Commit | Line | Data |
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fb32e03f MD |
1 | # |
2 | # General architecture dependent options | |
3 | # | |
125e5645 MD |
4 | |
5 | config OPROFILE | |
b309a294 | 6 | tristate "OProfile system profiling" |
125e5645 MD |
7 | depends on PROFILING |
8 | depends on HAVE_OPROFILE | |
d69d59f4 | 9 | select RING_BUFFER |
9a5963eb | 10 | select RING_BUFFER_ALLOW_SWAP |
125e5645 MD |
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 | ||
4d4036e0 JY |
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 | ||
125e5645 | 30 | config HAVE_OPROFILE |
9ba16087 | 31 | bool |
125e5645 | 32 | |
dcfce4a0 RR |
33 | config OPROFILE_NMI_TIMER |
34 | def_bool y | |
35 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI | |
36 | ||
125e5645 MD |
37 | config KPROBES |
38 | bool "Kprobes" | |
05ed160e | 39 | depends on MODULES |
125e5645 | 40 | depends on HAVE_KPROBES |
05ed160e | 41 | select KALLSYMS |
125e5645 MD |
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 | ||
45f81b1c | 49 | config JUMP_LABEL |
c5905afb | 50 | bool "Optimize very unlikely/likely branches" |
45f81b1c SR |
51 | depends on HAVE_ARCH_JUMP_LABEL |
52 | help | |
c5905afb IM |
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 | ||
45f81b1c | 61 | If it is detected that the compiler has support for "asm goto", |
c5905afb IM |
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. | |
45f81b1c | 70 | |
c5905afb IM |
71 | ( On 32-bit x86, the necessary options added to the compiler |
72 | flags may increase the size of the kernel slightly. ) | |
45f81b1c | 73 | |
afd66255 | 74 | config OPTPROBES |
5cc718b9 MH |
75 | def_bool y |
76 | depends on KPROBES && HAVE_OPTPROBES | |
afd66255 | 77 | depends on !PREEMPT |
afd66255 | 78 | |
2b144498 | 79 | config UPROBES |
7b2d81d4 | 80 | bool "Transparent user-space probes (EXPERIMENTAL)" |
ec83db0f | 81 | depends on UPROBE_EVENT && PERF_EVENTS |
2b144498 | 82 | default n |
22b361d1 | 83 | select PERCPU_RWSEM |
2b144498 | 84 | help |
7b2d81d4 IM |
85 | Uprobes is the user-space counterpart to kprobes: they |
86 | enable instrumentation applications (such as 'perf probe') | |
87 | to establish unintrusive probes in user-space binaries and | |
88 | libraries, by executing handler functions when the probes | |
89 | are hit by user-space applications. | |
90 | ||
91 | ( These probes come in the form of single-byte breakpoints, | |
92 | managed by the kernel and kept transparent to the probed | |
93 | application. ) | |
2b144498 SD |
94 | |
95 | If in doubt, say "N". | |
96 | ||
c19fa94a JH |
97 | config HAVE_64BIT_ALIGNED_ACCESS |
98 | def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS | |
99 | help | |
100 | Some architectures require 64 bit accesses to be 64 bit | |
101 | aligned, which also requires structs containing 64 bit values | |
102 | to be 64 bit aligned too. This includes some 32 bit | |
103 | architectures which can do 64 bit accesses, as well as 64 bit | |
104 | architectures without unaligned access. | |
105 | ||
106 | This symbol should be selected by an architecture if 64 bit | |
107 | accesses are required to be 64 bit aligned in this way even | |
108 | though it is not a 64 bit architecture. | |
109 | ||
110 | See Documentation/unaligned-memory-access.txt for more | |
111 | information on the topic of unaligned memory accesses. | |
112 | ||
58340a07 | 113 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
9ba16087 | 114 | bool |
58340a07 JB |
115 | help |
116 | Some architectures are unable to perform unaligned accesses | |
