# SPDX-License-Identifier: GPL-2.0
  #
  # General architecture dependent options
  #
  
  #
  # Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
  # override the default values in this file.
  #
  source "arch/$(SRCARCH)/Kconfig"
  
  menu "General architecture-dependent options"
  
  config CRASH_CORE
  	bool
  
  config KEXEC_CORE
  	select CRASH_CORE
  	bool
  
  config KEXEC_ELF
  	bool
  
  config HAVE_IMA_KEXEC
  	bool
  
  config HOTPLUG_SMT
  	bool
  
  config OPROFILE
  	tristate "OProfile system profiling"
  	depends on PROFILING
  	depends on HAVE_OPROFILE
  	select RING_BUFFER
  	select RING_BUFFER_ALLOW_SWAP
  	help
  	  OProfile is a profiling system capable of profiling the
  	  whole system, include the kernel, kernel modules, libraries,
  	  and applications.
  
  	  If unsure, say N.
  
  config OPROFILE_EVENT_MULTIPLEX
  	bool "OProfile multiplexing support (EXPERIMENTAL)"
  	default n
  	depends on OPROFILE && X86
  	help
  	  The number of hardware counters is limited. The multiplexing
  	  feature enables OProfile to gather more events than counters
  	  are provided by the hardware. This is realized by switching
  	  between events at a user specified time interval.
  
  	  If unsure, say N.
  
  config HAVE_OPROFILE
  	bool
  
  config OPROFILE_NMI_TIMER
  	def_bool y
  	depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64
  
  config KPROBES
  	bool "Kprobes"
  	depends on MODULES
  	depends on HAVE_KPROBES
  	select KALLSYMS
  	help
  	  Kprobes allows you to trap at almost any kernel address and
  	  execute a callback function.  register_kprobe() establishes
  	  a probepoint and specifies the callback.  Kprobes is useful
  	  for kernel debugging, non-intrusive instrumentation and testing.
  	  If in doubt, say "N".
  
  config JUMP_LABEL
         bool "Optimize very unlikely/likely branches"
         depends on HAVE_ARCH_JUMP_LABEL
         depends on CC_HAS_ASM_GOTO
         help
           This option enables a transparent branch optimization that
  	 makes certain almost-always-true or almost-always-false branch
  	 conditions even cheaper to execute within the kernel.
  
  	 Certain performance-sensitive kernel code, such as trace points,
  	 scheduler functionality, networking code and KVM have such
  	 branches and include support for this optimization technique.
  
           If it is detected that the compiler has support for "asm goto",
  	 the kernel will compile such branches with just a nop
  	 instruction. When the condition flag is toggled to true, the
  	 nop will be converted to a jump instruction to execute the
  	 conditional block of instructions.
  
  	 This technique lowers overhead and stress on the branch prediction
  	 of the processor and generally makes the kernel faster. The update
  	 of the condition is slower, but those are always very rare.
  
  	 ( On 32-bit x86, the necessary options added to the compiler
  	   flags may increase the size of the kernel slightly. )
  
  config STATIC_KEYS_SELFTEST
  	bool "Static key selftest"
  	depends on JUMP_LABEL
  	help
  	  Boot time self-test of the branch patching code.
  
  config OPTPROBES
  	def_bool y
  	depends on KPROBES && HAVE_OPTPROBES
  	select TASKS_RCU if PREEMPTION
  
  config KPROBES_ON_FTRACE
  	def_bool y
  	depends on KPROBES && HAVE_KPROBES_ON_FTRACE
  	depends on DYNAMIC_FTRACE_WITH_REGS
  	help
  	 If function tracer is enabled and the arch supports full
  	 passing of pt_regs to function tracing, then kprobes can
  	 optimize on top of function tracing.
  
  config UPROBES
  	def_bool n
  	depends on ARCH_SUPPORTS_UPROBES
  	help
  	  Uprobes is the user-space counterpart to kprobes: they
  	  enable instrumentation applications (such as 'perf probe')
  	  to establish unintrusive probes in user-space binaries and
  	  libraries, by executing handler functions when the probes
  	  are hit by user-space applications.
  
  	  ( These probes come in the form of single-byte breakpoints,
  	    managed by the kernel and kept transparent to the probed
  	    application. )
  
  config HAVE_EFFICIENT_UNALIGNED_ACCESS
  	bool
  	help
  	  Some architectures are unable to perform unaligned accesses
  	  without the use of get_unaligned/put_unaligned. Others are
  	  unable to perform such accesses efficiently (e.g. trap on
  	  unaligned access and require fixing it up in the exception
  	  handler.)
  
