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_FUNCTION_GRAPH_RETVAL
  35	bool
  36
  37config HAVE_DYNAMIC_FTRACE
  38	bool
  39	help
  40	  See Documentation/trace/ftrace-design.rst
  41
  42config HAVE_DYNAMIC_FTRACE_WITH_REGS
  43	bool
  44
  45config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
  46	bool
  47
  48config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
  49	bool
  50
  51config HAVE_DYNAMIC_FTRACE_WITH_ARGS
  52	bool
  53	help
  54	 If this is set, then arguments and stack can be found from
  55	 the ftrace_regs passed into the function callback regs parameter
  56	 by default, even without setting the REGS flag in the ftrace_ops.
  57	 This allows for use of ftrace_regs_get_argument() and
  58	 ftrace_regs_get_stack_pointer().
  59
  60config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
  61	bool
  62	help
  63	  If the architecture generates __patchable_function_entries sections
  64	  but does not want them included in the ftrace locations.
  65
  66config HAVE_FTRACE_MCOUNT_RECORD
  67	bool
  68	help
  69	  See Documentation/trace/ftrace-design.rst
  70
  71config HAVE_SYSCALL_TRACEPOINTS
  72	bool
  73	help
  74	  See Documentation/trace/ftrace-design.rst
  75
  76config HAVE_FENTRY
  77	bool
  78	help
  79	  Arch supports the gcc options -pg with -mfentry
  80
  81config HAVE_NOP_MCOUNT
  82	bool
  83	help
  84	  Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
  85
  86config HAVE_OBJTOOL_MCOUNT
  87	bool
  88	help
  89	  Arch supports objtool --mcount
  90
  91config HAVE_OBJTOOL_NOP_MCOUNT
  92	bool
  93	help
  94	  Arch supports the objtool options --mcount with --mnop.
  95	  An architecture can select this if it wants to enable nop'ing
  96	  of ftrace locations.
  97
  98config HAVE_C_RECORDMCOUNT
  99	bool
 100	help
 101	  C version of recordmcount available?
 102
 103config HAVE_BUILDTIME_MCOUNT_SORT
 104       bool
 105       help
 106         An architecture selects this if it sorts the mcount_loc section
 107	 at build time.
 108
 109config BUILDTIME_MCOUNT_SORT
 110       bool
 111       default y
 112       depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE
 113       help
 114         Sort the mcount_loc section at build time.
 115
 116config TRACER_MAX_TRACE
 117	bool
 118
 119config TRACE_CLOCK
 120	bool
 121
 122config RING_BUFFER
 123	bool
 124	select TRACE_CLOCK
 125	select IRQ_WORK
 126
 127config EVENT_TRACING
 128	select CONTEXT_SWITCH_TRACER
 129	select GLOB
 130	bool
 131
 132config CONTEXT_SWITCH_TRACER
 133	bool
 134
 135config RING_BUFFER_ALLOW_SWAP
 136	bool
 137	help
 138	 Allow the use of ring_buffer_swap_cpu.
 139	 Adds a very slight overhead to tracing when enabled.
 140
 141config PREEMPTIRQ_TRACEPOINTS
 142	bool
 143	depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
 144	select TRACING
 145	default y
 146	help
 147	  Create preempt/irq toggle tracepoints if needed, so that other parts
 148	  of the kernel can use them to generate or add hooks to them.
 149
 150# All tracer options should select GENERIC_TRACER. For those options that are
 151# enabled by all tracers (context switch and event tracer) they select TRACING.
 152# This allows those options to appear when no other tracer is selected. But the
 153# options do not appear when something else selects it. We need the two options
 154# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
 155# hiding of the automatic options.
 156
 157config TRACING
 158	bool
 159	select RING_BUFFER
 160	select STACKTRACE if STACKTRACE_SUPPORT
 161	select TRACEPOINTS
 162	select NOP_TRACER
 163	select BINARY_PRINTF
 164	select EVENT_TRACING
 165	select TRACE_CLOCK
 166	select NEED_TASKS_RCU
 167
 168config GENERIC_TRACER
 169	bool
 170	select TRACING
 171
 172#
 173# Minimum requirements an architecture has to meet for us to
 174# be able to offer generic tracing facilities:
 175#
 176config TRACING_SUPPORT
 177	bool
 178	depends on TRACE_IRQFLAGS_SUPPORT
 179	depends on STACKTRACE_SUPPORT
 180	default y
 181
 182menuconfig FTRACE
 183	bool "Tracers"
 184	depends on TRACING_SUPPORT
 185	default y if DEBUG_KERNEL
 186	help
 187	  Enable the kernel tracing infrastructure.
 188
 189if FTRACE
 190
 191config BOOTTIME_TRACING
 192	bool "Boot-time Tracing support"
 193	depends on TRACING
 194	select BOOT_CONFIG
 195	help
 196	  Enable developer to setup ftrace subsystem via supplemental
 197	  kernel cmdline at boot time for debugging (tracing) driver
 198	  initialization and boot process.
 199
 200config FUNCTION_TRACER
 201	bool "Kernel Function Tracer"
 202	depends on HAVE_FUNCTION_TRACER
 203	select KALLSYMS
 204	select GENERIC_TRACER
 205	select CONTEXT_SWITCH_TRACER
 206	select GLOB
 207	select NEED_TASKS_RCU
 208	select TASKS_RUDE_RCU
 209	help
 210	  Enable the kernel to trace every kernel function. This is done
 211	  by using a compiler feature to insert a small, 5-byte No-Operation
 212	  instruction at the beginning of every kernel function, which NOP
 213	  sequence is then dynamically patched into a tracer call when
 214	  tracing is enabled by the administrator. If it's runtime disabled
 215	  (the bootup default), then the overhead of the instructions is very
 216	  small and not measurable even in micro-benchmarks (at least on
 217	  x86, but may have impact on other architectures).
