4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Zijlstra <pet...@infradead.org>

commit 9e0e3c5130e949c389caabc8033e9799b129e429 upstream.

Annotate the indirect calls/jumps in the CALL_NOSPEC/JUMP_NOSPEC
alternatives.

Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Reviewed-by: David Woodhouse <d...@amazon.co.uk>
Acked-by: Thomas Gleixner <t...@linutronix.de>
Acked-by: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Arjan van de Ven <ar...@linux.intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: David Woodhouse <dw...@infradead.org>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/x86/include/asm/nospec-branch.h |   27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -68,6 +68,18 @@
 .endm
 
 /*
+ * This should be used immediately before an indirect jump/call. It tells
+ * objtool the subsequent indirect jump/call is vouched safe for retpoline
+ * builds.
+ */
+.macro ANNOTATE_RETPOLINE_SAFE
+       .Lannotate_\@:
+       .pushsection .discard.retpoline_safe
+       _ASM_PTR .Lannotate_\@
+       .popsection
+.endm
+
+/*
  * These are the bare retpoline primitives for indirect jmp and call.
  * Do not use these directly; they only exist to make the ALTERNATIVE
  * invocation below less ugly.
@@ -103,9 +115,9 @@
 .macro JMP_NOSPEC reg:req
 #ifdef CONFIG_RETPOLINE
        ANNOTATE_NOSPEC_ALTERNATIVE
-       ALTERNATIVE_2 __stringify(jmp *\reg),                           \
+       ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg),  \
                __stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \
-               __stringify(lfence; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
+               __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), 
X86_FEATURE_RETPOLINE_AMD
 #else
        jmp     *\reg
 #endif
@@ -114,9 +126,9 @@
 .macro CALL_NOSPEC reg:req
 #ifdef CONFIG_RETPOLINE
        ANNOTATE_NOSPEC_ALTERNATIVE
-       ALTERNATIVE_2 __stringify(call *\reg),                          \
+       ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg), \
                __stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\
-               __stringify(lfence; call *\reg), X86_FEATURE_RETPOLINE_AMD
+               __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), 
X86_FEATURE_RETPOLINE_AMD
 #else
        call    *\reg
 #endif
@@ -144,6 +156,12 @@
        ".long 999b - .\n\t"                                    \
        ".popsection\n\t"
 
+#define ANNOTATE_RETPOLINE_SAFE                                        \
+       "999:\n\t"                                              \
+       ".pushsection .discard.retpoline_safe\n\t"              \
+       _ASM_PTR " 999b\n\t"                                    \
+       ".popsection\n\t"
+
 #if defined(CONFIG_X86_64) && defined(RETPOLINE)
 
 /*
@@ -153,6 +171,7 @@
 # define CALL_NOSPEC                                           \
        ANNOTATE_NOSPEC_ALTERNATIVE                             \
        ALTERNATIVE(                                            \
+       ANNOTATE_RETPOLINE_SAFE                                 \
        "call *%[thunk_target]\n",                              \
        "call __x86_indirect_thunk_%V[thunk_target]\n",         \
        X86_FEATURE_RETPOLINE)


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