linux-kernel - [PATCH 3/3] x86/speculation: Support intra-function call validation

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Message-Id: <20240226094101.95544-4-qirui.001@bytedance.com>
Date: Mon, 26 Feb 2024 17:41:01 +0800
From: "$(name)" <qirui.001@...edance.com>
To: bp@...en8.de,
	mingo@...hat.com,
	tglx@...utronix.de,
	hpa@...or.com,
	jpoimboe@...hat.com,
	peterz@...radead.org,
	mbenes@...e.cz,
	gregkh@...uxfoundation.org,
	stable@...r.kernel.org,
	alexandre.chartre@...cle.com
Cc: x86@...nel.org,
	linux-kernel@...r.kernel.org,
	qirui.001@...edance.com
Subject: [PATCH 3/3] x86/speculation: Support intra-function call validation

From: Rui Qi <qirui.001@...edance.com>

commit 8afd1c7da2b0 ("x86/speculation: Change FILL_RETURN_BUFFER
 to work with objtool") does not support intra-function call
 stack validation, which causes kernel live patching to fail.
This commit adds support for this, and after testing, the kernel
 live patching feature is restored to normal.

Fixes: 8afd1c7da2b0 ("x86/speculation: Change FILL_RETURN_BUFFER to work with objtool")

Signed-off-by: Rui Qi <qirui.001@...edance.com>
---
 arch/x86/include/asm/nospec-branch.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index c8819358a332..a88135c358c0 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -13,6 +13,8 @@
 #include <asm/unwind_hints.h>
 #include <asm/percpu.h>
 
+#include <linux/frame.h>
+#include <asm/unwind_hints.h>
 /*
  * This should be used immediately before a retpoline alternative. It tells
  * objtool where the retpolines are so that it can make sense of the control
@@ -51,14 +53,18 @@
 #define __FILL_RETURN_BUFFER(reg, nr, sp)	\
 	mov	$(nr/2), reg;			\
 771:						\
+	ANNOTATE_INTRA_FUNCTION_CALL;           \
 	call	772f;				\
 773:	/* speculation trap */			\
+	UNWIND_HINT_EMPTY;		\
 	pause;					\
 	lfence;					\
 	jmp	773b;				\
 772:						\
+	ANNOTATE_INTRA_FUNCTION_CALL;           \
 	call	774f;				\
 775:	/* speculation trap */			\
+	UNWIND_HINT_EMPTY;                      \
 	pause;					\
 	lfence;					\
 	jmp	775b;				\
@@ -152,6 +158,7 @@
 .endm
 
 .macro ISSUE_UNBALANCED_RET_GUARD
+	ANNOTATE_INTRA_FUNCTION_CALL;
 	call .Lunbalanced_ret_guard_\@
 	int3
 .Lunbalanced_ret_guard_\@:
-- 
2.39.2 (Apple Git-143)