Documentation/livepatch/module-elf-format.rst

30 table, symbol table, and relocation section indices, ELF information is
47 symbols while taking into account its scope and what module the symbol
103 Every symbol referenced by a rela in a livepatch relocation section is a
104 livepatch symbol. These must be resolved before livepatch can call
175       Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
185   Every symbol referenced by a relocation is a livepatch symbol.
194 resolves exported syms, and not every symbol referenced by the new patched
196 also in cases where we cannot immediately know the address of a symbol when
206 in their symbol tables, and the symbol table is made accessible through
209 4.1 A livepatch module's symbol table
211 Normally, a stripped down copy of a module's symbol table (containing only
213 in kernel/module/kallsyms.c). For livepatch modules, the symbol table copied
214 into memory on module load must be exactly the same as the symbol table produced
216 livepatch relocation section refer to their respective symbols with their symbol
217 indices, and the original symbol indices (and thus the symtab ordering) must be
218 preserved in order for apply_relocate_add() to find the right symbol.
223       Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
226 This rela refers to the symbol '.klp.sym.vmlinux.printk,0', and the symbol
227 index is encoded in 'Info'. Here its symbol index is 0x5e, which is 94 in
228 decimal, which refers to the symbol index 94.
230 And in this patch module's corresponding symbol table, symbol index 94 refers
231 to that very symbol::
237 4.2 Livepatch symbol format
244 Livepatch symbol names must conform to the following format::
252   The symbol name is prefixed with the string ".klp.sym."
256   which the symbol belongs follows immediately after the prefix.
259   The actual name of the symbol.
262   The position of the symbol in the object (as according to kallsyms)
264   object. The symbol position is expressed numerically (0, 1, 2...).
265   The symbol position of a unique symbol is 0.
270 **Livepatch symbol names:**
282   Symbol table '.symtab' contains 127 entries:
297 5. Symbol table and ELF section access
299 A livepatch module's symbol table is accessible through module->symtab.
302 symbol table, and relocation section indices, ELF information is preserved for