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_CALL_OPS
46	bool
47
48config HAVE_DYNAMIC_FTRACE_WITH_ARGS
49	bool
50	help
51	 If this is set, then arguments and stack can be found from
52	 the ftrace_regs passed into the function callback regs parameter
53	 by default, even without setting the REGS flag in the ftrace_ops.
54	 This allows for use of ftrace_regs_get_argument() and
55	 ftrace_regs_get_stack_pointer().
56
57config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
58	bool
59	help
60	  If the architecture generates __patchable_function_entries sections
61	  but does not want them included in the ftrace locations.
62
63config HAVE_FTRACE_MCOUNT_RECORD
64	bool
65	help
66	  See Documentation/trace/ftrace-design.rst
67
68config HAVE_SYSCALL_TRACEPOINTS
69	bool
70	help
71	  See Documentation/trace/ftrace-design.rst
72
73config HAVE_FENTRY
74	bool
75	help
76	  Arch supports the gcc options -pg with -mfentry
77
78config HAVE_NOP_MCOUNT
79	bool
80	help
81	  Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
82
83config HAVE_OBJTOOL_MCOUNT
84	bool
85	help
86	  Arch supports objtool --mcount
87
88config HAVE_OBJTOOL_NOP_MCOUNT
89	bool
90	help
91	  Arch supports the objtool options --mcount with --mnop.
92	  An architecture can select this if it wants to enable nop'ing
93	  of ftrace locations.
94
95config HAVE_C_RECORDMCOUNT
96	bool
97	help
98	  C version of recordmcount available?
99
100config HAVE_BUILDTIME_MCOUNT_SORT
101       bool
102       help
103         An architecture selects this if it sorts the mcount_loc section
104	 at build time.
105
106config BUILDTIME_MCOUNT_SORT
107       bool
108       default y
109       depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE
110       help
111         Sort the mcount_loc section at build time.
112
113config TRACER_MAX_TRACE
114	bool
115
116config TRACE_CLOCK
117	bool
118
119config RING_BUFFER
120	bool
121	select TRACE_CLOCK
122	select IRQ_WORK
123
124config EVENT_TRACING
125	select CONTEXT_SWITCH_TRACER
126	select GLOB
127	bool
128
129config CONTEXT_SWITCH_TRACER
130	bool
131
132config RING_BUFFER_ALLOW_SWAP
133	bool
134	help
135	 Allow the use of ring_buffer_swap_cpu.
136	 Adds a very slight overhead to tracing when enabled.
137
138config PREEMPTIRQ_TRACEPOINTS
139	bool
140	depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
141	select TRACING
142	default y
143	help
144	  Create preempt/irq toggle tracepoints if needed, so that other parts
145	  of the kernel can use them to generate or add hooks to them.
146
147# All tracer options should select GENERIC_TRACER. For those options that are
148# enabled by all tracers (context switch and event tracer) they select TRACING.
149# This allows those options to appear when no other tracer is selected. But the
150# options do not appear when something else selects it. We need the two options
151# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
152# hiding of the automatic options.
153
154config TRACING
155	bool
156	select RING_BUFFER
157	select STACKTRACE if STACKTRACE_SUPPORT
158	select TRACEPOINTS
159	select NOP_TRACER
160	select BINARY_PRINTF
161	select EVENT_TRACING
162	select TRACE_CLOCK
163	select TASKS_RCU if PREEMPTION
164
165config GENERIC_TRACER
166	bool
167	select TRACING
168
169#
170# Minimum requirements an architecture has to meet for us to
171# be able to offer generic tracing facilities:
172#
173config TRACING_SUPPORT
174	bool
175	depends on TRACE_IRQFLAGS_SUPPORT
176	depends on STACKTRACE_SUPPORT
177	default y
178
179menuconfig FTRACE
180	bool "Tracers"
181	depends on TRACING_SUPPORT
182	default y if DEBUG_KERNEL
183	help
184	  Enable the kernel tracing infrastructure.
185
186if FTRACE
187
188config BOOTTIME_TRACING
189	bool "Boot-time Tracing support"
190	depends on TRACING
191	select BOOT_CONFIG
192	help
193	  Enable developer to setup ftrace subsystem via supplemental
194	  kernel cmdline at boot time for debugging (tracing) driver
195	  initialization and boot process.
196
197config FUNCTION_TRACER
198	bool "Kernel Function Tracer"
199	depends on HAVE_FUNCTION_TRACER
200	select KALLSYMS
201	select GENERIC_TRACER
202	select CONTEXT_SWITCH_TRACER
203	select GLOB
204	select TASKS_RCU if PREEMPTION
205	select TASKS_RUDE_RCU
206	help
207	  Enable the kernel to trace every kernel function. This is done
208	  by using a compiler feature to insert a small, 5-byte No-Operation
209	  instruction at the beginning of every kernel function, which NOP
210	  sequence is then dynamically patched into a tracer call when
211	  tracing is enabled by the administrator. If it's runtime disabled
212	  (the bootup default), then the overhead of the instructions is very
213	  small and not measurable even in micro-benchmarks (at least on
214	  x86, but may have impact on other architectures).
