[RFC][PATCH 01/16] objtool: Introduce validate_return()

Peter Zijlstra
2020-03-12T13:52:02Z

Trivial 'cleanup' to save one indentation level and match
validate_call().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
tools/objtool/check.c | 64 ++++++++++++++++++++++++++++----------------------
1 file changed, 36 insertions(+), 28 deletions(-)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1935,6 +1935,41 @@ static int validate_sibling_call(struct
return validate_call(insn, state);
}

+static int validate_return(struct symbol *func, struct instruction *insn, struct insn_state *state)
+{
+ if (state->uaccess && !func_uaccess_safe(func)) {
+ WARN_FUNC("return with UACCESS enabled",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (!state->uaccess && func_uaccess_safe(func)) {
+ WARN_FUNC("return with UACCESS disabled from a UACCESS-safe function",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (state->df) {
+ WARN_FUNC("return with DF set",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (func && has_modified_stack_frame(state)) {
+ WARN_FUNC("return with modified stack frame",
+ insn->sec, insn->offset);
+ return 1;
+ }
+
+ if (state->bp_scratch) {
+ WARN("%s uses BP as a scratch register",
+ func->name);
+ return 1;
+ }
+
+ return 0;
+}
+
/*
* Follow the branch starting at the given instruction, and recursively follow
* any other branches (jumps). Meanwhile, track the frame pointer state at
@@ -2050,34 +2085,7 @@ static int validate_branch(struct objtoo
switch (insn->type) {

case INSN_RETURN:
- if (state.uaccess && !func_uaccess_safe(func)) {
- WARN_FUNC("return with UACCESS enabled", sec, insn->offset);
- return 1;
- }
-
- if (!state.uaccess && func_uaccess_safe(func)) {
- WARN_FUNC("return with UACCESS disabled from a UACCESS-safe function", sec, insn->offset);
- return 1;
- }
-
- if (state.df) {
- WARN_FUNC("return with DF set", sec, insn->offset);
- return 1;
- }
-
- if (func && has_modified_stack_frame(&state)) {
- WARN_FUNC("return with modified stack frame",
- sec, insn->offset);
- return 1;
- }
-
- if (state.bp_scratch) {
- WARN("%s uses BP as a scratch register",
- func->name);
- return 1;
- }
-
- return 0;
+ return validate_return(func, insn, &state);