Re: [RFC PATCH v2 2/6] module: preserve Elf information for livepatch modules
From: Petr Mladek <pmladek@suse.com>
Date: 2015-12-17 16:26:19
Also in:
linux-s390, lkml
On Mon 2015-11-30 23:21:15, Jessica Yu wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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. Best Regards, Petr