 218
 219config FUNCTION_GRAPH_TRACER
 220	bool "Kernel Function Graph Tracer"
 221	depends on HAVE_FUNCTION_GRAPH_TRACER
 222	depends on FUNCTION_TRACER
 223	depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
 224	default y
 225	help
 226	  Enable the kernel to trace a function at both its return
 227	  and its entry.
 228	  Its first purpose is to trace the duration of functions and
 229	  draw a call graph for each thread with some information like
 230	  the return value. This is done by setting the current return
 231	  address on the current task structure into a stack of calls.
 232
 233config FUNCTION_GRAPH_RETVAL
 234	bool "Kernel Function Graph Return Value"
 235	depends on HAVE_FUNCTION_GRAPH_RETVAL
 236	depends on FUNCTION_GRAPH_TRACER
 237	default n
 238	help
 239	  Support recording and printing the function return value when
 240	  using function graph tracer. It can be helpful to locate functions
 241	  that return errors. This feature is off by default, and you can
 242	  enable it via the trace option funcgraph-retval.
 243	  See Documentation/trace/ftrace.rst
 244
 245config FUNCTION_GRAPH_RETADDR
 246	bool "Kernel Function Graph Return Address"
 247	depends on FUNCTION_GRAPH_TRACER
 248	default n
 249	help
 250	  Support recording and printing the function return address when
 251	  using function graph tracer. It can be helpful to locate code line that
 252	  the function is called. This feature is off by default, and you can
 253	  enable it via the trace option funcgraph-retaddr.
 254
 255config DYNAMIC_FTRACE
 256	bool "enable/disable function tracing dynamically"
 257	depends on FUNCTION_TRACER
 258	depends on HAVE_DYNAMIC_FTRACE
 259	default y
 260	help
 261	  This option will modify all the calls to function tracing
 262	  dynamically (will patch them out of the binary image and
 263	  replace them with a No-Op instruction) on boot up. During
 264	  compile time, a table is made of all the locations that ftrace
 265	  can function trace, and this table is linked into the kernel
 266	  image. When this is enabled, functions can be individually
 267	  enabled, and the functions not enabled will not affect
 268	  performance of the system.
 269
 270	  See the files in /sys/kernel/tracing:
 271	    available_filter_functions
 272	    set_ftrace_filter
 273	    set_ftrace_notrace
 274
 275	  This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 276	  otherwise has native performance as long as no tracing is active.
 277
 278config DYNAMIC_FTRACE_WITH_REGS
 279	def_bool y
 280	depends on DYNAMIC_FTRACE
 281	depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
 282
 283config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 284	def_bool y
 285	depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
 286	depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 287
 288config DYNAMIC_FTRACE_WITH_CALL_OPS
 289	def_bool y
 290	depends on HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
 291
 292config DYNAMIC_FTRACE_WITH_ARGS
 293	def_bool y
 294	depends on DYNAMIC_FTRACE
 295	depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
 296
 297config FPROBE
 298	bool "Kernel Function Probe (fprobe)"
 299	depends on FUNCTION_TRACER
 300	depends on DYNAMIC_FTRACE_WITH_REGS
 301	depends on HAVE_RETHOOK
 302	select RETHOOK
 303	default n
 304	help
 305	  This option enables kernel function probe (fprobe) based on ftrace.
 306	  The fprobe is similar to kprobes, but probes only for kernel function
 307	  entries and exits. This also can probe multiple functions by one
 308	  fprobe.
 309
 310	  If unsure, say N.
 311
 312config FUNCTION_PROFILER
 313	bool "Kernel function profiler"
 314	depends on FUNCTION_TRACER
 315	default n
 316	help
 317	  This option enables the kernel function profiler. A file is created
 318	  in debugfs called function_profile_enabled which defaults to zero.
 319	  When a 1 is echoed into this file profiling begins, and when a
 320	  zero is entered, profiling stops. A "functions" file is created in
 321	  the trace_stat directory; this file shows the list of functions that
 322	  have been hit and their counters.
 323
 324	  If in doubt, say N.
 325
 326config STACK_TRACER
 327	bool "Trace max stack"
 328	depends on HAVE_FUNCTION_TRACER
 329	select FUNCTION_TRACER
 330	select STACKTRACE
 331	select KALLSYMS
 332	help
 333	  This special tracer records the maximum stack footprint of the
 334	  kernel and displays it in /sys/kernel/tracing/stack_trace.
 335
 336	  This tracer works by hooking into every function call that the
 337	  kernel executes, and keeping a maximum stack depth value and
 338	  stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 339	  then it will not have any overhead while the stack tracer
 340	  is disabled.
 341
 342	  To enable the stack tracer on bootup, pass in 'stacktrace'
 343	  on the kernel command line.
 344
 345	  The stack tracer can also be enabled or disabled via the
 346	  sysctl kernel.stack_tracer_enabled
 347
 348	  Say N if unsure.
 349
 350config TRACE_PREEMPT_TOGGLE
 351	bool
 352	help
 353	  Enables hooks which will be called when preemption is first disabled,
 354	  and last enabled.
