arch/riscv/Kconfig - linux - Git at Google

 # SPDX-License-Identifier: GPL-2.0-only
 #
 # For a description of the syntax of this configuration file,
 # see Documentation/kbuild/kconfig-language.rst.
 #

 config 64BIT
 	bool

 config 32BIT
 	bool

 config RISCV
 	def_bool y
 	select OF
 	select OF_EARLY_FLATTREE
 	select OF_IRQ
 	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_WANT_FRAME_POINTERS
 	select CLONE_BACKWARDS
 	select COMMON_CLK
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_CPU_DEVICES
 	select GENERIC_IRQ_SHOW
 	select GENERIC_PCI_IOMAP
 	select GENERIC_SCHED_CLOCK
 	select GENERIC_STRNCPY_FROM_USER if MMU
 	select GENERIC_STRNLEN_USER if MMU
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_ATOMIC64 if !64BIT
 	select GENERIC_IOREMAP
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ASM_MODVERSIONS
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_DMA_CONTIGUOUS if MMU
 	select HAVE_FUTEX_CMPXCHG if FUTEX
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_SYSCALL_TRACEPOINTS
 	select IRQ_DOMAIN
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_PCI
 	select MODULES_USE_ELF_RELA if MODULES
 	select MODULE_SECTIONS if MODULES
 	select THREAD_INFO_IN_TASK
 	select PCI_DOMAINS_GENERIC if PCI
 	select PCI_MSI if PCI
 	select RISCV_TIMER
 	select GENERIC_IRQ_MULTI_HANDLER
 	select GENERIC_ARCH_TOPOLOGY if SMP
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_MMIOWB
 	select ARCH_HAS_DEBUG_VIRTUAL
 	select HAVE_EBPF_JIT
 	select EDAC_SUPPORT
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
 	select SPARSEMEM_STATIC if 32BIT
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select HAVE_COPY_THREAD_TLS
 	select HAVE_ARCH_KASAN if MMU && 64BIT

 config ARCH_MMAP_RND_BITS_MIN
 	default 18 if 64BIT
 	default 8

 # max bits determined by the following formula:
 #  VA_BITS - PAGE_SHIFT - 3
 config ARCH_MMAP_RND_BITS_MAX
 	default 24 if 64BIT # SV39 based
 	default 17

 # set if we run in machine mode, cleared if we run in supervisor mode
 config RISCV_M_MODE
 	bool
 	default !MMU

 # set if we are running in S-mode and can use SBI calls
 config RISCV_SBI
 	bool
 	depends on !RISCV_M_MODE
 	default y

 config MMU
 	bool "MMU-based Paged Memory Management Support"
 	default y
 	help
 	  Select if you want MMU-based virtualised addressing space
 	  support by paged memory management. If unsure, say 'Y'.

 config ZONE_DMA32
 	bool
 	default y if 64BIT

 config VA_BITS
 	int
 	default 32 if 32BIT
 	default 39 if 64BIT

 config PA_BITS
 	int
 	default 34 if 32BIT
 	default 56 if 64BIT

 config PAGE_OFFSET
 	hex
 	default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
 	default 0x80000000 if 64BIT && !MMU
 	default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
 	default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB

 config ARCH_FLATMEM_ENABLE
 	def_bool y

 config ARCH_SPARSEMEM_ENABLE
 	def_bool y
 	depends on MMU
 	select SPARSEMEM_VMEMMAP_ENABLE

 config ARCH_SELECT_MEMORY_MODEL
 	def_bool ARCH_SPARSEMEM_ENABLE

 config ARCH_WANT_GENERAL_HUGETLB
 	def_bool y

 config SYS_SUPPORTS_HUGETLBFS
 	def_bool y

 config STACKTRACE_SUPPORT
 	def_bool y

 config TRACE_IRQFLAGS_SUPPORT
 	def_bool y

 config GENERIC_BUG
 	def_bool y
 	depends on BUG
 	select GENERIC_BUG_RELATIVE_POINTERS if 64BIT