  	  This symbol should be selected by an architecture if it can
  	  perform unaligned accesses efficiently to allow different
  	  code paths to be selected for these cases. Some network
  	  drivers, for example, could opt to not fix up alignment
  	  problems with received packets if doing so would not help
  	  much.
  
  	  See Documentation/unaligned-memory-access.txt for more
  	  information on the topic of unaligned memory accesses.
  
  config ARCH_USE_BUILTIN_BSWAP
         bool
         help
  	 Modern versions of GCC (since 4.4) have builtin functions
  	 for handling byte-swapping. Using these, instead of the old
  	 inline assembler that the architecture code provides in the
  	 __arch_bswapXX() macros, allows the compiler to see what's
  	 happening and offers more opportunity for optimisation. In
  	 particular, the compiler will be able to combine the byteswap
  	 with a nearby load or store and use load-and-swap or
  	 store-and-swap instructions if the architecture has them. It
  	 should almost *never* result in code which is worse than the
  	 hand-coded assembler in <asm/swab.h>.  But just in case it
  	 does, the use of the builtins is optional.
  
  	 Any architecture with load-and-swap or store-and-swap
  	 instructions should set this. And it shouldn't hurt to set it
  	 on architectures that don't have such instructions.
  
  config KRETPROBES
  	def_bool y
  	depends on KPROBES && HAVE_KRETPROBES
  
  config USER_RETURN_NOTIFIER
  	bool
  	depends on HAVE_USER_RETURN_NOTIFIER
  	help
  	  Provide a kernel-internal notification when a cpu is about to
  	  switch to user mode.
  
  config HAVE_IOREMAP_PROT
  	bool
  
  config HAVE_KPROBES
  	bool
  
  config HAVE_KRETPROBES
  	bool
  
  config HAVE_OPTPROBES
  	bool
  
  config HAVE_KPROBES_ON_FTRACE
  	bool
  
  config HAVE_FUNCTION_ERROR_INJECTION
  	bool
  
  config HAVE_NMI
  	bool
  
  #
  # An arch should select this if it provides all these things:
  #
  #	task_pt_regs()		in asm/processor.h or asm/ptrace.h
  #	arch_has_single_step()	if there is hardware single-step support
  #	arch_has_block_step()	if there is hardware block-step support
  #	asm/syscall.h		supplying asm-generic/syscall.h interface
  #	linux/regset.h		user_regset interfaces
  #	CORE_DUMP_USE_REGSET	#define'd in linux/elf.h
  #	TIF_SYSCALL_TRACE	calls tracehook_report_syscall_{entry,exit}
  #	TIF_NOTIFY_RESUME	calls tracehook_notify_resume()
  #	signal delivery		calls tracehook_signal_handler()
  #
  config HAVE_ARCH_TRACEHOOK
  	bool
  
  config HAVE_DMA_CONTIGUOUS
  	bool
  
  config GENERIC_SMP_IDLE_THREAD
         bool
  
  config GENERIC_IDLE_POLL_SETUP
         bool
  
  config ARCH_HAS_FORTIFY_SOURCE
  	bool
  	help
  	  An architecture should select this when it can successfully
  	  build and run with CONFIG_FORTIFY_SOURCE.
  
  #
  # Select if the arch provides a historic keepinit alias for the retain_initrd
  # command line option
  #
  config ARCH_HAS_KEEPINITRD
  	bool
  
  # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
  config ARCH_HAS_SET_MEMORY
  	bool
  
  # Select if arch has all set_direct_map_invalid/default() functions
  config ARCH_HAS_SET_DIRECT_MAP
  	bool
  
  #
  # Select if arch has an uncached kernel segment and provides the
  # uncached_kernel_address / cached_kernel_address symbols to use it
  #
  config ARCH_HAS_UNCACHED_SEGMENT
  	select ARCH_HAS_DMA_PREP_COHERENT
  	bool
  
  # Select if arch init_task must go in the __init_task_data section
  config ARCH_TASK_STRUCT_ON_STACK
         bool
  
  # Select if arch has its private alloc_task_struct() function
  config ARCH_TASK_STRUCT_ALLOCATOR
  	bool
  
  config HAVE_ARCH_THREAD_STRUCT_WHITELIST
  	bool
  	depends on !ARCH_TASK_STRUCT_ALLOCATOR
  	help
  	  An architecture should select this to provide hardened usercopy
  	  knowledge about what region of the thread_struct should be
  	  whitelisted for copying to userspace. Normally this is only the
  	  FPU registers. Specifically, arch_thread_struct_whitelist()
  	  should be implemented. Without this, the entire thread_struct
  	  field in task_struct will be left whitelisted.
  