 355
 356config IRQSOFF_TRACER
 357	bool "Interrupts-off Latency Tracer"
 358	default n
 359	depends on TRACE_IRQFLAGS_SUPPORT
 360	select TRACE_IRQFLAGS
 361	select GENERIC_TRACER
 362	select TRACER_MAX_TRACE
 363	select RING_BUFFER_ALLOW_SWAP
 364	select TRACER_SNAPSHOT
 365	select TRACER_SNAPSHOT_PER_CPU_SWAP
 366	help
 367	  This option measures the time spent in irqs-off critical
 368	  sections, with microsecond accuracy.
 369
 370	  The default measurement method is a maximum search, which is
 371	  disabled by default and can be runtime (re-)started
 372	  via:
 373
 374	      echo 0 > /sys/kernel/tracing/tracing_max_latency
 375
 376	  (Note that kernel size and overhead increase with this option
 377	  enabled. This option and the preempt-off timing option can be
 378	  used together or separately.)
 379
 380config PREEMPT_TRACER
 381	bool "Preemption-off Latency Tracer"
 382	default n
 383	depends on PREEMPTION
 384	select GENERIC_TRACER
 385	select TRACER_MAX_TRACE
 386	select RING_BUFFER_ALLOW_SWAP
 387	select TRACER_SNAPSHOT
 388	select TRACER_SNAPSHOT_PER_CPU_SWAP
 389	select TRACE_PREEMPT_TOGGLE
 390	help
 391	  This option measures the time spent in preemption-off critical
 392	  sections, with microsecond accuracy.
 393
 394	  The default measurement method is a maximum search, which is
 395	  disabled by default and can be runtime (re-)started
 396	  via:
 397
 398	      echo 0 > /sys/kernel/tracing/tracing_max_latency
 399
 400	  (Note that kernel size and overhead increase with this option
 401	  enabled. This option and the irqs-off timing option can be
 402	  used together or separately.)
 403
 404config SCHED_TRACER
 405	bool "Scheduling Latency Tracer"
 406	select GENERIC_TRACER
 407	select CONTEXT_SWITCH_TRACER
 408	select TRACER_MAX_TRACE
 409	select TRACER_SNAPSHOT
 410	help
 411	  This tracer tracks the latency of the highest priority task
 412	  to be scheduled in, starting from the point it has woken up.
 413
 414config HWLAT_TRACER
 415	bool "Tracer to detect hardware latencies (like SMIs)"
 416	select GENERIC_TRACER
 417	select TRACER_MAX_TRACE
 418	help
 419	 This tracer, when enabled will create one or more kernel threads,
 420	 depending on what the cpumask file is set to, which each thread
 421	 spinning in a loop looking for interruptions caused by
 422	 something other than the kernel. For example, if a
 423	 System Management Interrupt (SMI) takes a noticeable amount of
 424	 time, this tracer will detect it. This is useful for testing
 425	 if a system is reliable for Real Time tasks.
 426
 427	 Some files are created in the tracing directory when this
 428	 is enabled:
 429
 430	   hwlat_detector/width   - time in usecs for how long to spin for
 431	   hwlat_detector/window  - time in usecs between the start of each
 432				     iteration
 433
 434	 A kernel thread is created that will spin with interrupts disabled
 435	 for "width" microseconds in every "window" cycle. It will not spin
 436	 for "window - width" microseconds, where the system can
 437	 continue to operate.
 438
 439	 The output will appear in the trace and trace_pipe files.
 440
 441	 When the tracer is not running, it has no affect on the system,
 442	 but when it is running, it can cause the system to be
 443	 periodically non responsive. Do not run this tracer on a
 444	 production system.
 445
 446	 To enable this tracer, echo in "hwlat" into the current_tracer
 447	 file. Every time a latency is greater than tracing_thresh, it will
 448	 be recorded into the ring buffer.
 449
 450config OSNOISE_TRACER
 451	bool "OS Noise tracer"
 452	select GENERIC_TRACER
 453	select TRACER_MAX_TRACE
 454	help
 455	  In the context of high-performance computing (HPC), the Operating
 456	  System Noise (osnoise) refers to the interference experienced by an
 457	  application due to activities inside the operating system. In the
 458	  context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
 459	  can cause noise to the system. Moreover, hardware-related jobs can
 460	  also cause noise, for example, via SMIs.
 461
 462	  The osnoise tracer leverages the hwlat_detector by running a similar
 463	  loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
 464	  the sources of osnoise during its execution. The osnoise tracer takes
 465	  note of the entry and exit point of any source of interferences,
 466	  increasing a per-cpu interference counter. It saves an interference
 467	  counter for each source of interference. The interference counter for
 468	  NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
 469	  observes these interferences' entry events. When a noise happens
 470	  without any interference from the operating system level, the
 471	  hardware noise counter increases, pointing to a hardware-related
 472	  noise. In this way, osnoise can account for any source of
 473	  interference. At the end of the period, the osnoise tracer prints
 474	  the sum of all noise, the max single noise, the percentage of CPU
 475	  available for the thread, and the counters for the noise sources.
 476
 477	  In addition to the tracer, a set of tracepoints were added to
 478	  facilitate the identification of the osnoise source.
 479
 480	  The output will appear in the trace and trace_pipe files.
 481
 482	  To enable this tracer, echo in "osnoise" into the current_tracer
 483          file.
 484
 485config TIMERLAT_TRACER
 486	bool "Timerlat tracer"
 487	select OSNOISE_TRACER
 488	select GENERIC_TRACER
 489	help
 490	  The timerlat tracer aims to help the preemptive kernel developers
 491	  to find sources of wakeup latencies of real-time threads.
