Merge branch 'x86/bugs' into x86/core, to pick up pending changes before dependent patches

Merge in pending alternatives patching infrastructure changes, before
applying more patches.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 20 insertions, 23 deletions

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index ea3a28e7b613..72cc9c90e9f3 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -49,7 +49,7 @@ lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc.o copy_mc_64.o
 lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
 lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
 lib-$(CONFIG_FUNCTION_ERROR_INJECTION)	+= error-inject.o
-lib-$(CONFIG_RETPOLINE) += retpoline.o
+lib-$(CONFIG_MITIGATION_RETPOLINE) += retpoline.o
 
 obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
 obj-y += iomem.o
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index 7b2589877d06..721b528da9ac 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -71,7 +71,7 @@ SYM_CODE_END(__x86_indirect_thunk_array)
 #include <asm/GEN-for-each-reg.h>
 #undef GEN
 
-#ifdef CONFIG_CALL_DEPTH_TRACKING
+#ifdef CONFIG_MITIGATION_CALL_DEPTH_TRACKING
 .macro CALL_THUNK reg
 	.align RETPOLINE_THUNK_SIZE
 
@@ -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
@@ -138,7 +138,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
  */
 	.section .text..__x86.return_thunk
 
-#ifdef CONFIG_CPU_SRSO
+#ifdef CONFIG_MITIGATION_SRSO
 
 /*
  * srso_alias_untrain_ret() and srso_alias_safe_ret() are placed at
@@ -225,12 +225,12 @@ SYM_CODE_END(srso_return_thunk)
 
 #define JMP_SRSO_UNTRAIN_RET "jmp srso_untrain_ret"
 #define JMP_SRSO_ALIAS_UNTRAIN_RET "jmp srso_alias_untrain_ret"
-#else /* !CONFIG_CPU_SRSO */
+#else /* !CONFIG_MITIGATION_SRSO */
 #define JMP_SRSO_UNTRAIN_RET "ud2"
 #define JMP_SRSO_ALIAS_UNTRAIN_RET "ud2"
-#endif /* CONFIG_CPU_SRSO */
+#endif /* CONFIG_MITIGATION_SRSO */
 
-#ifdef CONFIG_CPU_UNRET_ENTRY
+#ifdef CONFIG_MITIGATION_UNRET_ENTRY
 
 /*
  * Some generic notes on the untraining sequences:
@@ -312,11 +312,11 @@ SYM_CODE_END(retbleed_return_thunk)
 SYM_FUNC_END(retbleed_untrain_ret)
 
 #define JMP_RETBLEED_UNTRAIN_RET "jmp retbleed_untrain_ret"
-#else /* !CONFIG_CPU_UNRET_ENTRY */
+#else /* !CONFIG_MITIGATION_UNRET_ENTRY */
 #define JMP_RETBLEED_UNTRAIN_RET "ud2"
-#endif /* CONFIG_CPU_UNRET_ENTRY */
+#endif /* CONFIG_MITIGATION_UNRET_ENTRY */
 
-#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_SRSO)
+#if defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO)
 
 SYM_FUNC_START(entry_untrain_ret)
 	ALTERNATIVE_2 JMP_RETBLEED_UNTRAIN_RET,				\
@@ -325,9 +325,9 @@ SYM_FUNC_START(entry_untrain_ret)
 SYM_FUNC_END(entry_untrain_ret)
 __EXPORT_THUNK(entry_untrain_ret)
 
-#endif /* CONFIG_CPU_UNRET_ENTRY || CONFIG_CPU_SRSO */
+#endif /* CONFIG_MITIGATION_UNRET_ENTRY || CONFIG_MITIGATION_SRSO */
 
-#ifdef CONFIG_CALL_DEPTH_TRACKING
+#ifdef CONFIG_MITIGATION_CALL_DEPTH_TRACKING
 
 	.align 64
 SYM_FUNC_START(call_depth_return_thunk)
@@ -359,7 +359,7 @@ SYM_FUNC_START(call_depth_return_thunk)
 	int3
 SYM_FUNC_END(call_depth_return_thunk)
 
-#endif /* CONFIG_CALL_DEPTH_TRACKING */
+#endif /* CONFIG_MITIGATION_CALL_DEPTH_TRACKING */
 
 /*
  * This function name is magical and is used by -mfunction-return=thunk-extern
@@ -369,21 +369,18 @@ SYM_FUNC_END(call_depth_return_thunk)
  * 'JMP __x86_return_thunk' sites are changed to something else by
  * apply_returns().
  *
- * This should be converted eventually to call a warning function which
- * should scream loudly when the default return thunk is called after
- * alternatives have been applied.
- *
- * That warning function cannot BUG() because the bug splat cannot be
- * displayed in all possible configurations, leading to users not really
- * knowing why the machine froze.
+ * The ALTERNATIVE below adds a really loud warning to catch the case
+ * where the insufficient default return thunk ends up getting used for
+ * whatever reason like miscompilation or failure of
+ * objtool/alternatives/etc to patch all the return sites.
  */
 SYM_CODE_START(__x86_return_thunk)
 	UNWIND_HINT_FUNC
 	ANNOTATE_NOENDBR
-	ANNOTATE_UNRET_SAFE
-	ret
+	ALTERNATIVE __stringify(ANNOTATE_UNRET_SAFE; ret), \
+		   "jmp warn_thunk_thunk", X86_FEATURE_ALWAYS
 	int3
 SYM_CODE_END(__x86_return_thunk)
 EXPORT_SYMBOL(__x86_return_thunk)
 
-#endif /* CONFIG_RETHUNK */
+#endif /* CONFIG_MITIGATION_RETHUNK */