215
216config FUNCTION_GRAPH_TRACER
217	bool "Kernel Function Graph Tracer"
218	depends on HAVE_FUNCTION_GRAPH_TRACER
219	depends on FUNCTION_TRACER
220	depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
221	default y
222	help
223	  Enable the kernel to trace a function at both its return
224	  and its entry.
225	  Its first purpose is to trace the duration of functions and
226	  draw a call graph for each thread with some information like
227	  the return value. This is done by setting the current return
228	  address on the current task structure into a stack of calls.
229
230config DYNAMIC_FTRACE
231	bool "enable/disable function tracing dynamically"
232	depends on FUNCTION_TRACER
233	depends on HAVE_DYNAMIC_FTRACE
234	default y
235	help
236	  This option will modify all the calls to function tracing
237	  dynamically (will patch them out of the binary image and
238	  replace them with a No-Op instruction) on boot up. During
239	  compile time, a table is made of all the locations that ftrace
240	  can function trace, and this table is linked into the kernel
241	  image. When this is enabled, functions can be individually
242	  enabled, and the functions not enabled will not affect
243	  performance of the system.
244
245	  See the files in /sys/kernel/tracing:
246	    available_filter_functions
247	    set_ftrace_filter
248	    set_ftrace_notrace
249
250	  This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
251	  otherwise has native performance as long as no tracing is active.
252
253config DYNAMIC_FTRACE_WITH_REGS
254	def_bool y
255	depends on DYNAMIC_FTRACE
256	depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
257
258config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
259	def_bool y
260	depends on DYNAMIC_FTRACE_WITH_REGS
261	depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
262
263config DYNAMIC_FTRACE_WITH_CALL_OPS
264	def_bool y
265	depends on HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
266
267config DYNAMIC_FTRACE_WITH_ARGS
268	def_bool y
269	depends on DYNAMIC_FTRACE
270	depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
271
272config FPROBE
273	bool "Kernel Function Probe (fprobe)"
274	depends on FUNCTION_TRACER
275	depends on DYNAMIC_FTRACE_WITH_REGS
276	depends on HAVE_RETHOOK
277	select RETHOOK
278	default n
279	help
280	  This option enables kernel function probe (fprobe) based on ftrace.
281	  The fprobe is similar to kprobes, but probes only for kernel function
282	  entries and exits. This also can probe multiple functions by one
283	  fprobe.
284
285	  If unsure, say N.
286
287config FUNCTION_PROFILER
288	bool "Kernel function profiler"
289	depends on FUNCTION_TRACER
290	default n
291	help
292	  This option enables the kernel function profiler. A file is created
293	  in debugfs called function_profile_enabled which defaults to zero.
294	  When a 1 is echoed into this file profiling begins, and when a
295	  zero is entered, profiling stops. A "functions" file is created in
296	  the trace_stat directory; this file shows the list of functions that
297	  have been hit and their counters.
298
299	  If in doubt, say N.
300
301config STACK_TRACER
302	bool "Trace max stack"
303	depends on HAVE_FUNCTION_TRACER
304	select FUNCTION_TRACER
305	select STACKTRACE
306	select KALLSYMS
307	help
308	  This special tracer records the maximum stack footprint of the
309	  kernel and displays it in /sys/kernel/tracing/stack_trace.
310
311	  This tracer works by hooking into every function call that the
312	  kernel executes, and keeping a maximum stack depth value and
313	  stack-trace saved.  If this is configured with DYNAMIC_FTRACE
314	  then it will not have any overhead while the stack tracer
315	  is disabled.
316
317	  To enable the stack tracer on bootup, pass in 'stacktrace'
318	  on the kernel command line.
319
320	  The stack tracer can also be enabled or disabled via the
321	  sysctl kernel.stack_tracer_enabled
322
323	  Say N if unsure.
324
325config TRACE_PREEMPT_TOGGLE
326	bool
327	help
328	  Enables hooks which will be called when preemption is first disabled,
329	  and last enabled.
330
331config IRQSOFF_TRACER
332	bool "Interrupts-off Latency Tracer"
333	default n
334	depends on TRACE_IRQFLAGS_SUPPORT
335	select TRACE_IRQFLAGS
336	select GENERIC_TRACER
337	select TRACER_MAX_TRACE
338	select RING_BUFFER_ALLOW_SWAP
339	select TRACER_SNAPSHOT
340	select TRACER_SNAPSHOT_PER_CPU_SWAP
341	help
342	  This option measures the time spent in irqs-off critical
343	  sections, with microsecond accuracy.
