On 22/07/20 9:55 am, Michael Ellerman wrote: > 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 >> sha256 digest, relocations may have to be applied to the purgatory. >> So, add support to relocate purgatory in kexec_file_load system call >> by setting up TOC pointer and applying RELA relocations as needed. >> >> 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> >> --- >> >> * Michael, can you share your opinion on the below: >> - https://lore.kernel.org/patchwork/patch/1272027/ >> - My intention in cover note. > > It seems like a lot of complexity for little benefit. > > AFAICS your final purgatory_64.c is only 36 lines, and all it does is a > single (open coded) memcpy(). > > It seems like we could write that in not many more lines of assembler > and avoid all this code. Hi Michael, I am not sure if you would agree with me on this, but I am looking at the purgatory code as work in progress. As mentioned in the cover note, I intend to add log messaging, sha256 verification into purgatory. And also change it to position independent executable after moving common purgatory code (sha256 verification) to arch-independent code. When I initially took this up, I wanted to add all the above changes too, but cut down on it, in the interest of time, first to get kdump (kexec -s -p) working in v5.9 merge window. But as the logic in patches 07/12 & 08/12 has been tested in kexec-tools code a lot of times and there are unlikely to be any changes to them except for __kexec_do_relocs() function (afaics), when -PIE would be used, I submitted them. With patch 09/12, I tried for a change that uses relocations while is minimal for now. Would you prefer it to be absolutely minimal by dropping patches 7 & 8 for now and writing the backup data copy code in assembler? Thanks Hari _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
