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Diffstat (limited to 'tools/objtool/check.c')
-rw-r--r--tools/objtool/check.c191
1 files changed, 180 insertions, 11 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index cb57c526ba17..368275de5f23 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -100,7 +100,6 @@ static bool gcov_enabled(struct objtool_file *file)
static bool ignore_func(struct objtool_file *file, struct symbol *func)
{
struct rela *rela;
- struct instruction *insn;
/* check for STACK_FRAME_NON_STANDARD */
if (file->whitelist && file->whitelist->rela)
@@ -113,11 +112,6 @@ static bool ignore_func(struct objtool_file *file, struct symbol *func)
return true;
}
- /* check if it has a context switching instruction */
- func_for_each_insn(file, func, insn)
- if (insn->type == INSN_CONTEXT_SWITCH)
- return true;
-
return false;
}
@@ -879,6 +873,99 @@ static int add_switch_table_alts(struct objtool_file *file)
return 0;
}
+static int read_unwind_hints(struct objtool_file *file)
+{
+ struct section *sec, *relasec;
+ struct rela *rela;
+ struct unwind_hint *hint;
+ struct instruction *insn;
+ struct cfi_reg *cfa;
+ int i;
+
+ sec = find_section_by_name(file->elf, ".discard.unwind_hints");
+ if (!sec)
+ return 0;
+
+ relasec = sec->rela;
+ if (!relasec) {
+ WARN("missing .rela.discard.unwind_hints section");
+ return -1;
+ }
+
+ if (sec->len % sizeof(struct unwind_hint)) {
+ WARN("struct unwind_hint size mismatch");
+ return -1;
+ }
+
+ file->hints = true;
+
+ for (i = 0; i < sec->len / sizeof(struct unwind_hint); i++) {
+ hint = (struct unwind_hint *)sec->data->d_buf + i;
+
+ rela = find_rela_by_dest(sec, i * sizeof(*hint));
+ if (!rela) {
+ WARN("can't find rela for unwind_hints[%d]", i);
+ return -1;
+ }
+
+ insn = find_insn(file, rela->sym->sec, rela->addend);
+ if (!insn) {
+ WARN("can't find insn for unwind_hints[%d]", i);
+ return -1;
+ }
+
+ cfa = &insn->state.cfa;
+
+ if (hint->type == UNWIND_HINT_TYPE_SAVE) {
+ insn->save = true;
+ continue;
+
+ } else if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
+ insn->restore = true;
+ insn->hint = true;
+ continue;
+ }
+
+ insn->hint = true;
+
+ switch (hint->sp_reg) {
+ case ORC_REG_UNDEFINED:
+ cfa->base = CFI_UNDEFINED;
+ break;
+ case ORC_REG_SP:
+ cfa->base = CFI_SP;
+ break;
+ case ORC_REG_BP:
+ cfa->base = CFI_BP;
+ break;
+ case ORC_REG_SP_INDIRECT:
+ cfa->base = CFI_SP_INDIRECT;
+ break;
+ case ORC_REG_R10:
+ cfa->base = CFI_R10;
+ break;
+ case ORC_REG_R13:
+ cfa->base = CFI_R13;
+ break;
+ case ORC_REG_DI:
+ cfa->base = CFI_DI;
+ break;
+ case ORC_REG_DX:
+ cfa->base = CFI_DX;
+ break;
+ default:
+ WARN_FUNC("unsupported unwind_hint sp base reg %d",
+ insn->sec, insn->offset, hint->sp_reg);
+ return -1;
+ }
+
+ cfa->offset = hint->sp_offset;
+ insn->state.type = hint->type;
+ }
+
+ return 0;
+}
+
static int decode_sections(struct objtool_file *file)
{
int ret;
@@ -909,6 +996,10 @@ static int decode_sections(struct objtool_file *file)
if (ret)
return ret;
+ ret = read_unwind_hints(file);
+ if (ret)
+ return ret;
+
return 0;
}
@@ -1382,7 +1473,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
struct insn_state state)
{
struct alternative *alt;
- struct instruction *insn;
