demand_paging: add infra for demand paging modules

Backing stores and eviction algorithms will be included here.
Exactly one must be chosen, with a default option to leave
the implementation to the application.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>

subsys/CMakeLists.txt

@@ -26,3 +26,4 @@ add_subdirectory(tracing)
 add_subdirectory_ifdef(CONFIG_JWT jwt)
 add_subdirectory(canbus)
 add_subdirectory_ifdef(CONFIG_TIMING_FUNCTIONS     timing)
+add_subdirectory_ifdef(CONFIG_DEMAND_PAGING        demand_paging)

subsys/Kconfig

@@ -58,4 +58,6 @@ source "subsys/timing/Kconfig"
 
 source "subsys/tracing/Kconfig"
 
+source "subsys/demand_paging/Kconfig"
+
 endmenu

subsys/demand_paging/CMakeLists.txt

@@ -0,0 +1,5 @@
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+add_subdirectory(eviction)
+add_subdirectory(backing_store)

subsys/demand_paging/Kconfig

@@ -0,0 +1,11 @@
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+menu "Demand Paging modules"
+	depends on DEMAND_PAGING
+
+source "subsys/demand_paging/eviction/Kconfig"
+
+source "subsys/demand_paging/backing_store/Kconfig"
+
+endmenu

subsys/demand_paging/backing_store/CMakeLists.txt

@@ -0,0 +1,2 @@
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0

subsys/demand_paging/backing_store/Kconfig

@@ -0,0 +1,15 @@
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+choice BACKING_STORE_CHOICE
+	prompt "Backing store algorithms"
+	default BACKING_STORE_CUSTOM
+
+config BACKING_STORE_CUSTOM
+	bool "Custom backing store implementation"
+	help
+	  This option is chosen when the backing store will be implemented in
+	  the application. This will be typical as these tend to be very
+	  hardware-dependent.
+
+endchoice

subsys/demand_paging/eviction/CMakeLists.txt

@@ -0,0 +1,2 @@
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0

subsys/demand_paging/eviction/Kconfig

@@ -0,0 +1,17 @@
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+#
+# Demand paging sample eviction algorithms
+
+choice EVICTION_CHOICE
+	prompt "Page frame eviction algorithms"
+	default EVICTION_CUSTOM
+	depends on DEMAND_PAGING
+
+config EVICTION_CUSTOM
+	bool "Custom eviction algorithm"
+	help
+	  This option is chosen when the eviction algorithm will be implemented
+	  by the application, instead of using one included in Zephyr.
+
+endchoice