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ebe864b553
Livepatch needs some ELF magic which linkers don't like:
- Two relocation sections (.rela*, .klp.rela*) for the same text
section.
- Use of SHN_LIVEPATCH to mark livepatch symbols.
Unfortunately linkers tend to mangle such things. To work around that,
klp diff generates a linker-compliant intermediate binary which encodes
the relevant KLP section/reloc/symbol metadata.
After module linking, the .ko then needs to be converted to an actual
livepatch module. Introduce a new klp post-link subcommand to do so.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
36 lines
1.0 KiB
C
36 lines
1.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#ifndef _OBJTOOL_KLP_H
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#define _OBJTOOL_KLP_H
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#define SHF_RELA_LIVEPATCH 0x00100000
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#define SHN_LIVEPATCH 0xff20
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/*
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* __klp_objects and __klp_funcs are created by klp diff and used by the patch
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* module init code to build the klp_patch, klp_object and klp_func structs
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* needed by the livepatch API.
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*/
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#define KLP_OBJECTS_SEC "__klp_objects"
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#define KLP_FUNCS_SEC "__klp_funcs"
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/*
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* __klp_relocs is an intermediate section which are created by klp diff and
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* converted into KLP symbols/relas by "objtool klp post-link". This is needed
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* to work around the linker, which doesn't preserve SHN_LIVEPATCH or
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* SHF_RELA_LIVEPATCH, nor does it support having two RELA sections for a
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* single PROGBITS section.
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*/
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#define KLP_RELOCS_SEC "__klp_relocs"
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#define KLP_STRINGS_SEC ".rodata.klp.str1.1"
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struct klp_reloc {
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void *offset;
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void *sym;
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u32 type;
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};
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int cmd_klp_diff(int argc, const char **argv);
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int cmd_klp_post_link(int argc, const char **argv);
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#endif /* _OBJTOOL_KLP_H */
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