 492
 493	  The tracer creates a per-cpu kernel thread with real-time priority.
 494	  The tracer thread sets a periodic timer to wakeup itself, and goes
 495	  to sleep waiting for the timer to fire. At the wakeup, the thread
 496	  then computes a wakeup latency value as the difference between
 497	  the current time and the absolute time that the timer was set
 498	  to expire.
 499
 500	  The tracer prints two lines at every activation. The first is the
 501	  timer latency observed at the hardirq context before the
 502	  activation of the thread. The second is the timer latency observed
 503	  by the thread, which is the same level that cyclictest reports. The
 504	  ACTIVATION ID field serves to relate the irq execution to its
 505	  respective thread execution.
 506
 507	  The tracer is build on top of osnoise tracer, and the osnoise:
 508	  events can be used to trace the source of interference from NMI,
 509	  IRQs and other threads. It also enables the capture of the
 510	  stacktrace at the IRQ context, which helps to identify the code
 511	  path that can cause thread delay.
 512
 513config MMIOTRACE
 514	bool "Memory mapped IO tracing"
 515	depends on HAVE_MMIOTRACE_SUPPORT && PCI
 516	select GENERIC_TRACER
 517	help
 518	  Mmiotrace traces Memory Mapped I/O access and is meant for
 519	  debugging and reverse engineering. It is called from the ioremap
 520	  implementation and works via page faults. Tracing is disabled by
 521	  default and can be enabled at run-time.
 522
 523	  See Documentation/trace/mmiotrace.rst.
 524	  If you are not helping to develop drivers, say N.
 525
 526config ENABLE_DEFAULT_TRACERS
 527	bool "Trace process context switches and events"
 528	depends on !GENERIC_TRACER
 529	select TRACING
 530	help
 531	  This tracer hooks to various trace points in the kernel,
 532	  allowing the user to pick and choose which trace point they
 533	  want to trace. It also includes the sched_switch tracer plugin.
 534
 535config FTRACE_SYSCALLS
 536	bool "Trace syscalls"
 537	depends on HAVE_SYSCALL_TRACEPOINTS
 538	select GENERIC_TRACER
 539	select KALLSYMS
 540	help
 541	  Basic tracer to catch the syscall entry and exit events.
 542
 543config TRACER_SNAPSHOT
 544	bool "Create a snapshot trace buffer"
 545	select TRACER_MAX_TRACE
 546	help
 547	  Allow tracing users to take snapshot of the current buffer using the
 548	  ftrace interface, e.g.:
 549
 550	      echo 1 > /sys/kernel/tracing/snapshot
 551	      cat snapshot
 552
 553config TRACER_SNAPSHOT_PER_CPU_SWAP
 554	bool "Allow snapshot to swap per CPU"
 555	depends on TRACER_SNAPSHOT
 556	select RING_BUFFER_ALLOW_SWAP
 557	help
 558	  Allow doing a snapshot of a single CPU buffer instead of a
 559	  full swap (all buffers). If this is set, then the following is
 560	  allowed:
 561
 562	      echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot
 563
 564	  After which, only the tracing buffer for CPU 2 was swapped with
 565	  the main tracing buffer, and the other CPU buffers remain the same.
 566
 567	  When this is enabled, this adds a little more overhead to the
 568	  trace recording, as it needs to add some checks to synchronize
 569	  recording with swaps. But this does not affect the performance
 570	  of the overall system. This is enabled by default when the preempt
 571	  or irq latency tracers are enabled, as those need to swap as well
 572	  and already adds the overhead (plus a lot more).
 573
 574config TRACE_BRANCH_PROFILING
 575	bool
 576	select GENERIC_TRACER
 577
 578choice
 579	prompt "Branch Profiling"
 580	default BRANCH_PROFILE_NONE
 581	help
 582	 The branch profiling is a software profiler. It will add hooks
 583	 into the C conditionals to test which path a branch takes.
 584
 585	 The likely/unlikely profiler only looks at the conditions that
 586	 are annotated with a likely or unlikely macro.
 587
 588	 The "all branch" profiler will profile every if-statement in the
 589	 kernel. This profiler will also enable the likely/unlikely
 590	 profiler.
 591
 592	 Either of the above profilers adds a bit of overhead to the system.
 593	 If unsure, choose "No branch profiling".
 594
 595config BRANCH_PROFILE_NONE
 596	bool "No branch profiling"
 597	help
 598	  No branch profiling. Branch profiling adds a bit of overhead.
 599	  Only enable it if you want to analyse the branching behavior.
 600	  Otherwise keep it disabled.
 601
 602config PROFILE_ANNOTATED_BRANCHES
 603	bool "Trace likely/unlikely profiler"
 604	select TRACE_BRANCH_PROFILING
 605	help
 606	  This tracer profiles all likely and unlikely macros
 607	  in the kernel. It will display the results in:
 608
 609	  /sys/kernel/tracing/trace_stat/branch_annotated
 610
 611	  Note: this will add a significant overhead; only turn this
 612	  on if you need to profile the system's use of these macros.
 613
 614config PROFILE_ALL_BRANCHES
 615	bool "Profile all if conditionals" if !FORTIFY_SOURCE
 616	select TRACE_BRANCH_PROFILING
 617	help
 618	  This tracer profiles all branch conditions. Every if ()
 619	  taken in the kernel is recorded whether it hit or miss.
