x86/xen: Add ANNOTATE_NOENDBR to startup_xen()

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2121207



commit 1ab80a0d
Author: Josh Poimboeuf <jpoimboe@redhat.com>
Date:   Mon Apr 18 09:50:25 2022 -0700

    x86/xen: Add ANNOTATE_NOENDBR to startup_xen()

    The startup_xen() kernel entry point is referenced by the ".note.Xen"
    section, and is the real entry point of the VM. Control transfer is
    through IRET, which *could* set NEED_ENDBR, however Xen currently does
    no such thing.

    Add ANNOTATE_NOENDBR to silence future objtool warnings.

    Fixes: ed53a0d9 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
    Link: https://lkml.kernel.org/r/a87bd48b06d11ec4b98122a429e71e489b4e48c3.1650300597.git.jpoimboe@redhat.com



Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>

arch/x86/xen/xen-head.S

@@ -46,6 +46,7 @@ SYM_CODE_END(hypercall_page)
 	__INIT
 SYM_CODE_START(startup_xen)
 	UNWIND_HINT_EMPTY
+	ANNOTATE_NOENDBR
 	cld
 
 	/* Clear .bss */