kernel: dynamic: Add a constraint for user stacks

Support for dynamic thread stack on userspace only
works with MMU. On MPUs we depend in the number of
partitions available in the hw and in the number of
partitions used.

Because of this constraint, enable heap based allocation
only when userspace is not enabled in MPU devices.

Signed-off-by: Flavio Ceolin <[email protected]>

kernel/Kconfig

@@ -220,6 +220,7 @@ config DYNAMIC_THREAD_STACK_SIZE
 	help
 	  Default stack size (in bytes) for dynamic threads.
 
+if !USERSPACE || (USERSPACE && MMU)
 config DYNAMIC_THREAD_ALLOC
 	bool "Support heap-allocated thread objects and stacks"
 	help
@@ -228,6 +229,7 @@ config DYNAMIC_THREAD_ALLOC
 
 	  Only use this type of allocation in situations
 	  where malloc is permitted.
+endif
 
 config DYNAMIC_THREAD_POOL_SIZE
 	int "Number of statically pre-allocated threads"
@@ -248,12 +250,14 @@ choice DYNAMIC_THREAD_PREFER
 	  CONFIG_DYNAMIC_THREAD_POOL_SIZE > 0, then the user may
 	  specify the order in which allocation is attmpted.
 
+if !USERSPACE || (USERSPACE && MMU)
 config DYNAMIC_THREAD_PREFER_ALLOC
 	bool "Prefer heap-based allocation"
 	depends on DYNAMIC_THREAD_ALLOC
 	help
 	  Select this option to attempt a heap-based allocation
 	  prior to any pool-based allocation.
+endif
 
 config DYNAMIC_THREAD_PREFER_POOL
 	bool "Prefer pool-based allocation"