 620	  The results will be displayed in:
 621
 622	  /sys/kernel/tracing/trace_stat/branch_all
 623
 624	  This option also enables the likely/unlikely profiler.
 625
 626	  This configuration, when enabled, will impose a great overhead
 627	  on the system. This should only be enabled when the system
 628	  is to be analyzed in much detail.
 629endchoice
 630
 631config TRACING_BRANCHES
 632	bool
 633	help
 634	  Selected by tracers that will trace the likely and unlikely
 635	  conditions. This prevents the tracers themselves from being
 636	  profiled. Profiling the tracing infrastructure can only happen
 637	  when the likelys and unlikelys are not being traced.
 638
 639config BRANCH_TRACER
 640	bool "Trace likely/unlikely instances"
 641	depends on TRACE_BRANCH_PROFILING
 642	select TRACING_BRANCHES
 643	help
 644	  This traces the events of likely and unlikely condition
 645	  calls in the kernel.  The difference between this and the
 646	  "Trace likely/unlikely profiler" is that this is not a
 647	  histogram of the callers, but actually places the calling
 648	  events into a running trace buffer to see when and where the
 649	  events happened, as well as their results.
 650
 651	  Say N if unsure.
 652
 653config BLK_DEV_IO_TRACE
 654	bool "Support for tracing block IO actions"
 655	depends on SYSFS
 656	depends on BLOCK
 657	select RELAY
 658	select DEBUG_FS
 659	select TRACEPOINTS
 660	select GENERIC_TRACER
 661	select STACKTRACE
 662	help
 663	  Say Y here if you want to be able to trace the block layer actions
 664	  on a given queue. Tracing allows you to see any traffic happening
 665	  on a block device queue. For more information (and the userspace
 666	  support tools needed), fetch the blktrace tools from:
 667
 668	  git://git.kernel.dk/blktrace.git
 669
 670	  Tracing also is possible using the ftrace interface, e.g.:
 671
 672	    echo 1 > /sys/block/sda/sda1/trace/enable
 673	    echo blk > /sys/kernel/tracing/current_tracer
 674	    cat /sys/kernel/tracing/trace_pipe
 675
 676	  If unsure, say N.
 677
 678config FPROBE_EVENTS
 679	depends on FPROBE
 680	depends on HAVE_REGS_AND_STACK_ACCESS_API
 681	bool "Enable fprobe-based dynamic events"
 682	select TRACING
 683	select PROBE_EVENTS
 684	select DYNAMIC_EVENTS
 685	default y
 686	help
 687	  This allows user to add tracing events on the function entry and
 688	  exit via ftrace interface. The syntax is same as the kprobe events
 689	  and the kprobe events on function entry and exit will be
 690	  transparently converted to this fprobe events.
 691
 692config PROBE_EVENTS_BTF_ARGS
 693	depends on HAVE_FUNCTION_ARG_ACCESS_API
 694	depends on FPROBE_EVENTS || KPROBE_EVENTS
 695	depends on DEBUG_INFO_BTF && BPF_SYSCALL
 696	bool "Support BTF function arguments for probe events"
 697	default y
 698	help
 699	  The user can specify the arguments of the probe event using the names
 700	  of the arguments of the probed function, when the probe location is a
 701	  kernel function entry or a tracepoint.
 702	  This is available only if BTF (BPF Type Format) support is enabled.
 703
 704config KPROBE_EVENTS
 705	depends on KPROBES
 706	depends on HAVE_REGS_AND_STACK_ACCESS_API
 707	bool "Enable kprobes-based dynamic events"
 708	select TRACING
 709	select PROBE_EVENTS
 710	select DYNAMIC_EVENTS
 711	default y
 712	help
 713	  This allows the user to add tracing events (similar to tracepoints)
 714	  on the fly via the ftrace interface. See
 715	  Documentation/trace/kprobetrace.rst for more details.
 716
 717	  Those events can be inserted wherever kprobes can probe, and record
 718	  various register and memory values.
 719
 720	  This option is also required by perf-probe subcommand of perf tools.
 721	  If you want to use perf tools, this option is strongly recommended.
 722
 723config KPROBE_EVENTS_ON_NOTRACE
 724	bool "Do NOT protect notrace function from kprobe events"
 725	depends on KPROBE_EVENTS
 726	depends on DYNAMIC_FTRACE
 727	default n
 728	help
 729	  This is only for the developers who want to debug ftrace itself
 730	  using kprobe events.
 731
 732	  If kprobes can use ftrace instead of breakpoint, ftrace related
 733	  functions are protected from kprobe-events to prevent an infinite
 734	  recursion or any unexpected execution path which leads to a kernel
 735	  crash.
 736
 737	  This option disables such protection and allows you to put kprobe
 738	  events on ftrace functions for debugging ftrace by itself.
 739	  Note that this might let you shoot yourself in the foot.
 740
 741	  If unsure, say N.
 742
 743config UPROBE_EVENTS
 744	bool "Enable uprobes-based dynamic events"
 745	depends on ARCH_SUPPORTS_UPROBES
 746	depends on MMU
 747	depends on PERF_EVENTS
 748	select UPROBES
 749	select PROBE_EVENTS
 750	select DYNAMIC_EVENTS
 751	select TRACING
 752	default y
 753	help
 754	  This allows the user to add tracing events on top of userspace
 755	  dynamic events (similar to tracepoints) on the fly via the trace
 756	  events interface. Those events can be inserted wherever uprobes
 757	  can probe, and record various registers.
 758	  This option is required if you plan to use perf-probe subcommand
 759	  of perf tools on user space applications.