 config GENERIC_BUG_RELATIVE_POINTERS
 	bool

 config GENERIC_CALIBRATE_DELAY
 	def_bool y

 config GENERIC_CSUM
 	def_bool y

 config GENERIC_HWEIGHT
 	def_bool y

 config FIX_EARLYCON_MEM
 	def_bool MMU

 config PGTABLE_LEVELS
 	int
 	default 3 if 64BIT
 	default 2

 source "arch/riscv/Kconfig.socs"

 menu "Platform type"

 choice
 	prompt "Base ISA"
 	default ARCH_RV64I
 	help
 	  This selects the base ISA that this kernel will target and must match
 	  the target platform.

 config ARCH_RV32I
 	bool "RV32I"
 	select 32BIT
 	select GENERIC_LIB_ASHLDI3
 	select GENERIC_LIB_ASHRDI3
 	select GENERIC_LIB_LSHRDI3
 	select GENERIC_LIB_UCMPDI2
 	select MMU

 config ARCH_RV64I
 	bool "RV64I"
 	select 64BIT
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && GCC_VERSION >= 50000
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_DYNAMIC_FTRACE if MMU
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
 	select SWIOTLB if MMU

 endchoice

 # We must be able to map all physical memory into the kernel, but the compiler
 # is still a bit more efficient when generating code if it's setup in a manner
 # such that it can only map 2GiB of memory.
 choice
 	prompt "Kernel Code Model"
 	default CMODEL_MEDLOW if 32BIT
 	default CMODEL_MEDANY if 64BIT

 	config CMODEL_MEDLOW
 		bool "medium low code model"
 	config CMODEL_MEDANY
 		bool "medium any code model"
 endchoice

 config MODULE_SECTIONS
 	bool
 	select HAVE_MOD_ARCH_SPECIFIC

 choice
 	prompt "Maximum Physical Memory"
 	default MAXPHYSMEM_2GB if 32BIT
 	default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
 	default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY

 	config MAXPHYSMEM_2GB
 		bool "2GiB"
 	config MAXPHYSMEM_128GB
 		depends on 64BIT && CMODEL_MEDANY
 		bool "128GiB"
 endchoice


 config SMP
 	bool "Symmetric Multi-Processing"
 	help
 	  This enables support for systems with more than one CPU.  If
 	  you say N here, the kernel will run on single and
 	  multiprocessor machines, but will use only one CPU of a
 	  multiprocessor machine. If you say Y here, the kernel will run
 	  on many, but not all, single processor machines. On a single
 	  processor machine, the kernel will run faster if you say N
 	  here.

 	  If you don't know what to do here, say N.

 config NR_CPUS
 	int "Maximum number of CPUs (2-32)"
 	range 2 32
 	depends on SMP
 	default "8"

 choice
 	prompt "CPU Tuning"
 	default TUNE_GENERIC

 config TUNE_GENERIC
 	bool "generic"

 endchoice

 config RISCV_ISA_C
 	bool "Emit compressed instructions when building Linux"
 	default y
 	help
 	   Adds "C" to the ISA subsets that the toolchain is allowed to emit
 	   when building Linux, which results in compressed instructions in the
 	   Linux binary.

 	   If you don't know what to do here, say Y.

 menu "supported PMU type"
 	depends on PERF_EVENTS

 config RISCV_BASE_PMU
 	bool "Base Performance Monitoring Unit"
 	def_bool y
 	help
 	  A base PMU that serves as a reference implementation and has limited
 	  feature of perf.  It can run on any RISC-V machines so serves as the
 	  fallback, but this option can also be disable to reduce kernel size.

 endmenu

 config FPU
 	bool "FPU support"
 	default y
 	help
 	  Say N here if you want to disable all floating-point related procedure
 	  in the kernel.

