888 lines
28 KiB
Plaintext
888 lines
28 KiB
Plaintext
# General architecture configuration options
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# Copyright (c) 2014-2015 Wind River Systems, Inc.
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# Copyright (c) 2015 Intel Corporation
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# Copyright (c) 2016 Cadence Design Systems, Inc.
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# SPDX-License-Identifier: Apache-2.0
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# Include these first so that any properties (e.g. defaults) below can be
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# overridden (by defining symbols in multiple locations)
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# Note: $ARCH might be a glob pattern
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source "$(ARCH_DIR)/$(ARCH)/Kconfig"
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# Architecture symbols
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#
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# Should be 'select'ed by low-level symbols like SOC_SERIES_* or, lacking that,
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# by SOC_*.
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config ARC
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bool
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select ARCH_IS_SET
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select HAS_DTS
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imply XIP
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select ARCH_HAS_THREAD_LOCAL_STORAGE
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help
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ARC architecture
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config ARM
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bool
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select ARCH_IS_SET
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select ARCH_SUPPORTS_COREDUMP if CPU_CORTEX_M
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select HAS_DTS
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# FIXME: current state of the code for all ARM requires this, but
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# is really only necessary for Cortex-M with ARM MPU!
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select GEN_PRIV_STACKS
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select ARCH_HAS_THREAD_LOCAL_STORAGE if CPU_AARCH32_CORTEX_R || CPU_CORTEX_M || CPU_AARCH32_CORTEX_A
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help
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ARM architecture
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config ARM64
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bool
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select ARCH_IS_SET
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select 64BIT
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select HAS_DTS
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select HAS_ARM_SMCCC
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select ARCH_HAS_THREAD_LOCAL_STORAGE
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select USE_SWITCH
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select USE_SWITCH_SUPPORTED
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select IRQ_OFFLOAD_NESTED if IRQ_OFFLOAD
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help
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ARM64 (AArch64) architecture
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config MIPS
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bool
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select ARCH_IS_SET
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select ATOMIC_OPERATIONS_C
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select HAS_DTS
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help
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MIPS architecture
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config SPARC
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bool
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select ARCH_IS_SET
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select HAS_DTS
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select USE_SWITCH
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select USE_SWITCH_SUPPORTED
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select BIG_ENDIAN
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select ATOMIC_OPERATIONS_BUILTIN if SPARC_CASA
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select ATOMIC_OPERATIONS_C if !SPARC_CASA
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select ARCH_HAS_THREAD_LOCAL_STORAGE
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select ARCH_HAS_EXTRA_EXCEPTION_INFO
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help
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SPARC architecture
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config X86
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bool
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select ARCH_IS_SET
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select ATOMIC_OPERATIONS_BUILTIN
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select HAS_DTS
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select ARCH_SUPPORTS_COREDUMP
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select CPU_HAS_MMU
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select ARCH_MEM_DOMAIN_DATA if USERSPACE && !X86_COMMON_PAGE_TABLE
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select ARCH_MEM_DOMAIN_SYNCHRONOUS_API if USERSPACE
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select ARCH_HAS_GDBSTUB if !X86_64
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select ARCH_HAS_TIMING_FUNCTIONS
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select ARCH_HAS_THREAD_LOCAL_STORAGE
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select ARCH_HAS_DEMAND_PAGING
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select IRQ_OFFLOAD_NESTED if IRQ_OFFLOAD
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select NEED_LIBC_MEM_PARTITION if USERSPACE && TIMING_FUNCTIONS \
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&& !BOARD_HAS_TIMING_FUNCTIONS \
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&& !SOC_HAS_TIMING_FUNCTIONS
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help
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x86 architecture
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config NIOS2
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bool
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select ARCH_IS_SET
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select ATOMIC_OPERATIONS_C
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select HAS_DTS
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imply XIP
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select ARCH_HAS_TIMING_FUNCTIONS
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help
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Nios II Gen 2 architecture
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config RISCV
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bool
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select ARCH_IS_SET
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select HAS_DTS
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select ARCH_SUPPORTS_COREDUMP
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select ARCH_HAS_THREAD_LOCAL_STORAGE
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select IRQ_OFFLOAD_NESTED if IRQ_OFFLOAD
