1# SPDX-License-Identifier: GPL-2.0-only
2#
3# Architectures that offer an FUNCTION_TRACER implementation should
4#  select HAVE_FUNCTION_TRACER:
5#
6
7config USER_STACKTRACE_SUPPORT
8	bool
9
10config NOP_TRACER
11	bool
12
13config HAVE_RETHOOK
14	bool
15
16config RETHOOK
17	bool
18	depends on HAVE_RETHOOK
19	help
20	  Enable generic return hooking feature. This is an internal
21	  API, which will be used by other function-entry hooking
22	  features like fprobe and kprobes.
23
24config HAVE_FUNCTION_TRACER
25	bool
26	help
27	  See Documentation/trace/ftrace-design.rst
28
29config HAVE_FUNCTION_GRAPH_TRACER
30	bool
31	help
32	  See Documentation/trace/ftrace-design.rst
33
34config HAVE_DYNAMIC_FTRACE
35	bool
36	help
37	  See Documentation/trace/ftrace-design.rst
38
39config HAVE_DYNAMIC_FTRACE_WITH_REGS
40	bool
41
42config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
43	bool
44
45config HAVE_DYNAMIC_FTRACE_WITH_ARGS
46	bool
47	help
48	 If this is set, then arguments and stack can be found from
49	 the pt_regs passed into the function callback regs parameter
50	 by default, even without setting the REGS flag in the ftrace_ops.
51	 This allows for use of regs_get_kernel_argument() and
52	 kernel_stack_pointer().
53
54config HAVE_FTRACE_MCOUNT_RECORD
55	bool
56	help
57	  See Documentation/trace/ftrace-design.rst
58
59config HAVE_SYSCALL_TRACEPOINTS
60	bool
61	help
62	  See Documentation/trace/ftrace-design.rst
63
64config HAVE_FENTRY
65	bool
66	help
67	  Arch supports the gcc options -pg with -mfentry
68
69config HAVE_NOP_MCOUNT
70	bool
71	help
72	  Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
73
74config HAVE_OBJTOOL_MCOUNT
75	bool
76	help
77	  Arch supports objtool --mcount
78
79config HAVE_C_RECORDMCOUNT
80	bool
81	help
82	  C version of recordmcount available?
83
84config HAVE_BUILDTIME_MCOUNT_SORT
85       bool
86       help
87         An architecture selects this if it sorts the mcount_loc section
88	 at build time.
89
90config BUILDTIME_MCOUNT_SORT
91       bool
92       default y
93       depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE
94       help
95         Sort the mcount_loc section at build time.
96
97config TRACER_MAX_TRACE
98	bool
99
100config TRACE_CLOCK
101	bool
102
103config RING_BUFFER
104	bool
105	select TRACE_CLOCK
106	select IRQ_WORK
107
108config EVENT_TRACING
109	select CONTEXT_SWITCH_TRACER
110	select GLOB
111	bool
112
113config CONTEXT_SWITCH_TRACER
114	bool
115
116config RING_BUFFER_ALLOW_SWAP
117	bool
118	help
119	 Allow the use of ring_buffer_swap_cpu.
120	 Adds a very slight overhead to tracing when enabled.
121
122config PREEMPTIRQ_TRACEPOINTS
123	bool
124	depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
125	select TRACING
126	default y
127	help
128	  Create preempt/irq toggle tracepoints if needed, so that other parts
129	  of the kernel can use them to generate or add hooks to them.
130
131# All tracer options should select GENERIC_TRACER. For those options that are
132# enabled by all tracers (context switch and event tracer) they select TRACING.
133# This allows those options to appear when no other tracer is selected. But the
134# options do not appear when something else selects it. We need the two options
135# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
136# hiding of the automatic options.
137
138config TRACING
139	bool
140	select RING_BUFFER
141	select STACKTRACE if STACKTRACE_SUPPORT
142	select TRACEPOINTS
143	select NOP_TRACER
144	select BINARY_PRINTF
145	select EVENT_TRACING
146	select TRACE_CLOCK
147	select TASKS_RCU if PREEMPTION
148
149config GENERIC_TRACER
150	bool
151	select TRACING
152
153#
154# Minimum requirements an architecture has to meet for us to
155# be able to offer generic tracing facilities:
156#
157config TRACING_SUPPORT
158	bool
159	depends on TRACE_IRQFLAGS_SUPPORT
160	depends on STACKTRACE_SUPPORT
161	default y
162
163menuconfig FTRACE
164	bool "Tracers"
165	depends on TRACING_SUPPORT
166	default y if DEBUG_KERNEL
167	help
168	  Enable the kernel tracing infrastructure.
169
170if FTRACE
171
172config BOOTTIME_TRACING
173	bool "Boot-time Tracing support"
174	depends on TRACING
175	select BOOT_CONFIG
176	help
177	  Enable developer to setup ftrace subsystem via supplemental
178	  kernel cmdline at boot time for debugging (tracing) driver
179	  initialization and boot process.
