linux/arch/riscv/Kconfig

# 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 ARCH_CLOCKSOURCE_INIT
	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
	select ARCH_HAS_BINFMT_FLAT
	select ARCH_HAS_CURRENT_STACK_POINTER
	select ARCH_HAS_DEBUG_VM_PGTABLE
	select ARCH_HAS_DEBUG_VIRTUAL if MMU
	select ARCH_HAS_DEBUG_WX
	select ARCH_HAS_FORTIFY_SOURCE
	select ARCH_HAS_GCOV_PROFILE_ALL
	select ARCH_HAS_GIGANTIC_PAGE
	select ARCH_HAS_KCOV
	select ARCH_HAS_MMIOWB
	select ARCH_HAS_PTE_SPECIAL
	select ARCH_HAS_SET_DIRECT_MAP if MMU
	select ARCH_HAS_SET_MEMORY if MMU
	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
	select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
	select ARCH_HAS_UBSAN_SANITIZE_ALL
	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
	select ARCH_STACKWALK
	select ARCH_SUPPORTS_ATOMIC_RMW
	select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
	select ARCH_SUPPORTS_HUGETLBFS if MMU
	select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
	select ARCH_USE_MEMTEST
	select ARCH_USE_QUEUED_RWLOCKS
	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
	select ARCH_WANT_FRAME_POINTERS
	select ARCH_WANT_GENERAL_HUGETLB
	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
	select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
	select BUILDTIME_TABLE_SORT if MMU
	select CLONE_BACKWARDS
	select CLINT_TIMER if !MMU
	select COMMON_CLK
	select CPU_PM if CPU_IDLE
	select EDAC_SUPPORT
	select GENERIC_ARCH_TOPOLOGY if SMP
	select GENERIC_ATOMIC64 if !64BIT
	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
	select GENERIC_EARLY_IOREMAP
	select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
	select GENERIC_IDLE_POLL_SETUP
	select GENERIC_IOREMAP if MMU
	select GENERIC_IRQ_MULTI_HANDLER
	select GENERIC_IRQ_SHOW
	select GENERIC_IRQ_SHOW_LEVEL
	select GENERIC_LIB_DEVMEM_IS_ALLOWED
	select GENERIC_PCI_IOMAP
	select GENERIC_PTDUMP if MMU
	select GENERIC_SCHED_CLOCK
	select GENERIC_SMP_IDLE_THREAD
	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
	select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
	select HAVE_ARCH_AUDITSYSCALL
	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
	select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
	select HAVE_ARCH_KASAN if MMU && 64BIT
	select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
	select HAVE_ARCH_KFENCE if MMU && 64BIT
	select HAVE_ARCH_KGDB if !XIP_KERNEL
	select HAVE_ARCH_KGDB_QXFER_PKT
	select HAVE_ARCH_MMAP_RND_BITS if MMU
	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
	select HAVE_ARCH_SECCOMP_FILTER
	select HAVE_ARCH_TRACEHOOK
	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
	select HAVE_ARCH_VMAP_STACK if MMU && 64BIT
	select HAVE_ASM_MODVERSIONS
	select HAVE_CONTEXT_TRACKING_USER
	select HAVE_DEBUG_KMEMLEAK
	select HAVE_DMA_CONTIGUOUS if MMU
	select HAVE_EBPF_JIT if MMU
	select HAVE_FUNCTION_ERROR_INJECTION
	select HAVE_GCC_PLUGINS
	select HAVE_GENERIC_VDSO if MMU && 64BIT
	select HAVE_IRQ_TIME_ACCOUNTING
	select HAVE_KPROBES if !XIP_KERNEL
	select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
	select HAVE_KRETPROBES if !XIP_KERNEL
	select HAVE_MOVE_PMD
	select HAVE_MOVE_PUD
	select HAVE_PCI
	select HAVE_PERF_EVENTS
	select HAVE_PERF_REGS
	select HAVE_PERF_USER_STACK_DUMP
	select HAVE_REGS_AND_STACK_ACCESS_API
	select HAVE_FUNCTION_ARG_ACCESS_API
	select HAVE_STACKPROTECTOR
	select HAVE_SYSCALL_TRACEPOINTS
	select HAVE_RSEQ
	select IRQ_DOMAIN
	select IRQ_FORCED_THREADING
	select MODULES_USE_ELF_RELA if MODULES
	select MODULE_SECTIONS if MODULES
	select OF
	select OF_DMA_DEFAULT_COHERENT
	select OF_EARLY_FLATTREE
	select OF_IRQ
	select PCI_DOMAINS_GENERIC if PCI
	select PCI_MSI if PCI
	select RISCV_INTC
	select RISCV_TIMER if RISCV_SBI
	select SPARSE_IRQ
	select SYSCTL_EXCEPTION_TRACE
	select THREAD_INFO_IN_TASK
	select TRACE_IRQFLAGS_SUPPORT
	select UACCESS_MEMCPY if !MMU
	select ZONE_DMA32 if 64BIT

