arch/arm/core/cortex_m/Kconfig

# Kconfig - ARM Cortex-M platform configuration options

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

config ISA_THUMB2
	bool
	# Omit prompt to signify "hidden" option
	default n
	help
	  From: http://www.arm.com/products/processors/technologies/instruction-set-architectures.php

	  Thumb-2 technology is the instruction set underlying the ARM Cortex
	  architecture which provides enhanced levels of performance, energy
	  efficiency, and code density for a wide range of embedded
	  applications.

	  Thumb-2 technology builds on the success of Thumb, the innovative
	  high code density instruction set for ARM microprocessor cores, to
	  increase the power of the ARM microprocessor core available to
	  developers of low cost, high performance systems.

	  The technology is backwards compatible with existing ARM and Thumb
	  solutions, while significantly extending the features available to
	  the Thumb instructions set. This allows more of the application to
	  benefit from the best in class code density of Thumb.

	  For performance optimized code Thumb-2 technology uses 31 percent
	  less memory to reduce system cost, while providing up to 38 percent
	  higher performance than existing high density code, which can be used
	  to prolong battery-life or to enrich the product feature set. Thumb-2
	  technology is featured in the  processor, and in all ARMv7
	  architecture-based processors.

config CPU_CORTEX_M_HAS_BASEPRI
	bool
	# Omit prompt to signify "hidden" option
	default n
	help
	  This option signifies the CPU has the BASEPRI register.

config CPU_CORTEX_M_HAS_PROGRAMMABLE_FAULT_PRIOS
	bool
	# Omit prompt to signify "hidden" option
	default n
	help
	  This option signifies the CPU faults other than the hard fault, and
	  needs to reserve a priority for them.

config ARMV6_M
	bool
	# Omit prompt to signify "hidden" option
	default n
	select ATOMIC_OPERATIONS_C
	select ISA_THUMB2
	help
	  This option signifies the use of an ARMv6-M processor implementation.

config ARMV7_M
	bool
	# Omit prompt to signify "hidden" option
	default n
	select ATOMIC_OPERATIONS_BUILTIN
	select ISA_THUMB2
	select CPU_CORTEX_M_HAS_BASEPRI
	select CPU_CORTEX_M_HAS_PROGRAMMABLE_FAULT_PRIOS
	help
	  This option signifies the use of an ARMv7-M processor implementation.

config CPU_CORTEX_M0
	bool
	# Omit prompt to signify "hidden" option
	select ARMV6_M
	help
	  This option signifies the use of a Cortex-M0 CPU

config CPU_CORTEX_M0PLUS
	bool
	# Omit prompt to signify "hidden" option
	select ARMV6_M
	help
	  This option signifies the use of a Cortex-M0+ CPU

config CPU_CORTEX_M3
	bool
	# Omit prompt to signify "hidden" option
	select ARMV7_M
	help
	  This option signifies the use of a Cortex-M3 CPU

config CPU_CORTEX_M4
	bool
	# Omit prompt to signify "hidden" option
	select ARMV7_M
	help
	  This option signifies the use of a Cortex-M4 CPU

config CPU_CORTEX_M7
	bool
	# Omit prompt to signify "hidden" option
	select ARMV7_M
	default n
	help
	  This option signifies the use of a Cortex-M7 CPU

menu "ARM Cortex-M options"
	depends on CPU_CORTEX_M

config LDREX_STREX_AVAILABLE
	bool
	default y

config DATA_ENDIANNESS_LITTLE
	bool
	default y
	help
	  This is driven by the processor implementation, since it is fixed in
	  hardware. The board should set this value to 'n' if the data is
	  implemented as big endian.

config STACK_ALIGN_DOUBLE_WORD
	bool
	prompt "Align stacks on double-words (8 octets)"
	default y
	help
	  This is needed to conform to AAPCS, the procedure call standard for
	  the ARM. It wastes stack space.

config RUNTIME_NMI
	bool
	prompt "Attach an NMI handler at runtime"
	select REBOOT
	default n
	help
	  The kernel provides a simple NMI handler that simply hangs in a tight
	  loop if triggered. This fills the requirement that there must be an
	  NMI handler installed when the CPU boots. If a custom handler is
	  needed, enable this option and attach it via _NmiHandlerSet().

config FAULT_DUMP
	int
	prompt "Fault dump level"
	default 2
	range 0 2
	help
	  Different levels for display information when a fault occurs.

	  2: The default. Display specific and verbose information. Consumes
		the most memory (long strings).

	  1: Display general and short information. Consumes less memory
		(short strings).

	  0: Off.

config XIP
	default y
endmenu

menu "ARM Cortex-M0/M0+/M3/M4/M7 options"
	depends on ARMV6_M || ARMV7_M

config GEN_ISR_TABLES
	default y

config ZERO_LATENCY_IRQS
	bool
	prompt "Enable zero-latency interrupts"
	default n
	depends on CPU_CORTEX_M_HAS_BASEPRI
	help
	  Interrupt locking is done by setting exception masking to priority
	  one, thus allowing exception of priority zero to still come in. By
	  default, the kernel verifies, via __ASSERT() statements, that the
	  interrupt priority is not set to zero when either connecting them or
	  setting their priority. Enabling this option disables the check,
	  thus allowing setting the priority of interrupts to zero.

	  Note that this is a somewhat dangerous option: ISRs of priority zero
	  interrupts cannot use any kernel functionality.

config ARCH_HAS_THREAD_ABORT
	bool
	# omit prompt to signify a "hidden" option
	default y

endmenu