180
181config FUNCTION_TRACER
182	bool "Kernel Function Tracer"
183	depends on HAVE_FUNCTION_TRACER
184	select KALLSYMS
185	select GENERIC_TRACER
186	select CONTEXT_SWITCH_TRACER
187	select GLOB
188	select TASKS_RCU if PREEMPTION
189	select TASKS_RUDE_RCU
190	help
191	  Enable the kernel to trace every kernel function. This is done
192	  by using a compiler feature to insert a small, 5-byte No-Operation
193	  instruction at the beginning of every kernel function, which NOP
194	  sequence is then dynamically patched into a tracer call when
195	  tracing is enabled by the administrator. If it's runtime disabled
196	  (the bootup default), then the overhead of the instructions is very
197	  small and not measurable even in micro-benchmarks (at least on
198	  x86, but may have impact on other architectures).
199
200config FUNCTION_GRAPH_TRACER
201	bool "Kernel Function Graph Tracer"
202	depends on HAVE_FUNCTION_GRAPH_TRACER
203	depends on FUNCTION_TRACER
204	depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
205	default y
206	help
207	  Enable the kernel to trace a function at both its return
208	  and its entry.
209	  Its first purpose is to trace the duration of functions and
210	  draw a call graph for each thread with some information like
211	  the return value. This is done by setting the current return
212	  address on the current task structure into a stack of calls.
213
214config DYNAMIC_FTRACE
215	bool "enable/disable function tracing dynamically"
216	depends on FUNCTION_TRACER
217	depends on HAVE_DYNAMIC_FTRACE
218	default y
219	help
220	  This option will modify all the calls to function tracing
221	  dynamically (will patch them out of the binary image and
222	  replace them with a No-Op instruction) on boot up. During
223	  compile time, a table is made of all the locations that ftrace
224	  can function trace, and this table is linked into the kernel
225	  image. When this is enabled, functions can be individually
226	  enabled, and the functions not enabled will not affect
227	  performance of the system.
228
229	  See the files in /sys/kernel/debug/tracing:
230	    available_filter_functions
231	    set_ftrace_filter
232	    set_ftrace_notrace
233
234	  This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
235	  otherwise has native performance as long as no tracing is active.
236
237config DYNAMIC_FTRACE_WITH_REGS
238	def_bool y
239	depends on DYNAMIC_FTRACE
240	depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
241
242config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
243	def_bool y
244	depends on DYNAMIC_FTRACE_WITH_REGS
245	depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
246
247config DYNAMIC_FTRACE_WITH_ARGS
248	def_bool y
249	depends on DYNAMIC_FTRACE
250	depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
251
252config FPROBE
253	bool "Kernel Function Probe (fprobe)"
254	depends on FUNCTION_TRACER
255	depends on DYNAMIC_FTRACE_WITH_REGS
256	depends on HAVE_RETHOOK
257	select RETHOOK
258	default n
259	help
260	  This option enables kernel function probe (fprobe) based on ftrace.
261	  The fprobe is similar to kprobes, but probes only for kernel function
262	  entries and exits. This also can probe multiple functions by one
263	  fprobe.
264
265	  If unsure, say N.
266
267config FUNCTION_PROFILER
268	bool "Kernel function profiler"
269	depends on FUNCTION_TRACER
270	default n
271	help
272	  This option enables the kernel function profiler. A file is created
273	  in debugfs called function_profile_enabled which defaults to zero.
274	  When a 1 is echoed into this file profiling begins, and when a
275	  zero is entered, profiling stops. A "functions" file is created in
276	  the trace_stat directory; this file shows the list of functions that
277	  have been hit and their counters.
278
279	  If in doubt, say N.
280
281config STACK_TRACER
282	bool "Trace max stack"
283	depends on HAVE_FUNCTION_TRACER
284	select FUNCTION_TRACER
285	select STACKTRACE
286	select KALLSYMS
287	help
288	  This special tracer records the maximum stack footprint of the
289	  kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
290
291	  This tracer works by hooking into every function call that the
292	  kernel executes, and keeping a maximum stack depth value and
293	  stack-trace saved.  If this is configured with DYNAMIC_FTRACE
294	  then it will not have any overhead while the stack tracer
295	  is disabled.
296
297	  To enable the stack tracer on bootup, pass in 'stacktrace'
298	  on the kernel command line.
299
300	  The stack tracer can also be enabled or disabled via the
301	  sysctl kernel.stack_tracer_enabled
302
303	  Say N if unsure.
304
305config TRACE_PREEMPT_TOGGLE
306	bool
307	help
308	  Enables hooks which will be called when preemption is first disabled,
309	  and last enabled.