config ARCH_MMAP_RND_BITS_MIN
	default 18 if 64BIT
	default 8

config ARCH_MMAP_RND_COMPAT_BITS_MIN
	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

config ARCH_MMAP_RND_COMPAT_BITS_MAX
	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 PAGE_OFFSET
	hex
	default 0xC0000000 if 32BIT
	default 0x80000000 if 64BIT && !MMU
	default 0xff60000000000000 if 64BIT

config KASAN_SHADOW_OFFSET
	hex
	depends on KASAN_GENERIC
	default 0xdfffffff00000000 if 64BIT
	default 0xffffffff if 32BIT

config ARCH_FLATMEM_ENABLE
	def_bool !NUMA

config ARCH_SPARSEMEM_ENABLE
	def_bool y
	depends on MMU
	select SPARSEMEM_STATIC if 32BIT && SPARSEMEM
	select SPARSEMEM_VMEMMAP_ENABLE if 64BIT

config ARCH_SELECT_MEMORY_MODEL
	def_bool ARCH_SPARSEMEM_ENABLE

config ARCH_SUPPORTS_UPROBES
	def_bool y

config STACKTRACE_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 5 if 64BIT
	default 2

config LOCKDEP_SUPPORT
	def_bool y

config RISCV_DMA_NONCOHERENT
	bool
	select ARCH_HAS_DMA_PREP_COHERENT
	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
	select ARCH_HAS_SYNC_DMA_FOR_CPU
	select ARCH_HAS_SETUP_DMA_OPS
	select DMA_DIRECT_REMAP

source "arch/riscv/Kconfig.socs"
source "arch/riscv/Kconfig.erratas"

menu "Platform type"

config NONPORTABLE
	bool "Allow configurations that result in non-portable kernels"
	help
	  RISC-V kernel binaries are compatible between all known systems
	  whenever possible, but there are some use cases that can only be
	  satisfied by configurations that result in kernel binaries that are
	  not portable between systems.

	  Selecting N does not guarantee kernels will be portable to all known
	  systems.  Selecting any of the options guarded by NONPORTABLE will
	  result in kernel binaries that are unlikely to be portable between
	  systems.

	  If unsure, say N.

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"
	depends on NONPORTABLE
	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
	select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8)
	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
	select HAVE_FUNCTION_GRAPH_TRACER
	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
	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

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"

config HOTPLUG_CPU
	bool "Support for hot-pluggable CPUs"
	depends on SMP
	select GENERIC_IRQ_MIGRATION
	help

	  Say Y here to experiment with turning CPUs off and on.  CPUs
	  can be controlled through /sys/devices/system/cpu.

	  Say N if you want to disable CPU hotplug.

choice
	prompt "CPU Tuning"
	default TUNE_GENERIC

config TUNE_GENERIC
	bool "generic"

endchoice

# Common NUMA Features
config NUMA
	bool "NUMA Memory Allocation and Scheduler Support"
	depends on SMP && MMU
	select GENERIC_ARCH_NUMA
	select OF_NUMA
	select ARCH_SUPPORTS_NUMA_BALANCING
	select USE_PERCPU_NUMA_NODE_ID
	select NEED_PER_CPU_EMBED_FIRST_CHUNK
	help
	  Enable NUMA (Non-Uniform Memory Access) support.

