Patch "objtool: Fix retpoline detection in asm code" has been added to the 5.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    objtool: Fix retpoline detection in asm code

to the 5.11-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-fix-retpoline-detection-in-asm-code.patch
and it can be found in the queue-5.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit cac84e9b4ef2caeb740ac08847d50f70272c1e4f
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Date:   Thu Jan 21 15:29:18 2021 -0600

    objtool: Fix retpoline detection in asm code
    
    [ Upstream commit 1f9a1b74942485a0a29e7c4a9a9f2fe8aea17766 ]
    
    The JMP_NOSPEC macro branches to __x86_retpoline_*() rather than the
    __x86_indirect_thunk_*() wrappers used by C code.  Detect jumps to
    __x86_retpoline_*() as retpoline dynamic jumps.
    
    Presumably this doesn't trigger a user-visible bug.  I only found it
    when testing vmlinux.o validation.
    
    Fixes: 39b735332cb8 ("objtool: Detect jumps to retpoline thunks")
    Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/31f5833e2e4f01e3d755889ac77e3661e906c09f.1611263461.git.jpoimboe@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index fd4af88c0ea52..151b13d0a2676 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -48,7 +48,7 @@ bool arch_support_alt_relocation(struct special_alt *special_alt,
 	 * replacement group.
 	 */
 	return insn->offset == special_alt->new_off &&
-	       (insn->type == INSN_CALL || is_static_jump(insn));
+	       (insn->type == INSN_CALL || is_jump(insn));
 }
 
 /*
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2e154f00ccec2..48e22e3c6f186 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -789,7 +789,8 @@ static int add_jump_destinations(struct objtool_file *file)
 			dest_sec = reloc->sym->sec;
 			dest_off = reloc->sym->sym.st_value +
 				   arch_dest_reloc_offset(reloc->addend);
-		} else if (strstr(reloc->sym->name, "_indirect_thunk_")) {
+		} else if (!strncmp(reloc->sym->name, "__x86_indirect_thunk_", 21) ||
+			   !strncmp(reloc->sym->name, "__x86_retpoline_", 16)) {
 			/*
 			 * Retpoline jumps are really dynamic jumps in
 			 * disguise, so convert them accordingly.
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index 5ec00a4b891b6..2804848e628e3 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -54,6 +54,17 @@ static inline bool is_static_jump(struct instruction *insn)
 	       insn->type == INSN_JUMP_UNCONDITIONAL;
 }
 
+static inline bool is_dynamic_jump(struct instruction *insn)
+{
+	return insn->type == INSN_JUMP_DYNAMIC ||
+	       insn->type == INSN_JUMP_DYNAMIC_CONDITIONAL;
+}
+
+static inline bool is_jump(struct instruction *insn)
+{
+	return is_static_jump(insn) || is_dynamic_jump(insn);
+}
+
 struct instruction *find_insn(struct objtool_file *file,
 			      struct section *sec, unsigned long offset);