310
311config IRQSOFF_TRACER
312	bool "Interrupts-off Latency Tracer"
313	default n
314	depends on TRACE_IRQFLAGS_SUPPORT
315	select TRACE_IRQFLAGS
316	select GENERIC_TRACER
317	select TRACER_MAX_TRACE
318	select RING_BUFFER_ALLOW_SWAP
319	select TRACER_SNAPSHOT
320	select TRACER_SNAPSHOT_PER_CPU_SWAP
321	help
322	  This option measures the time spent in irqs-off critical
323	  sections, with microsecond accuracy.
324
325	  The default measurement method is a maximum search, which is
326	  disabled by default and can be runtime (re-)started
327	  via:
328
329	      echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
330
331	  (Note that kernel size and overhead increase with this option
332	  enabled. This option and the preempt-off timing option can be
333	  used together or separately.)
334
335config PREEMPT_TRACER
336	bool "Preemption-off Latency Tracer"
337	default n
338	depends on PREEMPTION
339	select GENERIC_TRACER
340	select TRACER_MAX_TRACE
341	select RING_BUFFER_ALLOW_SWAP
342	select TRACER_SNAPSHOT
343	select TRACER_SNAPSHOT_PER_CPU_SWAP
344	select TRACE_PREEMPT_TOGGLE
345	help
346	  This option measures the time spent in preemption-off critical
347	  sections, with microsecond accuracy.
348
349	  The default measurement method is a maximum search, which is
350	  disabled by default and can be runtime (re-)started
351	  via:
352
353	      echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
354
355	  (Note that kernel size and overhead increase with this option
356	  enabled. This option and the irqs-off timing option can be
357	  used together or separately.)
358
359config SCHED_TRACER
360	bool "Scheduling Latency Tracer"
361	select GENERIC_TRACER
362	select CONTEXT_SWITCH_TRACER
363	select TRACER_MAX_TRACE
364	select TRACER_SNAPSHOT
365	help
366	  This tracer tracks the latency of the highest priority task
367	  to be scheduled in, starting from the point it has woken up.
368
369config HWLAT_TRACER
370	bool "Tracer to detect hardware latencies (like SMIs)"
371	select GENERIC_TRACER
372	help
373	 This tracer, when enabled will create one or more kernel threads,
374	 depending on what the cpumask file is set to, which each thread
375	 spinning in a loop looking for interruptions caused by
376	 something other than the kernel. For example, if a
377	 System Management Interrupt (SMI) takes a noticeable amount of
378	 time, this tracer will detect it. This is useful for testing
379	 if a system is reliable for Real Time tasks.
380
381	 Some files are created in the tracing directory when this
382	 is enabled:
383
384	   hwlat_detector/width   - time in usecs for how long to spin for
385	   hwlat_detector/window  - time in usecs between the start of each
386				     iteration
387
388	 A kernel thread is created that will spin with interrupts disabled
389	 for "width" microseconds in every "window" cycle. It will not spin
390	 for "window - width" microseconds, where the system can
391	 continue to operate.
392
393	 The output will appear in the trace and trace_pipe files.
394
395	 When the tracer is not running, it has no affect on the system,
396	 but when it is running, it can cause the system to be
397	 periodically non responsive. Do not run this tracer on a
398	 production system.
399
400	 To enable this tracer, echo in "hwlat" into the current_tracer
401	 file. Every time a latency is greater than tracing_thresh, it will
402	 be recorded into the ring buffer.
403
404config OSNOISE_TRACER
405	bool "OS Noise tracer"
406	select GENERIC_TRACER
407	help
408	  In the context of high-performance computing (HPC), the Operating
409	  System Noise (osnoise) refers to the interference experienced by an
410	  application due to activities inside the operating system. In the
411	  context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
412	  can cause noise to the system. Moreover, hardware-related jobs can
413	  also cause noise, for example, via SMIs.
414
415	  The osnoise tracer leverages the hwlat_detector by running a similar
416	  loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
417	  the sources of osnoise during its execution. The osnoise tracer takes
418	  note of the entry and exit point of any source of interferences,
419	  increasing a per-cpu interference counter. It saves an interference
420	  counter for each source of interference. The interference counter for
421	  NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
422	  observes these interferences' entry events. When a noise happens
423	  without any interference from the operating system level, the
424	  hardware noise counter increases, pointing to a hardware-related
425	  noise. In this way, osnoise can account for any source of
426	  interference. At the end of the period, the osnoise tracer prints
427	  the sum of all noise, the max single noise, the percentage of CPU
428	  available for the thread, and the counters for the noise sources.
429
430	  In addition to the tracer, a set of tracepoints were added to
431	  facilitate the identification of the osnoise source.
432
433	  The output will appear in the trace and trace_pipe files.
434
435	  To enable this tracer, echo in "osnoise" into the current_tracer
436          file.
437
438config TIMERLAT_TRACER
439	bool "Timerlat tracer"
440	select OSNOISE_TRACER
441	select GENERIC_TRACER
442	help
443	  The timerlat tracer aims to help the preemptive kernel developers
444	  to find sources of wakeup latencies of real-time threads.