	  The kernel will try to allocate memory used by a CPU on the
	  local memory of the CPU and add some more NUMA awareness to the kernel.

config NODES_SHIFT
	int "Maximum NUMA Nodes (as a power of 2)"
	range 1 10
	default "2"
	depends on NUMA
	help
	  Specify the maximum number of NUMA Nodes available on the target
	  system.  Increases memory reserved to accommodate various tables.

config RISCV_ALTERNATIVE
	bool
	depends on !XIP_KERNEL
	help
	  This Kconfig allows the kernel to automatically patch the
	  errata required by the execution platform at run time. The
	  code patching is performed once in the boot stages. It means
	  that the overhead from this mechanism is just taken once.

config RISCV_ALTERNATIVE_EARLY
	bool
	depends on RISCV_ALTERNATIVE
	help
	  Allows early patching of the kernel for special errata

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.

config RISCV_ISA_SVPBMT
	bool "SVPBMT extension support"
	depends on 64BIT && MMU
	select RISCV_ALTERNATIVE
	default y
	help
	   Adds support to dynamically detect the presence of the SVPBMT
	   ISA-extension (Supervisor-mode: page-based memory types) and
	   enable its usage.

	   The memory type for a page contains a combination of attributes
	   that indicate the cacheability, idempotency, and ordering
	   properties for access to that page.

	   The SVPBMT extension is only available on 64Bit cpus.

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

config CC_HAS_ZICBOM
	bool
	default y if 64BIT && $(cc-option,-mabi=lp64 -march=rv64ima_zicbom)
	default y if 32BIT && $(cc-option,-mabi=ilp32 -march=rv32ima_zicbom)

config RISCV_ISA_ZICBOM
	bool "Zicbom extension support for non-coherent DMA operation"
	depends on CC_HAS_ZICBOM
	depends on !XIP_KERNEL && MMU
	select RISCV_DMA_NONCOHERENT
	select RISCV_ALTERNATIVE
	default y
	help
	   Adds support to dynamically detect the presence of the ZICBOM
	   extension (Cache Block Management Operations) and enable its
	   usage.

	   The Zicbom extension can be used to handle for example
	   non-coherent DMA support on devices that need it.

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

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 # "Platform type"

menu "Kernel features"

source "kernel/Kconfig.hz"

config RISCV_SBI_V01
	bool "SBI v0.1 support"
	depends on RISCV_SBI
	help
	  This config allows kernel to use SBI v0.1 APIs. This will be
	  deprecated in future once legacy M-mode software are no longer in use.

config RISCV_BOOT_SPINWAIT
	bool "Spinwait booting method"
	depends on SMP
	default y if RISCV_SBI_V01 || RISCV_M_MODE
	help
	  This enables support for booting Linux via spinwait method. In the
	  spinwait method, all cores randomly jump to Linux. One of the cores
	  gets chosen via lottery and all other keep spinning on a percpu
	  variable. This method cannot support CPU hotplug and sparse hartid
	  scheme. It should be only enabled for M-mode Linux or platforms relying
	  on older firmware without SBI HSM extension. All other platforms should
	  rely on ordered booting via SBI HSM extension which gets chosen
	  dynamically at runtime if the firmware supports it.

	  Since spinwait is incompatible with sparse hart IDs, it requires
	  NR_CPUS be large enough to contain the physical hart ID of the first
	  hart to enter Linux.

	  If unsure what to do here, say N.

config KEXEC
	bool "Kexec system call"
	select KEXEC_CORE
	select HOTPLUG_CPU if SMP
	depends on MMU
	help
	  kexec is a system call that implements the ability to shutdown your
	  current kernel, and to start another kernel. It is like a reboot
	  but it is independent of the system firmware. And like a reboot
	  you can start any kernel with it, not just Linux.

	  The name comes from the similarity to the exec system call.

config KEXEC_FILE
	bool "kexec file based systmem call"
	select KEXEC_CORE
	select KEXEC_ELF
	select HAVE_IMA_KEXEC if IMA
	depends on 64BIT
	help
	  This is new version of kexec system call. This system call is
	  file based and takes file descriptors as system call argument
	  for kernel and initramfs as opposed to list of segments as
	  accepted by previous system call.

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

config ARCH_HAS_KEXEC_PURGATORY
	def_bool KEXEC_FILE
	depends on CRYPTO=y
	depends on CRYPTO_SHA256=y

config CRASH_DUMP
	bool "Build kdump crash kernel"
	help
	  Generate crash dump after being started by kexec. This should
	  be normally only set in special crash dump kernels which are
	  loaded in the main kernel with kexec-tools into a specially
	  reserved region and then later executed after a crash by
	  kdump/kexec.

