x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK

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

[ mingo: Added one more case. ]
Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-11-leitao@debian.org

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
@@ -2505,7 +2505,7 @@ 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
@@ -2518,7 +2518,7 @@ config RETHUNK
 
 config MITIGATION_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.
@@ -2572,7 +2572,7 @@ config MITIGATION_IBRS_ENTRY
 
 config MITIGATION_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.

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

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

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))

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_MITIGATION_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_MITIGATION_SLS

arch/x86/include/asm/nospec-branch.h

@@ -289,7 +289,7 @@
  * where we have a stack but before any RET instruction.
  */
 .macro __UNTRAIN_RET ibpb_feature, call_depth_insns
-#if defined(CONFIG_RETHUNK) || defined(CONFIG_MITIGATION_IBPB_ENTRY)
+#if defined(CONFIG_MITIGATION_RETHUNK) || defined(CONFIG_MITIGATION_IBPB_ENTRY)
 	VALIDATE_UNRET_END
 	ALTERNATIVE_3 "",						\
 		      CALL_UNTRAIN_RET, X86_FEATURE_UNRET,		\
@@ -328,7 +328,7 @@ extern retpoline_thunk_t __x86_indirect_thunk_array[];
 extern retpoline_thunk_t __x86_indirect_call_thunk_array[];
 extern retpoline_thunk_t __x86_indirect_jump_thunk_array[];
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 extern void __x86_return_thunk(void);
 #else
 static inline void __x86_return_thunk(void) {}

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

arch/x86/kernel/alternative.c

@@ -769,7 +769,7 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
 	}
 }
 
-#ifdef CONFIG_RETHUNK
+#ifdef CONFIG_MITIGATION_RETHUNK
 
 /*
  * Rewrite the compiler generated return thunk tail-calls.
@@ -842,7 +842,7 @@ 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 */
 

arch/x86/kernel/static_call.c

@@ -172,7 +172,7 @@ void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
 }
 EXPORT_SYMBOL_GPL(arch_static_call_transform);
 
-#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

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
@@ -386,4 +386,4 @@ SYM_CODE_START(__x86_return_thunk)
 SYM_CODE_END(__x86_return_thunk)
 EXPORT_SYMBOL(__x86_return_thunk)
 
-#endif /* CONFIG_RETHUNK */
+#endif /* CONFIG_MITIGATION_RETHUNK */

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_MITIGATION_SLS)			+= --sls
 objtool-args-$(CONFIG_STACK_VALIDATION)			+= --stackval
 objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE)		+= --static-call

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))

tools/objtool/check.c

@@ -3980,7 +3980,7 @@ 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 {