 	  If you don't know what to do here, say Y.

 endmenu

 menu "Kernel features"

 source "kernel/Kconfig.hz"

 config SECCOMP
 	bool "Enable seccomp to safely compute untrusted bytecode"
 	help
 	  This kernel feature is useful for number crunching applications
 	  that may need to compute untrusted bytecode during their
 	  execution. By using pipes or other transports made available to
 	  the process as file descriptors supporting the read/write
 	  syscalls, it's possible to isolate those applications in
 	  their own address space using seccomp. Once seccomp is
 	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
 	  and the task is only allowed to execute a few safe syscalls
 	  defined by each seccomp mode.

 endmenu

 menu "Boot options"

 config CMDLINE
 	string "Built-in kernel command line"
 	help
 	  For most platforms, the arguments for the kernel's command line
 	  are provided at run-time, during boot. However, there are cases
 	  where either no arguments are being provided or the provided
 	  arguments are insufficient or even invalid.

 	  When that occurs, it is possible to define a built-in command
 	  line here and choose how the kernel should use it later on.

 choice
 	prompt "Built-in command line usage" if CMDLINE != ""
 	default CMDLINE_FALLBACK
 	help
 	  Choose how the kernel will handle the provided built-in command
 	  line.

 config CMDLINE_FALLBACK
 	bool "Use bootloader kernel arguments if available"
 	help
 	  Use the built-in command line as fallback in case we get nothing
 	  during boot. This is the default behaviour.

 config CMDLINE_EXTEND
 	bool "Extend bootloader kernel arguments"
 	help
 	  The command-line arguments provided during boot will be
 	  appended to the built-in command line. This is useful in
 	  cases where the provided arguments are insufficient and
 	  you don't want to or cannot modify them.


 config CMDLINE_FORCE
 	bool "Always use the default kernel command string"
 	help
 	  Always use the built-in command line, even if we get one during
 	  boot. This is useful in case you need to override the provided
 	  command line on systems where you don't have or want control
 	  over it.

 endchoice

 endmenu

 menu "Power management options"

 source "kernel/power/Kconfig"

 endmenu
	# SPDX-License-Identifier: GPL-2.0-only
	#
	# For a description of the syntax of this configuration file,
	# see Documentation/kbuild/kconfig-language.rst.
	#

	config 64BIT
	bool

	config 32BIT
	bool

	config RISCV
	def_bool y
	select OF
	select OF_EARLY_FLATTREE
	select OF_IRQ
	select ARCH_HAS_BINFMT_FLAT
	select ARCH_WANT_FRAME_POINTERS
	select CLONE_BACKWARDS
	select COMMON_CLK
	select GENERIC_CLOCKEVENTS
	select GENERIC_CPU_DEVICES
	select GENERIC_IRQ_SHOW
	select GENERIC_PCI_IOMAP
	select GENERIC_SCHED_CLOCK
	select GENERIC_STRNCPY_FROM_USER if MMU
	select GENERIC_STRNLEN_USER if MMU
	select GENERIC_SMP_IDLE_THREAD
	select GENERIC_ATOMIC64 if !64BIT
	select GENERIC_IOREMAP
	select HAVE_ARCH_AUDITSYSCALL
	select HAVE_ARCH_SECCOMP_FILTER
	select HAVE_ASM_MODVERSIONS
	select HAVE_MEMBLOCK_NODE_MAP
	select HAVE_DMA_CONTIGUOUS if MMU
	select HAVE_FUTEX_CMPXCHG if FUTEX
	select HAVE_PERF_EVENTS
	select HAVE_PERF_REGS
	select HAVE_PERF_USER_STACK_DUMP
	select HAVE_SYSCALL_TRACEPOINTS
	select IRQ_DOMAIN
	select SPARSE_IRQ
	select SYSCTL_EXCEPTION_TRACE
	select HAVE_ARCH_TRACEHOOK
	select HAVE_PCI
	select MODULES_USE_ELF_RELA if MODULES
	select MODULE_SECTIONS if MODULES
	select THREAD_INFO_IN_TASK
	select PCI_DOMAINS_GENERIC if PCI
	select PCI_MSI if PCI
	select RISCV_TIMER
	select GENERIC_IRQ_MULTI_HANDLER
	select GENERIC_ARCH_TOPOLOGY if SMP
	select ARCH_HAS_PTE_SPECIAL
	select ARCH_HAS_MMIOWB
	select ARCH_HAS_DEBUG_VIRTUAL
	select HAVE_EBPF_JIT
	select EDAC_SUPPORT
	select ARCH_HAS_GIGANTIC_PAGE
	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
	select SPARSEMEM_STATIC if 32BIT
	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
	select HAVE_ARCH_MMAP_RND_BITS if MMU
	select ARCH_HAS_GCOV_PROFILE_ALL
	select HAVE_COPY_THREAD_TLS
	select HAVE_ARCH_KASAN if MMU && 64BIT