	  For more details see Documentation/admin-guide/kdump/kdump.rst

config COMPAT
	bool "Kernel support for 32-bit U-mode"
	default 64BIT
	depends on 64BIT && MMU
	help
	  This option enables support for a 32-bit U-mode running under a 64-bit
	  kernel at S-mode. riscv32-specific components such as system calls,
	  the user helper functions (vdso), signal rt_frame functions and the
	  ptrace interface are handled appropriately by the kernel.

	  If you want to execute 32-bit userspace applications, say Y.

endmenu # "Kernel features"

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

config EFI_STUB
	bool

config EFI
	bool "UEFI runtime support"
	depends on OF && !XIP_KERNEL
	select LIBFDT
	select UCS2_STRING
	select EFI_PARAMS_FROM_FDT
	select EFI_STUB
	select EFI_GENERIC_STUB
	select EFI_RUNTIME_WRAPPERS
	select RISCV_ISA_C
	depends on MMU
	default y
	help
	  This option provides support for runtime services provided
	  by UEFI firmware (such as non-volatile variables, realtime
	  clock, and platform reset). A UEFI stub is also provided to
	  allow the kernel to be booted as an EFI application. This
	  is only useful on systems that have UEFI firmware.

config CC_HAVE_STACKPROTECTOR_TLS
	def_bool $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=tp -mstack-protector-guard-offset=0)

config STACKPROTECTOR_PER_TASK
	def_bool y
	depends on !RANDSTRUCT
	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS

config PHYS_RAM_BASE_FIXED
	bool "Explicitly specified physical RAM address"
	depends on NONPORTABLE
	default n

config PHYS_RAM_BASE
	hex "Platform Physical RAM address"
	depends on PHYS_RAM_BASE_FIXED
	default "0x80000000"
	help
	  This is the physical address of RAM in the system. It has to be
	  explicitly specified to run early relocations of read-write data
	  from flash to RAM.

config XIP_KERNEL
	bool "Kernel Execute-In-Place from ROM"
	depends on MMU && SPARSEMEM && NONPORTABLE
	# This prevents XIP from being enabled by all{yes,mod}config, which
	# fail to build since XIP doesn't support large kernels.
	depends on !COMPILE_TEST
	select PHYS_RAM_BASE_FIXED
	help
	  Execute-In-Place allows the kernel to run from non-volatile storage
	  directly addressable by the CPU, such as NOR flash. This saves RAM
	  space since the text section of the kernel is not loaded from flash
	  to RAM.  Read-write sections, such as the data section and stack,
	  are still copied to RAM.  The XIP kernel is not compressed since
	  it has to run directly from flash, so it will take more space to
	  store it.  The flash address used to link the kernel object files,
	  and for storing it, is configuration dependent. Therefore, if you
	  say Y here, you must know the proper physical address where to
	  store the kernel image depending on your own flash memory usage.

	  Also note that the make target becomes "make xipImage" rather than
	  "make zImage" or "make Image".  The final kernel binary to put in
	  ROM memory will be arch/riscv/boot/xipImage.

	  SPARSEMEM is required because the kernel text and rodata that are
	  flash resident are not backed by memmap, then any attempt to get
	  a struct page on those regions will trigger a fault.

	  If unsure, say N.

config XIP_PHYS_ADDR
	hex "XIP Kernel Physical Location"
	depends on XIP_KERNEL
	default "0x21000000"
	help
	  This is the physical address in your flash memory the kernel will
	  be linked for and stored to.  This address is dependent on your
	  own flash usage.

endmenu # "Boot options"

config BUILTIN_DTB
	bool
	depends on OF && NONPORTABLE
	default y if XIP_KERNEL

config PORTABLE
	bool
	default !NONPORTABLE
	select EFI
	select OF
	select MMU

menu "Power management options"

source "kernel/power/Kconfig"

endmenu # "Power management options"

menu "CPU Power Management"

source "drivers/cpuidle/Kconfig"

endmenu # "CPU Power Management"

source "arch/riscv/kvm/Kconfig"