344
345	  The default measurement method is a maximum search, which is
346	  disabled by default and can be runtime (re-)started
347	  via:
348
349	      echo 0 > /sys/kernel/tracing/tracing_max_latency
350
351	  (Note that kernel size and overhead increase with this option
352	  enabled. This option and the preempt-off timing option can be
353	  used together or separately.)
354
355config PREEMPT_TRACER
356	bool "Preemption-off Latency Tracer"
357	default n
358	depends on PREEMPTION
359	select GENERIC_TRACER
360	select TRACER_MAX_TRACE
361	select RING_BUFFER_ALLOW_SWAP
362	select TRACER_SNAPSHOT
363	select TRACER_SNAPSHOT_PER_CPU_SWAP
364	select TRACE_PREEMPT_TOGGLE
365	help
366	  This option measures the time spent in preemption-off critical
367	  sections, with microsecond accuracy.
368
369	  The default measurement method is a maximum search, which is
370	  disabled by default and can be runtime (re-)started
371	  via:
372
373	      echo 0 > /sys/kernel/tracing/tracing_max_latency
374
375	  (Note that kernel size and overhead increase with this option
376	  enabled. This option and the irqs-off timing option can be
377	  used together or separately.)
378
379config SCHED_TRACER
380	bool "Scheduling Latency Tracer"
381	select GENERIC_TRACER
382	select CONTEXT_SWITCH_TRACER
383	select TRACER_MAX_TRACE
384	select TRACER_SNAPSHOT
385	help
386	  This tracer tracks the latency of the highest priority task
387	  to be scheduled in, starting from the point it has woken up.
388
389config HWLAT_TRACER
390	bool "Tracer to detect hardware latencies (like SMIs)"
391	select GENERIC_TRACER
392	select TRACER_MAX_TRACE
393	help
394	 This tracer, when enabled will create one or more kernel threads,
395	 depending on what the cpumask file is set to, which each thread
396	 spinning in a loop looking for interruptions caused by
397	 something other than the kernel. For example, if a
398	 System Management Interrupt (SMI) takes a noticeable amount of
399	 time, this tracer will detect it. This is useful for testing
400	 if a system is reliable for Real Time tasks.
401
402	 Some files are created in the tracing directory when this
403	 is enabled:
404
405	   hwlat_detector/width   - time in usecs for how long to spin for
406	   hwlat_detector/window  - time in usecs between the start of each
407				     iteration
408
409	 A kernel thread is created that will spin with interrupts disabled
410	 for "width" microseconds in every "window" cycle. It will not spin
411	 for "window - width" microseconds, where the system can
412	 continue to operate.
413
414	 The output will appear in the trace and trace_pipe files.
415
416	 When the tracer is not running, it has no affect on the system,
417	 but when it is running, it can cause the system to be
418	 periodically non responsive. Do not run this tracer on a
419	 production system.
420
421	 To enable this tracer, echo in "hwlat" into the current_tracer
422	 file. Every time a latency is greater than tracing_thresh, it will
423	 be recorded into the ring buffer.
424
425config OSNOISE_TRACER
426	bool "OS Noise tracer"
427	select GENERIC_TRACER
428	select TRACER_MAX_TRACE
429	help
430	  In the context of high-performance computing (HPC), the Operating
431	  System Noise (osnoise) refers to the interference experienced by an
432	  application due to activities inside the operating system. In the
433	  context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
434	  can cause noise to the system. Moreover, hardware-related jobs can
435	  also cause noise, for example, via SMIs.
436
437	  The osnoise tracer leverages the hwlat_detector by running a similar
438	  loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
439	  the sources of osnoise during its execution. The osnoise tracer takes
440	  note of the entry and exit point of any source of interferences,
441	  increasing a per-cpu interference counter. It saves an interference
442	  counter for each source of interference. The interference counter for
443	  NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
444	  observes these interferences' entry events. When a noise happens
445	  without any interference from the operating system level, the
446	  hardware noise counter increases, pointing to a hardware-related
447	  noise. In this way, osnoise can account for any source of
448	  interference. At the end of the period, the osnoise tracer prints
449	  the sum of all noise, the max single noise, the percentage of CPU
450	  available for the thread, and the counters for the noise sources.
451
452	  In addition to the tracer, a set of tracepoints were added to
453	  facilitate the identification of the osnoise source.
454
455	  The output will appear in the trace and trace_pipe files.
456
457	  To enable this tracer, echo in "osnoise" into the current_tracer
458          file.
459
460config TIMERLAT_TRACER
461	bool "Timerlat tracer"
462	select OSNOISE_TRACER
463	select GENERIC_TRACER
464	help
465	  The timerlat tracer aims to help the preemptive kernel developers
466	  to find sources of wakeup latencies of real-time threads.
467
468	  The tracer creates a per-cpu kernel thread with real-time priority.
469	  The tracer thread sets a periodic timer to wakeup itself, and goes
470	  to sleep waiting for the timer to fire. At the wakeup, the thread
471	  then computes a wakeup latency value as the difference between
472	  the current time and the absolute time that the timer was set
473	  to expire.
