Revert "objtool: Warn on functions with ambiguous -ffunction-sections section names"

This reverts commit 9c7dc1d.

The check-function-names.sh script now provides the function name
checking functionality for all architectures, making the objtool check
redundant.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/c7d549d4de8bd1490d106b99630eea5efc69a4dd.1763669451.git.jpoimboe@kernel.org

Author: jpoimboe

tools/objtool/Documentation/objtool.txt

@@ -456,13 +456,6 @@ the objtool maintainers.
     these special names and does not use module_init() / module_exit()
     macros to create them.
 
-13. file.o: warning: func() function name creates ambiguity with -ffunctions-sections
-
-    Functions named startup(), exit(), split(), unlikely(), hot(), and
-    unknown() are not allowed due to the ambiguity of their section
-    names when compiled with -ffunction-sections.  For more information,
-    see the comment above TEXT_MAIN in include/asm-generic/vmlinux.lds.h.
-
 
 If the error doesn't seem to make sense, it could be a bug in objtool.
 Feel free to ask objtool maintainers for help.

tools/objtool/check.c

@@ -2642,37 +2642,6 @@ static int decode_sections(struct objtool_file *file)
 	return 0;
 }
 
-/*
- * Certain function names are disallowed due to section name ambiguities
- * introduced by -ffunction-sections.
- *
- * See the comment above TEXT_MAIN in include/asm-generic/vmlinux.lds.h.
- */
-static int validate_function_names(struct objtool_file *file)
-{
-	struct symbol *func;
-	int warnings = 0;
-
-	for_each_sym(file->elf, func) {
-		if (!is_func_sym(func))
-			continue;
-
-		if (!strcmp(func->name, "startup")	|| strstarts(func->name, "startup.")	||
-		    !strcmp(func->name, "exit")		|| strstarts(func->name, "exit.")	||
-		    !strcmp(func->name, "split")	|| strstarts(func->name, "split.")	||
-		    !strcmp(func->name, "unlikely")	|| strstarts(func->name, "unlikely.")	||
-		    !strcmp(func->name, "hot")		|| strstarts(func->name, "hot.")	||
-		    !strcmp(func->name, "unknown")	|| strstarts(func->name, "unknown.")) {
-
-			WARN("%s() function name creates ambiguity with -ffunction-sections",
-			     func->name);
-			warnings++;
-		}
-	}
-
-	return warnings;
-}
-
 static bool is_special_call(struct instruction *insn)
 {
 	if (insn->type == INSN_CALL) {
@@ -4942,8 +4911,6 @@ int check(struct objtool_file *file)
 	if (!nr_insns)
 		goto out;
 
-	warnings += validate_function_names(file);
-
 	if (opts.retpoline)
 		warnings += validate_retpoline(file);