Commit 96db4a98 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

objtool: Read the NOENDBR annotation 



Read the new NOENDBR annotation. While there, attempt to not bloat
struct instruction.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.586815435@infradead.org
parent 3515899b

tools/objtool/check.c

+27 −0
Original line number Diff line number Diff line
@@ -1866,6 +1866,29 @@ static int read_unwind_hints(struct objtool_file *file) 
	return 0;

}



static int read_noendbr_hints(struct objtool_file *file)

{

	struct section *sec;

	struct instruction *insn;

	struct reloc *reloc;



	sec = find_section_by_name(file->elf, ".rela.discard.noendbr");

	if (!sec)

		return 0;



	list_for_each_entry(reloc, &sec->reloc_list, list) {

		insn = find_insn(file, reloc->sym->sec, reloc->sym->offset + reloc->addend);

		if (!insn) {

			WARN("bad .discard.noendbr entry");

			return -1;

		}



		insn->noendbr = 1;

	}



	return 0;

}



static int read_retpoline_hints(struct objtool_file *file)

{

	struct section *sec;
@@ -2099,6 +2122,10 @@ static int decode_sections(struct objtool_file *file) 
	if (ret)

		return ret;



	ret = read_noendbr_hints(file);

	if (ret)

		return ret;



	/*

	 * Must be before add_{jump_call}_destination.

	 */

tools/objtool/include/objtool/check.h

+10 −3
Original line number Diff line number Diff line
@@ -45,11 +45,18 @@ struct instruction { 
	unsigned int len;

	enum insn_type type;

	unsigned long immediate;

	bool dead_end, ignore, ignore_alts;

	bool hint;

	bool retpoline_safe;



	u8 dead_end	: 1,

	   ignore	: 1,

	   ignore_alts	: 1,

	   hint		: 1,

	   retpoline_safe : 1,

	   noendbr	: 1;

		/* 2 bit hole */

	s8 instr;

	u8 visited;

	/* u8 hole */



	struct alt_group *alt_group;

	struct symbol *call_dest;

	struct instruction *jump_dest;