  # Select if arch has its private alloc_thread_stack() function
  config ARCH_THREAD_STACK_ALLOCATOR
  	bool
  
  # Select if arch wants to size task_struct dynamically via arch_task_struct_size:
  config ARCH_WANTS_DYNAMIC_TASK_STRUCT
  	bool
  
  config ARCH_32BIT_OFF_T
  	bool
  	depends on !64BIT
  	help
  	  All new 32-bit architectures should have 64-bit off_t type on
  	  userspace side which corresponds to the loff_t kernel type. This
  	  is the requirement for modern ABIs. Some existing architectures
  	  still support 32-bit off_t. This option is enabled for all such
  	  architectures explicitly.
  
  config HAVE_ASM_MODVERSIONS
  	bool
  	help
  	  This symbol should be selected by an architecure if it provides
  	  <asm/asm-prototypes.h> to support the module versioning for symbols
  	  exported from assembly code.
  
  config HAVE_REGS_AND_STACK_ACCESS_API
  	bool
  	help
  	  This symbol should be selected by an architecure if it supports
  	  the API needed to access registers and stack entries from pt_regs,
  	  declared in asm/ptrace.h
  	  For example the kprobes-based event tracer needs this API.
  
  config HAVE_RSEQ
  	bool
  	depends on HAVE_REGS_AND_STACK_ACCESS_API
  	help
  	  This symbol should be selected by an architecture if it
  	  supports an implementation of restartable sequences.
  
  config HAVE_FUNCTION_ARG_ACCESS_API
  	bool
  	help
  	  This symbol should be selected by an architecure if it supports
  	  the API needed to access function arguments from pt_regs,
  	  declared in asm/ptrace.h
  
  config HAVE_CLK
  	bool
  	help
  	  The <linux/clk.h> calls support software clock gating and
  	  thus are a key power management tool on many systems.
  
  config HAVE_HW_BREAKPOINT
  	bool
  	depends on PERF_EVENTS
  
  config HAVE_MIXED_BREAKPOINTS_REGS
  	bool
  	depends on HAVE_HW_BREAKPOINT
  	help
  	  Depending on the arch implementation of hardware breakpoints,
  	  some of them have separate registers for data and instruction
  	  breakpoints addresses, others have mixed registers to store
  	  them but define the access type in a control register.
  	  Select this option if your arch implements breakpoints under the
  	  latter fashion.
  
  config HAVE_USER_RETURN_NOTIFIER
  	bool
  
  config HAVE_PERF_EVENTS_NMI
  	bool
  	help
  	  System hardware can generate an NMI using the perf event
  	  subsystem.  Also has support for calculating CPU cycle events
  	  to determine how many clock cycles in a given period.
  
  config HAVE_HARDLOCKUP_DETECTOR_PERF
  	bool
  	depends on HAVE_PERF_EVENTS_NMI
  	help
  	  The arch chooses to use the generic perf-NMI-based hardlockup
  	  detector. Must define HAVE_PERF_EVENTS_NMI.
  
  config HAVE_NMI_WATCHDOG
  	depends on HAVE_NMI
  	bool
  	help
  	  The arch provides a low level NMI watchdog. It provides
  	  asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
  
  config HAVE_HARDLOCKUP_DETECTOR_ARCH
  	bool
  	select HAVE_NMI_WATCHDOG
  	help
  	  The arch chooses to provide its own hardlockup detector, which is
  	  a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
  	  interfaces and parameters provided by hardlockup detector subsystem.
  
  config HAVE_PERF_REGS
  	bool
  	help
  	  Support selective register dumps for perf events. This includes
  	  bit-mapping of each registers and a unique architecture id.
  
  config HAVE_PERF_USER_STACK_DUMP
  	bool
  	help
  	  Support user stack dumps for perf event samples. This needs
  	  access to the user stack pointer which is not unified across
  	  architectures.
  
  config HAVE_ARCH_JUMP_LABEL
  	bool
  
  config HAVE_ARCH_JUMP_LABEL_RELATIVE
  	bool
  
  config HAVE_RCU_TABLE_FREE
  	bool
  
  config HAVE_MMU_GATHER_PAGE_SIZE
  	bool
  
  config MMU_GATHER_NO_RANGE
  	bool
  
  config HAVE_MMU_GATHER_NO_GATHER
  	bool
  
  config ARCH_HAVE_NMI_SAFE_CMPXCHG
  	bool
  
  config HAVE_ALIGNED_STRUCT_PAGE
  	bool
  	help
  	  This makes sure that struct pages are double word aligned and that
  	  e.g. the SLUB allocator can perform double word atomic operations
  	  on a struct page for better performance. However selecting this
  	  might increase the size of a struct page by a word.
  
