# Kernel configuration options

# Copyright (c) 2014-2015 Wind River Systems, Inc.
# SPDX-License-Identifier: Apache-2.0

menu "Memory Domains"

config MAX_DOMAIN_PARTITIONS
	int "Maximum number of partitions per memory domain"
	default 16
	range 0 $(UINT8_MAX)
	depends on USERSPACE
	help
	  Configure the maximum number of partitions per memory domain.

config ARCH_MEM_DOMAIN_DATA
	bool
	depends on USERSPACE
	help
	  This hidden option is selected by the target architecture if
	  architecture-specific data is needed on a per memory domain basis.
	  If so, the architecture defines a 'struct arch_mem_domain' which is
	  embedded within every struct k_mem_domain. The architecture
	  must also define the arch_mem_domain_init() function to set this up
	  when a memory domain is created.

	  Typical uses might be a set of page tables for that memory domain.

config ARCH_MEM_DOMAIN_SYNCHRONOUS_API
	bool
	depends on USERSPACE
	help
	  This hidden option is selected by the target architecture if
	  modifying a memory domain's partitions at runtime, or changing
	  a memory domain's thread membership requires synchronous calls
	  into the architecture layer.

	  If enabled, the architecture layer must implement the following
	  APIs:

	  arch_mem_domain_thread_add
	  arch_mem_domain_thread_remove
	  arch_mem_domain_partition_remove
	  arch_mem_domain_partition_add

	  It's important to note that although supervisor threads can be
	  members of memory domains, they have no implications on supervisor
	  thread access to memory. Memory domain APIs may only be invoked from
	  supervisor mode.

	  For these reasons, on uniprocessor systems unless memory access
	  policy is managed in separate software constructions like page
	  tables, these APIs don't need to be implemented as the underlying
	  memory management hardware will be reprogrammed on context switch
	  anyway.

config ARCH_MEM_DOMAIN_SUPPORTS_ISOLATED_STACKS
	bool
	help
	  This hidden option is selected by the target architecture if
	  the architecture supports isolating thread stacks for threads
	  within the same memory domain.

config MEM_DOMAIN_ISOLATED_STACKS
	bool
	default y
	depends on (MMU || MPU) && ARCH_MEM_DOMAIN_SUPPORTS_ISOLATED_STACKS
	help
	  If enabled, thread stacks within the same memory domains are
	  isolated which means threads within the same memory domains
	  have no access to others threads' stacks.

	  If disabled, threads within the same memory domains can access
	  other threads' stacks.

	  Regardless of this settings, threads cannot access the stacks of
	  threads outside of their domains.

endmenu