[RFC PATCH-for-9.0 02/11] target/arm: Add target_aarch64_available() helper

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

We want to build HW models once, but don't want to
register types when all prerequisites are satisfied. Add
the target_aarch64_available() to know at runtime whether
TARGET_AARCH64 is built-in.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/arm/cpu-qom.h | 2 ++
 target/arm/cpu.c     | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/target/arm/cpu-qom.h b/target/arm/cpu-qom.h
index 02b914c876..bf6b3604ed 100644
--- a/target/arm/cpu-qom.h
+++ b/target/arm/cpu-qom.h
@@ -33,4 +33,6 @@ typedef struct AArch64CPUClass AArch64CPUClass;
 DECLARE_CLASS_CHECKERS(AArch64CPUClass, AARCH64_CPU,
                        TYPE_AARCH64_CPU)
 
+bool target_aarch64_available(void);
+
 #endif
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 25e9d2ae7b..1990c04089 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -2548,3 +2548,12 @@ static void arm_cpu_register_types(void)
 }
 
 type_init(arm_cpu_register_types)
+
+bool target_aarch64_available(void)
+{
+#ifdef TARGET_AARCH64
+    return true;
+#else
+    return false;
+#endif
+}
-- 
2.41.0