On Tue, Apr 28, 2020 at 09:31:57AM -0500, Josh Poimboeuf wrote:
> That's quite the monstrosity, and I still don't see the point. I
> thought we decided to just disallow CFI changes in alternatives anyway?
> That can be done much simpler.
Something like so then ?
---
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 8443ec690051..d14d83e6edb0 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -940,6 +940,7 @@ static int handle_group_alt(struct objtool_file *file,
last_new_insn = insn;
+ insn->alt_group = true;
insn->ignore = orig_insn->ignore_alts;
insn->func = orig_insn->func;
@@ -2242,6 +2243,11 @@ static int handle_insn_ops(struct instruction *insn,
struct insn_state *state)
list_for_each_entry(op, &insn->stack_ops, list) {
int res;
+ if (insn->alt_group) {
+ WARN_FUNC("alternative has CFI", insn->sec,
insn->offset);
+ return 1;
+ }
+
res = update_cfi_state(insn, &state->cfi, op);
if (res)
return res;
@@ -2439,12 +2445,6 @@ static int validate_branch(struct objtool_file *file,
struct symbol *func,
sec = insn->sec;
- if (insn->alt_group && list_empty(&insn->alts)) {
- WARN_FUNC("don't know how to handle branch to middle of
alternative instruction group",
- sec, insn->offset);
- return 1;
- }
-
while (1) {
next_insn = next_insn_same_sec(file, insn);
@@ -2494,8 +2494,16 @@ static int validate_branch(struct objtool_file *file,
struct symbol *func,
}
}
- if (skip_orig)
+ if (skip_orig) {
+ struct instruction *prev_insn = insn;
+ sec_for_each_insn_continue(file, insn) {
+ if (!insn->alt_group)
+ break;
+ if (!insn->visited)
+ insn->cfi = prev_insn->cfi;
+ }
return 0;
+ }
}
if (handle_insn_ops(insn, &state))
