x86/xen: Add UNTRAIN_RET

commit d147553b64bad34d2f92cb7d8ba454ae95c3baac upstream.

Ensure the Xen entry also passes through UNTRAIN_RET.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index ebeeb01..f9afa65 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -320,6 +320,12 @@ SYM_CODE_END(ret_from_fork)
 #endif
 .endm
 
+SYM_CODE_START_LOCAL(xen_error_entry)
+       UNWIND_HINT_FUNC
+       UNTRAIN_RET
+       RET
+SYM_CODE_END(xen_error_entry)
+
 /**
  * idtentry_body - Macro to emit code calling the C function
  * @cfunc:             C function to be called
@@ -339,7 +345,7 @@ SYM_CODE_END(ret_from_fork)
         * switch the CR3.  So it can skip invoking error_entry().
         */
        ALTERNATIVE "call error_entry; movq %rax, %rsp", \
-               "", X86_FEATURE_XENPV
+                   "call xen_error_entry", X86_FEATURE_XENPV
 
        ENCODE_FRAME_POINTER
        UNWIND_HINT_REGS