117 | without the use of get_unaligned/put_unaligned. Others are | |
118 | unable to perform such accesses efficiently (e.g. trap on | |
119 | unaligned access and require fixing it up in the exception | |
120 | handler.) | |
121 | ||
122 | This symbol should be selected by an architecture if it can | |
123 | perform unaligned accesses efficiently to allow different | |
124 | code paths to be selected for these cases. Some network | |
125 | drivers, for example, could opt to not fix up alignment | |
126 | problems with received packets if doing so would not help | |
127 | much. | |
128 | ||
129 | See Documentation/unaligned-memory-access.txt for more | |
130 | information on the topic of unaligned memory accesses. | |
131 | ||
cf66bb93 DW |
132 | config ARCH_USE_BUILTIN_BSWAP |
133 | bool | |
134 | help | |
135 | Modern versions of GCC (since 4.4) have builtin functions | |
136 | for handling byte-swapping. Using these, instead of the old | |
137 | inline assembler that the architecture code provides in the | |
138 | __arch_bswapXX() macros, allows the compiler to see what's | |
139 | happening and offers more opportunity for optimisation. In | |
140 | particular, the compiler will be able to combine the byteswap | |
141 | with a nearby load or store and use load-and-swap or | |
142 | store-and-swap instructions if the architecture has them. It | |
143 | should almost *never* result in code which is worse than the | |
144 | hand-coded assembler in <asm/swab.h>. But just in case it | |
145 | does, the use of the builtins is optional. | |
146 | ||
147 | Any architecture with load-and-swap or store-and-swap | |
148 | instructions should set this. And it shouldn't hurt to set it | |
149 | on architectures that don't have such instructions. | |
150 | ||
1a94bc34 HC |
151 | config HAVE_SYSCALL_WRAPPERS |
152 | bool | |
153 | ||
9edddaa2 AM |
154 | config KRETPROBES |
155 | def_bool y | |
156 | depends on KPROBES && HAVE_KRETPROBES | |
157 | ||
7c68af6e AK |
158 | config USER_RETURN_NOTIFIER |
159 | bool | |
160 | depends on HAVE_USER_RETURN_NOTIFIER | |
161 | help | |
162 | Provide a kernel-internal notification when a cpu is about to | |
163 | switch to user mode. | |
164 | ||
28b2ee20 | 165 | config HAVE_IOREMAP_PROT |
9ba16087 | 166 | bool |
28b2ee20 | 167 | |
125e5645 | 168 | config HAVE_KPROBES |
9ba16087 | 169 | bool |
9edddaa2 AM |
170 | |
171 | config HAVE_KRETPROBES | |
9ba16087 | 172 | bool |
74bc7cee | 173 | |
afd66255 MH |
174 | config HAVE_OPTPROBES |
175 | bool | |
d314d74c CW |
176 | |
177 | config HAVE_NMI_WATCHDOG | |
178 | bool | |
1f5a4ad9 RM |
179 | # |
180 | # An arch should select this if it provides all these things: | |
181 | # | |
182 | # task_pt_regs() in asm/processor.h or asm/ptrace.h | |
183 | # arch_has_single_step() if there is hardware single-step support | |
184 | # arch_has_block_step() if there is hardware block-step support | |
1f5a4ad9 RM |
185 | # asm/syscall.h supplying asm-generic/syscall.h interface |
186 | # linux/regset.h user_regset interfaces | |
187 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h | |
188 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} | |
189 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() | |
190 | # signal delivery calls tracehook_signal_handler() | |
191 | # | |
192 | config HAVE_ARCH_TRACEHOOK | |
9ba16087 | 193 | bool |
1f5a4ad9 | 194 | |
74bc7cee | 195 | config HAVE_DMA_ATTRS |
9ba16087 | 196 | bool |
3d442233 | 197 | |
c64be2bb MS |
198 | config HAVE_DMA_CONTIGUOUS |
199 | bool | |
200 | ||
3d442233 | 201 | config USE_GENERIC_SMP_HELPERS |
9ba16087 | 202 | bool |