  config HAVE_CMPXCHG_LOCAL
  	bool
  
  config HAVE_CMPXCHG_DOUBLE
  	bool
  
  config ARCH_WEAK_RELEASE_ACQUIRE
  	bool
  
  config ARCH_WANT_IPC_PARSE_VERSION
  	bool
  
  config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
  	bool
  
  config ARCH_WANT_OLD_COMPAT_IPC
  	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
  	bool
  
  config HAVE_ARCH_SECCOMP_FILTER
  	bool
  	help
  	  An arch should select this symbol if it provides all of these things:
  	  - syscall_get_arch()
  	  - syscall_get_arguments()
  	  - syscall_rollback()
  	  - syscall_set_return_value()
  	  - SIGSYS siginfo_t support
  	  - secure_computing is called from a ptrace_event()-safe context
  	  - secure_computing return value is checked and a return value of -1
  	    results in the system call being skipped immediately.
  	  - seccomp syscall wired up
  
  config SECCOMP_FILTER
  	def_bool y
  	depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
  	help
  	  Enable tasks to build secure computing environments defined
  	  in terms of Berkeley Packet Filter programs which implement
  	  task-defined system call filtering polices.
  
  	  See Documentation/userspace-api/seccomp_filter.rst for details.
  
  config HAVE_ARCH_STACKLEAK
  	bool
  	help
  	  An architecture should select this if it has the code which
  	  fills the used part of the kernel stack with the STACKLEAK_POISON
  	  value before returning from system calls.
  
  config HAVE_STACKPROTECTOR
  	bool
  	help
  	  An arch should select this symbol if:
  	  - it has implemented a stack canary (e.g. __stack_chk_guard)
  
  config CC_HAS_STACKPROTECTOR_NONE
  	def_bool $(cc-option,-fno-stack-protector)
  
  config STACKPROTECTOR
  	bool "Stack Protector buffer overflow detection"
  	depends on HAVE_STACKPROTECTOR
  	depends on $(cc-option,-fstack-protector)
  	default y
  	help
  	  This option turns on the "stack-protector" GCC feature. This
  	  feature puts, at the beginning of functions, a canary value on
  	  the stack just before the return address, and validates
  	  the value just before actually returning.  Stack based buffer
  	  overflows (that need to overwrite this return address) now also
  	  overwrite the canary, which gets detected and the attack is then
  	  neutralized via a kernel panic.
  
  	  Functions will have the stack-protector canary logic added if they
  	  have an 8-byte or larger character array on the stack.
  
  	  This feature requires gcc version 4.2 or above, or a distribution
  	  gcc with the feature backported ("-fstack-protector").
  
  	  On an x86 "defconfig" build, this feature adds canary checks to
  	  about 3% of all kernel functions, which increases kernel code size
  	  by about 0.3%.
  
  config STACKPROTECTOR_STRONG
  	bool "Strong Stack Protector"
  	depends on STACKPROTECTOR
  	depends on $(cc-option,-fstack-protector-strong)
  	default y
  	help
  	  Functions will have the stack-protector canary logic added in any
  	  of the following conditions:
  
  	  - local variable's address used as part of the right hand side of an
  	    assignment or function argument
  	  - local variable is an array (or union containing an array),
  	    regardless of array type or length
  	  - uses register local variables
  
  	  This feature requires gcc version 4.9 or above, or a distribution
  	  gcc with the feature backported ("-fstack-protector-strong").
  
  	  On an x86 "defconfig" build, this feature adds canary checks to
  	  about 20% of all kernel functions, which increases the kernel code
  	  size by about 2%.
  
  config ARCH_SUPPORTS_SHADOW_CALL_STACK
  	bool
  	help
  	  An architecture should select this if it supports Clang's Shadow
  	  Call Stack, has asm/scs.h, and implements runtime support for shadow
  	  stack switching.
  
