://lore.kernel.org/linuxppc-dev/5009580.5GxAkTrMYA@morokweng/ > Reported-by: kernel test robot <lkp@xxxxxxxxx> > [lkp: In v1, 'struct mem_sym' was declared in parameter list] > Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxx> > --- > > v2 -> v3: > * Fixed get_toc_section() to return the section info that had relocations > applied, to calculate the correct toc pointer. > * Fixed how relocation value is converted to relative while applying > R_PPC64_REL64 & R_PPC64_REL32 relocations. > > v1 -> v2: > * Fixed wrong use of 'struct mem_sym' in local_entry_offset() as > reported by lkp. lkp report for reference: > - https://lore.kernel.org/patchwork/patch/1264421/ > > > arch/powerpc/kexec/file_load_64.c | 337 ++++++++++++++++++++++++++++++++ > arch/powerpc/purgatory/trampoline_64.S | 8 + > 2 files changed, 345 insertions(+) -- Thiago Jung Bauermann IBM Linux Technology Center _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
