[mirror_ubuntu-zesty-kernel.git] / arch / Kconfig

#
# 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

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 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 HAVE_SYSCALL_WRAPPERS
	bool

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_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 USE_GENERIC_SMP_HELPERS
	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_ARCH_JUMP_LABEL
	bool

config HAVE_ARCH_MUTEX_CPU_RELAX
	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_OLD_COMPAT_IPC
	bool

config HAVE_ARCH_SECCOMP_FILTER
	bool
	help
	  This symbol should be selected by an architecure if it provides:
	  asm/syscall.h:
	  - syscall_get_arch()
	  - syscall_get_arguments()
	  - syscall_rollback()
	  - syscall_set_return_value()
	  SIGSYS siginfo_t support must be implemented.
	  __secure_computing()/secure_computing()'s return value must be
	  checked, with -1 resulting in the syscall being skipped.

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.

source "kernel/gcov/Kconfig"
Commit	Line	Data
	1	#
	2	# General architecture dependent options
	3	#
	4
	5	config OPROFILE
	6	tristate "OProfile system profiling"
	7	depends on PROFILING
	8	depends on HAVE_OPROFILE
	9	select RING_BUFFER
	10	select RING_BUFFER_ALLOW_SWAP
	11	help
	12	OProfile is a profiling system capable of profiling the
	13	whole system, include the kernel, kernel modules, libraries,
	14	and applications.
	15
	16	If unsure, say N.
	17
	18	config OPROFILE_EVENT_MULTIPLEX
	19	bool "OProfile multiplexing support (EXPERIMENTAL)"
	20	default n
	21	depends on OPROFILE && X86
	22	help
	23	The number of hardware counters is limited. The multiplexing
	24	feature enables OProfile to gather more events than counters
	25	are provided by the hardware. This is realized by switching
	26	between events at an user specified time interval.
	27
	28	If unsure, say N.
	29
	30	config HAVE_OPROFILE
	31	bool
	32
	33	config OPROFILE_NMI_TIMER
	34	def_bool y
	35	depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
	36
	37	config KPROBES
	38	bool "Kprobes"
	39	depends on MODULES
	40	depends on HAVE_KPROBES
	41	select KALLSYMS
	42	help
	43	Kprobes allows you to trap at almost any kernel address and
	44	execute a callback function. register_kprobe() establishes
	45	a probepoint and specifies the callback. Kprobes is useful
	46	for kernel debugging, non-intrusive instrumentation and testing.
	47	If in doubt, say "N".
	48
	49	config JUMP_LABEL
	50	bool "Optimize very unlikely/likely branches"
	51	depends on HAVE_ARCH_JUMP_LABEL
	52	help
	53	This option enables a transparent branch optimization that
	54	makes certain almost-always-true or almost-always-false branch
	55	conditions even cheaper to execute within the kernel.
	56
	57	Certain performance-sensitive kernel code, such as trace points,
	58	scheduler functionality, networking code and KVM have such
	59	branches and include support for this optimization technique.
	60
	61	If it is detected that the compiler has support for "asm goto",
	62	the kernel will compile such branches with just a nop
	63	instruction. When the condition flag is toggled to true, the
	64	nop will be converted to a jump instruction to execute the
	65	conditional block of instructions.
	66
	67	This technique lowers overhead and stress on the branch prediction
	68	of the processor and generally makes the kernel faster. The update
	69	of the condition is slower, but those are always very rare.
	70
	71	( On 32-bit x86, the necessary options added to the compiler
	72	flags may increase the size of the kernel slightly. )
	73
	74	config OPTPROBES
	75	def_bool y
	76	depends on KPROBES && HAVE_OPTPROBES
	77	depends on !PREEMPT
	78
	79	config HAVE_EFFICIENT_UNALIGNED_ACCESS
	80	bool
	81	help
	82	Some architectures are unable to perform unaligned accesses
	83	without the use of get_unaligned/put_unaligned. Others are
	84	unable to perform such accesses efficiently (e.g. trap on
	85	unaligned access and require fixing it up in the exception
	86	handler.)
	87
	88	This symbol should be selected by an architecture if it can
	89	perform unaligned accesses efficiently to allow different
	90	code paths to be selected for these cases. Some network
	91	drivers, for example, could opt to not fix up alignment
	92	problems with received packets if doing so would not help
