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authorJosh Poimboeuf <[email protected]>2018-01-11 21:46:23 +0000
committerThomas Gleixner <[email protected]>2018-01-12 00:14:28 +0100
commit39b735332cb8b33a27c28592d969e4016c86c3ea (patch)
tree0a53711d68fc092321ee01f755a31e16585d754e
parent445b69e3b75e42362a5bdc13c8b8f61599e2228a (diff)
objtool: Detect jumps to retpoline thunks
A direct jump to a retpoline thunk is really an indirect jump in disguise. Change the objtool instruction type accordingly. Objtool needs to know where indirect branches are so it can detect switch statement jump tables. This fixes a bunch of warnings with CONFIG_RETPOLINE like: arch/x86/events/intel/uncore_nhmex.o: warning: objtool: nhmex_rbox_msr_enable_event()+0x44: sibling call from callable instruction with modified stack frame kernel/signal.o: warning: objtool: copy_siginfo_to_user()+0x91: sibling call from callable instruction with modified stack frame ... Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: David Woodhouse <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: Rik van Riel <[email protected]> Cc: Andi Kleen <[email protected]> Cc: [email protected] Cc: Peter Zijlstra <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Kees Cook <[email protected]> Cc: Tim Chen <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Paul Turner <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
-rw-r--r--tools/objtool/check.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 9b341584eb1b..de053fb7049b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -456,6 +456,13 @@ static int add_jump_destinations(struct objtool_file *file)
} else if (rela->sym->sec->idx) {
dest_sec = rela->sym->sec;
dest_off = rela->sym->sym.st_value + rela->addend + 4;
+ } else if (strstr(rela->sym->name, "_indirect_thunk_")) {
+ /*
+ * Retpoline jumps are really dynamic jumps in
+ * disguise, so convert them accordingly.
+ */
+ insn->type = INSN_JUMP_DYNAMIC;
+ continue;
} else {
/* sibling call */
insn->jump_dest = 0;