  config SHADOW_CALL_STACK
  	bool "Clang Shadow Call Stack"
  	depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
  	help
  	  This option enables Clang's Shadow Call Stack, which uses a
  	  shadow stack to protect function return addresses from being
  	  overwritten by an attacker. More information can be found from
  	  Clang's documentation:
  
  	    https://clang.llvm.org/docs/ShadowCallStack.html
  
  	  Note that security guarantees in the kernel differ from the ones
  	  documented for user space. The kernel must store addresses of shadow
  	  stacks used by other tasks and interrupt handlers in memory, which
  	  means an attacker capable reading and writing arbitrary memory may
  	  be able to locate them and hijack control flow by modifying shadow
  	  stacks that are not currently in use.
  
  config SHADOW_CALL_STACK_VMAP
  	bool "Use virtually mapped shadow call stacks"
  	depends on SHADOW_CALL_STACK
  	default y
  	help
  	  Use virtually mapped shadow call stacks. Selecting this option
  	  provides better stack exhaustion protection, but increases per-thread
  	  memory consumption as a full page is allocated for each shadow stack.
  
  config LTO
  	bool
  
  config ARCH_SUPPORTS_LTO_CLANG
  	bool
  	help
  	  An architecture should select this option if it supports:
  	  - compiling with Clang,
  	  - compiling inline assembly with Clang's integrated assembler,
  	  - and linking with LLD.
  
  config ARCH_SUPPORTS_THINLTO
  	bool
  	help
  	  An architecture should select this if it supports Clang ThinLTO.
  
  config THINLTO
  	bool "Use Clang's ThinLTO (EXPERIMENTAL)"
  	depends on LTO_CLANG && ARCH_SUPPORTS_THINLTO
  	default y
  	help
  	  Use ThinLTO to speed up Link Time Optimization.
  
  choice
  	prompt "Link-Time Optimization (LTO) (EXPERIMENTAL)"
  	default LTO_NONE
  	help
  	  This option turns on Link-Time Optimization (LTO).
  
  config LTO_NONE
  	bool "None"
  
  config LTO_CLANG
  	bool "Use Clang's Link Time Optimization (LTO) (EXPERIMENTAL)"
  	depends on ARCH_SUPPORTS_LTO_CLANG
  	depends on !KASAN
  	depends on !FTRACE_MCOUNT_RECORD || HAVE_C_RECORDMCOUNT
  	depends on CC_IS_CLANG && CLANG_VERSION >= 100000 && LD_IS_LLD
  	select LTO
  	help
            This option enables Clang's Link Time Optimization (LTO), which allows
            the compiler to optimize the kernel globally at link time. If you
            enable this option, the compiler generates LLVM IR instead of object
            files, and the actual compilation from IR occurs at the LTO link step,
            which may take several minutes.
  
  endchoice
  
  config CFI_CLANG
  	bool "Use Clang's Control Flow Integrity (CFI)"
  	depends on LTO_CLANG && KALLSYMS
  	depends on !GCOV_KERNEL
  	help
  	  This option enables Clang's Control Flow Integrity (CFI), which adds
  	  runtime checking for indirect function calls.
  
  config CFI_CLANG_SHADOW
  	bool "Use CFI shadow to speed up cross-module checks"
  	default y
  	depends on CFI_CLANG
  	help
  	  If you select this option, the kernel builds a fast look-up table of
  	  CFI check functions in loaded modules to reduce overhead.
  
  config CFI_PERMISSIVE
  	bool "Use CFI in permissive mode"
  	depends on CFI_CLANG
  	help
  	  When selected, Control Flow Integrity (CFI) violations result in a
  	  warning instead of a kernel panic. This option is useful for finding
  	  CFI violations during development.
  
  config HAVE_ARCH_WITHIN_STACK_FRAMES
  	bool
  	help
  	  An architecture should select this if it can walk the kernel stack
  	  frames to determine if an object is part of either the arguments
  	  or local variables (i.e. that it excludes saved return addresses,
  	  and similar) by implementing an inline arch_within_stack_frames(),
  	  which is used by CONFIG_HARDENED_USERCOPY.
  
  config HAVE_CONTEXT_TRACKING
  	bool
  	help
  	  Provide kernel/user boundaries probes necessary for subsystems
  	  that need it, such as userspace RCU extended quiescent state.
  	  Syscalls need to be wrapped inside user_exit()-user_enter() through
  	  the slow path using TIF_NOHZ flag. Exceptions handlers must be
  	  wrapped as well. Irqs are already protected inside
  	  rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
  	  irq exit still need to be protected.
  
  config HAVE_VIRT_CPU_ACCOUNTING
  	bool
  
  config ARCH_HAS_SCALED_CPUTIME
  	bool
  
  config HAVE_VIRT_CPU_ACCOUNTING_GEN
  	bool
  	default y if 64BIT
  	help
  	  With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
  	  Before enabling this option, arch code must be audited
  	  to ensure there are no races in concurrent read/write of
  	  cputime_t. For example, reading/writing 64-bit cputime_t on
  	  some 32-bit arches may require multiple accesses, so proper
  	  locking is needed to protect against concurrent accesses.
  