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select USE_SWITCH_SUPPORTED
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select USE_SWITCH
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select SCHED_IPI_SUPPORTED if SMP
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imply XIP
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help
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RISCV architecture
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config XTENSA
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bool
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select ARCH_IS_SET
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select HAS_DTS
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select USE_SWITCH
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select USE_SWITCH_SUPPORTED
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select IRQ_OFFLOAD_NESTED if IRQ_OFFLOAD
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select ARCH_HAS_TIMING_FUNCTIONS
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imply ATOMIC_OPERATIONS_ARCH
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help
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Xtensa architecture
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config ARCH_POSIX
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bool
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select ARCH_IS_SET
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select HAS_DTS
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select ATOMIC_OPERATIONS_BUILTIN
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select ARCH_HAS_CUSTOM_SWAP_TO_MAIN
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select ARCH_HAS_CUSTOM_BUSY_WAIT
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select ARCH_HAS_THREAD_ABORT
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select NATIVE_APPLICATION
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select HAS_COVERAGE_SUPPORT
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help
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POSIX (native) architecture
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config ARCH_IS_SET
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bool
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help
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Helper symbol to detect SoCs forgetting to select one of the arch
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symbols above. See the top-level CMakeLists.txt.
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menu "General Architecture Options"
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source "$(ARCH_DIR)/common/Kconfig"
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module = ARCH
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module-str = arch
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source "subsys/logging/Kconfig.template.log_config"
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config BIG_ENDIAN
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bool
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help
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This option tells the build system that the target system is big-endian.
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Little-endian architecture is the default and should leave this option
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unselected. This option is selected by arch/$ARCH/Kconfig,
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soc/**/Kconfig, or boards/**/Kconfig and the user should generally avoid
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modifying it. The option is used to select linker script OUTPUT_FORMAT
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and command line option for gen_isr_tables.py.
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config 64BIT
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bool
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help
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This option tells the build system that the target system is
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using a 64-bit address space, meaning that pointer and long types
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are 64 bits wide. This option is selected by arch/$ARCH/Kconfig,
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soc/**/Kconfig, or boards/**/Kconfig and the user should generally
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avoid modifying it.
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# Workaround for not being able to have commas in macro arguments
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DT_CHOSEN_Z_SRAM := zephyr,sram
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config SRAM_SIZE
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int "SRAM Size in kB"
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default $(dt_chosen_reg_size_int,$(DT_CHOSEN_Z_SRAM),0,K)
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help
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The SRAM size in kB. The default value comes from /chosen/zephyr,sram in
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devicetree. The user should generally avoid changing it via menuconfig or
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in configuration files.
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config SRAM_BASE_ADDRESS
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hex "SRAM Base Address"
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default $(dt_chosen_reg_addr_hex,$(DT_CHOSEN_Z_SRAM))
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help
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The SRAM base address. The default value comes from from
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/chosen/zephyr,sram in devicetree. The user should generally avoid
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changing it via menuconfig or in configuration files.
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if ARC || ARM || ARM64 || NIOS2 || X86
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# Workaround for not being able to have commas in macro arguments
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DT_CHOSEN_Z_FLASH := zephyr,flash
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config FLASH_SIZE
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int "Flash Size in kB"
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default $(dt_chosen_reg_size_int,$(DT_CHOSEN_Z_FLASH),0,K) if (XIP && (ARM ||ARM64)) || !ARM
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help
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This option specifies the size of the flash in kB. It is normally set by
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the board's defconfig file and the user should generally avoid modifying
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it via the menu configuration.
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config FLASH_BASE_ADDRESS
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hex "Flash Base Address"
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default $(dt_chosen_reg_addr_hex,$(DT_CHOSEN_Z_FLASH)) if (XIP && (ARM || ARM64)) || !ARM
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help
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This option specifies the base address of the flash on the board. It is
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normally set by the board's defconfig file and the user should generally
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avoid modifying it via the menu configuration.
