Patch "objtool: Detect jumps to retpoline thunks" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

objtool: Detect jumps to retpoline thunks

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
objtool-detect-jumps-to-retpoline-thunks.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Josh Poimboeuf <[email protected]>
Date: Thu, 11 Jan 2018 21:46:23 +0000
Subject: objtool: Detect jumps to retpoline thunks

From: Josh Poimboeuf <[email protected]>

commit 39b735332cb8b33a27c28592d969e4016c86c3ea upstream.

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
...

---
 tools/objtool/check.c |    7 +++++++
 1 file changed, 7 insertions(+)

@@ -456,6 +456,13 @@ static int add_jump_destinations(struct
 		} 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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch queue-4.14/objtool-allow-alternatives-to-be-ignored.patch queue-4.14/x86-retpoline-add-initial-retpoline-support.patch