kpatch/LoongArch: change local labels with sections symbols

Here fix error like: "tcp.o: symbol changed sections: .LBB7266.
create-diff-object: unreconcilable difference".
Due to LoongArch GCC generating local labels such as .LBB7266,
it is difficult to compare the modified sections in the
corresponding object files of the two files before and after
the patch, so change them with sections symbols in rela section,
and delete them in other sections.

Co-developed-by: zhanghongchen <[email protected]>
Signed-off-by: George Guo <[email protected]>

Author: georgejguo

kpatch-build/kpatch-elf.c

@@ -336,6 +336,22 @@ static void kpatch_create_rela_list(struct kpatch_elf *kelf,
 				      rela->sym->name, rela->addend);
 		}
 
+		if (kelf->arch == LOONGARCH64) {
+			/*
+			 * LoongArch GCC creates local labels such as .LBB7266,
+			 * replace them with section symbols.
+			 */
+			if (rela->sym->sec && (rela->sym->type == STT_NOTYPE) &&
+				(rela->sym->bind == STB_LOCAL)) {
+				log_debug("local label: %s -> ", rela->sym->name);
+
+				rela->addend += rela->sym->sym.st_value;
+				rela->sym = rela->sym->sec->secsym;
+				log_debug("section symbol: %s\n", rela->sym->name);
+			}
+		}
+
+
 		if (skip)
 			continue;
 		log_debug("offset %d, type %d, %s %s %ld", rela->offset,
@@ -625,6 +641,18 @@ struct kpatch_elf *kpatch_elf_open(const char *name)
 		if (find_section_by_name(&kelf->sections, "__patchable_function_entries"))
 			kelf->has_pfe = true;
 
+	if (kelf->arch == LOONGARCH64) {
+		struct symbol *sym, *tmp;
+
+		/* Delete local labels created by LoongArch GCC */
+		list_for_each_entry_safe(sym, tmp, &kelf->symbols, list) {
+			if (sym->sec && !is_rela_section(sym->sec) &&
+				(sym->type == STT_NOTYPE) &&
+				(sym->bind == STB_LOCAL))
+				list_del(&sym->list);
+		}
+	}
+
 	return kelf;
 }