1
2
3
4
5config 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
18config 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
30config HAVE_OPROFILE
31 bool
32
33config OPROFILE_NMI_TIMER
34 def_bool y
35 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
36
37config 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
49config 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
74config OPTPROBES
75 def_bool y
76 depends on KPROBES && HAVE_OPTPROBES
77 depends on !PREEMPT
78
79config KPROBES_ON_FTRACE
80 def_bool y
81 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
82 depends on DYNAMIC_FTRACE_WITH_REGS
83 help
84 If function tracer is enabled and the arch supports full
85 passing of pt_regs to function tracing, then kprobes can
86 optimize on top of function tracing.
87
88config UPROBES
89 bool "Transparent user-space probes (EXPERIMENTAL)"
90 depends on UPROBE_EVENT && PERF_EVENTS
91 default n
92 select PERCPU_RWSEM
93 help
94 Uprobes is the user-space counterpart to kprobes: they
95 enable instrumentation applications (such as 'perf probe')
96 to establish unintrusive probes in user-space binaries and
97 libraries, by executing handler functions when the probes
98 are hit by user-space applications.
99
100 ( These probes come in the form of single-byte breakpoints,
101 managed by the kernel and kept transparent to the probed
102 application. )
103
104 If in doubt, say "N".
105
106config HAVE_64BIT_ALIGNED_ACCESS
107 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
108 help
109 Some architectures require 64 bit accesses to be 64 bit
110 aligned, which also requires structs containing 64 bit values
111 to be 64 bit aligned too. This includes some 32 bit
112 architectures which can do 64 bit accesses, as well as 64 bit
113 architectures without unaligned access.
114
115 This symbol should be selected by an architecture if 64 bit
116 accesses are required to be 64 bit aligned in this way even
117 though it is not a 64 bit architecture.
118
119 See Documentation/unaligned-memory-access.txt for more
120 information on the topic of unaligned memory accesses.
121
122config HAVE_EFFICIENT_UNALIGNED_ACCESS
123 bool
124 help
125 Some architectures are unable to perform unaligned accesses
126 without the use of get_unaligned/put_unaligned. Others are
127 unable to perform such accesses efficiently (e.g. trap on
128 unaligned access and require fixing it up in the exception
129 handler.)
130
131 This symbol should be selected by an architecture if it can
132 perform unaligned accesses efficiently to allow different
133 code paths to be selected for these cases. Some network
134 drivers, for example, could opt to not fix up alignment
135 problems with received packets if doing so would not help
136 much.
137
138 See Documentation/unaligned-memory-access.txt for more
139 information on the topic of unaligned memory accesses.
140
141config ARCH_USE_BUILTIN_BSWAP
142 bool
143 help
144 Modern versions of GCC (since 4.4) have builtin functions
145 for handling byte-swapping. Using these, instead of the old
146 inline assembler that the architecture code provides in the
147 __arch_bswapXX() macros, allows the compiler to see what's
148 happening and offers more opportunity for optimisation. In
149 particular, the compiler will be able to combine the byteswap
150 with a nearby load or store and use load-and-swap or
151 store-and-swap instructions if the architecture has them. It
152 should almost *never* result in code which is worse than the
153 hand-coded assembler in <asm/swab.h>. But just in case it
154 does, the use of the builtins is optional.
155
156 Any architecture with load-and-swap or store-and-swap
157 instructions should set this. And it shouldn't hurt to set it
158 on architectures that don't have such instructions.
159
160config KRETPROBES
161 def_bool y
162 depends on KPROBES && HAVE_KRETPROBES
163
164config USER_RETURN_NOTIFIER
165 bool
166 depends on HAVE_USER_RETURN_NOTIFIER
167 help
168 Provide a kernel-internal notification when a cpu is about to
169 switch to user mode.
170
171config HAVE_IOREMAP_PROT
172 bool
173
174config HAVE_KPROBES
175 bool
176
177config HAVE_KRETPROBES
178 bool
179
180config HAVE_OPTPROBES
181 bool
182
183config HAVE_KPROBES_ON_FTRACE
184 bool
185
186config HAVE_NMI_WATCHDOG
187 bool
188
189
190
191
192
193
194
195
196
197
198
199
200
201config HAVE_ARCH_TRACEHOOK
202 bool
203
204config HAVE_DMA_ATTRS
205 bool
206
207config HAVE_DMA_CONTIGUOUS
208 bool
209
210config USE_GENERIC_SMP_HELPERS
211 bool
212
213config GENERIC_SMP_IDLE_THREAD
214 bool
215
216config GENERIC_IDLE_POLL_SETUP
217 bool
218
219
220config ARCH_INIT_TASK
221 bool
222
223
224config ARCH_TASK_STRUCT_ALLOCATOR
225 bool
226
227
228config ARCH_THREAD_INFO_ALLOCATOR
229 bool
230
231config HAVE_REGS_AND_STACK_ACCESS_API
232 bool
233 help
234 This symbol should be selected by an architecure if it supports
235 the API needed to access registers and stack entries from pt_regs,
236 declared in asm/ptrace.h
237 For example the kprobes-based event tracer needs this API.
238
239config HAVE_CLK
240 bool
241 help
242 The <linux/clk.h> calls support software clock gating and
243 thus are a key power management tool on many systems.
244
245config HAVE_DMA_API_DEBUG
246 bool
247
248config HAVE_HW_BREAKPOINT
249 bool
250 depends on PERF_EVENTS
251
252config HAVE_MIXED_BREAKPOINTS_REGS
253 bool
254 depends on HAVE_HW_BREAKPOINT
255 help
256 Depending on the arch implementation of hardware breakpoints,
257 some of them have separate registers for data and instruction
258 breakpoints addresses, others have mixed registers to store
259 them but define the access type in a control register.