	config ARCH_MMAP_RND_BITS_MIN
	default 18 if 64BIT
	default 8

	# max bits determined by the following formula:
	# VA_BITS - PAGE_SHIFT - 3
	config ARCH_MMAP_RND_BITS_MAX
	default 24 if 64BIT # SV39 based
	default 17

	# set if we run in machine mode, cleared if we run in supervisor mode
	config RISCV_M_MODE
	bool
	default !MMU

	# set if we are running in S-mode and can use SBI calls
	config RISCV_SBI
	bool
	depends on !RISCV_M_MODE
	default y

	config MMU
	bool "MMU-based Paged Memory Management Support"
	default y
	help
	Select if you want MMU-based virtualised addressing space
	support by paged memory management. If unsure, say 'Y'.

	config ZONE_DMA32
	bool
	default y if 64BIT

	config VA_BITS
	int
	default 32 if 32BIT
	default 39 if 64BIT

	config PA_BITS
	int
	default 34 if 32BIT
	default 56 if 64BIT

	config PAGE_OFFSET
	hex
	default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
	default 0x80000000 if 64BIT && !MMU
	default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
	default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB

	config ARCH_FLATMEM_ENABLE
	def_bool y

	config ARCH_SPARSEMEM_ENABLE
	def_bool y
	depends on MMU
	select SPARSEMEM_VMEMMAP_ENABLE

	config ARCH_SELECT_MEMORY_MODEL
	def_bool ARCH_SPARSEMEM_ENABLE

	config ARCH_WANT_GENERAL_HUGETLB
	def_bool y

	config SYS_SUPPORTS_HUGETLBFS
	def_bool y

	config STACKTRACE_SUPPORT
	def_bool y

	config TRACE_IRQFLAGS_SUPPORT
	def_bool y

	config GENERIC_BUG
	def_bool y
	depends on BUG
	select GENERIC_BUG_RELATIVE_POINTERS if 64BIT

	config GENERIC_BUG_RELATIVE_POINTERS
	bool

	config GENERIC_CALIBRATE_DELAY
	def_bool y

	config GENERIC_CSUM
	def_bool y

	config GENERIC_HWEIGHT
	def_bool y

	config FIX_EARLYCON_MEM
	def_bool MMU

	config PGTABLE_LEVELS
	int
	default 3 if 64BIT
	default 2

	source "arch/riscv/Kconfig.socs"

	menu "Platform type"

	choice
	prompt "Base ISA"
	default ARCH_RV64I
	help
	This selects the base ISA that this kernel will target and must match
	the target platform.

	config ARCH_RV32I
	bool "RV32I"
	select 32BIT
	select GENERIC_LIB_ASHLDI3
	select GENERIC_LIB_ASHRDI3
	select GENERIC_LIB_LSHRDI3
	select GENERIC_LIB_UCMPDI2
	select MMU

	config ARCH_RV64I
	bool "RV64I"
	select 64BIT
	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && GCC_VERSION >= 50000
	select HAVE_FUNCTION_TRACER
	select HAVE_FUNCTION_GRAPH_TRACER
	select HAVE_FTRACE_MCOUNT_RECORD
	select HAVE_DYNAMIC_FTRACE if MMU
	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
	select SWIOTLB if MMU

	endchoice

	# We must be able to map all physical memory into the kernel, but the compiler
	# is still a bit more efficient when generating code if it's setup in a manner
	# such that it can only map 2GiB of memory.
	choice
	prompt "Kernel Code Model"
	default CMODEL_MEDLOW if 32BIT
	default CMODEL_MEDANY if 64BIT

