#
  # General architecture dependent options
  #

  
  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 an 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
         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 OPTPROBES

  	def_bool y
  	depends on KPROBES && HAVE_OPTPROBES

  	depends on !PREEMPT

  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

  	select PERCPU_RWSEM

  	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_64BIT_ALIGNED_ACCESS
  	def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
  	help
  	  Some architectures require 64 bit accesses to be 64 bit
  	  aligned, which also requires structs containing 64 bit values
  	  to be 64 bit aligned too. This includes some 32 bit
  	  architectures which can do 64 bit accesses, as well as 64 bit
  	  architectures without unaligned access.
  
  	  This symbol should be selected by an architecture if 64 bit
  	  accesses are required to be 64 bit aligned in this way even
  	  though it is not a 64 bit architecture.
  
  	  See Documentation/unaligned-memory-access.txt for more
  	  information on the topic of unaligned memory accesses.

  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_NMI_WATCHDOG
  	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_ATTRS

  	bool

  config HAVE_DMA_CONTIGUOUS
  	bool

  config GENERIC_SMP_IDLE_THREAD
         bool

  config GENERIC_IDLE_POLL_SETUP
         bool

  # Select if arch init_task initializer is different to init/init_task.c
  config ARCH_INIT_TASK

         bool

  # Select if arch has its private alloc_task_struct() function
  config ARCH_TASK_STRUCT_ALLOCATOR
  	bool
  
  # Select if arch has its private alloc_thread_info() function
  config ARCH_THREAD_INFO_ALLOCATOR
  	bool

  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_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_DMA_API_DEBUG
  	bool

  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_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_RCU_TABLE_FREE
  	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_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

  	  For best performance, an arch should use seccomp_phase1 and
  	  seccomp_phase2 directly.  It should call seccomp_phase1 for all
  	  syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not
  	  need to be called from a ptrace-safe context.  It must then
  	  call seccomp_phase2 if seccomp_phase1 returns anything other
  	  than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP.
  
  	  As an additional optimization, an arch may provide seccomp_data
  	  directly to seccomp_phase1; this avoids multiple calls
  	  to the syscall_xyz helpers for every syscall.

  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/prctl/seccomp_filter.txt for details.

  config HAVE_CC_STACKPROTECTOR
  	bool
  	help
  	  An arch should select this symbol if:
  	  - its compiler supports the -fstack-protector option
  	  - it has implemented a stack canary (e.g. __stack_chk_guard)
  
  config CC_STACKPROTECTOR

  	def_bool n
  	help
  	  Set when a stack-protector mode is enabled, so that the build
  	  can enable kernel-side support for the GCC feature.
  
  choice
  	prompt "Stack Protector buffer overflow detection"

  	depends on HAVE_CC_STACKPROTECTOR

  	default CC_STACKPROTECTOR_NONE

  	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.

  config CC_STACKPROTECTOR_NONE
  	bool "None"
  	help
  	  Disable "stack-protector" GCC feature.
  
  config CC_STACKPROTECTOR_REGULAR
  	bool "Regular"
  	select CC_STACKPROTECTOR
  	help
  	  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 CC_STACKPROTECTOR_STRONG
  	bool "Strong"
  	select CC_STACKPROTECTOR
  	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%.
  
  endchoice

  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 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_ARCH_TRANSPARENT_HUGEPAGE
  	bool

  config HAVE_ARCH_HUGE_VMAP
  	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_UNDERSCORE_SYMBOL_PREFIX
  	bool
  	help
  	  Some architectures generate an _ in front of C symbols; things like
  	  module loading and assembly files need to know about this.

  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()

  #
  # 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

  source "kernel/gcov/Kconfig"