445
446	  The tracer creates a per-cpu kernel thread with real-time priority.
447	  The tracer thread sets a periodic timer to wakeup itself, and goes
448	  to sleep waiting for the timer to fire. At the wakeup, the thread
449	  then computes a wakeup latency value as the difference between
450	  the current time and the absolute time that the timer was set
451	  to expire.
452
453	  The tracer prints two lines at every activation. The first is the
454	  timer latency observed at the hardirq context before the
455	  activation of the thread. The second is the timer latency observed
456	  by the thread, which is the same level that cyclictest reports. The
457	  ACTIVATION ID field serves to relate the irq execution to its
458	  respective thread execution.
459
460	  The tracer is build on top of osnoise tracer, and the osnoise:
461	  events can be used to trace the source of interference from NMI,
462	  IRQs and other threads. It also enables the capture of the
463	  stacktrace at the IRQ context, which helps to identify the code
464	  path that can cause thread delay.
465
466config MMIOTRACE
467	bool "Memory mapped IO tracing"
468	depends on HAVE_MMIOTRACE_SUPPORT && PCI
469	select GENERIC_TRACER
470	help
471	  Mmiotrace traces Memory Mapped I/O access and is meant for
472	  debugging and reverse engineering. It is called from the ioremap
473	  implementation and works via page faults. Tracing is disabled by
474	  default and can be enabled at run-time.
475
476	  See Documentation/trace/mmiotrace.rst.
477	  If you are not helping to develop drivers, say N.
478
479config ENABLE_DEFAULT_TRACERS
480	bool "Trace process context switches and events"
481	depends on !GENERIC_TRACER
482	select TRACING
483	help
484	  This tracer hooks to various trace points in the kernel,
485	  allowing the user to pick and choose which trace point they
486	  want to trace. It also includes the sched_switch tracer plugin.
487
488config FTRACE_SYSCALLS
489	bool "Trace syscalls"
490	depends on HAVE_SYSCALL_TRACEPOINTS
491	select GENERIC_TRACER
492	select KALLSYMS
493	help
494	  Basic tracer to catch the syscall entry and exit events.
495
496config TRACER_SNAPSHOT
497	bool "Create a snapshot trace buffer"
498	select TRACER_MAX_TRACE
499	help
500	  Allow tracing users to take snapshot of the current buffer using the
501	  ftrace interface, e.g.:
502
503	      echo 1 > /sys/kernel/debug/tracing/snapshot
504	      cat snapshot
505
506config TRACER_SNAPSHOT_PER_CPU_SWAP
507	bool "Allow snapshot to swap per CPU"
508	depends on TRACER_SNAPSHOT
509	select RING_BUFFER_ALLOW_SWAP
510	help
511	  Allow doing a snapshot of a single CPU buffer instead of a
512	  full swap (all buffers). If this is set, then the following is
513	  allowed:
514
515	      echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
516
517	  After which, only the tracing buffer for CPU 2 was swapped with
518	  the main tracing buffer, and the other CPU buffers remain the same.
519
520	  When this is enabled, this adds a little more overhead to the
521	  trace recording, as it needs to add some checks to synchronize
522	  recording with swaps. But this does not affect the performance
523	  of the overall system. This is enabled by default when the preempt
524	  or irq latency tracers are enabled, as those need to swap as well
525	  and already adds the overhead (plus a lot more).
526
527config TRACE_BRANCH_PROFILING
528	bool
529	select GENERIC_TRACER
530
531choice
532	prompt "Branch Profiling"
533	default BRANCH_PROFILE_NONE
534	help
535	 The branch profiling is a software profiler. It will add hooks
536	 into the C conditionals to test which path a branch takes.
537
538	 The likely/unlikely profiler only looks at the conditions that
539	 are annotated with a likely or unlikely macro.
540
541	 The "all branch" profiler will profile every if-statement in the
542	 kernel. This profiler will also enable the likely/unlikely
543	 profiler.
544
545	 Either of the above profilers adds a bit of overhead to the system.
546	 If unsure, choose "No branch profiling".
547
548config BRANCH_PROFILE_NONE
549	bool "No branch profiling"
550	help
551	  No branch profiling. Branch profiling adds a bit of overhead.
552	  Only enable it if you want to analyse the branching behavior.
553	  Otherwise keep it disabled.
554
555config PROFILE_ANNOTATED_BRANCHES
556	bool "Trace likely/unlikely profiler"
557	select TRACE_BRANCH_PROFILING
558	help
559	  This tracer profiles all likely and unlikely macros
560	  in the kernel. It will display the results in:
561
562	  /sys/kernel/debug/tracing/trace_stat/branch_annotated
563
564	  Note: this will add a significant overhead; only turn this
565	  on if you need to profile the system's use of these macros.