  
  config HAVE_IRQ_TIME_ACCOUNTING
  	bool
  	help
  	  Archs need to ensure they use a high enough resolution clock to
  	  support irq time accounting and then call enable_sched_clock_irqtime().
  
  config HAVE_MOVE_PMD
  	bool
  	help
  	  Archs that select this are able to move page tables at the PMD level.
  
  config HAVE_ARCH_TRANSPARENT_HUGEPAGE
  	bool
  
  config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
  	bool
  
  config HAVE_ARCH_HUGE_VMAP
  	bool
  
  config ARCH_WANT_HUGE_PMD_SHARE
  	bool
  
  config HAVE_ARCH_SOFT_DIRTY
  	bool
  
  config HAVE_MOD_ARCH_SPECIFIC
  	bool
  	help
  	  The arch uses struct mod_arch_specific to store data.  Many arches
  	  just need a simple module loader without arch specific data - those
  	  should not enable this.
  
  config MODULES_USE_ELF_RELA
  	bool
  	help
  	  Modules only use ELF RELA relocations.  Modules with ELF REL
  	  relocations will give an error.
  
  config MODULES_USE_ELF_REL
  	bool
  	help
  	  Modules only use ELF REL relocations.  Modules with ELF RELA
  	  relocations will give an error.
  
  config HAVE_IRQ_EXIT_ON_IRQ_STACK
  	bool
  	help
  	  Architecture doesn't only execute the irq handler on the irq stack
  	  but also irq_exit(). This way we can process softirqs on this irq
  	  stack instead of switching to a new one when we call __do_softirq()
  	  in the end of an hardirq.
  	  This spares a stack switch and improves cache usage on softirq
  	  processing.
  
  config PGTABLE_LEVELS
  	int
  	default 2
  
  config ARCH_HAS_ELF_RANDOMIZE
  	bool
  	help
  	  An architecture supports choosing randomized locations for
  	  stack, mmap, brk, and ET_DYN. Defined functions:
  	  - arch_mmap_rnd()
  	  - arch_randomize_brk()
  
  config HAVE_ARCH_MMAP_RND_BITS
  	bool
  	help
  	  An arch should select this symbol if it supports setting a variable
  	  number of bits for use in establishing the base address for mmap
  	  allocations, has MMU enabled and provides values for both:
  	  - ARCH_MMAP_RND_BITS_MIN
  	  - ARCH_MMAP_RND_BITS_MAX
  
  config HAVE_EXIT_THREAD
  	bool
  	help
  	  An architecture implements exit_thread.
  
  config ARCH_MMAP_RND_BITS_MIN
  	int
  
  config ARCH_MMAP_RND_BITS_MAX
  	int
  
  config ARCH_MMAP_RND_BITS_DEFAULT
  	int
  
  config ARCH_MMAP_RND_BITS
  	int "Number of bits to use for ASLR of mmap base address" if EXPERT
  	range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
  	default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
  	default ARCH_MMAP_RND_BITS_MIN
  	depends on HAVE_ARCH_MMAP_RND_BITS
  	help
  	  This value can be used to select the number of bits to use to
  	  determine the random offset to the base address of vma regions
  	  resulting from mmap allocations. This value will be bounded
  	  by the architecture's minimum and maximum supported values.
  
  	  This value can be changed after boot using the
  	  /proc/sys/vm/mmap_rnd_bits tunable
  
  config HAVE_ARCH_MMAP_RND_COMPAT_BITS
  	bool
  	help
  	  An arch should select this symbol if it supports running applications
  	  in compatibility mode, supports setting a variable number of bits for
  	  use in establishing the base address for mmap allocations, has MMU
  	  enabled and provides values for both:
  	  - ARCH_MMAP_RND_COMPAT_BITS_MIN
  	  - ARCH_MMAP_RND_COMPAT_BITS_MAX
  
  config ARCH_MMAP_RND_COMPAT_BITS_MIN
  	int
  
  config ARCH_MMAP_RND_COMPAT_BITS_MAX
  	int
  
  config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
  	int
  
  config ARCH_MMAP_RND_COMPAT_BITS
  	int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
  	range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
  	default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
  	default ARCH_MMAP_RND_COMPAT_BITS_MIN
  	depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
  	help
  	  This value can be used to select the number of bits to use to
  	  determine the random offset to the base address of vma regions
  	  resulting from mmap allocations for compatible applications This
  	  value will be bounded by the architecture's minimum and maximum
  	  supported values.
  