 760
 761config BPF_EVENTS
 762	depends on BPF_SYSCALL
 763	depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
 764	bool
 765	default y
 766	help
 767	  This allows the user to attach BPF programs to kprobe, uprobe, and
 768	  tracepoint events.
 769
 770config DYNAMIC_EVENTS
 771	def_bool n
 772
 773config PROBE_EVENTS
 774	def_bool n
 775
 776config BPF_KPROBE_OVERRIDE
 777	bool "Enable BPF programs to override a kprobed function"
 778	depends on BPF_EVENTS
 779	depends on FUNCTION_ERROR_INJECTION
 780	default n
 781	help
 782	 Allows BPF to override the execution of a probed function and
 783	 set a different return value.  This is used for error injection.
 784
 785config FTRACE_MCOUNT_RECORD
 786	def_bool y
 787	depends on DYNAMIC_FTRACE
 788	depends on HAVE_FTRACE_MCOUNT_RECORD
 789
 790config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 791	bool
 792	depends on FTRACE_MCOUNT_RECORD
 793
 794config FTRACE_MCOUNT_USE_CC
 795	def_bool y
 796	depends on $(cc-option,-mrecord-mcount)
 797	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 798	depends on FTRACE_MCOUNT_RECORD
 799
 800config FTRACE_MCOUNT_USE_OBJTOOL
 801	def_bool y
 802	depends on HAVE_OBJTOOL_MCOUNT
 803	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 804	depends on !FTRACE_MCOUNT_USE_CC
 805	depends on FTRACE_MCOUNT_RECORD
 806	select OBJTOOL
 807
 808config FTRACE_MCOUNT_USE_RECORDMCOUNT
 809	def_bool y
 810	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 811	depends on !FTRACE_MCOUNT_USE_CC
 812	depends on !FTRACE_MCOUNT_USE_OBJTOOL
 813	depends on FTRACE_MCOUNT_RECORD
 814
 815config TRACING_MAP
 816	bool
 817	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
 818	help
 819	  tracing_map is a special-purpose lock-free map for tracing,
 820	  separated out as a stand-alone facility in order to allow it
 821	  to be shared between multiple tracers.  It isn't meant to be
 822	  generally used outside of that context, and is normally
 823	  selected by tracers that use it.
 824
 825config SYNTH_EVENTS
 826	bool "Synthetic trace events"
 827	select TRACING
 828	select DYNAMIC_EVENTS
 829	default n
 830	help
 831	  Synthetic events are user-defined trace events that can be
 832	  used to combine data from other trace events or in fact any
 833	  data source.  Synthetic events can be generated indirectly
 834	  via the trace() action of histogram triggers or directly
 835	  by way of an in-kernel API.
 836
 837	  See Documentation/trace/events.rst or
 838	  Documentation/trace/histogram.rst for details and examples.
 839
 840	  If in doubt, say N.
 841
 842config USER_EVENTS
 843	bool "User trace events"
 844	select TRACING
 845	select DYNAMIC_EVENTS
 
 846	help
 847	  User trace events are user-defined trace events that
 848	  can be used like an existing kernel trace event.  User trace
 849	  events are generated by writing to a tracefs file.  User
 850	  processes can determine if their tracing events should be
 851	  generated by registering a value and bit with the kernel
 852	  that reflects when it is enabled or not.
 853
 854	  See Documentation/trace/user_events.rst.
 855	  If in doubt, say N.
 856
 857config HIST_TRIGGERS
 858	bool "Histogram triggers"
 859	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
 860	select TRACING_MAP
 861	select TRACING
 862	select DYNAMIC_EVENTS
 863	select SYNTH_EVENTS
 864	default n
 865	help
 866	  Hist triggers allow one or more arbitrary trace event fields
 867	  to be aggregated into hash tables and dumped to stdout by
 868	  reading a debugfs/tracefs file.  They're useful for
 869	  gathering quick and dirty (though precise) summaries of
 870	  event activity as an initial guide for further investigation
 871	  using more advanced tools.
 872
 873	  Inter-event tracing of quantities such as latencies is also
 874	  supported using hist triggers under this option.
 875
 876	  See Documentation/trace/histogram.rst.
 877	  If in doubt, say N.
 878
 879config TRACE_EVENT_INJECT
 880	bool "Trace event injection"
 881	depends on TRACING
 882	help
 883	  Allow user-space to inject a specific trace event into the ring
 884	  buffer. This is mainly used for testing purpose.
 885
 886	  If unsure, say N.
 887
 888config TRACEPOINT_BENCHMARK
 889	bool "Add tracepoint that benchmarks tracepoints"
 890	help
 891	 This option creates the tracepoint "benchmark:benchmark_event".
 892	 When the tracepoint is enabled, it kicks off a kernel thread that
 893	 goes into an infinite loop (calling cond_resched() to let other tasks
 894	 run), and calls the tracepoint. Each iteration will record the time
 895	 it took to write to the tracepoint and the next iteration that
 896	 data will be passed to the tracepoint itself. That is, the tracepoint
 897	 will report the time it took to do the previous tracepoint.
 898	 The string written to the tracepoint is a static string of 128 bytes
 899	 to keep the time the same. The initial string is simply a write of
 900	 "START". The second string records the cold cache time of the first
 901	 write which is not added to the rest of the calculations.
 902
 903	 As it is a tight loop, it benchmarks as hot cache. That's fine because
 904	 we care most about hot paths that are probably in cache already.
