# ARM core configuration options # Copyright (c) 2015 Wind River Systems, Inc. # SPDX-License-Identifier: Apache-2.0 config CPU_CORTEX_M bool select CPU_CORTEX select ARCH_HAS_CUSTOM_SWAP_TO_MAIN select HAS_CMSIS_CORE select HAS_FLASH_LOAD_OFFSET select ARCH_HAS_SINGLE_THREAD_SUPPORT select ARCH_HAS_THREAD_ABORT select ARCH_HAS_TRUSTED_EXECUTION if ARM_TRUSTZONE_M select ARCH_HAS_STACK_PROTECTION if (ARM_MPU && !ARMV6_M_ARMV8_M_BASELINE) || CPU_CORTEX_M_HAS_SPLIM select ARCH_HAS_USERSPACE if ARM_MPU select ARCH_HAS_NOCACHE_MEMORY_SUPPORT if ARM_MPU && CPU_HAS_ARM_MPU && CPU_CORTEX_M7 select ARCH_HAS_RAMFUNC_SUPPORT select ARCH_HAS_NESTED_EXCEPTION_DETECTION select SWAP_NONATOMIC select ARCH_HAS_EXTRA_EXCEPTION_INFO select ARCH_HAS_TIMING_FUNCTIONS if CPU_CORTEX_M_HAS_DWT select ARCH_SUPPORTS_ARCH_HW_INIT imply XIP help This option signifies the use of a CPU of the Cortex-M family. config CPU_CORTEX_R bool select CPU_CORTEX select HAS_CMSIS_CORE select HAS_FLASH_LOAD_OFFSET select ARCH_HAS_EXTRA_EXCEPTION_INFO help This option signifies the use of a CPU of the Cortex-R family. config ISA_THUMB2 bool 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 ISA_ARM bool help From: https://developer.arm.com/products/architecture/instruction-sets/a32-and-t32-instruction-sets A32 instructions, known as Arm instructions in pre-Armv8 architectures, are 32 bits wide, and are aligned on 4-byte boundaries. A32 instructions are supported by both A-profile and R-profile architectures. A32 was traditionally used in applications requiring the highest performance, or for handling hardware exceptions such as interrupts and processor start-up. Much of its functionality was subsumed into T32 with the introduction of Thumb-2 technology. config ASSEMBLER_ISA_THUMB2 bool default y if ISA_THUMB2 && !ISA_ARM depends on !ISA_ARM help This helper symbol specifies the default target instruction set for the assembler. When only the Thumb-2 ISA is supported (i.e. on Cortex-M cores), the assembler must use the Thumb-2 instruction set. When both the Thumb-2 and ARM ISAs are supported (i.e. on Cortex-A and Cortex-R cores), the assembler must use the ARM instruction set because the architecture assembly code makes use of the ARM instructions. config COMPILER_ISA_THUMB2 bool "Compile C/C++ functions using Thumb-2 instruction set" depends on ISA_THUMB2 default y help This option configures the compiler to compile all C/C++ functions using the Thumb-2 instruction set. N.B. The scope of this symbol is not necessarily limited to the C and C++ languages; in fact, this symbol refers to all forms of "compiled" code. When an additional natively-compiled language support is added in the future, this symbol shall also specify the Thumb-2 instruction set for that language. config NUM_IRQS int config STACK_ALIGN_DOUBLE_WORD bool "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. The option also enforces alignment of stack upon exception entry on Cortex-M3 and Cortex-M4 (ARMv7-M). Note that for ARMv6-M, ARMv8-M, and Cortex-M7 MCUs stack alignment on exception entry is enabled by default and it is not configurable. config RUNTIME_NMI bool "Attach an NMI handler at runtime" select REBOOT 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 PLATFORM_SPECIFIC_INIT bool "Enable platform (SOC) specific startup hook" help The platform specific initialization code (z_platform_init) is executed at the beginning of the startup code (__start). config FAULT_DUMP int "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 BUILTIN_STACK_GUARD bool "Thread Stack Guards based on built-in ARM stack limit checking" depends on CPU_CORTEX_M_HAS_SPLIM select THREAD_STACK_INFO help Enable Thread/Interrupt Stack Guards via built-in Stack Pointer limit checking. The functionality must be supported by HW. config ARM_STACK_PROTECTION bool default y if HW_STACK_PROTECTION imply BUILTIN_STACK_GUARD if CPU_CORTEX_M_HAS_SPLIM select MPU_STACK_GUARD if (!BUILTIN_STACK_GUARD && ARM_MPU) help This option enables either: - The built-in Stack Pointer limit checking, or - the MPU-based stack guard to cause a system fatal error if the bounds of the current process stack are overflowed. The two stack guard options are mutually exclusive. The selection of the built-in Stack Pointer limit checking is prioritized over the MPU-based stack guard. The developer still has the option to manually select the MPU-based stack guard, if this is desired. config ARM_SECURE_FIRMWARE bool depends on ARMV8_M_SE default y if TRUSTED_EXECUTION_SECURE help This option indicates that we are building a Zephyr image that is intended to execute in Secure state. The option is only applicable to ARMv8-M MCUs that implement the Security Extension. This option enables Zephyr to include code that executes in Secure state, as well as to exclude code that is designed to execute only in Non-secure state. Code executing in Secure state has access to both the Secure and Non-Secure resources of the Cortex-M MCU. Code executing in Non-Secure state may trigger Secure Faults, if Secure MCU resources are accessed from the Non-Secure state. Secure Faults may only be handled by code executing in Secure state. config ARM_NONSECURE_FIRMWARE bool depends on !ARM_SECURE_FIRMWARE depends on ARMV8_M_SE default y if TRUSTED_EXECUTION_NONSECURE help This option indicates that we are building a Zephyr image that is intended to execute in Non-Secure state. Execution of this image is triggered by Secure firmware that executes in Secure state. The option is only applicable to ARMv8-M MCUs that implement the Security Extension. This option enables Zephyr to include code that executes in Non-Secure state only, as well as to exclude code that is designed to execute only in Secure state. Code executing in Non-Secure state has no access to Secure resources of the Cortex-M MCU, and, therefore, it shall avoid accessing them. config ARM_NONSECURE_PREEMPTIBLE_SECURE_CALLS bool "Allow secure function calls to be preempted" depends on ARM_NONSECURE_FIRMWARE help When enabled, this option indicates that preemptible Zephyr threads performing secure function calls, are allowed to be preempted. When disabled, the option indicates that such threads many not be context-switched-out while doing a Secure function call. config ARM_STORE_EXC_RETURN bool default y if FPU_SHARING || ARM_NONSECURE_PREEMPTIBLE_SECURE_CALLS help Store the EXC_RETURN value when switching threads. This is needed when switching between threads that differ in either FPU usage or security domain. choice prompt "Floating point ABI" default FP_HARDABI depends on FPU config FP_HARDABI bool "Floating point Hard ABI" depends on !BUILD_WITH_TFM help This option selects the Floating point ABI in which hardware floating point instructions are generated and uses FPU-specific calling conventions. Note: the option is disabled for Zephyr builds with TF-M, as TF-M does not currently support building with Hard ABI, hence linking Zephyr with TF-M libraries would not be possible. config FP_SOFTABI bool "Floating point Soft ABI" help This option selects the Floating point ABI in which hardware floating point instructions are generated but soft-float calling conventions. endchoice rsource "cortex_m/Kconfig" rsource "cortex_a_r/Kconfig" rsource "mpu/Kconfig"