Re: module: preserve Elf information for livepatch modules

[Jessica Yu]

+++ Jessica Yu [30/11/15 23:21 -0500]:
> 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@xxxxxxxxxx>
> ---
> 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
>
> 	/* The command line arguments (may be mangled).  People like
> @@ -461,6 +469,7 @@ struct module {
> #endif
>
> #ifdef CONFIG_LIVEPATCH
> +	bool klp; /* Is this a livepatch module? */

Gah. I believe this field should be outside the #ifdef. 

Jessica
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