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endif # ARM || ARM64 || ARC || NIOS2 || X86
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if ARCH_HAS_TRUSTED_EXECUTION
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config TRUSTED_EXECUTION_SECURE
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bool "Trusted Execution: Secure firmware image"
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help
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Select this option to enable building a Secure firmware
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image for a platform that supports Trusted Execution. A
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Secure firmware image will execute in Secure state. It may
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allow the CPU to execute in Non-Secure (Normal) state.
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Therefore, a Secure firmware image shall be able to
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configure security attributions of CPU resources (memory
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areas, peripherals, interrupts, etc.) as well as to handle
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faults, related to security violations. It may optionally
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allow certain functions to be called from the Non-Secure
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(Normal) domain.
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config TRUSTED_EXECUTION_NONSECURE
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depends on !TRUSTED_EXECUTION_SECURE
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bool "Trusted Execution: Non-Secure firmware image"
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help
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Select this option to enable building a Non-Secure
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firmware image for a platform that supports Trusted
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Execution. A Non-Secure firmware image will execute
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in Non-Secure (Normal) state. Therefore, it shall not
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access CPU resources (memory areas, peripherals,
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interrupts etc.) belonging to the Secure domain.
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endif # ARCH_HAS_TRUSTED_EXECUTION
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config HW_STACK_PROTECTION
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bool "Hardware Stack Protection"
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depends on ARCH_HAS_STACK_PROTECTION
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help
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Select this option to enable hardware-based platform features to
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catch stack overflows when the system is running in privileged
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mode. If CONFIG_USERSPACE is not enabled, the system is always
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running in privileged mode.
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Note that this does not necessarily prevent corruption and assertions
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about the overall system state when a fault is triggered cannot be
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made.
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config USERSPACE
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bool "User mode threads"
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depends on ARCH_HAS_USERSPACE
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depends on RUNTIME_ERROR_CHECKS
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depends on SRAM_REGION_PERMISSIONS
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select THREAD_STACK_INFO
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help
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When enabled, threads may be created or dropped down to user mode,
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which has significantly restricted permissions and must interact
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with the kernel via system calls. See Zephyr documentation for more
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details about this feature.
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If a user thread overflows its stack, this will be caught and the
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kernel itself will be shielded from harm. Enabling this option
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may or may not catch stack overflows when the system is in
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privileged mode or handling a system call; to ensure these are always
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caught, enable CONFIG_HW_STACK_PROTECTION.
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config PRIVILEGED_STACK_SIZE
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int "Size of privileged stack"
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default 1024
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depends on ARCH_HAS_USERSPACE
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help
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This option sets the privileged stack region size that will be used
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in addition to the user mode thread stack. During normal execution,
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this region will be inaccessible from user mode. During system calls,
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this region will be utilized by the system call. This value must be
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a multiple of the minimum stack alignment.
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config KOBJECT_TEXT_AREA
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int "Size of kobject text area"
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default 512 if COVERAGE_GCOV
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default 512 if NO_OPTIMIZATIONS
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default 512 if STACK_CANARIES && RISCV
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default 256
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depends on ARCH_HAS_USERSPACE
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help
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Size of kernel object text area. Used in linker script.
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config KOBJECT_DATA_AREA_RESERVE_EXTRA_PERCENT
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int "Reserve extra kobject data area (in percentage)"
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default 100
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depends on ARCH_HAS_USERSPACE
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help
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Multiplication factor used to calculate the size of placeholder to
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reserve space for kobject metadata hash table. The hash table is
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generated via gperf is highly dependent on the absolute addresses of
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kobjects which might change between prebuilts. To reserve enough
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space for the hash table during final linking passes to keep
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kobjects in same place, the size of reserved space is calculated
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from the first prebuilt plus additional space calculated with
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this percentage (of the kobject data area in first prebuilt).
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config KOBJECT_RODATA_AREA_EXTRA_BYTES
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int "Reserve extra bytes for kobject rodata area"
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default 16
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depends on ARCH_HAS_USERSPACE
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help
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Reserve a few more bytes for the RODATA region for kobject metadata.
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This is to account for the uncertainty of tables generated by gperf.
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config GEN_PRIV_STACKS
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bool
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help
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Selected if the architecture requires that privilege elevation stacks
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be allocated in a separate memory area. This is typical of arches
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whose MPUs require regions to be power-of-two aligned/sized.
