[SRU][N][PATCH 2/3] x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK

Manuel Diewald manuel.diewald at canonical.com
Wed Mar 18 10:23:51 UTC 2026 

From: Breno Leitao <leitao at debian.org>

BugLink: https://bugs.launchpad.net/bugs/2144730

Step 10/10 of the namespace unification of CPU mitigations related Kconfig options.

[ mingo: Added one more case. ]

Suggested-by: Josh Poimboeuf <jpoimboe at kernel.org>
Signed-off-by: Breno Leitao <leitao at debian.org>
Signed-off-by: Ingo Molnar <mingo at kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe at kernel.org>
Cc: Linus Torvalds <torvalds at linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-11-leitao@debian.org
(backported from commit 0911b8c52c4d68c57d02f172daa55a42bce703f0)
[diewald: adjust context for missing commits
* e0b8fcfa3cfac ("x86/bugs: Rename CONFIG_CPU_IBPB_ENTRY       =>
  CONFIG_MITIGATION_IBPB_ENTRY")
* 7b75782ffd824 ("x86/bugs: Rename CONFIG_SLS                  =>
  CONFIG_MITIGATION_SLS")
and newer patches that have been included already:
* 0ef8047b737d7 ("x86/static-call: provide a way to do very early
  static-call updates")
* a75bf27fe41ab ("x86/its: Add support for ITS-safe return thunk")
* 8754e67ad4ac6 ("x86/its: Add support for ITS-safe indirect thunk")]
Signed-off-by: Manuel Diewald <manuel.diewald at canonical.com>
---
 arch/x86/Kconfig                               | 10 +++++-----
 arch/x86/Makefile                              |  2 +-
 arch/x86/configs/i386_defconfig                |  2 +-
 arch/x86/include/asm/alternative.h             |  2 +-
 arch/x86/include/asm/disabled-features.h       |  2 +-
 arch/x86/include/asm/linkage.h                 |  4 ++--
 arch/x86/include/asm/nospec-branch.h           |  4 ++--
 arch/x86/include/asm/static_call.h             |  2 +-
 arch/x86/kernel/alternative.c                  |  4 ++--
 arch/x86/kernel/static_call.c                  |  2 +-
 arch/x86/lib/retpoline.S                       |  4 ++--
 scripts/Makefile.lib                           |  2 +-
 tools/arch/x86/include/asm/disabled-features.h |  2 +-
 tools/objtool/check.c                          |  2 +-
 14 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7b59e728a8335..f16cb7d211286 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2462,7 +2462,7 @@ config FINEIBT
 
 config HAVE_CALL_THUNKS
 	def_bool y
-	depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
+	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
 
 config CALL_THUNKS
 	def_bool n
@@ -2509,7 +2509,7 @@ config MITIGATION_RETPOLINE
 	  branches. Requires a compiler with -mindirect-branch=thunk-extern
 	  support for full protection. The kernel may run slower.
 
-config RETHUNK
+config MITIGATION_RETHUNK
 	bool "Enable return-thunks"
 	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
 	select OBJTOOL if HAVE_OBJTOOL
@@ -2522,7 +2522,7 @@ config RETHUNK
 
 config CPU_UNRET_ENTRY
 	bool "Enable UNRET on kernel entry"
-	depends on CPU_SUP_AMD && RETHUNK && X86_64
+	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
 	default y
 	help
 	  Compile the kernel with support for the retbleed=unret mitigation.
@@ -2577,7 +2577,7 @@ config CPU_IBRS_ENTRY
 
 config CPU_SRSO
 	bool "Mitigate speculative RAS overflow on AMD"
-	depends on CPU_SUP_AMD && X86_64 && RETHUNK
+	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
 	default y
 	help
 	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
@@ -2635,7 +2635,7 @@ config MITIGATION_SPECTRE_BHI
 config MITIGATION_ITS
 	bool "Enable Indirect Target Selection mitigation"
 	depends on CPU_SUP_INTEL && X86_64
-	depends on MITIGATION_RETPOLINE && RETHUNK
+	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
 	default y
 	help
 	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 0f6dfafe4aa0f..cbdf9ca1cef28 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -22,7 +22,7 @@ RETPOLINE_VDSO_CFLAGS	:= -mretpoline
 endif
 RETPOLINE_CFLAGS	+= $(call cc-option,-mindirect-branch-cs-prefix)
 