474
475	  The tracer prints two lines at every activation. The first is the
476	  timer latency observed at the hardirq context before the
477	  activation of the thread. The second is the timer latency observed
478	  by the thread, which is the same level that cyclictest reports. The
479	  ACTIVATION ID field serves to relate the irq execution to its
480	  respective thread execution.
481
482	  The tracer is build on top of osnoise tracer, and the osnoise:
483	  events can be used to trace the source of interference from NMI,
484	  IRQs and other threads. It also enables the capture of the
485	  stacktrace at the IRQ context, which helps to identify the code
486	  path that can cause thread delay.
487
488config MMIOTRACE
489	bool "Memory mapped IO tracing"
490	depends on HAVE_MMIOTRACE_SUPPORT && PCI
491	select GENERIC_TRACER
492	help
493	  Mmiotrace traces Memory Mapped I/O access and is meant for
494	  debugging and reverse engineering. It is called from the ioremap
495	  implementation and works via page faults. Tracing is disabled by
496	  default and can be enabled at run-time.
497
498	  See Documentation/trace/mmiotrace.rst.
499	  If you are not helping to develop drivers, say N.
500
501config ENABLE_DEFAULT_TRACERS
502	bool "Trace process context switches and events"
503	depends on !GENERIC_TRACER
504	select TRACING
505	help
506	  This tracer hooks to various trace points in the kernel,
507	  allowing the user to pick and choose which trace point they
508	  want to trace. It also includes the sched_switch tracer plugin.
509
510config FTRACE_SYSCALLS
511	bool "Trace syscalls"
512	depends on HAVE_SYSCALL_TRACEPOINTS
513	select GENERIC_TRACER
514	select KALLSYMS
515	help
516	  Basic tracer to catch the syscall entry and exit events.
517
518config TRACER_SNAPSHOT
519	bool "Create a snapshot trace buffer"
520	select TRACER_MAX_TRACE
521	help
522	  Allow tracing users to take snapshot of the current buffer using the
523	  ftrace interface, e.g.:
524
525	      echo 1 > /sys/kernel/tracing/snapshot
526	      cat snapshot
527
528config TRACER_SNAPSHOT_PER_CPU_SWAP
529	bool "Allow snapshot to swap per CPU"
530	depends on TRACER_SNAPSHOT
531	select RING_BUFFER_ALLOW_SWAP
532	help
533	  Allow doing a snapshot of a single CPU buffer instead of a
534	  full swap (all buffers). If this is set, then the following is
535	  allowed:
536
537	      echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot
538
539	  After which, only the tracing buffer for CPU 2 was swapped with
540	  the main tracing buffer, and the other CPU buffers remain the same.
541
542	  When this is enabled, this adds a little more overhead to the
543	  trace recording, as it needs to add some checks to synchronize
544	  recording with swaps. But this does not affect the performance
545	  of the overall system. This is enabled by default when the preempt
546	  or irq latency tracers are enabled, as those need to swap as well
547	  and already adds the overhead (plus a lot more).
548
549config TRACE_BRANCH_PROFILING
550	bool
551	select GENERIC_TRACER
552
553choice
554	prompt "Branch Profiling"
555	default BRANCH_PROFILE_NONE
556	help
557	 The branch profiling is a software profiler. It will add hooks
558	 into the C conditionals to test which path a branch takes.
559
560	 The likely/unlikely profiler only looks at the conditions that
561	 are annotated with a likely or unlikely macro.
562
563	 The "all branch" profiler will profile every if-statement in the
564	 kernel. This profiler will also enable the likely/unlikely
565	 profiler.
566
567	 Either of the above profilers adds a bit of overhead to the system.
568	 If unsure, choose "No branch profiling".
569
570config BRANCH_PROFILE_NONE
571	bool "No branch profiling"
572	help
573	  No branch profiling. Branch profiling adds a bit of overhead.
574	  Only enable it if you want to analyse the branching behavior.
575	  Otherwise keep it disabled.
576
577config PROFILE_ANNOTATED_BRANCHES
578	bool "Trace likely/unlikely profiler"
579	select TRACE_BRANCH_PROFILING
580	help
581	  This tracer profiles all likely and unlikely macros
582	  in the kernel. It will display the results in:
583
584	  /sys/kernel/tracing/trace_stat/branch_annotated
585
586	  Note: this will add a significant overhead; only turn this
587	  on if you need to profile the system's use of these macros.
588
589config PROFILE_ALL_BRANCHES
590	bool "Profile all if conditionals" if !FORTIFY_SOURCE
591	select TRACE_BRANCH_PROFILING
592	help
593	  This tracer profiles all branch conditions. Every if ()
594	  taken in the kernel is recorded whether it hit or miss.
