Re: [RFC PATCH v2 12/20] objtool: Warn about non __ro_after_init static key usage in .noinstr

On 28/07/23 10:35, Josh Poimboeuf wrote:

On Thu, Jul 20, 2023 at 05:30:48PM +0100, Valentin Schneider wrote:

quoted

+static int validate_static_key(struct instruction *insn, struct insn_state *state)
+{
+	if (state->noinstr && state->instr <= 0) {
+		if ((strcmp(insn->key_sym->sec->name, ".data..ro_after_init"))) {
+			WARN_INSN(insn,
+				  "Non __ro_after_init static key \"%s\" in .noinstr section",

For consistency with other warnings, this should start with a lowercase
"n" and the string literal should be on the same line as the WARN_INSN,
like

                      WARN_INSN(insn, "non __ro_after_init static key \"%s\" in .noinstr section",
                                ...

quoted

diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index 91b1950f5bd8a..1f76cfd815bf3 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c

@@ -127,6 +127,9 @@ static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
                     return -1;
             }
             alt->key_addend = reloc_addend(key_reloc);
+
+		reloc_to_sec_off(key_reloc, &sec, &offset);
+		alt->key_sym = find_symbol_by_offset(sec, offset & ~2);

Bits 0 and 1 can both store data, should be ~3?

Quite so, that needs to be the same as jump_entry_key().

--
Josh