-ifdef CONFIG_RETHUNK
+ifdef CONFIG_MITIGATION_RETHUNK
 RETHUNK_CFLAGS		:= -mfunction-return=thunk-extern
 RETPOLINE_CFLAGS	+= $(RETHUNK_CFLAGS)
 endif
diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig
index 73abbbdd26f87..91801138b10bb 100644
--- a/arch/x86/configs/i386_defconfig
+++ b/arch/x86/configs/i386_defconfig
@@ -42,7 +42,7 @@ CONFIG_EFI_STUB=y
 CONFIG_HZ_1000=y
 CONFIG_KEXEC=y
 CONFIG_CRASH_DUMP=y
-# CONFIG_RETHUNK is not set
+# CONFIG_MITIGATION_RETHUNK is not set
 CONFIG_HIBERNATION=y
 CONFIG_PM_DEBUG=y
 CONFIG_PM_TRACE_RTC=y
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 068b9270e3511..f23d1e2b39a11 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -152,7 +152,7 @@ static inline u8 *its_static_thunk(int reg)
 }
 #endif
 
-#if defined(CONFIG_RETHUNK) && defined(CONFIG_OBJTOOL)
+#if defined(CONFIG_MITIGATION_RETHUNK) && defined(CONFIG_OBJTOOL)
 extern bool cpu_wants_rethunk(void);
 extern bool cpu_wants_rethunk_at(void *addr);
 #else
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 47257a1dc8111..637db4c2a5cef 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -57,7 +57,7 @@
 				 (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31)))
 #endif
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 # define DISABLE_RETHUNK	0
 #else
 # define DISABLE_RETHUNK	(1 << (X86_FEATURE_RETHUNK & 31))
diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h
index c5165204c66f0..b200ed7d099d8 100644
--- a/arch/x86/include/asm/linkage.h
+++ b/arch/x86/include/asm/linkage.h
@@ -40,7 +40,7 @@
 
 #ifdef __ASSEMBLY__
 
-#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
+#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
 #define RET	jmp __x86_return_thunk
 #else /* CONFIG_MITIGATION_RETPOLINE */
 #ifdef CONFIG_SLS
@@ -52,7 +52,7 @@
 
 #else /* __ASSEMBLY__ */
 
-#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
+#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO)
 #define ASM_RET	"jmp __x86_return_thunk\n\t"
 #else /* CONFIG_MITIGATION_RETPOLINE */
 #ifdef CONFIG_SLS
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 04f92d8cdfe64..c5455c89f52b4 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -297,7 +297,7 @@
  * where we have a stack but before any RET instruction.
  */
 .macro __UNTRAIN_RET ibpb_feature, call_depth_insns
-#if defined(CONFIG_RETHUNK) || defined(CONFIG_CPU_IBPB_ENTRY)
+#if defined(CONFIG_MITIGATION_RETHUNK) || defined(CONFIG_CPU_IBPB_ENTRY)
 	VALIDATE_UNRET_END
 	CALL_UNTRAIN_RET
 	ALTERNATIVE_2 "",						\
@@ -379,7 +379,7 @@ extern retpoline_thunk_t __x86_indirect_call_thunk_array[];
 extern retpoline_thunk_t __x86_indirect_jump_thunk_array[];
 extern its_thunk_t	 __x86_indirect_its_thunk_array[];
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 extern void __x86_return_thunk(void);
 #else
 static inline void __x86_return_thunk(void) {}
diff --git a/arch/x86/include/asm/static_call.h b/arch/x86/include/asm/static_call.h
index 35d75c19b1e32..41502bd2afd64 100644
--- a/arch/x86/include/asm/static_call.h
+++ b/arch/x86/include/asm/static_call.h
@@ -46,7 +46,7 @@
 #define ARCH_DEFINE_STATIC_CALL_TRAMP(name, func)			\
 	__ARCH_DEFINE_STATIC_CALL_TRAMP(name, ".byte 0xe9; .long " #func " - (. + 4)")
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 #define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)			\
 	__ARCH_DEFINE_STATIC_CALL_TRAMP(name, "jmp __x86_return_thunk")
 #else
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 8f0098196d308..371b5f140af7c 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -954,7 +954,7 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
 	}
 }
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 
 bool cpu_wants_rethunk(void)
 {
@@ -1042,7 +1042,7 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end)
 }
 #else
 void __init_or_module noinline apply_returns(s32 *start, s32 *end) { }
-#endif /* CONFIG_RETHUNK */
+#endif /* CONFIG_MITIGATION_RETHUNK */
 