566
567config PROFILE_ALL_BRANCHES
568	bool "Profile all if conditionals" if !FORTIFY_SOURCE
569	select TRACE_BRANCH_PROFILING
570	help
571	  This tracer profiles all branch conditions. Every if ()
572	  taken in the kernel is recorded whether it hit or miss.
573	  The results will be displayed in:
574
575	  /sys/kernel/debug/tracing/trace_stat/branch_all
576
577	  This option also enables the likely/unlikely profiler.
578
579	  This configuration, when enabled, will impose a great overhead
580	  on the system. This should only be enabled when the system
581	  is to be analyzed in much detail.
582endchoice
583
584config TRACING_BRANCHES
585	bool
586	help
587	  Selected by tracers that will trace the likely and unlikely
588	  conditions. This prevents the tracers themselves from being
589	  profiled. Profiling the tracing infrastructure can only happen
590	  when the likelys and unlikelys are not being traced.
591
592config BRANCH_TRACER
593	bool "Trace likely/unlikely instances"
594	depends on TRACE_BRANCH_PROFILING
595	select TRACING_BRANCHES
596	help
597	  This traces the events of likely and unlikely condition
598	  calls in the kernel.  The difference between this and the
599	  "Trace likely/unlikely profiler" is that this is not a
600	  histogram of the callers, but actually places the calling
601	  events into a running trace buffer to see when and where the
602	  events happened, as well as their results.
603
604	  Say N if unsure.
605
606config BLK_DEV_IO_TRACE
607	bool "Support for tracing block IO actions"
608	depends on SYSFS
609	depends on BLOCK
610	select RELAY
611	select DEBUG_FS
612	select TRACEPOINTS
613	select GENERIC_TRACER
614	select STACKTRACE
615	help
616	  Say Y here if you want to be able to trace the block layer actions
617	  on a given queue. Tracing allows you to see any traffic happening
618	  on a block device queue. For more information (and the userspace
619	  support tools needed), fetch the blktrace tools from:
620
621	  git://git.kernel.dk/blktrace.git
622
623	  Tracing also is possible using the ftrace interface, e.g.:
624
625	    echo 1 > /sys/block/sda/sda1/trace/enable
626	    echo blk > /sys/kernel/debug/tracing/current_tracer
627	    cat /sys/kernel/debug/tracing/trace_pipe
628
629	  If unsure, say N.
630
631config KPROBE_EVENTS
632	depends on KPROBES
633	depends on HAVE_REGS_AND_STACK_ACCESS_API
634	bool "Enable kprobes-based dynamic events"
635	select TRACING
636	select PROBE_EVENTS
637	select DYNAMIC_EVENTS
638	default y
639	help
640	  This allows the user to add tracing events (similar to tracepoints)
641	  on the fly via the ftrace interface. See
642	  Documentation/trace/kprobetrace.rst for more details.
643
644	  Those events can be inserted wherever kprobes can probe, and record
645	  various register and memory values.
646
647	  This option is also required by perf-probe subcommand of perf tools.
648	  If you want to use perf tools, this option is strongly recommended.
649
650config KPROBE_EVENTS_ON_NOTRACE
651	bool "Do NOT protect notrace function from kprobe events"
652	depends on KPROBE_EVENTS
653	depends on DYNAMIC_FTRACE
654	default n
655	help
656	  This is only for the developers who want to debug ftrace itself
657	  using kprobe events.
658
659	  If kprobes can use ftrace instead of breakpoint, ftrace related
660	  functions are protected from kprobe-events to prevent an infinite
661	  recursion or any unexpected execution path which leads to a kernel
662	  crash.
663
664	  This option disables such protection and allows you to put kprobe
665	  events on ftrace functions for debugging ftrace by itself.
666	  Note that this might let you shoot yourself in the foot.
667
668	  If unsure, say N.
669
670config UPROBE_EVENTS
671	bool "Enable uprobes-based dynamic events"
672	depends on ARCH_SUPPORTS_UPROBES
673	depends on MMU
674	depends on PERF_EVENTS
675	select UPROBES
676	select PROBE_EVENTS
677	select DYNAMIC_EVENTS
678	select TRACING
679	default y
680	help
681	  This allows the user to add tracing events on top of userspace
682	  dynamic events (similar to tracepoints) on the fly via the trace
683	  events interface. Those events can be inserted wherever uprobes
684	  can probe, and record various registers.
685	  This option is required if you plan to use perf-probe subcommand
686	  of perf tools on user space applications.
687
688config BPF_EVENTS
689	depends on BPF_SYSCALL
690	depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
691	bool
692	default y
693	help
694	  This allows the user to attach BPF programs to kprobe, uprobe, and
695	  tracepoint events.
696
697config DYNAMIC_EVENTS
698	def_bool n
699
700config PROBE_EVENTS
701	def_bool n
702
703config BPF_KPROBE_OVERRIDE
704	bool "Enable BPF programs to override a kprobed function"
705	depends on BPF_EVENTS
706	depends on FUNCTION_ERROR_INJECTION
707	default n
708	help
709	 Allows BPF to override the execution of a probed function and
710	 set a different return value.  This is used for error injection.
