linux-kernel - [tip: x86/urgent] x86/xen: Add ANNOTATE_NOENDBR to startup

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Date:   Tue, 19 Apr 2022 20:08:36 -0000
From:   "tip-bot2 for Josh Poimboeuf" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Josh Poimboeuf <jpoimboe@...hat.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Andrew Cooper <andrew.cooper3@...rix.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/xen: Add ANNOTATE_NOENDBR to startup_xen()

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     1ab80a0da4c4a4dd496fc14faabbc8bde61a605c
Gitweb:        https://git.kernel.org/tip/1ab80a0da4c4a4dd496fc14faabbc8bde61a605c
Author:        Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate:    Mon, 18 Apr 2022 09:50:25 -07:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Tue, 19 Apr 2022 21:58:49 +02:00

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: ed53a0d97192 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls")
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@...rix.com>
Link: https://lkml.kernel.org/r/a87bd48b06d11ec4b98122a429e71e489b4e48c3.1650300597.git.jpoimboe@redhat.com
---
 arch/x86/xen/xen-head.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index ac17196..3a2cd93 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -45,6 +45,7 @@ SYM_CODE_END(hypercall_page)
 	__INIT
 SYM_CODE_START(startup_xen)
 	UNWIND_HINT_EMPTY
+	ANNOTATE_NOENDBR
 	cld
 
 	/* Clear .bss */