[patch 07/38] objtool: Track init section

Thomas Gleixner
2022-07-16T23:17:45Z

From: Peter Zijlstra <peterz@infradead.org>

For future usage of .init.text exclusion track the init section in the
instruction decoder and use the result in retpoline validation.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
tools/objtool/check.c | 17 ++++++++++-------
tools/objtool/include/objtool/elf.h | 2 +-
2 files changed, 11 insertions(+), 8 deletions(-)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -380,6 +380,15 @@ static int decode_instructions(struct ob
!strncmp(sec->name, ".text.__x86.", 12))
sec->noinstr = true;

+ /*
+ * .init.text code is ran before userspace and thus doesn't
+ * strictly need retpolines, except for modules which are
+ * loaded late, they very much do need retpoline in their
+ * .init.text
+ */
+ if (!strcmp(sec->name, ".init.text") && !opts.module)
+ sec->init = true;
+
for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
insn = malloc(sizeof(*insn));
if (!insn) {
@@ -3720,13 +3729,7 @@ static int validate_retpoline(struct obj
if (insn->retpoline_safe)
continue;

- /*
- * .init.text code is ran before userspace and thus doesn't
- * strictly need retpolines, except for modules which are
- * loaded late, they very much do need retpoline in their
- * .init.text
- */
- if (!strcmp(insn->sec->name, ".init.text") && !opts.module)
+ if (insn->sec->init)
continue;

if (insn->type == INSN_RETURN) {
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -38,7 +38,7 @@ struct section {
Elf_Data *data;
char *name;
int idx;
- bool changed, text, rodata, noinstr;
+ bool changed, text, rodata, noinstr, init;
};

struct symbol {