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FIXME: This should be removed and replaced with checks against
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CONFIG_MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT, but both ARM and ARC
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changes will be necessary for this.
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config STACK_GROWS_UP
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bool "Stack grows towards higher memory addresses"
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help
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Select this option if the architecture has upward growing thread
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stacks. This is not common.
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config NO_UNUSED_STACK_INSPECTION
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bool
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help
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Selected if the architecture will generate a fault if unused stack
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memory is examined, which is the region between the current stack
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pointer and the deepest available address in the current stack
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region.
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config MAX_THREAD_BYTES
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int "Bytes to use when tracking object thread permissions"
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default 2
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depends on USERSPACE
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help
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Every kernel object will have an associated bitfield to store
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thread permissions for that object. This controls the size of the
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bitfield (in bytes) and imposes a limit on how many threads can
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be created in the system.
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config DYNAMIC_OBJECTS
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bool "Allow kernel objects to be allocated at runtime"
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depends on USERSPACE
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help
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Enabling this option allows for kernel objects to be requested from
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the calling thread's resource pool, at a slight cost in performance
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due to the supplemental run-time tables required to validate such
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objects.
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Objects allocated in this way can be freed with a supervisor-only
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API call, or when the number of references to that object drops to
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zero.
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config NOCACHE_MEMORY
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bool "Support for uncached memory"
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depends on ARCH_HAS_NOCACHE_MEMORY_SUPPORT
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help
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Add a "nocache" read-write memory section that is configured to
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not be cached. This memory section can be used to perform DMA
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transfers when cache coherence issues are not optimal or can not
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be solved using cache maintenance operations.
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menu "Interrupt Configuration"
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config DYNAMIC_INTERRUPTS
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bool "Installation of IRQs at runtime"
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help
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Enable installation of interrupts at runtime, which will move some
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interrupt-related data structures to RAM instead of ROM, and
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on some architectures increase code size.
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config GEN_ISR_TABLES
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bool "Use generated IRQ tables"
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help
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This option controls whether a platform uses the gen_isr_tables
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script to generate its interrupt tables. This mechanism will create
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an appropriate hardware vector table and/or software IRQ table.
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config GEN_IRQ_VECTOR_TABLE
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bool "Generate an interrupt vector table"
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default y
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depends on GEN_ISR_TABLES
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help
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This option controls whether a platform using gen_isr_tables
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needs an interrupt vector table created. Only disable this if the
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platform does not use a vector table at all, or requires the vector
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table to be in a format that is not an array of function pointers
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indexed by IRQ line. In the latter case, the vector table must be
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supplied by the application or architecture code.
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config ARCH_IRQ_VECTOR_TABLE_ALIGN
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int "Alignment size of the interrupt vector table"
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default 4
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depends on GEN_IRQ_VECTOR_TABLE
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help
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This option controls alignment size of generated
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_irq_vector_table. Some architecture needs an IRQ vector table
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to be aligned to architecture specific size. The default
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size is 0 for no alignment.
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choice IRQ_VECTOR_TABLE_TYPE
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prompt "IRQ vector table type"
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depends on GEN_IRQ_VECTOR_TABLE
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default IRQ_VECTOR_TABLE_JUMP_BY_CODE if (RISCV && !RISCV_HAS_CLIC)
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default IRQ_VECTOR_TABLE_JUMP_BY_ADDRESS
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config IRQ_VECTOR_TABLE_JUMP_BY_ADDRESS
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bool "Jump by address"
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help
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The IRQ vector table contains the address of the interrupt handler.
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config IRQ_VECTOR_TABLE_JUMP_BY_CODE
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bool "Jump by code"
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help
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The IRQ vector table contains the opcode of a jump instruction to the
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interrupt handler address.
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endchoice
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config GEN_SW_ISR_TABLE
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bool "Generate a software ISR table"
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default y
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depends on GEN_ISR_TABLES
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help
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This option controls whether a platform using gen_isr_tables
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needs a software ISR table table created. This is an array of struct
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_isr_table_entry containing the interrupt service routine and supplied
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parameter.