595	  The results will be displayed in:
596
597	  /sys/kernel/tracing/trace_stat/branch_all
598
599	  This option also enables the likely/unlikely profiler.
600
601	  This configuration, when enabled, will impose a great overhead
602	  on the system. This should only be enabled when the system
603	  is to be analyzed in much detail.
604endchoice
605
606config TRACING_BRANCHES
607	bool
608	help
609	  Selected by tracers that will trace the likely and unlikely
610	  conditions. This prevents the tracers themselves from being
611	  profiled. Profiling the tracing infrastructure can only happen
612	  when the likelys and unlikelys are not being traced.
613
614config BRANCH_TRACER
615	bool "Trace likely/unlikely instances"
616	depends on TRACE_BRANCH_PROFILING
617	select TRACING_BRANCHES
618	help
619	  This traces the events of likely and unlikely condition
620	  calls in the kernel.  The difference between this and the
621	  "Trace likely/unlikely profiler" is that this is not a
622	  histogram of the callers, but actually places the calling
623	  events into a running trace buffer to see when and where the
624	  events happened, as well as their results.
625
626	  Say N if unsure.
627
628config BLK_DEV_IO_TRACE
629	bool "Support for tracing block IO actions"
630	depends on SYSFS
631	depends on BLOCK
632	select RELAY
633	select DEBUG_FS
634	select TRACEPOINTS
635	select GENERIC_TRACER
636	select STACKTRACE
637	help
638	  Say Y here if you want to be able to trace the block layer actions
639	  on a given queue. Tracing allows you to see any traffic happening
640	  on a block device queue. For more information (and the userspace
641	  support tools needed), fetch the blktrace tools from:
642
643	  git://git.kernel.dk/blktrace.git
644
645	  Tracing also is possible using the ftrace interface, e.g.:
646
647	    echo 1 > /sys/block/sda/sda1/trace/enable
648	    echo blk > /sys/kernel/tracing/current_tracer
649	    cat /sys/kernel/tracing/trace_pipe
650
651	  If unsure, say N.
652
653config KPROBE_EVENTS
654	depends on KPROBES
655	depends on HAVE_REGS_AND_STACK_ACCESS_API
656	bool "Enable kprobes-based dynamic events"
657	select TRACING
658	select PROBE_EVENTS
659	select DYNAMIC_EVENTS
660	default y
661	help
662	  This allows the user to add tracing events (similar to tracepoints)
663	  on the fly via the ftrace interface. See
664	  Documentation/trace/kprobetrace.rst for more details.
665
666	  Those events can be inserted wherever kprobes can probe, and record
667	  various register and memory values.
668
669	  This option is also required by perf-probe subcommand of perf tools.
670	  If you want to use perf tools, this option is strongly recommended.
671
672config KPROBE_EVENTS_ON_NOTRACE
673	bool "Do NOT protect notrace function from kprobe events"
674	depends on KPROBE_EVENTS
675	depends on DYNAMIC_FTRACE
676	default n
677	help
678	  This is only for the developers who want to debug ftrace itself
679	  using kprobe events.
680
681	  If kprobes can use ftrace instead of breakpoint, ftrace related
682	  functions are protected from kprobe-events to prevent an infinite
683	  recursion or any unexpected execution path which leads to a kernel
684	  crash.
685
686	  This option disables such protection and allows you to put kprobe
687	  events on ftrace functions for debugging ftrace by itself.
688	  Note that this might let you shoot yourself in the foot.
689
690	  If unsure, say N.
691
692config UPROBE_EVENTS
693	bool "Enable uprobes-based dynamic events"
694	depends on ARCH_SUPPORTS_UPROBES
695	depends on MMU
696	depends on PERF_EVENTS
697	select UPROBES
698	select PROBE_EVENTS
699	select DYNAMIC_EVENTS
700	select TRACING
701	default y
702	help
703	  This allows the user to add tracing events on top of userspace
704	  dynamic events (similar to tracepoints) on the fly via the trace
705	  events interface. Those events can be inserted wherever uprobes
706	  can probe, and record various registers.
707	  This option is required if you plan to use perf-probe subcommand
708	  of perf tools on user space applications.
709
710config BPF_EVENTS
711	depends on BPF_SYSCALL
712	depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
713	bool
714	default y
715	help
716	  This allows the user to attach BPF programs to kprobe, uprobe, and
717	  tracepoint events.
718
719config DYNAMIC_EVENTS
720	def_bool n
721
722config PROBE_EVENTS
723	def_bool n
724
725config BPF_KPROBE_OVERRIDE
726	bool "Enable BPF programs to override a kprobed function"
727	depends on BPF_EVENTS
728	depends on FUNCTION_ERROR_INJECTION
729	default n
730	help
731	 Allows BPF to override the execution of a probed function and
732	 set a different return value.  This is used for error injection.
