Kconfig 11.0 KB
Newer Older
M
Mathieu Desnoyers 已提交
1 2 3
#
# General architecture dependent options
#
4 5

config OPROFILE
6
	tristate "OProfile system profiling"
7 8
	depends on PROFILING
	depends on HAVE_OPROFILE
I
Ingo Molnar 已提交
9
	select RING_BUFFER
10
	select RING_BUFFER_ALLOW_SWAP
11 12 13 14 15 16 17
	help
	  OProfile is a profiling system capable of profiling the
	  whole system, include the kernel, kernel modules, libraries,
	  and applications.

	  If unsure, say N.

18 19 20 21 22 23 24 25 26 27 28 29
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.

30
config HAVE_OPROFILE
31
	bool
32

33 34 35 36
config OPROFILE_NMI_TIMER
	def_bool y
	depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI

37 38
config KPROBES
	bool "Kprobes"
39
	depends on MODULES
40
	depends on HAVE_KPROBES
41
	select KALLSYMS
42 43 44 45 46 47 48
	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".

49
config JUMP_LABEL
50
       bool "Optimize very unlikely/likely branches"
51 52
       depends on HAVE_ARCH_JUMP_LABEL
       help
53 54 55 56 57 58 59 60
         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.

61
         If it is detected that the compiler has support for "asm goto",
62 63 64 65 66 67 68 69
	 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.
70

71 72
	 ( On 32-bit x86, the necessary options added to the compiler
	   flags may increase the size of the kernel slightly. )
73

74
config OPTPROBES
75 76
	def_bool y
	depends on KPROBES && HAVE_OPTPROBES
77 78
	depends on !PREEMPT

79
config UPROBES
80
	bool "Transparent user-space probes (EXPERIMENTAL)"
81
	depends on UPROBE_EVENT && PERF_EVENTS
82
	default n
83
	select PERCPU_RWSEM
84
	help
85 86 87 88 89 90 91 92 93
	  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. )
94 95 96

	  If in doubt, say "N".

97
config HAVE_EFFICIENT_UNALIGNED_ACCESS
98
	bool
99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115
	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.

116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134
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.

135 136 137
config HAVE_SYSCALL_WRAPPERS
	bool

138 139 140 141
config KRETPROBES
	def_bool y
	depends on KPROBES && HAVE_KRETPROBES

A
Avi Kivity 已提交
142 143 144 145 146 147 148
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.

149
config HAVE_IOREMAP_PROT
150
	bool
151

152
config HAVE_KPROBES
153
	bool
154 155

config HAVE_KRETPROBES
156
	bool
157

158 159
config HAVE_OPTPROBES
	bool
160 161 162

config HAVE_NMI_WATCHDOG
	bool
163 164 165 166 167 168 169 170 171 172 173 174 175 176
#
# 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
177
	bool
178

179
config HAVE_DMA_ATTRS
180
	bool
181

182 183 184
config HAVE_DMA_CONTIGUOUS
	bool

185
config USE_GENERIC_SMP_HELPERS
186
	bool
187

188 189 190
config GENERIC_SMP_IDLE_THREAD
       bool

191 192
# Select if arch init_task initializer is different to init/init_task.c
config ARCH_INIT_TASK
193 194
       bool

195 196 197 198 199 200 201 202
# 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

203 204
config HAVE_REGS_AND_STACK_ACCESS_API
	bool
205 206 207 208 209
	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.
210

211
config HAVE_CLK
212
	bool
213 214 215 216
	help
	  The <linux/clk.h> calls support software clock gating and
	  thus are a key power management tool on many systems.

J
Joerg Roedel 已提交
217 218
config HAVE_DMA_API_DEBUG
	bool
219

220 221
config HAVE_HW_BREAKPOINT
	bool
222
	depends on PERF_EVENTS
223

224 225 226 227 228 229 230 231 232 233 234
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.

A
Avi Kivity 已提交
235 236
config HAVE_USER_RETURN_NOTIFIER
	bool
237

238 239
config HAVE_PERF_EVENTS_NMI
	bool
240 241 242 243
	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.
244

245 246 247 248 249 250
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.

251 252 253 254 255 256 257
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.

258 259 260
config HAVE_ARCH_JUMP_LABEL
	bool

261 262 263
config HAVE_ARCH_MUTEX_CPU_RELAX
	bool

264 265 266
config HAVE_RCU_TABLE_FREE
	bool

267 268 269
config ARCH_HAVE_NMI_SAFE_CMPXCHG
	bool

270 271 272 273 274 275 276 277
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.

278 279 280
config HAVE_CMPXCHG_LOCAL
	bool

281 282 283
config HAVE_CMPXCHG_DOUBLE
	bool

284 285 286 287 288 289
config ARCH_WANT_IPC_PARSE_VERSION
	bool

config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
	bool

290
config ARCH_WANT_OLD_COMPAT_IPC
291
	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
292 293
	bool

294 295 296
config HAVE_ARCH_SECCOMP_FILTER
	bool
	help
297
	  An arch should select this symbol if it provides all of these things:
W
Will Drewry 已提交
298 299 300 301
	  - syscall_get_arch()
	  - syscall_get_arguments()
	  - syscall_rollback()
	  - syscall_set_return_value()
302 303 304 305
	  - 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.
306 307 308 309 310 311 312 313 314 315 316

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.

317
config HAVE_CONTEXT_TRACKING
318 319
	bool
	help
320 321 322 323 324 325 326
	  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.
327

328 329 330
config HAVE_VIRT_CPU_ACCOUNTING
	bool

331 332 333 334 335 336
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().

337 338 339
config HAVE_ARCH_TRANSPARENT_HUGEPAGE
	bool

340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358
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.

359 360 361
config GENERIC_SIGALTSTACK
	bool

A
Al Viro 已提交
362 363 364
config GENERIC_COMPAT_RT_SIGPROCMASK
	bool

A
Al Viro 已提交
365 366 367
config GENERIC_COMPAT_RT_SIGPENDING
	bool

A
Al Viro 已提交
368 369 370
config GENERIC_COMPAT_RT_SIGQUEUEINFO
	bool

A
Al Viro 已提交
371 372 373
config GENERIC_COMPAT_RT_SIGACTION
	bool

A
Al Viro 已提交
374 375 376 377 378 379 380 381 382 383 384 385 386 387
#
# 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.

388 389 390 391 392
config ODD_RT_SIGACTION
	bool
	help
	  Architecture has unusual rt_sigaction(2) arguments

393 394 395 396 397 398 399 400 401 402
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)

403
source "kernel/gcov/Kconfig"