 905
 906	 An example of the output:
 907
 908	      START
 909	      first=3672 [COLD CACHED]
 910	      last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
 911	      last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
 912	      last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
 913	      last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
 914	      last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
 915	      last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
 916
 917
 918config RING_BUFFER_BENCHMARK
 919	tristate "Ring buffer benchmark stress tester"
 920	depends on RING_BUFFER
 921	help
 922	  This option creates a test to stress the ring buffer and benchmark it.
 923	  It creates its own ring buffer such that it will not interfere with
 924	  any other users of the ring buffer (such as ftrace). It then creates
 925	  a producer and consumer that will run for 10 seconds and sleep for
 926	  10 seconds. Each interval it will print out the number of events
 927	  it recorded and give a rough estimate of how long each iteration took.
 928
 929	  It does not disable interrupts or raise its priority, so it may be
 930	  affected by processes that are running.
 931
 932	  If unsure, say N.
 933
 934config TRACE_EVAL_MAP_FILE
 935       bool "Show eval mappings for trace events"
 936       depends on TRACING
 937       help
 938	The "print fmt" of the trace events will show the enum/sizeof names
 939	instead of their values. This can cause problems for user space tools
 940	that use this string to parse the raw data as user space does not know
 941	how to convert the string to its value.
 942
 943	To fix this, there's a special macro in the kernel that can be used
 944	to convert an enum/sizeof into its value. If this macro is used, then
 945	the print fmt strings will be converted to their values.
 946
 947	If something does not get converted properly, this option can be
 948	used to show what enums/sizeof the kernel tried to convert.
 949
 950	This option is for debugging the conversions. A file is created
 951	in the tracing directory called "eval_map" that will show the
 952	names matched with their values and what trace event system they
 953	belong too.
 954
 955	Normally, the mapping of the strings to values will be freed after
 956	boot up or module load. With this option, they will not be freed, as
 957	they are needed for the "eval_map" file. Enabling this option will
 958	increase the memory footprint of the running kernel.
 959
 960	If unsure, say N.
 961
 962config FTRACE_RECORD_RECURSION
 963	bool "Record functions that recurse in function tracing"
 964	depends on FUNCTION_TRACER
 965	help
 966	  All callbacks that attach to the function tracing have some sort
 967	  of protection against recursion. Even though the protection exists,
 968	  it adds overhead. This option will create a file in the tracefs
 969	  file system called "recursed_functions" that will list the functions
 970	  that triggered a recursion.
 971
 972	  This will add more overhead to cases that have recursion.
 973
 974	  If unsure, say N
 975
 976config FTRACE_RECORD_RECURSION_SIZE
 977	int "Max number of recursed functions to record"
 978	default 128
 979	depends on FTRACE_RECORD_RECURSION
 980	help
 981	  This defines the limit of number of functions that can be
 982	  listed in the "recursed_functions" file, that lists all
 983	  the functions that caused a recursion to happen.
 984	  This file can be reset, but the limit can not change in
 985	  size at runtime.
 986
 987config FTRACE_VALIDATE_RCU_IS_WATCHING
 988	bool "Validate RCU is on during ftrace execution"
 989	depends on FUNCTION_TRACER
 990	depends on ARCH_WANTS_NO_INSTR
 991	help
 992	  All callbacks that attach to the function tracing have some sort of
 993	  protection against recursion. This option is only to verify that
 994	  ftrace (and other users of ftrace_test_recursion_trylock()) are not
 995	  called outside of RCU, as if they are, it can cause a race. But it
 996	  also has a noticeable overhead when enabled.
 997
 998	  If unsure, say N
 999
1000config RING_BUFFER_RECORD_RECURSION
1001	bool "Record functions that recurse in the ring buffer"
1002	depends on FTRACE_RECORD_RECURSION
1003	# default y, because it is coupled with FTRACE_RECORD_RECURSION
1004	default y
1005	help
1006	  The ring buffer has its own internal recursion. Although when
1007	  recursion happens it won't cause harm because of the protection,
1008	  but it does cause unwanted overhead. Enabling this option will
1009	  place where recursion was detected into the ftrace "recursed_functions"
1010	  file.
1011
1012	  This will add more overhead to cases that have recursion.
1013
1014config GCOV_PROFILE_FTRACE
1015	bool "Enable GCOV profiling on ftrace subsystem"
1016	depends on GCOV_KERNEL
1017	help
1018	  Enable GCOV profiling on ftrace subsystem for checking
1019	  which functions/lines are tested.
1020
1021	  If unsure, say N.
1022
1023	  Note that on a kernel compiled with this config, ftrace will
1024	  run significantly slower.
1025
1026config FTRACE_SELFTEST
1027	bool
1028
1029config FTRACE_STARTUP_TEST
1030	bool "Perform a startup test on ftrace"
1031	depends on GENERIC_TRACER
1032	select FTRACE_SELFTEST
1033	help
1034	  This option performs a series of startup tests on ftrace. On bootup
1035	  a series of tests are made to verify that the tracer is
1036	  functioning properly. It will do tests on all the configured
1037	  tracers of ftrace.
1038
1039config EVENT_TRACE_STARTUP_TEST
1040	bool "Run selftest on trace events"
1041	depends on FTRACE_STARTUP_TEST
1042	default y
1043	help
1044	  This option performs a test on all trace events in the system.
1045	  It basically just enables each event and runs some code that
1046	  will trigger events (not necessarily the event it enables)
1047	  This may take some time run as there are a lot of events.
1048
1049config EVENT_TRACE_TEST_SYSCALLS
1050	bool "Run selftest on syscall events"
1051	depends on EVENT_TRACE_STARTUP_TEST
1052	help
1053	 This option will also enable testing every syscall event.
1054	 It only enables the event and disables it and runs various loads
1055	 with the event enabled. This adds a bit more time for kernel boot
1056	 up since it runs this on every system call defined.