711
712config FTRACE_MCOUNT_RECORD
713	def_bool y
714	depends on DYNAMIC_FTRACE
715	depends on HAVE_FTRACE_MCOUNT_RECORD
716
717config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
718	bool
719	depends on FTRACE_MCOUNT_RECORD
720
721config FTRACE_MCOUNT_USE_CC
722	def_bool y
723	depends on $(cc-option,-mrecord-mcount)
724	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
725	depends on FTRACE_MCOUNT_RECORD
726
727config FTRACE_MCOUNT_USE_OBJTOOL
728	def_bool y
729	depends on HAVE_OBJTOOL_MCOUNT
730	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
731	depends on !FTRACE_MCOUNT_USE_CC
732	depends on FTRACE_MCOUNT_RECORD
733	select OBJTOOL
734
735config FTRACE_MCOUNT_USE_RECORDMCOUNT
736	def_bool y
737	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
738	depends on !FTRACE_MCOUNT_USE_CC
739	depends on !FTRACE_MCOUNT_USE_OBJTOOL
740	depends on FTRACE_MCOUNT_RECORD
741
742config TRACING_MAP
743	bool
744	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
745	help
746	  tracing_map is a special-purpose lock-free map for tracing,
747	  separated out as a stand-alone facility in order to allow it
748	  to be shared between multiple tracers.  It isn't meant to be
749	  generally used outside of that context, and is normally
750	  selected by tracers that use it.
751
752config SYNTH_EVENTS
753	bool "Synthetic trace events"
754	select TRACING
755	select DYNAMIC_EVENTS
756	default n
757	help
758	  Synthetic events are user-defined trace events that can be
759	  used to combine data from other trace events or in fact any
760	  data source.  Synthetic events can be generated indirectly
761	  via the trace() action of histogram triggers or directly
762	  by way of an in-kernel API.
763
764	  See Documentation/trace/events.rst or
765	  Documentation/trace/histogram.rst for details and examples.
766
767	  If in doubt, say N.
768
769config USER_EVENTS
770	bool "User trace events"
771	select TRACING
772	select DYNAMIC_EVENTS
773	depends on BROKEN || COMPILE_TEST # API needs to be straighten out
774	help
775	  User trace events are user-defined trace events that
776	  can be used like an existing kernel trace event.  User trace
777	  events are generated by writing to a tracefs file.  User
778	  processes can determine if their tracing events should be
779	  generated by memory mapping a tracefs file and checking for
780	  an associated byte being non-zero.
781
782	  If in doubt, say N.
783
784config HIST_TRIGGERS
785	bool "Histogram triggers"
786	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
787	select TRACING_MAP
788	select TRACING
789	select DYNAMIC_EVENTS
790	select SYNTH_EVENTS
791	default n
792	help
793	  Hist triggers allow one or more arbitrary trace event fields
794	  to be aggregated into hash tables and dumped to stdout by
795	  reading a debugfs/tracefs file.  They're useful for
796	  gathering quick and dirty (though precise) summaries of
797	  event activity as an initial guide for further investigation
798	  using more advanced tools.
799
800	  Inter-event tracing of quantities such as latencies is also
801	  supported using hist triggers under this option.
802
803	  See Documentation/trace/histogram.rst.
804	  If in doubt, say N.
805
806config TRACE_EVENT_INJECT
807	bool "Trace event injection"
808	depends on TRACING
809	help
810	  Allow user-space to inject a specific trace event into the ring
811	  buffer. This is mainly used for testing purpose.
812
813	  If unsure, say N.
814
815config TRACEPOINT_BENCHMARK
816	bool "Add tracepoint that benchmarks tracepoints"
817	help
818	 This option creates the tracepoint "benchmark:benchmark_event".
819	 When the tracepoint is enabled, it kicks off a kernel thread that
820	 goes into an infinite loop (calling cond_resched() to let other tasks
821	 run), and calls the tracepoint. Each iteration will record the time
822	 it took to write to the tracepoint and the next iteration that
823	 data will be passed to the tracepoint itself. That is, the tracepoint
824	 will report the time it took to do the previous tracepoint.
825	 The string written to the tracepoint is a static string of 128 bytes
826	 to keep the time the same. The initial string is simply a write of
827	 "START". The second string records the cold cache time of the first
828	 write which is not added to the rest of the calculations.
829
830	 As it is a tight loop, it benchmarks as hot cache. That's fine because
831	 we care most about hot paths that are probably in cache already.