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config ARCH_SW_ISR_TABLE_ALIGN
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int "Alignment size of a software ISR table"
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default 4
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depends on GEN_SW_ISR_TABLE
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help
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This option controls alignment size of generated
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_sw_isr_table. Some architecture needs a software ISR table
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to be aligned to architecture specific size. The default
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size is 0 for no alignment.
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config GEN_IRQ_START_VECTOR
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int
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default 0
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depends on GEN_ISR_TABLES
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help
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On some architectures, part of the vector table may be reserved for
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system exceptions and is declared separately from the tables
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created by gen_isr_tables.py. When creating these tables, this value
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will be subtracted from CONFIG_NUM_IRQS to properly size them.
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This is a hidden option which needs to be set per architecture and
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left alone.
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config IRQ_OFFLOAD
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bool "IRQ offload"
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depends on TEST
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help
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Enable irq_offload() API which allows functions to be synchronously
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run in interrupt context. Only useful for test cases that need
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to validate the correctness of kernel objects in IRQ context.
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config IRQ_OFFLOAD_NESTED
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bool "irq_offload() supports nested IRQs"
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depends on IRQ_OFFLOAD
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help
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When set by the arch layer, indicates that irq_offload() may
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legally be called in interrupt context to cause a
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synchronous nested interrupt on the current CPU. Not all
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hardware is capable.
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config EXTRA_EXCEPTION_INFO
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bool "Collect extra exception info"
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depends on ARCH_HAS_EXTRA_EXCEPTION_INFO
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help
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This option enables the collection of extra information, such as
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register state, when a fault occurs. This information can be useful
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to collect for post-mortem analysis and debug of issues.
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endmenu # Interrupt configuration
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config INIT_ARCH_HW_AT_BOOT
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bool "Initialize internal architecture state at boot"
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depends on ARCH_SUPPORTS_ARCH_HW_INIT
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help
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This option instructs Zephyr to force the initialization
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of the internal architectural state (for example ARCH-level
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HW registers and system control blocks) during boot to
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the reset values as specified by the corresponding
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architecture manual. The option is useful when the Zephyr
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firmware image is chain-loaded, for example, by a debugger
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or a bootloader, and we need to guarantee that the internal
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states of the architecture core blocks are restored to the
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reset values (as specified by the architecture).
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Note: the functionality is architecture-specific. For the
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implementation details refer to each architecture where
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this feature is supported.
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endmenu
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#
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# Architecture Capabilities
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#
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config ARCH_HAS_SINGLE_THREAD_SUPPORT
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|
bool
|
|
|
|
config ARCH_HAS_TIMING_FUNCTIONS
|
|
bool
|
|
|
|
config ARCH_HAS_TRUSTED_EXECUTION
|
|
bool
|
|
|
|
config ARCH_HAS_STACK_PROTECTION
|
|
bool
|
|
|
|
config ARCH_HAS_USERSPACE
|
|
bool
|
|
|
|
config ARCH_HAS_EXECUTABLE_PAGE_BIT
|
|
bool
|
|
|
|
config ARCH_HAS_NOCACHE_MEMORY_SUPPORT
|
|
bool
|
|
|
|
config ARCH_HAS_RAMFUNC_SUPPORT
|
|
bool
|
|
|
|
config ARCH_HAS_NESTED_EXCEPTION_DETECTION
|
|
bool
|
|
|
|
config ARCH_SUPPORTS_COREDUMP
|
|
bool
|
|
|
|
config ARCH_SUPPORTS_ARCH_HW_INIT
|
|
bool
|
|
|
|
config ARCH_HAS_EXTRA_EXCEPTION_INFO
|
|
bool
|
|
|
|
config ARCH_HAS_GDBSTUB
|
|
bool
|
|
|
|
config ARCH_HAS_COHERENCE
|
|
bool
|
|
help
|
|
When selected, the architecture supports the
|
|
arch_mem_coherent() API and can link into incoherent/cached
|
|
memory using the ".cached" linker section.