	93	much.
	94
	95	See Documentation/unaligned-memory-access.txt for more
	96	information on the topic of unaligned memory accesses.
	97
	98	config HAVE_SYSCALL_WRAPPERS
	99	bool
	100
	101	config KRETPROBES
	102	def_bool y
	103	depends on KPROBES && HAVE_KRETPROBES
	104
	105	config USER_RETURN_NOTIFIER
	106	bool
	107	depends on HAVE_USER_RETURN_NOTIFIER
	108	help
	109	Provide a kernel-internal notification when a cpu is about to
	110	switch to user mode.
	111
	112	config HAVE_IOREMAP_PROT
	113	bool
	114
	115	config HAVE_KPROBES
	116	bool
	117
	118	config HAVE_KRETPROBES
	119	bool
	120
	121	config HAVE_OPTPROBES
	122	bool
	123
	124	config HAVE_NMI_WATCHDOG
	125	bool
	126	#
	127	# An arch should select this if it provides all these things:
	128	#
	129	# task_pt_regs() in asm/processor.h or asm/ptrace.h
	130	# arch_has_single_step() if there is hardware single-step support
	131	# arch_has_block_step() if there is hardware block-step support
	132	# asm/syscall.h supplying asm-generic/syscall.h interface
	133	# linux/regset.h user_regset interfaces
	134	# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
	135	# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
	136	# TIF_NOTIFY_RESUME calls tracehook_notify_resume()
	137	# signal delivery calls tracehook_signal_handler()
	138	#
	139	config HAVE_ARCH_TRACEHOOK
	140	bool
	141
	142	config HAVE_DMA_ATTRS
	143	bool
	144
	145	config USE_GENERIC_SMP_HELPERS
	146	bool
	147
	148	config HAVE_REGS_AND_STACK_ACCESS_API
	149	bool
	150	help
	151	This symbol should be selected by an architecure if it supports
	152	the API needed to access registers and stack entries from pt_regs,
	153	declared in asm/ptrace.h
	154	For example the kprobes-based event tracer needs this API.
	155
	156	config HAVE_CLK
	157	bool
	158	help
	159	The <linux/clk.h> calls support software clock gating and
	160	thus are a key power management tool on many systems.
	161
	162	config HAVE_DMA_API_DEBUG
	163	bool
	164
	165	config HAVE_HW_BREAKPOINT
	166	bool
	167	depends on PERF_EVENTS
	168
	169	config HAVE_MIXED_BREAKPOINTS_REGS
	170	bool
	171	depends on HAVE_HW_BREAKPOINT
	172	help
	173	Depending on the arch implementation of hardware breakpoints,
	174	some of them have separate registers for data and instruction
	175	breakpoints addresses, others have mixed registers to store
	176	them but define the access type in a control register.
	177	Select this option if your arch implements breakpoints under the
	178	latter fashion.
	179
	180	config HAVE_USER_RETURN_NOTIFIER
	181	bool
	182
	183	config HAVE_PERF_EVENTS_NMI
	184	bool
	185	help
	186	System hardware can generate an NMI using the perf event
	187	subsystem. Also has support for calculating CPU cycle events
	188	to determine how many clock cycles in a given period.
	189
	190	config HAVE_ARCH_JUMP_LABEL
	191	bool
	192
	193	config HAVE_ARCH_MUTEX_CPU_RELAX
	194	bool
	195
	196	config HAVE_RCU_TABLE_FREE
	197	bool
	198
	199	config ARCH_HAVE_NMI_SAFE_CMPXCHG
	200	bool
	201
	202	config HAVE_ALIGNED_STRUCT_PAGE
	203	bool
	204	help
	205	This makes sure that struct pages are double word aligned and that
	206	e.g. the SLUB allocator can perform double word atomic operations
	207	on a struct page for better performance. However selecting this
	208	might increase the size of a struct page by a word.
	209
	210	config HAVE_CMPXCHG_LOCAL
	211	bool
	212
	213	config HAVE_CMPXCHG_DOUBLE
	214	bool
	215
	216	config ARCH_WANT_OLD_COMPAT_IPC
	217	bool
	218
	219	config HAVE_ARCH_SECCOMP_FILTER
	220	bool
	221	help
	222	This symbol should be selected by an architecure if it provides:
	223	asm/syscall.h:
	224	- syscall_get_arch()
	225	- syscall_get_arguments()
	226	- syscall_rollback()
	227	- syscall_set_return_value()
	228	SIGSYS siginfo_t support must be implemented.
	229	__secure_computing()/secure_computing()'s return value must be
	230	checked, with -1 resulting in the syscall being skipped.
	231
	232	config SECCOMP_FILTER
	233	def_bool y
	234	depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
	235	help
	236	Enable tasks to build secure computing environments defined
	237	in terms of Berkeley Packet Filter programs which implement
	238	task-defined system call filtering polices.
	239
	240	See Documentation/prctl/seccomp_filter.txt for details.
	241
	242	source "kernel/gcov/Kconfig"