9483a578 | 203 | |
29d5e047 TG |
204 | config GENERIC_SMP_IDLE_THREAD |
205 | bool | |
206 | ||
a6359d1e TG |
207 | # Select if arch init_task initializer is different to init/init_task.c |
208 | config ARCH_INIT_TASK | |
a4a2eb49 TG |
209 | bool |
210 | ||
f5e10287 TG |
211 | # Select if arch has its private alloc_task_struct() function |
212 | config ARCH_TASK_STRUCT_ALLOCATOR | |
213 | bool | |
214 | ||
215 | # Select if arch has its private alloc_thread_info() function | |
216 | config ARCH_THREAD_INFO_ALLOCATOR | |
217 | bool | |
218 | ||
f850c30c HC |
219 | config HAVE_REGS_AND_STACK_ACCESS_API |
220 | bool | |
e01292b1 HC |
221 | help |
222 | This symbol should be selected by an architecure if it supports | |
223 | the API needed to access registers and stack entries from pt_regs, | |
224 | declared in asm/ptrace.h | |
225 | For example the kprobes-based event tracer needs this API. | |
f850c30c | 226 | |
9483a578 | 227 | config HAVE_CLK |
9ba16087 | 228 | bool |
9483a578 DB |
229 | help |
230 | The <linux/clk.h> calls support software clock gating and | |
231 | thus are a key power management tool on many systems. | |
232 | ||
5ee00bd4 JR |
233 | config HAVE_DMA_API_DEBUG |
234 | bool | |
36cd3c9f | 235 | |
62a038d3 P |
236 | config HAVE_HW_BREAKPOINT |
237 | bool | |
99e8c5a3 | 238 | depends on PERF_EVENTS |
62a038d3 | 239 | |
0102752e FW |
240 | config HAVE_MIXED_BREAKPOINTS_REGS |
241 | bool | |
242 | depends on HAVE_HW_BREAKPOINT | |
243 | help | |
244 | Depending on the arch implementation of hardware breakpoints, | |
245 | some of them have separate registers for data and instruction | |
246 | breakpoints addresses, others have mixed registers to store | |
247 | them but define the access type in a control register. | |
248 | Select this option if your arch implements breakpoints under the | |
249 | latter fashion. | |
250 | ||
7c68af6e AK |
251 | config HAVE_USER_RETURN_NOTIFIER |
252 | bool | |
a1922ed6 | 253 | |
c01d4323 FW |
254 | config HAVE_PERF_EVENTS_NMI |
255 | bool | |
23637d47 FW |
256 | help |
257 | System hardware can generate an NMI using the perf event | |
258 | subsystem. Also has support for calculating CPU cycle events | |
259 | to determine how many clock cycles in a given period. | |
c01d4323 | 260 | |
c5e63197 JO |
261 | config HAVE_PERF_REGS |
262 | bool | |
263 | help | |
264 | Support selective register dumps for perf events. This includes | |
265 | bit-mapping of each registers and a unique architecture id. | |
266 | ||
c5ebcedb JO |
267 | config HAVE_PERF_USER_STACK_DUMP |
268 | bool | |
269 | help | |
270 | Support user stack dumps for perf event samples. This needs | |
271 | access to the user stack pointer which is not unified across | |
272 | architectures. | |
273 | ||
bf5438fc JB |
274 | config HAVE_ARCH_JUMP_LABEL |
275 | bool | |
276 | ||
335d7afb GS |
277 | config HAVE_ARCH_MUTEX_CPU_RELAX |
278 | bool | |
279 | ||
26723911 PZ |
280 | config HAVE_RCU_TABLE_FREE |
281 | bool | |
282 | ||
df013ffb HY |
283 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
284 | bool | |
285 | ||
43570fd2 HC |
286 | config HAVE_ALIGNED_STRUCT_PAGE |
287 | bool | |
288 | help | |
289 | This makes sure that struct pages are double word aligned and that | |
290 | e.g. the SLUB allocator can perform double word atomic operations | |
291 | on a struct page for better performance. However selecting this | |
292 | might increase the size of a struct page by a word. | |
293 | ||
4156153c HC |
294 | config HAVE_CMPXCHG_LOCAL |
295 | bool | |
296 | ||
2565409f HC |