733
734config FTRACE_MCOUNT_RECORD
735	def_bool y
736	depends on DYNAMIC_FTRACE
737	depends on HAVE_FTRACE_MCOUNT_RECORD
738
739config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
740	bool
741	depends on FTRACE_MCOUNT_RECORD
742
743config FTRACE_MCOUNT_USE_CC
744	def_bool y
745	depends on $(cc-option,-mrecord-mcount)
746	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
747	depends on FTRACE_MCOUNT_RECORD
748
749config FTRACE_MCOUNT_USE_OBJTOOL
750	def_bool y
751	depends on HAVE_OBJTOOL_MCOUNT
752	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
753	depends on !FTRACE_MCOUNT_USE_CC
754	depends on FTRACE_MCOUNT_RECORD
755	select OBJTOOL
756
757config FTRACE_MCOUNT_USE_RECORDMCOUNT
758	def_bool y
759	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
760	depends on !FTRACE_MCOUNT_USE_CC
761	depends on !FTRACE_MCOUNT_USE_OBJTOOL
762	depends on FTRACE_MCOUNT_RECORD
763
764config TRACING_MAP
765	bool
766	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
767	help
768	  tracing_map is a special-purpose lock-free map for tracing,
769	  separated out as a stand-alone facility in order to allow it
770	  to be shared between multiple tracers.  It isn't meant to be
771	  generally used outside of that context, and is normally
772	  selected by tracers that use it.
773
774config SYNTH_EVENTS
775	bool "Synthetic trace events"
776	select TRACING
777	select DYNAMIC_EVENTS
778	default n
779	help
780	  Synthetic events are user-defined trace events that can be
781	  used to combine data from other trace events or in fact any
782	  data source.  Synthetic events can be generated indirectly
783	  via the trace() action of histogram triggers or directly
784	  by way of an in-kernel API.
785
786	  See Documentation/trace/events.rst or
787	  Documentation/trace/histogram.rst for details and examples.
788
789	  If in doubt, say N.
790
791config USER_EVENTS
792	bool "User trace events"
793	select TRACING
794	select DYNAMIC_EVENTS
795	depends on BROKEN || COMPILE_TEST # API needs to be straighten out
796	help
797	  User trace events are user-defined trace events that
798	  can be used like an existing kernel trace event.  User trace
799	  events are generated by writing to a tracefs file.  User
800	  processes can determine if their tracing events should be
801	  generated by memory mapping a tracefs file and checking for
802	  an associated byte being non-zero.
803
804	  If in doubt, say N.
805
806config HIST_TRIGGERS
807	bool "Histogram triggers"
808	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
809	select TRACING_MAP
810	select TRACING
811	select DYNAMIC_EVENTS
812	select SYNTH_EVENTS
813	default n
814	help
815	  Hist triggers allow one or more arbitrary trace event fields
816	  to be aggregated into hash tables and dumped to stdout by
817	  reading a debugfs/tracefs file.  They're useful for
818	  gathering quick and dirty (though precise) summaries of
819	  event activity as an initial guide for further investigation
820	  using more advanced tools.
821
822	  Inter-event tracing of quantities such as latencies is also
823	  supported using hist triggers under this option.
824
825	  See Documentation/trace/histogram.rst.
826	  If in doubt, say N.
827
828config TRACE_EVENT_INJECT
829	bool "Trace event injection"
830	depends on TRACING
831	help
832	  Allow user-space to inject a specific trace event into the ring
833	  buffer. This is mainly used for testing purpose.
834
835	  If unsure, say N.
836
837config TRACEPOINT_BENCHMARK
838	bool "Add tracepoint that benchmarks tracepoints"
839	help
840	 This option creates the tracepoint "benchmark:benchmark_event".
841	 When the tracepoint is enabled, it kicks off a kernel thread that
842	 goes into an infinite loop (calling cond_resched() to let other tasks
843	 run), and calls the tracepoint. Each iteration will record the time
844	 it took to write to the tracepoint and the next iteration that
845	 data will be passed to the tracepoint itself. That is, the tracepoint
846	 will report the time it took to do the previous tracepoint.
847	 The string written to the tracepoint is a static string of 128 bytes
848	 to keep the time the same. The initial string is simply a write of
849	 "START". The second string records the cold cache time of the first
850	 write which is not added to the rest of the calculations.
851
852	 As it is a tight loop, it benchmarks as hot cache. That's fine because
853	 we care most about hot paths that are probably in cache already.
854
855	 An example of the output:
856
857	      START
858	      first=3672 [COLD CACHED]
859	      last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
860	      last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
861	      last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
862	      last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
863	      last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
864	      last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
865
866
867config RING_BUFFER_BENCHMARK
868	tristate "Ring buffer benchmark stress tester"
869	depends on RING_BUFFER
870	help
871	  This option creates a test to stress the ring buffer and benchmark it.
872	  It creates its own ring buffer such that it will not interfere with
873	  any other users of the ring buffer (such as ftrace). It then creates
874	  a producer and consumer that will run for 10 seconds and sleep for
875	  10 seconds. Each interval it will print out the number of events
876	  it recorded and give a rough estimate of how long each iteration took.