|
|
|
|
config ARCH_HAS_THREAD_LOCAL_STORAGE
|
|
bool
|
|
|
|
config ARCH_HAS_SUSPEND_TO_RAM
|
|
bool
|
|
help
|
|
When selected, the architecture supports suspend-to-RAM (S2RAM).
|
|
|
|
#
|
|
# Other architecture related options
|
|
#
|
|
|
|
config ARCH_HAS_THREAD_ABORT
|
|
bool
|
|
|
|
#
|
|
# Hidden CPU family configs
|
|
#
|
|
|
|
config CPU_HAS_TEE
|
|
bool
|
|
help
|
|
This option is enabled when the CPU has support for Trusted
|
|
Execution Environment (e.g. when it has a security attribution
|
|
unit).
|
|
|
|
config CPU_HAS_DCLS
|
|
bool
|
|
help
|
|
This option is enabled when the processor hardware is configured in
|
|
Dual-redundant Core Lock-step (DCLS) topology.
|
|
|
|
config CPU_HAS_FPU
|
|
bool
|
|
help
|
|
This option is enabled when the CPU has hardware floating point
|
|
unit.
|
|
|
|
config CPU_HAS_FPU_DOUBLE_PRECISION
|
|
bool
|
|
select CPU_HAS_FPU
|
|
help
|
|
When enabled, this indicates that the CPU has a double floating point
|
|
precision unit.
|
|
|
|
config CPU_HAS_MPU
|
|
bool
|
|
help
|
|
This option is enabled when the CPU has a Memory Protection Unit (MPU).
|
|
|
|
config CPU_HAS_MMU
|
|
bool
|
|
help
|
|
This hidden option is selected when the CPU has a Memory Management Unit
|
|
(MMU).
|
|
|
|
config ARCH_HAS_DEMAND_PAGING
|
|
bool
|
|
help
|
|
This hidden configuration should be selected by the architecture if
|
|
demand paging is supported.
|
|
|
|
config ARCH_HAS_RESERVED_PAGE_FRAMES
|
|
bool
|
|
help
|
|
This hidden configuration should be selected by the architecture if
|
|
certain RAM page frames need to be marked as reserved and never used for
|
|
memory mappings. The architecture will need to implement
|
|
arch_reserved_pages_update().
|
|
|
|
config ARCH_MAPS_ALL_RAM
|
|
bool
|
|
help
|
|
This hidden option is selected by the architecture to inform the kernel
|
|
that all RAM is mapped at boot, and not just the bounds of the Zephyr image.
|
|
If RAM starts at 0x0, the first page must remain un-mapped to catch NULL
|
|
pointer dereferences. With this enabled, the kernel will not assume that
|
|
virtual memory addresses past the kernel image are available for mappings,
|
|
but instead takes into account an entire RAM mapping instead.
|
|
|
|
This is typically set by architectures which need direct access to all memory.
|
|
It is the architecture's responsibility to mark reserved memory regions
|
|
as such in arch_reserved_pages_update().
|
|
|
|
Although the kernel will not disturb this RAM mapping by re-mapping the associated
|
|
virtual addresses elsewhere, this is limited to only management of the
|
|
virtual address space. The kernel's page frame ontology will not consider
|
|
this mapping at all; non-kernel pages will be considered free (unless marked
|
|
as reserved) and Z_PAGE_FRAME_MAPPED will not be set.
|
|
|
|
menuconfig MPU
|
|
bool "MPU features"
|
|
depends on CPU_HAS_MPU
|
|
help
|
|
This option, when enabled, indicates to the core kernel that an MPU
|
|
is enabled.
|
|
|
|
if MPU
|
|
module = MPU
|
|
module-str = mpu
|
|
source "subsys/logging/Kconfig.template.log_config"
|
|
|
|
config MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT
|
|
bool
|
|
help
|
|
This option is enabled when the MPU requires a power of two alignment
|
|
and size for MPU regions.
|
|
|
|
config MPU_REQUIRES_NON_OVERLAPPING_REGIONS
|
|
bool
|
|
help
|
|
This option is enabled when the MPU requires the active (i.e. enabled)
|
|
MPU regions to be non-overlapping with each other.
