Messages in this thread Patch in this message | | | Date | Mon, 21 Dec 2015 00:44:20 -0500 | From | Jessica Yu <> | Subject | Re: module: preserve Elf information for livepatch modules |
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+++ Petr Mladek [17/12/15 17:26 +0100]: >On Mon 2015-11-30 23:21:15, Jessica Yu wrote: >> For livepatch modules, copy Elf section, symbol, and string information >> from the load_info struct in the module loader. >> >> Livepatch uses special relocation sections in order to be able to patch >> modules that are not yet loaded, as well as apply patches to the kernel >> when the addresses of symbols cannot be determined at compile time (for >> example, when kaslr is enabled). Livepatch modules must preserve Elf >> information such as section indices in order to apply the remaining >> relocation sections at the appropriate time (i.e. when the target module >> loads). >> >> Signed-off-by: Jessica Yu <jeyu@redhat.com> >> --- >> include/linux/module.h | 9 +++++ >> kernel/module.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++-- >> 2 files changed, 105 insertions(+), 2 deletions(-) >> >> diff --git a/include/linux/module.h b/include/linux/module.h >> index 3a19c79..9b46256 100644 >> --- a/include/linux/module.h >> +++ b/include/linux/module.h >> @@ -425,6 +425,14 @@ struct module { >> >> /* Notes attributes */ >> struct module_notes_attrs *notes_attrs; >> + >> + /* Elf information (optionally saved) */ >> + Elf_Ehdr *hdr; >> + Elf_Shdr *sechdrs; >> + char *secstrings; >> + struct { >> + unsigned int sym, str, mod, vers, info, pcpu; >> + } index; >> #endif > >I would hide this into a structure. It is 3 pointers and 6 integers >that are mostly unused. I think about using a pointer to struct load_info >here. We could set the unused stuff to zero and NULL. > >Any better idea how to share the definition with struct load_info >is welcome.
Sure. If we want to encapsulate all this information, we can perhaps replace this with a single pointer to a copy of load_info, and maybe move the struct definition of load_info to module.h.
Jessica
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