877
878	  It does not disable interrupts or raise its priority, so it may be
879	  affected by processes that are running.
880
881	  If unsure, say N.
882
883config TRACE_EVAL_MAP_FILE
884       bool "Show eval mappings for trace events"
885       depends on TRACING
886       help
887	The "print fmt" of the trace events will show the enum/sizeof names
888	instead of their values. This can cause problems for user space tools
889	that use this string to parse the raw data as user space does not know
890	how to convert the string to its value.
891
892	To fix this, there's a special macro in the kernel that can be used
893	to convert an enum/sizeof into its value. If this macro is used, then
894	the print fmt strings will be converted to their values.
895
896	If something does not get converted properly, this option can be
897	used to show what enums/sizeof the kernel tried to convert.
898
899	This option is for debugging the conversions. A file is created
900	in the tracing directory called "eval_map" that will show the
901	names matched with their values and what trace event system they
902	belong too.
903
904	Normally, the mapping of the strings to values will be freed after
905	boot up or module load. With this option, they will not be freed, as
906	they are needed for the "eval_map" file. Enabling this option will
907	increase the memory footprint of the running kernel.
908
909	If unsure, say N.
910
911config FTRACE_RECORD_RECURSION
912	bool "Record functions that recurse in function tracing"
913	depends on FUNCTION_TRACER
914	help
915	  All callbacks that attach to the function tracing have some sort
916	  of protection against recursion. Even though the protection exists,
917	  it adds overhead. This option will create a file in the tracefs
918	  file system called "recursed_functions" that will list the functions
919	  that triggered a recursion.
920
921	  This will add more overhead to cases that have recursion.
922
923	  If unsure, say N
924
925config FTRACE_RECORD_RECURSION_SIZE
926	int "Max number of recursed functions to record"
927	default	128
928	depends on FTRACE_RECORD_RECURSION
929	help
930	  This defines the limit of number of functions that can be
931	  listed in the "recursed_functions" file, that lists all
932	  the functions that caused a recursion to happen.
933	  This file can be reset, but the limit can not change in
934	  size at runtime.
935
936config RING_BUFFER_RECORD_RECURSION
937	bool "Record functions that recurse in the ring buffer"
938	depends on FTRACE_RECORD_RECURSION
939	# default y, because it is coupled with FTRACE_RECORD_RECURSION
940	default y
941	help
942	  The ring buffer has its own internal recursion. Although when
943	  recursion happens it won't cause harm because of the protection,
944	  but it does cause unwanted overhead. Enabling this option will
945	  place where recursion was detected into the ftrace "recursed_functions"
946	  file.
947
948	  This will add more overhead to cases that have recursion.
949
950config GCOV_PROFILE_FTRACE
951	bool "Enable GCOV profiling on ftrace subsystem"
952	depends on GCOV_KERNEL
953	help
954	  Enable GCOV profiling on ftrace subsystem for checking
955	  which functions/lines are tested.
956
957	  If unsure, say N.
958
959	  Note that on a kernel compiled with this config, ftrace will
960	  run significantly slower.
961
962config FTRACE_SELFTEST
963	bool
964
965config FTRACE_STARTUP_TEST
966	bool "Perform a startup test on ftrace"
967	depends on GENERIC_TRACER
968	select FTRACE_SELFTEST
969	help
970	  This option performs a series of startup tests on ftrace. On bootup
971	  a series of tests are made to verify that the tracer is
972	  functioning properly. It will do tests on all the configured
973	  tracers of ftrace.
974
975config EVENT_TRACE_STARTUP_TEST
976	bool "Run selftest on trace events"
977	depends on FTRACE_STARTUP_TEST
978	default y
979	help
980	  This option performs a test on all trace events in the system.
981	  It basically just enables each event and runs some code that
982	  will trigger events (not necessarily the event it enables)
983	  This may take some time run as there are a lot of events.
984
985config EVENT_TRACE_TEST_SYSCALLS
986	bool "Run selftest on syscall events"
987	depends on EVENT_TRACE_STARTUP_TEST
988	help
989	 This option will also enable testing every syscall event.
990	 It only enables the event and disables it and runs various loads
991	 with the event enabled. This adds a bit more time for kernel boot
992	 up since it runs this on every system call defined.
993
994	 TBD - enable a way to actually call the syscalls as we test their
995	       events
996
997config FTRACE_SORT_STARTUP_TEST
998       bool "Verify compile time sorting of ftrace functions"
999       depends on DYNAMIC_FTRACE
1000       depends on BUILDTIME_MCOUNT_SORT
1001       help
1002	 Sorting of the mcount_loc sections that is used to find the
1003	 where the ftrace knows where to patch functions for tracing
1004	 and other callbacks is done at compile time. But if the sort
1005	 is not done correctly, it will cause non-deterministic failures.