|
|
|
|
config MPU_GAP_FILLING
|
|
bool "Force MPU to be filling in background memory regions"
|
|
depends on MPU_REQUIRES_NON_OVERLAPPING_REGIONS
|
|
default y if !USERSPACE
|
|
help
|
|
This Kconfig option instructs the MPU driver to enforce
|
|
a full kernel SRAM partitioning, when it programs the
|
|
dynamic MPU regions (user thread stack, PRIV stack guard
|
|
and application memory domains) during context-switch. We
|
|
allow this to be a configurable option, in order to be able
|
|
to switch the option off and have an increased number of MPU
|
|
regions available for application memory domain programming.
|
|
|
|
Notes:
|
|
An increased number of MPU regions should only be required,
|
|
when building with USERSPACE support. As a result, when we
|
|
build without USERSPACE support, gap filling should always
|
|
be required.
|
|
|
|
When the option is switched off, access to memory areas not
|
|
covered by explicit MPU regions is restricted to privileged
|
|
code on an ARCH-specific basis. Refer to ARCH-specific
|
|
documentation for more information on how this option is
|
|
used.
|
|
|
|
endif # MPU
|
|
|
|
config SRAM_REGION_PERMISSIONS
|
|
bool "Assign appropriate permissions to kernel areas in SRAM"
|
|
depends on MMU || MPU
|
|
default y
|
|
help
|
|
This option indicates that memory protection hardware
|
|
is present, enabled, and regions have been configured at boot for memory
|
|
ranges within the kernel image.
|
|
|
|
If this option is turned on, certain areas of the kernel image will
|
|
have the following access policies applied for all threads, including
|
|
supervisor threads:
|
|
|
|
1) All program text will be have read-only, execute memory permission
|
|
2) All read-only data will have read-only permission, and execution
|
|
disabled if the hardware supports it.
|
|
3) All other RAM addresses will have read-write permission, and
|
|
execution disabled if the hardware supports it.
|
|
|
|
Options such as USERSPACE or HW_STACK_PROTECTION may additionally
|
|
impose additional policies on the memory map, which may be global
|
|
or local to the current running thread.
|
|
|
|
This option may consume additional memory to satisfy memory protection
|
|
hardware alignment constraints.
|
|
|
|
If this option is disabled, the entire kernel will have default memory
|
|
access permissions set, typically read/write/execute. It may be desirable
|
|
to turn this off on MMU systems which are using the MMU for demand
|
|
paging, do not need memory protection, and would rather not use up
|
|
RAM for the alignment between regions.
|
|
|
|
menu "Floating Point Options"
|
|
|
|
config FPU
|
|
bool "Floating point unit (FPU)"
|
|
depends on CPU_HAS_FPU
|
|
help
|
|
This option enables the hardware Floating Point Unit (FPU), in order to
|
|
support using the floating point registers and instructions.
|
|
|
|
When this option is enabled, by default, threads may use the floating
|
|
point registers only in an exclusive manner, and this usually means that
|
|
only one thread may perform floating point operations.
|
|
|
|
If it is necessary for multiple threads to perform concurrent floating
|
|
point operations, the "FPU register sharing" option must be enabled to
|
|
preserve the floating point registers across context switches.
|
|
|
|
Note that this option cannot be selected for the platforms that do not
|
|
include a hardware floating point unit; the floating point support for
|
|
those platforms is dependent on the availability of the toolchain-
|
|
provided software floating point library.
|
|
|
|
config FPU_SHARING
|
|
bool "FPU register sharing"
|
|
depends on FPU && MULTITHREADING
|
|
help
|
|
This option enables preservation of the hardware floating point registers
|
|
across context switches to allow multiple threads to perform concurrent
|
|
floating point operations.
|
|
|
|
Note that some compiler configurations may activate a floating point
|
|
context by generating FP instructions for any thread, and that
|
|
context must be preserved when switching such threads in and out.
|
|
The developers can still disable the FP sharing mode in their
|
|
application projects, and switch to Unshared FP registers mode,
|
|
if it is guaranteed that the image code does not generate FP
|
|
instructions outside the single thread context that is allowed
|
|
to do so.
