x86/calldepth: Rename __x86_return_skl() to call_depth_return_thunk()

For consistency with the other return thunks, rename __x86_return_skl()
to call_depth_return_thunk().
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/ae44e9f9976934e3b5b47a458d523ccb15867561.1693889988.git.jpoimboe@kernel.org

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

@@ -358,12 +358,7 @@ extern void entry_ibpb(void);
 extern void (*x86_return_thunk)(void);
 
 #ifdef CONFIG_CALL_DEPTH_TRACKING
-extern void __x86_return_skl(void);
-
-static inline void x86_set_skl_return_thunk(void)
-{
-	x86_return_thunk = &__x86_return_skl;
-}
+extern void call_depth_return_thunk(void);
 
 #define CALL_DEPTH_ACCOUNT					\
 	ALTERNATIVE("",						\
@@ -376,12 +371,12 @@ DECLARE_PER_CPU(u64, __x86_ret_count);
 DECLARE_PER_CPU(u64, __x86_stuffs_count);
 DECLARE_PER_CPU(u64, __x86_ctxsw_count);
 #endif
-#else
-static inline void x86_set_skl_return_thunk(void) {}
+#else /* !CONFIG_CALL_DEPTH_TRACKING */
 
+static inline void call_depth_return_thunk(void) {}
 #define CALL_DEPTH_ACCOUNT ""
 
-#endif
+#endif /* CONFIG_CALL_DEPTH_TRACKING */
 
 #ifdef CONFIG_RETPOLINE
 

arch/x86/kernel/cpu/bugs.c

@@ -1059,7 +1059,8 @@ static void __init retbleed_select_mitigation(void)
 	case RETBLEED_MITIGATION_STUFF:
 		setup_force_cpu_cap(X86_FEATURE_RETHUNK);
 		setup_force_cpu_cap(X86_FEATURE_CALL_DEPTH);
-		x86_set_skl_return_thunk();
+
+		x86_return_thunk = call_depth_return_thunk;
 		break;
 
 	default:

arch/x86/lib/retpoline.S

@@ -323,7 +323,7 @@ __EXPORT_THUNK(entry_untrain_ret)
 #ifdef CONFIG_CALL_DEPTH_TRACKING
 
 	.align 64
-SYM_FUNC_START(__x86_return_skl)
+SYM_FUNC_START(call_depth_return_thunk)
 	ANNOTATE_NOENDBR
 	/*
 	 * Keep the hotpath in a 16byte I-fetch for the non-debug
@@ -350,7 +350,7 @@ SYM_FUNC_START(__x86_return_skl)
 	ANNOTATE_UNRET_SAFE
 	ret
 	int3
-SYM_FUNC_END(__x86_return_skl)
+SYM_FUNC_END(call_depth_return_thunk)
 
 #endif /* CONFIG_CALL_DEPTH_TRACKING */