fatal: move enum definition to dedicated header

This allows enum values to be referenced in architecture `arch.h` files
without circular dependencies.

Signed-off-by: Jordan Yates <jordan.yates@data61.csiro.au>

include/zephyr/fatal.h

@@ -13,6 +13,7 @@
 
 #include <zephyr/arch/cpu.h>
 #include <zephyr/toolchain.h>
+#include <zephyr/fatal_types.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -24,27 +25,6 @@ extern "C" {
  * @{
  */
 
-enum k_fatal_error_reason {
-	/** Generic CPU exception, not covered by other codes */
-	K_ERR_CPU_EXCEPTION,
-
-	/** Unhandled hardware interrupt */
-	K_ERR_SPURIOUS_IRQ,
-
-	/** Faulting context overflowed its stack buffer */
-	K_ERR_STACK_CHK_FAIL,
-
-	/** Moderate severity software error */
-	K_ERR_KERNEL_OOPS,
-
-	/** High severity software error */
-	K_ERR_KERNEL_PANIC
-
-	/* TODO: add more codes for exception types that are common across
-	 * architectures
-	 */
-};
-
 /**
  * @brief Halt the system on a fatal error
  *

include/zephyr/fatal_types.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2023 CSIRO.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/** @file
+ *  @brief Fatal base type definitions
+ */
+
+#ifndef ZEPHYR_INCLUDE_FATAL_TYPES_H
+#define ZEPHYR_INCLUDE_FATAL_TYPES_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @defgroup fatal_types Fatal error base types
+ * @ingroup fatal_apis
+ * @{
+ */
+
+enum k_fatal_error_reason {
+	/** Generic CPU exception, not covered by other codes */
+	K_ERR_CPU_EXCEPTION,
+
+	/** Unhandled hardware interrupt */
+	K_ERR_SPURIOUS_IRQ,
+
+	/** Faulting context overflowed its stack buffer */
+	K_ERR_STACK_CHK_FAIL,
+
+	/** Moderate severity software error */
+	K_ERR_KERNEL_OOPS,
+
+	/** High severity software error */
+	K_ERR_KERNEL_PANIC,
+
+	/* TODO: add more codes for exception types that are common across
+	 * architectures
+	 */
+};
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_FATAL_TYPES_H */