1057
1058	 TBD - enable a way to actually call the syscalls as we test their
1059	       events
1060
1061config FTRACE_SORT_STARTUP_TEST
1062       bool "Verify compile time sorting of ftrace functions"
1063       depends on DYNAMIC_FTRACE
1064       depends on BUILDTIME_MCOUNT_SORT
1065       help
1066	 Sorting of the mcount_loc sections that is used to find the
1067	 where the ftrace knows where to patch functions for tracing
1068	 and other callbacks is done at compile time. But if the sort
1069	 is not done correctly, it will cause non-deterministic failures.
1070	 When this is set, the sorted sections will be verified that they
1071	 are in deed sorted and will warn if they are not.
1072
1073	 If unsure, say N
1074
1075config RING_BUFFER_STARTUP_TEST
1076       bool "Ring buffer startup self test"
1077       depends on RING_BUFFER
1078       help
1079	 Run a simple self test on the ring buffer on boot up. Late in the
1080	 kernel boot sequence, the test will start that kicks off
1081	 a thread per cpu. Each thread will write various size events
1082	 into the ring buffer. Another thread is created to send IPIs
1083	 to each of the threads, where the IPI handler will also write
1084	 to the ring buffer, to test/stress the nesting ability.
1085	 If any anomalies are discovered, a warning will be displayed
1086	 and all ring buffers will be disabled.
1087
1088	 The test runs for 10 seconds. This will slow your boot time
1089	 by at least 10 more seconds.
1090
1091	 At the end of the test, statistics and more checks are done.
1092	 It will output the stats of each per cpu buffer: What
1093	 was written, the sizes, what was read, what was lost, and
1094	 other similar details.
1095
1096	 If unsure, say N
1097
1098config RING_BUFFER_VALIDATE_TIME_DELTAS
1099	bool "Verify ring buffer time stamp deltas"
1100	depends on RING_BUFFER
1101	help
1102	  This will audit the time stamps on the ring buffer sub
1103	  buffer to make sure that all the time deltas for the
1104	  events on a sub buffer matches the current time stamp.
1105	  This audit is performed for every event that is not
1106	  interrupted, or interrupting another event. A check
1107	  is also made when traversing sub buffers to make sure
1108	  that all the deltas on the previous sub buffer do not
1109	  add up to be greater than the current time stamp.
1110
1111	  NOTE: This adds significant overhead to recording of events,
1112	  and should only be used to test the logic of the ring buffer.
1113	  Do not use it on production systems.
1114
1115	  Only say Y if you understand what this does, and you
1116	  still want it enabled. Otherwise say N
1117
1118config MMIOTRACE_TEST
1119	tristate "Test module for mmiotrace"
1120	depends on MMIOTRACE && m
1121	help
1122	  This is a dumb module for testing mmiotrace. It is very dangerous
1123	  as it will write garbage to IO memory starting at a given address.
1124	  However, it should be safe to use on e.g. unused portion of VRAM.
1125
1126	  Say N, unless you absolutely know what you are doing.
1127
1128config PREEMPTIRQ_DELAY_TEST
1129	tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
1130	depends on m
1131	help
1132	  Select this option to build a test module that can help test latency
1133	  tracers by executing a preempt or irq disable section with a user
1134	  configurable delay. The module busy waits for the duration of the
1135	  critical section.
1136
1137	  For example, the following invocation generates a burst of three
1138	  irq-disabled critical sections for 500us:
1139	  modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
1140
1141	  What's more, if you want to attach the test on the cpu which the latency
1142	  tracer is running on, specify cpu_affinity=cpu_num at the end of the
1143	  command.
1144
1145	  If unsure, say N
1146
1147config SYNTH_EVENT_GEN_TEST
1148	tristate "Test module for in-kernel synthetic event generation"
1149	depends on SYNTH_EVENTS && m
1150	help
1151          This option creates a test module to check the base
1152          functionality of in-kernel synthetic event definition and
1153          generation.
1154
1155          To test, insert the module, and then check the trace buffer
1156	  for the generated sample events.
1157
1158	  If unsure, say N.
1159
1160config KPROBE_EVENT_GEN_TEST
1161	tristate "Test module for in-kernel kprobe event generation"
1162	depends on KPROBE_EVENTS && m
1163	help
1164          This option creates a test module to check the base
1165          functionality of in-kernel kprobe event definition.
1166
1167          To test, insert the module, and then check the trace buffer
1168	  for the generated kprobe events.
1169
1170	  If unsure, say N.
1171
1172config HIST_TRIGGERS_DEBUG
1173	bool "Hist trigger debug support"
1174	depends on HIST_TRIGGERS
1175	help
1176          Add "hist_debug" file for each event, which when read will
1177          dump out a bunch of internal details about the hist triggers
1178          defined on that event.
1179
1180          The hist_debug file serves a couple of purposes:
1181
1182            - Helps developers verify that nothing is broken.
1183
1184            - Provides educational information to support the details
1185              of the hist trigger internals as described by
1186              Documentation/trace/histogram-design.rst.
1187
1188          The hist_debug output only covers the data structures
1189          related to the histogram definitions themselves and doesn't
1190          display the internals of map buckets or variable values of
1191          running histograms.
1192
1193          If unsure, say N.
1194
1195source "kernel/trace/rv/Kconfig"
1196
1197endif # FTRACE

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