From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 14 Jun 2022 21:16:01 +0000 (+0200)
Subject: x86/xen: Add UNTRAIN_RET
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d147553b64bad34d2f92cb7d8ba454ae95c3baac;p=linux.git

x86/xen: Add UNTRAIN_RET

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>
---

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index f4384a29086f1..0c88802e1155d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -328,6 +328,12 @@ 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
@@ -347,7 +353,7 @@ 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