 #else /* !CONFIG_MITIGATION_RETPOLINE || !CONFIG_OBJTOOL */
 
diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c
index bcea882e022f5..aae909d4ed785 100644
--- a/arch/x86/kernel/static_call.c
+++ b/arch/x86/kernel/static_call.c
@@ -180,7 +180,7 @@ noinstr void __static_call_update_early(void *tramp, void *func)
 	sync_core();
 }
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 /*
  * This is called by apply_returns() to fix up static call trampolines,
  * specifically ARCH_DEFINE_STATIC_CALL_NULL_TRAMP which is recorded as
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index bf387fbdcd1fd..4ff94cc70b79b 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -127,7 +127,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
 #undef GEN
 #endif
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 
 /*
  * Be careful here: that label cannot really be removed because in
@@ -430,4 +430,4 @@ SYM_CODE_START(__x86_return_thunk)
 SYM_CODE_END(__x86_return_thunk)
 EXPORT_SYMBOL(__x86_return_thunk)
 
-#endif /* CONFIG_RETHUNK */
+#endif /* CONFIG_MITIGATION_RETHUNK */
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index fae3b276c077f..a33b28d324d4f 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -263,7 +263,7 @@ objtool-args-$(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT)		+= --mnop
 endif
 objtool-args-$(CONFIG_UNWINDER_ORC)			+= --orc
 objtool-args-$(CONFIG_MITIGATION_RETPOLINE)		+= --retpoline
-objtool-args-$(CONFIG_RETHUNK)				+= --rethunk
+objtool-args-$(CONFIG_MITIGATION_RETHUNK)		+= --rethunk
 objtool-args-$(CONFIG_SLS)				+= --sls
 objtool-args-$(CONFIG_STACK_VALIDATION)			+= --stackval
 objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE)		+= --static-call
diff --git a/tools/arch/x86/include/asm/disabled-features.h b/tools/arch/x86/include/asm/disabled-features.h
index 44d34f269b1c5..d34021c304fa0 100644
--- a/tools/arch/x86/include/asm/disabled-features.h
+++ b/tools/arch/x86/include/asm/disabled-features.h
@@ -57,7 +57,7 @@
 				 (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31)))
 #endif
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 # define DISABLE_RETHUNK	0
 #else
 # define DISABLE_RETHUNK	(1 << (X86_FEATURE_RETHUNK & 31))
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f613ad066b113..9d4aebd62a3ce 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4001,7 +4001,7 @@ static int validate_retpoline(struct objtool_file *file)
 
 		if (insn->type == INSN_RETURN) {
 			if (opts.rethunk) {
-				WARN_INSN(insn, "'naked' return found in RETHUNK build");
+				WARN_INSN(insn, "'naked' return found in MITIGATION_RETHUNK build");
 			} else
 				continue;
 		} else {
-- 
2.34.1

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