1006	 When this is set, the sorted sections will be verified that they
1007	 are in deed sorted and will warn if they are not.
1008
1009	 If unsure, say N
1010
1011config RING_BUFFER_STARTUP_TEST
1012       bool "Ring buffer startup self test"
1013       depends on RING_BUFFER
1014       help
1015	 Run a simple self test on the ring buffer on boot up. Late in the
1016	 kernel boot sequence, the test will start that kicks off
1017	 a thread per cpu. Each thread will write various size events
1018	 into the ring buffer. Another thread is created to send IPIs
1019	 to each of the threads, where the IPI handler will also write
1020	 to the ring buffer, to test/stress the nesting ability.
1021	 If any anomalies are discovered, a warning will be displayed
1022	 and all ring buffers will be disabled.
1023
1024	 The test runs for 10 seconds. This will slow your boot time
1025	 by at least 10 more seconds.
1026
1027	 At the end of the test, statistics and more checks are done.
1028	 It will output the stats of each per cpu buffer: What
1029	 was written, the sizes, what was read, what was lost, and
1030	 other similar details.
1031
1032	 If unsure, say N
1033
1034config RING_BUFFER_VALIDATE_TIME_DELTAS
1035	bool "Verify ring buffer time stamp deltas"
1036	depends on RING_BUFFER
1037	help
1038	  This will audit the time stamps on the ring buffer sub
1039	  buffer to make sure that all the time deltas for the
1040	  events on a sub buffer matches the current time stamp.
1041	  This audit is performed for every event that is not
1042	  interrupted, or interrupting another event. A check
1043	  is also made when traversing sub buffers to make sure
1044	  that all the deltas on the previous sub buffer do not
1045	  add up to be greater than the current time stamp.
1046
1047	  NOTE: This adds significant overhead to recording of events,
1048	  and should only be used to test the logic of the ring buffer.
1049	  Do not use it on production systems.
1050
1051	  Only say Y if you understand what this does, and you
1052	  still want it enabled. Otherwise say N
1053
1054config MMIOTRACE_TEST
1055	tristate "Test module for mmiotrace"
1056	depends on MMIOTRACE && m
1057	help
1058	  This is a dumb module for testing mmiotrace. It is very dangerous
1059	  as it will write garbage to IO memory starting at a given address.
1060	  However, it should be safe to use on e.g. unused portion of VRAM.
1061
1062	  Say N, unless you absolutely know what you are doing.
1063
1064config PREEMPTIRQ_DELAY_TEST
1065	tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
1066	depends on m
1067	help
1068	  Select this option to build a test module that can help test latency
1069	  tracers by executing a preempt or irq disable section with a user
1070	  configurable delay. The module busy waits for the duration of the
1071	  critical section.
1072
1073	  For example, the following invocation generates a burst of three
1074	  irq-disabled critical sections for 500us:
1075	  modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
1076
1077	  What's more, if you want to attach the test on the cpu which the latency
1078	  tracer is running on, specify cpu_affinity=cpu_num at the end of the
1079	  command.
1080
1081	  If unsure, say N
1082
1083config SYNTH_EVENT_GEN_TEST
1084	tristate "Test module for in-kernel synthetic event generation"
1085	depends on SYNTH_EVENTS
1086	help
1087          This option creates a test module to check the base
1088          functionality of in-kernel synthetic event definition and
1089          generation.
1090
1091          To test, insert the module, and then check the trace buffer
1092	  for the generated sample events.
1093
1094	  If unsure, say N.
1095
1096config KPROBE_EVENT_GEN_TEST
1097	tristate "Test module for in-kernel kprobe event generation"
1098	depends on KPROBE_EVENTS
1099	help
1100          This option creates a test module to check the base
1101          functionality of in-kernel kprobe event definition.
1102
1103          To test, insert the module, and then check the trace buffer
1104	  for the generated kprobe events.
1105
1106	  If unsure, say N.
1107
1108config HIST_TRIGGERS_DEBUG
1109	bool "Hist trigger debug support"
1110	depends on HIST_TRIGGERS
1111	help
1112          Add "hist_debug" file for each event, which when read will
1113          dump out a bunch of internal details about the hist triggers
1114          defined on that event.
1115
1116          The hist_debug file serves a couple of purposes:
1117
1118            - Helps developers verify that nothing is broken.
1119
1120            - Provides educational information to support the details
1121              of the hist trigger internals as described by
1122              Documentation/trace/histogram-design.rst.
1123
1124          The hist_debug output only covers the data structures
1125          related to the histogram definitions themselves and doesn't
1126          display the internals of map buckets or variable values of
1127          running histograms.
1128
1129          If unsure, say N.
1130
1131source "kernel/trace/rv/Kconfig"
1132
1133endif # FTRACE
1134