[PATCH v4 10/15] objtool: When looking for switch tables also follow conditional and dynamic jumps
From: Christophe Leroy <hidden>
Date: 2023-07-11 16:09:17
Also in:
lkml
Subsystem:
objtool, the rest · Maintainers:
Josh Poimboeuf, Peter Zijlstra, Linus Torvalds
When walking backward to find the base address of a switch table, also take into account conditionnal branches and dynamic jumps from a previous switch table. To avoid mis-routing, break when stumbling on a function return. Signed-off-by: Christophe Leroy <redacted> --- tools/objtool/check.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 361c832aefc8..ea0945f2195f 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c@@ -2034,6 +2034,8 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn, alt->next = insn->alts; insn->alts = alt; prev_offset = reloc_offset(reloc); + if (!dest_insn->first_jump_src) + dest_insn->first_jump_src = insn; } if (!prev_offset) {
@@ -2068,6 +2070,9 @@ static struct reloc *find_jump_table(struct objtool_file *file, insn->gpr == orig_insn->gpr) break; + if (insn->type == INSN_RETURN) + break; + /* allow small jumps within the range */ if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest &&
@@ -2130,8 +2135,7 @@ static int mark_add_func_jump_tables(struct objtool_file *file, * that find_jump_table() can back-track using those and * avoid some potentially confusing code. */ - if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest && - insn->offset > last->offset && + if (is_static_jump(insn) && insn->jump_dest && insn->jump_dest->offset > insn->offset && !insn->jump_dest->first_jump_src) {
--
2.41.0