  	  This value can be changed after boot using the
  	  /proc/sys/vm/mmap_rnd_compat_bits tunable
  
  config HAVE_ARCH_COMPAT_MMAP_BASES
  	bool
  	help
  	  This allows 64bit applications to invoke 32-bit mmap() syscall
  	  and vice-versa 32-bit applications to call 64-bit mmap().
  	  Required for applications doing different bitness syscalls.
  
  # This allows to use a set of generic functions to determine mmap base
  # address by giving priority to top-down scheme only if the process
  # is not in legacy mode (compat task, unlimited stack size or
  # sysctl_legacy_va_layout).
  # Architecture that selects this option can provide its own version of:
  # - STACK_RND_MASK
  config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
  	bool
  	depends on MMU
  	select ARCH_HAS_ELF_RANDOMIZE
  
  config HAVE_COPY_THREAD_TLS
  	bool
  	help
  	  Architecture provides copy_thread_tls to accept tls argument via
  	  normal C parameter passing, rather than extracting the syscall
  	  argument from pt_regs.
  
  config HAVE_STACK_VALIDATION
  	bool
  	help
  	  Architecture supports the 'objtool check' host tool command, which
  	  performs compile-time stack metadata validation.
  
  config HAVE_RELIABLE_STACKTRACE
  	bool
  	help
  	  Architecture has a save_stack_trace_tsk_reliable() function which
  	  only returns a stack trace if it can guarantee the trace is reliable.
  
  config HAVE_ARCH_HASH
  	bool
  	default n
  	help
  	  If this is set, the architecture provides an <asm/hash.h>
  	  file which provides platform-specific implementations of some
  	  functions in <linux/hash.h> or fs/namei.c.
  
  config HAVE_ARCH_NVRAM_OPS
  	bool
  
  config ISA_BUS_API
  	def_bool ISA
  
  #
  # ABI hall of shame
  #
  config CLONE_BACKWARDS
  	bool
  	help
  	  Architecture has tls passed as the 4th argument of clone(2),
  	  not the 5th one.
  
  config CLONE_BACKWARDS2
  	bool
  	help
  	  Architecture has the first two arguments of clone(2) swapped.
  
  config CLONE_BACKWARDS3
  	bool
  	help
  	  Architecture has tls passed as the 3rd argument of clone(2),
  	  not the 5th one.
  
  config ODD_RT_SIGACTION
  	bool
  	help
  	  Architecture has unusual rt_sigaction(2) arguments
  
  config OLD_SIGSUSPEND
  	bool
  	help
  	  Architecture has old sigsuspend(2) syscall, of one-argument variety
  
  config OLD_SIGSUSPEND3
  	bool
  	help
  	  Even weirder antique ABI - three-argument sigsuspend(2)
  
  config OLD_SIGACTION
  	bool
  	help
  	  Architecture has old sigaction(2) syscall.  Nope, not the same
  	  as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
  	  but fairly different variant of sigaction(2), thanks to OSF/1
  	  compatibility...
  
  config COMPAT_OLD_SIGACTION
  	bool
  
  config 64BIT_TIME
  	def_bool y
  	help
  	  This should be selected by all architectures that need to support
  	  new system calls with a 64-bit time_t. This is relevant on all 32-bit
  	  architectures, and 64-bit architectures as part of compat syscall
  	  handling.
  
  config COMPAT_32BIT_TIME
  	def_bool !64BIT || COMPAT
  	help
  	  This enables 32 bit time_t support in addition to 64 bit time_t support.
  	  This is relevant on all 32-bit architectures, and 64-bit architectures
  	  as part of compat syscall handling.
  
  config ARCH_NO_PREEMPT
  	bool
  
  config ARCH_SUPPORTS_RT
  	bool
  
  config CPU_NO_EFFICIENT_FFS
  	def_bool n
  
  config HAVE_ARCH_VMAP_STACK
  	def_bool n
  	help
  	  An arch should select this symbol if it can support kernel stacks
  	  in vmalloc space.  This means:
  
  	  - vmalloc space must be large enough to hold many kernel stacks.
  	    This may rule out many 32-bit architectures.
  
  	  - Stacks in vmalloc space need to work reliably.  For example, if
  	    vmap page tables are created on demand, either this mechanism
  	    needs to work while the stack points to a virtual address with
  	    unpopulated page tables or arch code (switch_to() and switch_mm(),
  	    most likely) needs to ensure that the stack's page table entries
  	    are populated before running on a possibly unpopulated stack.
  
