tcg: Move cpu_req_mo() macro to target-agnostic 'backend-ldst.h'

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

accel/tcg/backend-ldst.h

@@ -0,0 +1,41 @@
+/*
+ * Internal memory barrier helpers for QEMU (target agnostic)
+ *
+ *  Copyright (c) 2003 Fabrice Bellard
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#ifndef ACCEL_TCG_BACKEND_LDST_H
+#define ACCEL_TCG_BACKEND_LDST_H
+
+#include "tcg-target-mo.h"
+
+/**
+ * tcg_req_mo:
+ * @guest_mo: Guest default memory order
+ * @type: TCGBar
+ *
+ * Filter @type to the barrier that is required for the guest
+ * memory ordering vs the host memory ordering.  A non-zero
+ * result indicates that some barrier is required.
+ */
+#define tcg_req_mo(guest_mo, type) \
+    ((type) & guest_mo & ~TCG_TARGET_DEFAULT_MO)
+
+/**
+ * cpu_req_mo:
+ * @cpu: CPUState
+ * @type: TCGBar
+ *
+ * If tcg_req_mo indicates a barrier for @type is required
+ * for the guest memory model, issue a host memory barrier.
+ */
+#define cpu_req_mo(cpu, type)     \
+    do {                          \
+        if (tcg_req_mo(cpu->cc->tcg_ops->guest_default_memory_order, type)) { \
+            smp_mb();             \
+        }                         \
+    } while (0)
+
+#endif