832
833	 An example of the output:
834
835	      START
836	      first=3672 [COLD CACHED]
837	      last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
838	      last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
839	      last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
840	      last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
841	      last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
842	      last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
843
844
845config RING_BUFFER_BENCHMARK
846	tristate "Ring buffer benchmark stress tester"
847	depends on RING_BUFFER
848	help
849	  This option creates a test to stress the ring buffer and benchmark it.
850	  It creates its own ring buffer such that it will not interfere with
851	  any other users of the ring buffer (such as ftrace). It then creates
852	  a producer and consumer that will run for 10 seconds and sleep for
853	  10 seconds. Each interval it will print out the number of events
854	  it recorded and give a rough estimate of how long each iteration took.
855
856	  It does not disable interrupts or raise its priority, so it may be
857	  affected by processes that are running.
858
859	  If unsure, say N.
860
861config TRACE_EVAL_MAP_FILE
862       bool "Show eval mappings for trace events"
863       depends on TRACING
864       help
865	The "print fmt" of the trace events will show the enum/sizeof names
866	instead of their values. This can cause problems for user space tools
867	that use this string to parse the raw data as user space does not know
868	how to convert the string to its value.
869
870	To fix this, there's a special macro in the kernel that can be used
871	to convert an enum/sizeof into its value. If this macro is used, then
872	the print fmt strings will be converted to their values.
873
874	If something does not get converted properly, this option can be
875	used to show what enums/sizeof the kernel tried to convert.
876
877	This option is for debugging the conversions. A file is created
878	in the tracing directory called "eval_map" that will show the
879	names matched with their values and what trace event system they
880	belong too.
881
882	Normally, the mapping of the strings to values will be freed after
883	boot up or module load. With this option, they will not be freed, as
884	they are needed for the "eval_map" file. Enabling this option will
885	increase the memory footprint of the running kernel.
886
887	If unsure, say N.
888
889config FTRACE_RECORD_RECURSION
890	bool "Record functions that recurse in function tracing"
891	depends on FUNCTION_TRACER
892	help
893	  All callbacks that attach to the function tracing have some sort
894	  of protection against recursion. Even though the protection exists,
895	  it adds overhead. This option will create a file in the tracefs
896	  file system called "recursed_functions" that will list the functions
897	  that triggered a recursion.
898
899	  This will add more overhead to cases that have recursion.
900
901	  If unsure, say N
902
903config FTRACE_RECORD_RECURSION_SIZE
904	int "Max number of recursed functions to record"
905	default	128
906	depends on FTRACE_RECORD_RECURSION
907	help
908	  This defines the limit of number of functions that can be
909	  listed in the "recursed_functions" file, that lists all
910	  the functions that caused a recursion to happen.
911	  This file can be reset, but the limit can not change in
912	  size at runtime.
913
914config RING_BUFFER_RECORD_RECURSION
915	bool "Record functions that recurse in the ring buffer"
916	depends on FTRACE_RECORD_RECURSION
917	# default y, because it is coupled with FTRACE_RECORD_RECURSION
918	default y
919	help
920	  The ring buffer has its own internal recursion. Although when
921	  recursion happens it wont cause harm because of the protection,
922	  but it does cause an unwanted overhead. Enabling this option will
923	  place where recursion was detected into the ftrace "recursed_functions"
924	  file.
925
926	  This will add more overhead to cases that have recursion.
927
928config GCOV_PROFILE_FTRACE
929	bool "Enable GCOV profiling on ftrace subsystem"
930	depends on GCOV_KERNEL
931	help
932	  Enable GCOV profiling on ftrace subsystem for checking
933	  which functions/lines are tested.
934
935	  If unsure, say N.
936
937	  Note that on a kernel compiled with this config, ftrace will
938	  run significantly slower.
939
940config FTRACE_SELFTEST
941	bool
942
943config FTRACE_STARTUP_TEST
944	bool "Perform a startup test on ftrace"
945	depends on GENERIC_TRACER
946	select FTRACE_SELFTEST
947	help
948	  This option performs a series of startup tests on ftrace. On bootup
949	  a series of tests are made to verify that the tracer is
950	  functioning properly. It will do tests on all the configured
951	  tracers of ftrace.
952
953config EVENT_TRACE_STARTUP_TEST
954	bool "Run selftest on trace events"
955	depends on FTRACE_STARTUP_TEST
956	default y
957	help
958	  This option performs a test on all trace events in the system.
959	  It basically just enables each event and runs some code that
960	  will trigger events (not necessarily the event it enables)
961	  This may take some time run as there are a lot of events.
962
963config EVENT_TRACE_TEST_SYSCALLS
964	bool "Run selftest on syscall events"
965	depends on EVENT_TRACE_STARTUP_TEST
966	help
967	 This option will also enable testing every syscall event.
968	 It only enables the event and disables it and runs various loads
969	 with the event enabled. This adds a bit more time for kernel boot
970	 up since it runs this on every system call defined.
971
972	 TBD - enable a way to actually call the syscalls as we test their
973	       events
974
975config FTRACE_SORT_STARTUP_TEST
976       bool "Verify compile time sorting of ftrace functions"
977       depends on DYNAMIC_FTRACE
978       depends on BUILDTIME_MCOUNT_SORT
979       help
980	 Sorting of the mcount_loc sections that is used to find the
981	 where the ftrace knows where to patch functions for tracing
982	 and other callbacks is done at compile time. But if the sort
983	 is not done correctly, it will cause non-deterministic failures.
