linux-kernel - [PATCH V2 9/9] x86/speculation: Remove all ANNOTATE_NOSPEC

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Date:   Tue,  7 Apr 2020 09:31:42 +0200
From:   Alexandre Chartre <alexandre.chartre@...cle.com>
To:     x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, jpoimboe@...hat.com,
        peterz@...radead.org, jthierry@...hat.com, tglx@...utronix.de,
        alexandre.chartre@...cle.com
Subject: [PATCH V2 9/9] x86/speculation: Remove all ANNOTATE_NOSPEC_ALTERNATIVE directives

Now that intra-function calls have been annotated and are supported
by objtool, that retpoline return instructions have been annotated,
and that __FILL_RETURN_BUFFER code is compatible with objtool, then
all ANNOTATE_NOSPEC_ALTERNATIVE directives can be removed.

Signed-off-by: Alexandre Chartre <alexandre.chartre@...cle.com>
---
 arch/x86/include/asm/nospec-branch.h | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 5ce2a40a26da..6480db4304a0 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -124,7 +124,6 @@
  */
 .macro JMP_NOSPEC reg:req
 #ifdef CONFIG_RETPOLINE
-	ANNOTATE_NOSPEC_ALTERNATIVE
 	ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg),	\
 		__stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE,	\
 		__stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
@@ -135,7 +134,6 @@
 
 .macro CALL_NOSPEC reg:req
 #ifdef CONFIG_RETPOLINE
-	ANNOTATE_NOSPEC_ALTERNATIVE
 	ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg),	\
 		__stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\
 		__stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), X86_FEATURE_RETPOLINE_AMD
@@ -150,7 +148,6 @@
   */
 .macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
 #ifdef CONFIG_RETPOLINE
-	ANNOTATE_NOSPEC_ALTERNATIVE
 	ALTERNATIVE "jmp .Lskip_rsb_\@",				\
 		__stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP))	\
 		\ftr
@@ -174,7 +171,6 @@
  * which is ensured when CONFIG_RETPOLINE is defined.
  */
 # define CALL_NOSPEC						\
-	ANNOTATE_NOSPEC_ALTERNATIVE				\
 	ALTERNATIVE_2(						\
 	ANNOTATE_RETPOLINE_SAFE					\
 	"call *%[thunk_target]\n",				\
@@ -193,7 +189,6 @@
  * here, anyway.
  */
 # define CALL_NOSPEC						\
-	ANNOTATE_NOSPEC_ALTERNATIVE				\
 	ALTERNATIVE_2(						\
 	ANNOTATE_RETPOLINE_SAFE					\
 	"call *%[thunk_target]\n",				\
@@ -261,8 +256,7 @@ static inline void vmexit_fill_RSB(void)
 #ifdef CONFIG_RETPOLINE
 	unsigned long loops;
 
-	asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
-		      ALTERNATIVE("jmp 910f",
+	asm volatile (ALTERNATIVE("jmp 910f",
 				  __stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)),
 				  X86_FEATURE_RETPOLINE)
 		      "910:"
-- 
2.18.2