  	  - If the stack overflows into a guard page, something reasonable
  	    should happen.  The definition of "reasonable" is flexible, but
  	    instantly rebooting without logging anything would be unfriendly.
  
  config VMAP_STACK
  	default y
  	bool "Use a virtually-mapped stack"
  	depends on HAVE_ARCH_VMAP_STACK && !KASAN
  	---help---
  	  Enable this if you want the use virtually-mapped kernel stacks
  	  with guard pages.  This causes kernel stack overflows to be
  	  caught immediately rather than causing difficult-to-diagnose
  	  corruption.
  
  	  This is presently incompatible with KASAN because KASAN expects
  	  the stack to map directly to the KASAN shadow map using a formula
  	  that is incorrect if the stack is in vmalloc space.
  
  config ARCH_OPTIONAL_KERNEL_RWX
  	def_bool n
  
  config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
  	def_bool n
  
  config ARCH_HAS_STRICT_KERNEL_RWX
  	def_bool n
  
  config STRICT_KERNEL_RWX
  	bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
  	depends on ARCH_HAS_STRICT_KERNEL_RWX
  	default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
  	help
  	  If this is set, kernel text and rodata memory will be made read-only,
  	  and non-text memory will be made non-executable. This provides
  	  protection against certain security exploits (e.g. executing the heap
  	  or modifying text)
  
  	  These features are considered standard security practice these days.
  	  You should say Y here in almost all cases.
  
  config ARCH_HAS_STRICT_MODULE_RWX
  	def_bool n
  
  config STRICT_MODULE_RWX
  	bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
  	depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
  	default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
  	help
  	  If this is set, module text and rodata memory will be made read-only,
  	  and non-text memory will be made non-executable. This provides
  	  protection against certain security exploits (e.g. writing to text)
  
  # select if the architecture provides an asm/dma-direct.h header
  config ARCH_HAS_PHYS_TO_DMA
  	bool
  
  config ARCH_HAS_REFCOUNT
  	bool
  	help
  	  An architecture selects this when it has implemented refcount_t
  	  using open coded assembly primitives that provide an optimized
  	  refcount_t implementation, possibly at the expense of some full
  	  refcount state checks of CONFIG_REFCOUNT_FULL=y.
  
  	  The refcount overflow check behavior, however, must be retained.
  	  Catching overflows is the primary security concern for protecting
  	  against bugs in reference counts.
  
  config REFCOUNT_FULL
  	bool "Perform full reference count validation at the expense of speed"
  	help
  	  Enabling this switches the refcounting infrastructure from a fast
  	  unchecked atomic_t implementation to a fully state checked
  	  implementation, which can be (slightly) slower but provides protections
  	  against various use-after-free conditions that can be used in
  	  security flaw exploits.
  
  config HAVE_ARCH_COMPILER_H
  	bool
  	help
  	  An architecture can select this if it provides an
  	  asm/compiler.h header that should be included after
  	  linux/compiler-*.h in order to override macro definitions that those
  	  headers generally provide.
  
  config HAVE_ARCH_PREL32_RELOCATIONS
  	bool
  	help
  	  May be selected by an architecture if it supports place-relative
  	  32-bit relocations, both in the toolchain and in the module loader,
  	  in which case relative references can be used in special sections
  	  for PCI fixup, initcalls etc which are only half the size on 64 bit
  	  architectures, and don't require runtime relocation on relocatable
  	  kernels.
  
  config ARCH_USE_MEMREMAP_PROT
  	bool
  
  config LOCK_EVENT_COUNTS
  	bool "Locking event counts collection"
  	depends on DEBUG_FS
  	---help---
  	  Enable light-weight counting of various locking related events
  	  in the system with minimal performance impact. This reduces
  	  the chance of application behavior change because of timing
  	  differences. The counts are reported via debugfs.
  
  # Select if the architecture has support for applying RELR relocations.
  config ARCH_HAS_RELR
  	bool
  
  config RELR
  	bool "Use RELR relocation packing"
  	depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
  	default y
  	help
  	  Store the kernel's dynamic relocations in the RELR relocation packing
  	  format. Requires a compatible linker (LLD supports this feature), as
  	  well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
  	  are compatible).
  
  config ARCH_HAS_MEM_ENCRYPT
  	bool
  
  source "kernel/gcov/Kconfig"
  
  source "scripts/gcc-plugins/Kconfig"
  
  endmenu