984	 When this is set, the sorted sections will be verified that they
985	 are in deed sorted and will warn if they are not.
986
987	 If unsure, say N
988
989config RING_BUFFER_STARTUP_TEST
990       bool "Ring buffer startup self test"
991       depends on RING_BUFFER
992       help
993	 Run a simple self test on the ring buffer on boot up. Late in the
994	 kernel boot sequence, the test will start that kicks off
995	 a thread per cpu. Each thread will write various size events
996	 into the ring buffer. Another thread is created to send IPIs
997	 to each of the threads, where the IPI handler will also write
998	 to the ring buffer, to test/stress the nesting ability.
999	 If any anomalies are discovered, a warning will be displayed
1000	 and all ring buffers will be disabled.
1001
1002	 The test runs for 10 seconds. This will slow your boot time
1003	 by at least 10 more seconds.
1004
1005	 At the end of the test, statics and more checks are done.
1006	 It will output the stats of each per cpu buffer. What
1007	 was written, the sizes, what was read, what was lost, and
1008	 other similar details.
1009
1010	 If unsure, say N
1011
1012config RING_BUFFER_VALIDATE_TIME_DELTAS
1013	bool "Verify ring buffer time stamp deltas"
1014	depends on RING_BUFFER
1015	help
1016	  This will audit the time stamps on the ring buffer sub
1017	  buffer to make sure that all the time deltas for the
1018	  events on a sub buffer matches the current time stamp.
1019	  This audit is performed for every event that is not
1020	  interrupted, or interrupting another event. A check
1021	  is also made when traversing sub buffers to make sure
1022	  that all the deltas on the previous sub buffer do not
1023	  add up to be greater than the current time stamp.
1024
1025	  NOTE: This adds significant overhead to recording of events,
1026	  and should only be used to test the logic of the ring buffer.
1027	  Do not use it on production systems.
1028
1029	  Only say Y if you understand what this does, and you
1030	  still want it enabled. Otherwise say N
1031
1032config MMIOTRACE_TEST
1033	tristate "Test module for mmiotrace"
1034	depends on MMIOTRACE && m
1035	help
1036	  This is a dumb module for testing mmiotrace. It is very dangerous
1037	  as it will write garbage to IO memory starting at a given address.
1038	  However, it should be safe to use on e.g. unused portion of VRAM.
1039
1040	  Say N, unless you absolutely know what you are doing.
1041
1042config PREEMPTIRQ_DELAY_TEST
1043	tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
1044	depends on m
1045	help
1046	  Select this option to build a test module that can help test latency
1047	  tracers by executing a preempt or irq disable section with a user
1048	  configurable delay. The module busy waits for the duration of the
1049	  critical section.
1050
1051	  For example, the following invocation generates a burst of three
1052	  irq-disabled critical sections for 500us:
1053	  modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
1054
1055	  What's more, if you want to attach the test on the cpu which the latency
1056	  tracer is running on, specify cpu_affinity=cpu_num at the end of the
1057	  command.
1058
1059	  If unsure, say N
1060
1061config SYNTH_EVENT_GEN_TEST
1062	tristate "Test module for in-kernel synthetic event generation"
1063	depends on SYNTH_EVENTS
1064	help
1065          This option creates a test module to check the base
1066          functionality of in-kernel synthetic event definition and
1067          generation.
1068
1069          To test, insert the module, and then check the trace buffer
1070	  for the generated sample events.
1071
1072	  If unsure, say N.
1073
1074config KPROBE_EVENT_GEN_TEST
1075	tristate "Test module for in-kernel kprobe event generation"
1076	depends on KPROBE_EVENTS
1077	help
1078          This option creates a test module to check the base
1079          functionality of in-kernel kprobe event definition.
1080
1081          To test, insert the module, and then check the trace buffer
1082	  for the generated kprobe events.
1083
1084	  If unsure, say N.
1085
1086config HIST_TRIGGERS_DEBUG
1087	bool "Hist trigger debug support"
1088	depends on HIST_TRIGGERS
1089	help
1090          Add "hist_debug" file for each event, which when read will
1091          dump out a bunch of internal details about the hist triggers
1092          defined on that event.
1093
1094          The hist_debug file serves a couple of purposes:
1095
1096            - Helps developers verify that nothing is broken.
1097
1098            - Provides educational information to support the details
1099              of the hist trigger internals as described by
1100              Documentation/trace/histogram-design.rst.
1101
1102          The hist_debug output only covers the data structures
1103          related to the histogram definitions themselves and doesn't
1104          display the internals of map buckets or variable values of
1105          running histograms.
1106
1107          If unsure, say N.
1108
1109endif # FTRACE
1110