|
|
|
|
endmenu
|
|
|
|
menu "Cache Options"
|
|
|
|
config DCACHE
|
|
bool "Data cache support"
|
|
default y
|
|
help
|
|
This option enables data cache (d-cache).
|
|
|
|
config CACHE_MANAGEMENT
|
|
bool "Cache management features"
|
|
help
|
|
This links in the cache management functions (for d-cache and i-cache
|
|
where possible).
|
|
|
|
config DCACHE_LINE_SIZE_DETECT
|
|
bool "Detect d-cache line size at runtime"
|
|
depends on CACHE_MANAGEMENT
|
|
help
|
|
This option enables querying some architecture-specific hardware for
|
|
finding the d-cache line size at the expense of taking more memory and
|
|
code and a slightly increased boot time.
|
|
|
|
If the CPU's d-cache line size is known in advance, disable this option and
|
|
manually enter the value for DCACHE_LINE_SIZE or set it in the DT
|
|
using the 'd-cache-line-size' property.
|
|
|
|
config DCACHE_LINE_SIZE
|
|
int "d-cache line size" if !DCACHE_LINE_SIZE_DETECT
|
|
depends on CACHE_MANAGEMENT
|
|
default 0
|
|
help
|
|
Size in bytes of a CPU d-cache line. If this is set to 0 the value is
|
|
obtained from the 'd-cache-line-size' DT property instead if present.
|
|
|
|
|
|
Detect automatically at runtime by selecting DCACHE_LINE_SIZE_DETECT.
|
|
|
|
config ICACHE_LINE_SIZE_DETECT
|
|
bool "Detect i-cache line size at runtime"
|
|
depends on CACHE_MANAGEMENT
|
|
help
|
|
This option enables querying some architecture-specific hardware for
|
|
finding the i-cache line size at the expense of taking more memory and
|
|
code and a slightly increased boot time.
|
|
|
|
If the CPU's i-cache line size is known in advance, disable this option and
|
|
manually enter the value for ICACHE_LINE_SIZE or set it in the DT
|
|
using the 'i-cache-line-size' property.
|
|
|
|
config ICACHE_LINE_SIZE
|
|
int "i-cache line size" if !ICACHE_LINE_SIZE_DETECT
|
|
depends on CACHE_MANAGEMENT
|
|
default 0
|
|
help
|
|
Size in bytes of a CPU i-cache line. If this is set to 0 the value is
|
|
obtained from the 'i-cache-line-size' DT property instead if present.
|
|
|
|
Detect automatically at runtime by selecting ICACHE_LINE_SIZE_DETECT.
|
|
|
|
choice CACHE_TYPE
|
|
prompt "Cache type"
|
|
depends on CACHE_MANAGEMENT
|
|
default HAS_ARCH_CACHE
|
|
|
|
config HAS_ARCH_CACHE
|
|
bool "Integrated cache controller"
|
|
help
|
|
"Integrated on-core cache controller"
|
|
|
|
config HAS_EXTERNAL_CACHE
|
|
bool "External cache controller"
|
|
help
|
|
"External cache controller or cache management system"
|
|
|
|
endchoice
|
|
|
|
endmenu
|
|
|
|
config ARCH
|
|
string
|
|
help
|
|
System architecture string.
|
|
|
|
config SOC
|
|
string
|
|
help
|
|
SoC name which can be found under soc/<arch>/<soc name>.
|
|
This option holds the directory name used by the build system to locate
|
|
the correct linker and header files for the SoC.
|
|
|
|
config SOC_SERIES
|
|
string
|
|
help
|
|
SoC series name which can be found under soc/<arch>/<family>/<series>.
|
|
This option holds the directory name used by the build system to locate
|
|
the correct linker and header files.
|
|
|
|
config SOC_FAMILY
|
|
string
|
|
help
|
|
SoC family name which can be found under soc/<arch>/<family>.
|
|
This option holds the directory name used by the build system to locate
|
|
the correct linker and header files.
|
|
|
|
config TOOLCHAIN_HAS_BUILTIN_FFS
|
|
bool
|
|
default y if !(64BIT && RISCV)
|
|
help
|
|
Hidden option to signal that toolchain has __builtin_ffs*().
|