	config CMODEL_MEDLOW
	bool "medium low code model"
	config CMODEL_MEDANY
	bool "medium any code model"
	endchoice

	config MODULE_SECTIONS
	bool
	select HAVE_MOD_ARCH_SPECIFIC

	choice
	prompt "Maximum Physical Memory"
	default MAXPHYSMEM_2GB if 32BIT
	default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
	default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY

	config MAXPHYSMEM_2GB
	bool "2GiB"
	config MAXPHYSMEM_128GB
	depends on 64BIT && CMODEL_MEDANY
	bool "128GiB"
	endchoice


	config SMP
	bool "Symmetric Multi-Processing"
	help
	This enables support for systems with more than one CPU. If
	you say N here, the kernel will run on single and
	multiprocessor machines, but will use only one CPU of a
	multiprocessor machine. If you say Y here, the kernel will run
	on many, but not all, single processor machines. On a single
	processor machine, the kernel will run faster if you say N
	here.

	If you don't know what to do here, say N.

	config NR_CPUS
	int "Maximum number of CPUs (2-32)"
	range 2 32
	depends on SMP
	default "8"

	choice
	prompt "CPU Tuning"
	default TUNE_GENERIC

	config TUNE_GENERIC
	bool "generic"

	endchoice

	config RISCV_ISA_C
	bool "Emit compressed instructions when building Linux"
	default y
	help
	Adds "C" to the ISA subsets that the toolchain is allowed to emit
	when building Linux, which results in compressed instructions in the
	Linux binary.

	If you don't know what to do here, say Y.

	menu "supported PMU type"
	depends on PERF_EVENTS

	config RISCV_BASE_PMU
	bool "Base Performance Monitoring Unit"
	def_bool y
	help
	A base PMU that serves as a reference implementation and has limited
	feature of perf. It can run on any RISC-V machines so serves as the
	fallback, but this option can also be disable to reduce kernel size.

	endmenu

	config FPU
	bool "FPU support"
	default y
	help
	Say N here if you want to disable all floating-point related procedure
	in the kernel.

	If you don't know what to do here, say Y.

	endmenu

	menu "Kernel features"

	source "kernel/Kconfig.hz"

	config SECCOMP
	bool "Enable seccomp to safely compute untrusted bytecode"
	help
	This kernel feature is useful for number crunching applications
	that may need to compute untrusted bytecode during their
	execution. By using pipes or other transports made available to
	the process as file descriptors supporting the read/write
	syscalls, it's possible to isolate those applications in
	their own address space using seccomp. Once seccomp is
	enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
	and the task is only allowed to execute a few safe syscalls
	defined by each seccomp mode.

	endmenu

	menu "Boot options"

	config CMDLINE
	string "Built-in kernel command line"
	help
	For most platforms, the arguments for the kernel's command line
	are provided at run-time, during boot. However, there are cases
	where either no arguments are being provided or the provided
	arguments are insufficient or even invalid.

	When that occurs, it is possible to define a built-in command
	line here and choose how the kernel should use it later on.

	choice
	prompt "Built-in command line usage" if CMDLINE != ""
	default CMDLINE_FALLBACK
	help
	Choose how the kernel will handle the provided built-in command
	line.

	config CMDLINE_FALLBACK
	bool "Use bootloader kernel arguments if available"
	help
	Use the built-in command line as fallback in case we get nothing
	during boot. This is the default behaviour.

	config CMDLINE_EXTEND
	bool "Extend bootloader kernel arguments"
	help
	The command-line arguments provided during boot will be
	appended to the built-in command line. This is useful in
	cases where the provided arguments are insufficient and
	you don't want to or cannot modify them.


	config CMDLINE_FORCE
	bool "Always use the default kernel command string"
	help
	Always use the built-in command line, even if we get one during
	boot. This is useful in case you need to override the provided
	command line on systems where you don't have or want control
	over it.

	endchoice

	endmenu

	menu "Power management options"

	source "kernel/power/Kconfig"

	endmenu