1 files changed, 25 insertions, 8 deletions

diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c
index 4eefaac64c6c..61592e41a6b1 100644
--- a/arch/x86/kernel/static_call.c
+++ b/arch/x86/kernel/static_call.c
@@ -26,6 +26,11 @@ static const u8 xor5rax[] = { 0x2e, 0x2e, 0x2e, 0x31, 0xc0 };
 
 static const u8 retinsn[] = { RET_INSN_OPCODE, 0xcc, 0xcc, 0xcc, 0xcc };
 
+/*
+ * ud1    (%edx),%rdi -- see __WARN_trap() / decode_bug()
+ */
+static const u8 warninsn[] = { 0x67, 0x48, 0x0f, 0xb9, 0x3a };
+
 static u8 __is_Jcc(u8 *insn) /* Jcc.d32 */
 {
 	u8 ret = 0;
@@ -45,8 +50,8 @@ asm (".global __static_call_return\n\t"
      ".type __static_call_return, @function\n\t"
      ASM_FUNC_ALIGN "\n\t"
      "__static_call_return:\n\t"
-     ANNOTATE_NOENDBR
-     ANNOTATE_RETPOLINE_SAFE
+     ANNOTATE_NOENDBR "\n\t"
+     ANNOTATE_RETPOLINE_SAFE "\n\t"
      "ret; int3\n\t"
      ".size __static_call_return, . - __static_call_return \n\t");
 
@@ -69,7 +74,10 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
 			emulate = code;
 			code = &xor5rax;
 		}
-
+		if (func == &__WARN_trap) {
+			emulate = code;
+			code = &warninsn;
+		}
 		break;
 
 	case NOP:
@@ -81,7 +89,7 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
 		break;
 
 	case RET:
-		if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
+		if (cpu_wants_rethunk_at(insn))
 			code = text_gen_insn(JMP32_INSN_OPCODE, insn, x86_return_thunk);
 		else
 			code = &retinsn;
@@ -90,7 +98,7 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
 	case JCC:
 		if (!func) {
 			func = __static_call_return;
-			if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
+			if (cpu_wants_rethunk())
 				func = x86_return_thunk;
 		}
 
@@ -108,7 +116,7 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
 	if (system_state == SYSTEM_BOOTING || modinit)
 		return text_poke_early(insn, code, size);
 
-	text_poke_bp(insn, code, size, emulate);
+	smp_text_poke_single(insn, code, size, emulate);
 }
 
 static void __static_call_validate(u8 *insn, bool tail, bool tramp)
@@ -128,7 +136,8 @@ static void __static_call_validate(u8 *insn, bool tail, bool tramp)
 	} else {
 		if (opcode == CALL_INSN_OPCODE ||
 		    !memcmp(insn, x86_nops[5], 5) ||
-		    !memcmp(insn, xor5rax, 5))
+		    !memcmp(insn, xor5rax, 5) ||
+		    !memcmp(insn, warninsn, 5))
 			return;
 	}
 
@@ -158,7 +167,7 @@ void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
 {
 	mutex_lock(&text_mutex);
 
-	if (tramp) {
+	if (tramp && !site) {
 		__static_call_validate(tramp, true, true);
 		__static_call_transform(tramp, __sc_insn(!func, true), func, false);
 	}
@@ -172,6 +181,14 @@ void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
 }
 EXPORT_SYMBOL_GPL(arch_static_call_transform);
 
+noinstr void __static_call_update_early(void *tramp, void *func)
+{
+	BUG_ON(system_state != SYSTEM_BOOTING);
+	BUG_ON(static_call_initialized);
+	__text_gen_insn(tramp, JMP32_INSN_OPCODE, tramp, func, JMP32_INSN_SIZE);
+	sync_core();
+}
+
 #ifdef CONFIG_MITIGATION_RETHUNK
 /*
  * This is called by apply_returns() to fix up static call trampolines,