+ struct instruction *insn, *next_insn;
struct section *sec;
struct symbol *func = NULL;
int ret;
@@ -1397,6 +1488,8 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
}
while (1) {
+ next_insn = next_insn_same_sec(file, insn);
+
if (file->c_file && insn->func) {
if (func && func != insn->func) {
WARN("%s() falls through to next function %s()",
@@ -1414,13 +1507,54 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
}
if (insn->visited) {
- if (!!insn_state_match(insn, &state))
+ if (!insn->hint && !insn_state_match(insn, &state))
return 1;
return 0;
}
- insn->state = state;
+ if (insn->hint) {
+ if (insn->restore) {
+ struct instruction *save_insn, *i;
+
+ i = insn;
+ save_insn = NULL;
+ func_for_each_insn_continue_reverse(file, func, i) {
+ if (i->save) {
+ save_insn = i;
+ break;
+ }
+ }
+
+ if (!save_insn) {
+ WARN_FUNC("no corresponding CFI save for CFI restore",
+ sec, insn->offset);
+ return 1;
+ }
+
+ if (!save_insn->visited) {
+ /*
+ * Oops, no state to copy yet.
+ * Hopefully we can reach this
+ * instruction from another branch
+ * after the save insn has been
+ * visited.
+ */
+ if (insn == first)
+ return 0;
+
+ WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo",
+ sec, insn->offset);
+ return 1;
+ }
+
+ insn->state = save_insn->state;
+ }
+
+ state = insn->state;
+
+ } else
+ insn->state = state;
insn->visited = true;
@@ -1497,6 +1631,14 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
return 0;
+ case INSN_CONTEXT_SWITCH:
+ if (func && (!next_insn || !next_insn->hint)) {
+ WARN_FUNC("unsupported instruction in callable function",
+ sec, insn->offset);
+ return 1;
+ }
+ return 0;
+
case INSN_STACK:
if (update_insn_state(insn, &state))
return -1;
@@ -1510,7 +1652,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
if (insn->dead_end)
return 0;
- insn = next_insn_same_sec(file, insn);
+ insn = next_insn;
if (!insn) {
WARN("%s: unexpected end of section", sec->name);
return 1;
@@ -1520,6 +1662,27 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
return 0;
}
+static int validate_unwind_hints(struct objtool_file *file)
+{
+ struct instruction *insn;
+ int ret, warnings = 0;
+ struct insn_state state;
+
+ if (!file->hints)
+ return 0;
+
+ clear_insn_state(&state);
+
+ for_each_insn(file, insn) {
+ if (insn->hint && !insn->visited) {
+ ret = validate_branch(file, insn, state);
+ warnings += ret;
+ }
+ }
+
+ return warnings;
+}
+
static bool is_kasan_insn(struct instruction *insn)
{
return (insn->type == INSN_CALL &&
@@ -1665,8 +1828,9 @@ int check(const char *_objname, bool _nofp, bool orc)
hash_init(file.insn_hash);
file.whitelist = find_section_by_name(file.elf, ".discard.func_stack_frame_non_standard");
file.rodata = find_section_by_name(file.elf, ".rodata");
- file.ignore_unreachables = false;
file.c_file = find_section_by_name(file.elf, ".comment");
+ file.ignore_unreachables = false;
+ file.hints = false;
arch_initial_func_cfi_state(&initial_func_cfi);
@@ -1683,6 +1847,11 @@ int check(const char *_objname, bool _nofp, bool orc)
goto out;
warnings += ret;
+ ret = validate_unwind_hints(&file);
+ if (ret < 0)
+ goto out;
+ warnings += ret;
+
if (!warnings) {
ret = validate_reachable_instructions(&file);
if (ret < 0)