260 Select this option if your arch implements breakpoints under the
261 latter fashion.
262
263config HAVE_USER_RETURN_NOTIFIER
264 bool
265
266config HAVE_PERF_EVENTS_NMI
267 bool
268 help
269 System hardware can generate an NMI using the perf event
270 subsystem. Also has support for calculating CPU cycle events
271 to determine how many clock cycles in a given period.
272
273config HAVE_PERF_REGS
274 bool
275 help
276 Support selective register dumps for perf events. This includes
277 bit-mapping of each registers and a unique architecture id.
278
279config HAVE_PERF_USER_STACK_DUMP
280 bool
281 help
282 Support user stack dumps for perf event samples. This needs
283 access to the user stack pointer which is not unified across
284 architectures.
285
286config HAVE_ARCH_JUMP_LABEL
287 bool
288
289config HAVE_ARCH_MUTEX_CPU_RELAX
290 bool
291
292config HAVE_RCU_TABLE_FREE
293 bool
294
295config ARCH_HAVE_NMI_SAFE_CMPXCHG
296 bool
297
298config HAVE_ALIGNED_STRUCT_PAGE
299 bool
300 help
301 This makes sure that struct pages are double word aligned and that
302 e.g. the SLUB allocator can perform double word atomic operations
303 on a struct page for better performance. However selecting this
304 might increase the size of a struct page by a word.
305
306config HAVE_CMPXCHG_LOCAL
307 bool
308
309config HAVE_CMPXCHG_DOUBLE
310 bool
311
312config ARCH_WANT_IPC_PARSE_VERSION
313 bool
314
315config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
316 bool
317
318config ARCH_WANT_OLD_COMPAT_IPC
319 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
320 bool
321
322config HAVE_ARCH_SECCOMP_FILTER
323 bool
324 help
325 An arch should select this symbol if it provides all of these things:
326 - syscall_get_arch()
327 - syscall_get_arguments()
328 - syscall_rollback()
329 - syscall_set_return_value()
330 - SIGSYS siginfo_t support
331 - secure_computing is called from a ptrace_event()-safe context
332 - secure_computing return value is checked and a return value of -1
333 results in the system call being skipped immediately.
334
335config SECCOMP_FILTER
336 def_bool y
337 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
338 help
339 Enable tasks to build secure computing environments defined
340 in terms of Berkeley Packet Filter programs which implement
341 task-defined system call filtering polices.
342
343 See Documentation/prctl/seccomp_filter.txt for details.
344
345config HAVE_CONTEXT_TRACKING
346 bool
347 help
348 Provide kernel/user boundaries probes necessary for subsystems
349 that need it, such as userspace RCU extended quiescent state.
350 Syscalls need to be wrapped inside user_exit()-user_enter() through
351 the slow path using TIF_NOHZ flag. Exceptions handlers must be
352 wrapped as well. Irqs are already protected inside
353 rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
354 irq exit still need to be protected.
355
356config HAVE_VIRT_CPU_ACCOUNTING
357 bool
358
359config HAVE_IRQ_TIME_ACCOUNTING
360 bool
361 help
362 Archs need to ensure they use a high enough resolution clock to
363 support irq time accounting and then call enable_sched_clock_irqtime().
364
365config HAVE_ARCH_TRANSPARENT_HUGEPAGE
366 bool
367
368config HAVE_ARCH_SOFT_DIRTY
369 bool
370
371config HAVE_MOD_ARCH_SPECIFIC
372 bool
373 help
374 The arch uses struct mod_arch_specific to store data. Many arches
375 just need a simple module loader without arch specific data - those
376 should not enable this.
377
378config MODULES_USE_ELF_RELA
379 bool
380 help
381 Modules only use ELF RELA relocations. Modules with ELF REL
382 relocations will give an error.
383
384config MODULES_USE_ELF_REL
385 bool
386 help
387 Modules only use ELF REL relocations. Modules with ELF RELA
388 relocations will give an error.
389
390config HAVE_UNDERSCORE_SYMBOL_PREFIX
391 bool
392 help
393 Some architectures generate an _ in front of C symbols; things like
394 module loading and assembly files need to know about this.
395
396
397
398
399config CLONE_BACKWARDS
400 bool
401 help
402 Architecture has tls passed as the 4th argument of clone(2),
403 not the 5th one.
404
405config CLONE_BACKWARDS2
406 bool
407 help
408 Architecture has the first two arguments of clone(2) swapped.
409
410config CLONE_BACKWARDS3
411 bool
412 help
413 Architecture has tls passed as the 3rd argument of clone(2),
414 not the 5th one.
415
416config ODD_RT_SIGACTION
417 bool
418 help
419 Architecture has unusual rt_sigaction(2) arguments
420
421config OLD_SIGSUSPEND
422 bool
423 help
424 Architecture has old sigsuspend(2) syscall, of one-argument variety
425
426config OLD_SIGSUSPEND3
427 bool
428 help
429 Even weirder antique ABI - three-argument sigsuspend(2)
430
431config OLD_SIGACTION
432 bool
433 help
434 Architecture has old sigaction(2) syscall. Nope, not the same
435 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
436 but fairly different variant of sigaction(2), thanks to OSF/1
437 compatibility...
438
439config COMPAT_OLD_SIGACTION
440 bool
441
442source "kernel/gcov/Kconfig"
443
