linux-kernel - [PATCH 5.18 08/61] x86/retpoline: Cleanup some #ifdefery

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Date:   Tue, 12 Jul 2022 20:39:05 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Borislav Petkov <bp@...e.de>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        Thadeu Lima de Souza Cascardo <cascardo@...onical.com>
Subject: [PATCH 5.18 08/61] x86/retpoline: Cleanup some #ifdefery

From: Peter Zijlstra <peterz@...radead.org>

commit 369ae6ffc41a3c1137cab697635a84d0cc7cdcea upstream.

On it's own not much of a cleanup but it prepares for more/similar
code.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@...nel.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@...onical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/include/asm/disabled-features.h |    9 ++++++++-
 arch/x86/include/asm/nospec-branch.h     |    7 +++----
 arch/x86/net/bpf_jit_comp.c              |    7 +++----
 3 files changed, 14 insertions(+), 9 deletions(-)

--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -56,6 +56,13 @@
 # define DISABLE_PTI		(1 << (X86_FEATURE_PTI & 31))
 #endif
 
+#ifdef CONFIG_RETPOLINE
+# define DISABLE_RETPOLINE	0
+#else
+# define DISABLE_RETPOLINE	((1 << (X86_FEATURE_RETPOLINE & 31)) | \
+				 (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31)))
+#endif
+
 #ifdef CONFIG_INTEL_IOMMU_SVM
 # define DISABLE_ENQCMD		0
 #else
@@ -82,7 +89,7 @@
 #define DISABLED_MASK8	0
 #define DISABLED_MASK9	(DISABLE_SMAP|DISABLE_SGX)
 #define DISABLED_MASK10	0
-#define DISABLED_MASK11	0
+#define DISABLED_MASK11	(DISABLE_RETPOLINE)
 #define DISABLED_MASK12	0
 #define DISABLED_MASK13	0
 #define DISABLED_MASK14	0
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -120,17 +120,16 @@
 	_ASM_PTR " 999b\n\t"					\
 	".popsection\n\t"
 
-#ifdef CONFIG_RETPOLINE
-
 typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE];
+extern retpoline_thunk_t __x86_indirect_thunk_array[];
+
+#ifdef CONFIG_RETPOLINE
 
 #define GEN(reg) \
 	extern retpoline_thunk_t __x86_indirect_thunk_ ## reg;
 #include <asm/GEN-for-each-reg.h>
 #undef GEN
 
-extern retpoline_thunk_t __x86_indirect_thunk_array[];
-
 #ifdef CONFIG_X86_64
 
 /*
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -407,16 +407,15 @@ static void emit_indirect_jump(u8 **ppro
 {
 	u8 *prog = *pprog;
 
-#ifdef CONFIG_RETPOLINE
 	if (cpu_feature_enabled(X86_FEATURE_RETPOLINE_LFENCE)) {
 		EMIT_LFENCE();
 		EMIT2(0xFF, 0xE0 + reg);
 	} else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) {
 		OPTIMIZER_HIDE_VAR(reg);
 		emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip);
-	} else
-#endif
-	EMIT2(0xFF, 0xE0 + reg);
+	} else {
+		EMIT2(0xFF, 0xE0 + reg);
+	}
 
 	*pprog = prog;
 }