297 | config HAVE_CMPXCHG_DOUBLE |
298 | bool | |
299 | ||
c1d7e01d WD |
300 | config ARCH_WANT_IPC_PARSE_VERSION |
301 | bool | |
302 | ||
303 | config ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
304 | bool | |
305 | ||
48b25c43 | 306 | config ARCH_WANT_OLD_COMPAT_IPC |
c1d7e01d | 307 | select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
48b25c43 CM |
308 | bool |
309 | ||
e2cfabdf WD |
310 | config HAVE_ARCH_SECCOMP_FILTER |
311 | bool | |
312 | help | |
fb0fadf9 | 313 | An arch should select this symbol if it provides all of these things: |
bb6ea430 WD |
314 | - syscall_get_arch() |
315 | - syscall_get_arguments() | |
316 | - syscall_rollback() | |
317 | - syscall_set_return_value() | |
fb0fadf9 WD |
318 | - SIGSYS siginfo_t support |
319 | - secure_computing is called from a ptrace_event()-safe context | |
320 | - secure_computing return value is checked and a return value of -1 | |
321 | results in the system call being skipped immediately. | |
e2cfabdf WD |
322 | |
323 | config SECCOMP_FILTER | |
324 | def_bool y | |
325 | depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET | |
326 | help | |
327 | Enable tasks to build secure computing environments defined | |
328 | in terms of Berkeley Packet Filter programs which implement | |
329 | task-defined system call filtering polices. | |
330 | ||
331 | See Documentation/prctl/seccomp_filter.txt for details. | |
332 | ||
91d1aa43 | 333 | config HAVE_CONTEXT_TRACKING |
2b1d5024 FW |
334 | bool |
335 | help | |
91d1aa43 FW |
336 | Provide kernel/user boundaries probes necessary for subsystems |
337 | that need it, such as userspace RCU extended quiescent state. | |
338 | Syscalls need to be wrapped inside user_exit()-user_enter() through | |
339 | the slow path using TIF_NOHZ flag. Exceptions handlers must be | |
340 | wrapped as well. Irqs are already protected inside | |
341 | rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on | |
342 | irq exit still need to be protected. | |
2b1d5024 | 343 | |
b952741c FW |
344 | config HAVE_VIRT_CPU_ACCOUNTING |
345 | bool | |
346 | ||
fdf9c356 FW |
347 | config HAVE_IRQ_TIME_ACCOUNTING |
348 | bool | |
349 | help | |
350 | Archs need to ensure they use a high enough resolution clock to | |
351 | support irq time accounting and then call enable_sched_clock_irqtime(). | |
352 | ||
15626062 GS |
353 | config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
354 | bool | |
355 | ||
786d35d4 DH |
356 | config HAVE_MOD_ARCH_SPECIFIC |
357 | bool | |
358 | help | |
359 | The arch uses struct mod_arch_specific to store data. Many arches | |
360 | just need a simple module loader without arch specific data - those | |
361 | should not enable this. | |
362 | ||
363 | config MODULES_USE_ELF_RELA | |
364 | bool | |
365 | help | |
366 | Modules only use ELF RELA relocations. Modules with ELF REL | |
367 | relocations will give an error. | |
368 | ||
369 | config MODULES_USE_ELF_REL | |
370 | bool | |
371 | help | |
372 | Modules only use ELF REL relocations. Modules with ELF RELA | |
373 | relocations will give an error. | |
374 | ||
6bf9adfc AV |
375 | config GENERIC_SIGALTSTACK |
376 | bool | |
377 | ||
d2125043 AV |
378 | # |
379 | # ABI hall of shame | |
380 | # | |
381 | config CLONE_BACKWARDS | |
382 | bool | |
383 | help | |
384 | Architecture has tls passed as the 4th argument of clone(2), | |
385 | not the 5th one. | |
386 | ||
387 | config CLONE_BACKWARDS2 | |
388 | bool | |
389 | help | |
390 | Architecture has the first two arguments of clone(2) swapped. | |
391 | ||
2521f2c2 | 392 | source "kernel/gcov/Kconfig" |