2 # General architecture dependent options
6 tristate "OProfile system profiling"
8 depends on HAVE_OPROFILE
10 select RING_BUFFER_ALLOW_SWAP
12 OProfile is a profiling system capable of profiling the
13 whole system, include the kernel, kernel modules, libraries,
18 config OPROFILE_EVENT_MULTIPLEX
19 bool "OProfile multiplexing support (EXPERIMENTAL)"
21 depends on OPROFILE && X86
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.
33 config OPROFILE_NMI_TIMER
35 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
40 depends on HAVE_KPROBES
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.
50 bool "Optimize very unlikely/likely branches"
51 depends on HAVE_ARCH_JUMP_LABEL
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.
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.
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.
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.
71 ( On 32-bit x86, the necessary options added to the compiler
72 flags may increase the size of the kernel slightly. )
76 depends on KPROBES && HAVE_OPTPROBES
80 bool "Transparent user-space probes (EXPERIMENTAL)"
81 depends on UPROBE_EVENT && PERF_EVENTS
84 Uprobes is the user-space counterpart to kprobes: they
85 enable instrumentation applications (such as 'perf probe')
86 to establish unintrusive probes in user-space binaries and
87 libraries, by executing handler functions when the probes
88 are hit by user-space applications.
90 ( These probes come in the form of single-byte breakpoints,
91 managed by the kernel and kept transparent to the probed
96 config HAVE_EFFICIENT_UNALIGNED_ACCESS
99 Some architectures are unable to perform unaligned accesses
100 without the use of get_unaligned/put_unaligned. Others are
101 unable to perform such accesses efficiently (e.g. trap on
102 unaligned access and require fixing it up in the exception
105 This symbol should be selected by an architecture if it can
106 perform unaligned accesses efficiently to allow different
107 code paths to be selected for these cases. Some network
108 drivers, for example, could opt to not fix up alignment
109 problems with received packets if doing so would not help
112 See Documentation/unaligned-memory-access.txt for more
113 information on the topic of unaligned memory accesses.
115 config HAVE_SYSCALL_WRAPPERS
120 depends on KPROBES && HAVE_KRETPROBES
122 config USER_RETURN_NOTIFIER
124 depends on HAVE_USER_RETURN_NOTIFIER
126 Provide a kernel-internal notification when a cpu is about to
129 config HAVE_IOREMAP_PROT
135 config HAVE_KRETPROBES
138 config HAVE_OPTPROBES
141 config HAVE_NMI_WATCHDOG
144 # An arch should select this if it provides all these things:
146 # task_pt_regs() in asm/processor.h or asm/ptrace.h
147 # arch_has_single_step() if there is hardware single-step support
148 # arch_has_block_step() if there is hardware block-step support
149 # asm/syscall.h supplying asm-generic/syscall.h interface
150 # linux/regset.h user_regset interfaces
151 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
152 # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
153 # TIF_NOTIFY_RESUME calls tracehook_notify_resume()
154 # signal delivery calls tracehook_signal_handler()
156 config HAVE_ARCH_TRACEHOOK
159 config HAVE_DMA_ATTRS
162 config HAVE_DMA_CONTIGUOUS
165 config USE_GENERIC_SMP_HELPERS
168 config GENERIC_SMP_IDLE_THREAD
171 # Select if arch init_task initializer is different to init/init_task.c
172 config ARCH_INIT_TASK
175 # Select if arch has its private alloc_task_struct() function
176 config ARCH_TASK_STRUCT_ALLOCATOR
179 # Select if arch has its private alloc_thread_info() function
180 config ARCH_THREAD_INFO_ALLOCATOR
183 config HAVE_REGS_AND_STACK_ACCESS_API
186 This symbol should be selected by an architecure if it supports
187 the API needed to access registers and stack entries from pt_regs,
188 declared in asm/ptrace.h
189 For example the kprobes-based event tracer needs this API.
194 The <linux/clk.h> calls support software clock gating and
195 thus are a key power management tool on many systems.
197 config HAVE_DMA_API_DEBUG
200 config HAVE_HW_BREAKPOINT
202 depends on PERF_EVENTS
204 config HAVE_MIXED_BREAKPOINTS_REGS
206 depends on HAVE_HW_BREAKPOINT
208 Depending on the arch implementation of hardware breakpoints,
209 some of them have separate registers for data and instruction
210 breakpoints addresses, others have mixed registers to store
211 them but define the access type in a control register.
212 Select this option if your arch implements breakpoints under the
215 config HAVE_USER_RETURN_NOTIFIER
218 config HAVE_PERF_EVENTS_NMI
221 System hardware can generate an NMI using the perf event
222 subsystem. Also has support for calculating CPU cycle events
223 to determine how many clock cycles in a given period.
225 config HAVE_ARCH_JUMP_LABEL
228 config HAVE_ARCH_MUTEX_CPU_RELAX
231 config HAVE_RCU_TABLE_FREE
234 config ARCH_HAVE_NMI_SAFE_CMPXCHG
237 config HAVE_ALIGNED_STRUCT_PAGE
240 This makes sure that struct pages are double word aligned and that
241 e.g. the SLUB allocator can perform double word atomic operations
242 on a struct page for better performance. However selecting this
243 might increase the size of a struct page by a word.
245 config HAVE_CMPXCHG_LOCAL
248 config HAVE_CMPXCHG_DOUBLE
251 config ARCH_WANT_IPC_PARSE_VERSION
254 config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
257 config ARCH_WANT_OLD_COMPAT_IPC
258 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
261 config GENERIC_KERNEL_THREAD
264 config HAVE_ARCH_SECCOMP_FILTER
267 An arch should select this symbol if it provides all of these things:
269 - syscall_get_arguments()
271 - syscall_set_return_value()
272 - SIGSYS siginfo_t support
273 - secure_computing is called from a ptrace_event()-safe context
274 - secure_computing return value is checked and a return value of -1
275 results in the system call being skipped immediately.
277 config SECCOMP_FILTER
279 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
281 Enable tasks to build secure computing environments defined
282 in terms of Berkeley Packet Filter programs which implement
283 task-defined system call filtering polices.
285 See Documentation/prctl/seccomp_filter.txt for details.
287 source "kernel/gcov/Kconfig"