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_FREGS 35 bool 36 37config HAVE_FTRACE_GRAPH_FUNC 38 bool 39 help 40 True if ftrace_graph_func() is defined. 41 42config HAVE_DYNAMIC_FTRACE 43 bool 44 help 45 See Documentation/trace/ftrace-design.rst 46 47config HAVE_DYNAMIC_FTRACE_WITH_REGS 48 bool 49 50config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 51 bool 52 53config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS 54 bool 55 56config HAVE_DYNAMIC_FTRACE_WITH_ARGS 57 bool 58 help 59 If this is set, then arguments and stack can be found from 60 the ftrace_regs passed into the function callback regs parameter 61 by default, even without setting the REGS flag in the ftrace_ops. 62 This allows for use of ftrace_regs_get_argument() and 63 ftrace_regs_get_stack_pointer(). 64 65config HAVE_FTRACE_REGS_HAVING_PT_REGS 66 bool 67 help 68 If this is set, ftrace_regs has pt_regs, thus it can convert to 69 pt_regs without allocating memory. 70 71config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 72 bool 73 help 74 If the architecture generates __patchable_function_entries sections 75 but does not want them included in the ftrace locations. 76 77config HAVE_FTRACE_MCOUNT_RECORD 78 bool 79 help 80 See Documentation/trace/ftrace-design.rst 81 82config HAVE_SYSCALL_TRACEPOINTS 83 bool 84 help 85 See Documentation/trace/ftrace-design.rst 86 87config HAVE_FENTRY 88 bool 89 help 90 Arch supports the gcc options -pg with -mfentry 91 92config HAVE_NOP_MCOUNT 93 bool 94 help 95 Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount 96 97config HAVE_OBJTOOL_MCOUNT 98 bool 99 help 100 Arch supports objtool --mcount 101 102config HAVE_OBJTOOL_NOP_MCOUNT 103 bool 104 help 105 Arch supports the objtool options --mcount with --mnop. 106 An architecture can select this if it wants to enable nop'ing 107 of ftrace locations. 108 109config HAVE_C_RECORDMCOUNT 110 bool 111 help 112 C version of recordmcount available? 113 114config HAVE_BUILDTIME_MCOUNT_SORT 115 bool 116 help 117 An architecture selects this if it sorts the mcount_loc section 118 at build time. 119 120config BUILDTIME_MCOUNT_SORT 121 bool 122 default y 123 depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE 124 help 125 Sort the mcount_loc section at build time. 126 127config TRACER_MAX_TRACE 128 bool 129 130config TRACE_CLOCK 131 bool 132 133config RING_BUFFER 134 bool 135 select TRACE_CLOCK 136 select IRQ_WORK 137 138config EVENT_TRACING 139 select CONTEXT_SWITCH_TRACER 140 select GLOB 141 bool 142 143config CONTEXT_SWITCH_TRACER 144 bool 145 146config RING_BUFFER_ALLOW_SWAP 147 bool 148 help 149 Allow the use of ring_buffer_swap_cpu. 150 Adds a very slight overhead to tracing when enabled. 151 152config PREEMPTIRQ_TRACEPOINTS 153 bool 154 depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS 155 select TRACING 156 default y 157 help 158 Create preempt/irq toggle tracepoints if needed, so that other parts 159 of the kernel can use them to generate or add hooks to them. 160 161# All tracer options should select GENERIC_TRACER. For those options that are 162# enabled by all tracers (context switch and event tracer) they select TRACING. 163# This allows those options to appear when no other tracer is selected. But the 164# options do not appear when something else selects it. We need the two options 165# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the 166# hiding of the automatic options. 167 168config TRACING 169 bool 170 select RING_BUFFER 171 select STACKTRACE if STACKTRACE_SUPPORT 172 select TRACEPOINTS 173 select NOP_TRACER 174 select BINARY_PRINTF 175 select EVENT_TRACING 176 select TRACE_CLOCK 177 select NEED_TASKS_RCU 178 179config GENERIC_TRACER 180 bool 181 select TRACING 182 183# 184# Minimum requirements an architecture has to meet for us to 185# be able to offer generic tracing facilities: 186# 187config TRACING_SUPPORT 188 bool 189 depends on TRACE_IRQFLAGS_SUPPORT 190 depends on STACKTRACE_SUPPORT 191 default y 192 193menuconfig FTRACE 194 bool "Tracers" 195 depends on TRACING_SUPPORT 196 default y if DEBUG_KERNEL 197 help 198 Enable the kernel tracing infrastructure. 199 200if FTRACE 201 202config BOOTTIME_TRACING 203 bool "Boot-time Tracing support" 204 depends on TRACING 205 select BOOT_CONFIG 206 help 207 Enable developer to setup ftrace subsystem via supplemental 208 kernel cmdline at boot time for debugging (tracing) driver 209 initialization and boot process. 210 211config FUNCTION_TRACER 212 bool "Kernel Function Tracer" 213 depends on HAVE_FUNCTION_TRACER 214 select KALLSYMS 215 select GENERIC_TRACER 216 select CONTEXT_SWITCH_TRACER 217 select GLOB 218 select NEED_TASKS_RCU 219 select TASKS_RUDE_RCU 220 help 221 Enable the kernel to trace every kernel function. This is done 222 by using a compiler feature to insert a small, 5-byte No-Operation 223 instruction at the beginning of every kernel function, which NOP 224 sequence is then dynamically patched into a tracer call when 225 tracing is enabled by the administrator. If it's runtime disabled 226 (the bootup default), then the overhead of the instructions is very 227 small and not measurable even in micro-benchmarks (at least on 228 x86, but may have impact on other architectures). 229 230config FUNCTION_GRAPH_TRACER 231 bool "Kernel Function Graph Tracer" 232 depends on HAVE_FUNCTION_GRAPH_TRACER 233 depends on FUNCTION_TRACER 234 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE 235 default y 236 help 237 Enable the kernel to trace a function at both its return 238 and its entry. 239 Its first purpose is to trace the duration of functions and 240 draw a call graph for each thread with some information like 241 the return value. This is done by setting the current return 242 address on the current task structure into a stack of calls. 243 244config FUNCTION_GRAPH_RETVAL 245 bool "Kernel Function Graph Return Value" 246 depends on HAVE_FUNCTION_GRAPH_FREGS 247 depends on FUNCTION_GRAPH_TRACER 248 default n 249 help 250 Support recording and printing the function return value when 251 using function graph tracer. It can be helpful to locate functions 252 that return errors. This feature is off by default, and you can 253 enable it via the trace option funcgraph-retval. 254 See Documentation/trace/ftrace.rst 255 256config FUNCTION_GRAPH_RETADDR 257 bool "Kernel Function Graph Return Address" 258 depends on FUNCTION_GRAPH_TRACER 259 default n 260 help 261 Support recording and printing the function return address when 262 using function graph tracer. It can be helpful to locate code line that 263 the function is called. This feature is off by default, and you can 264 enable it via the trace option funcgraph-retaddr. 265 266config FUNCTION_TRACE_ARGS 267 bool 268 depends on PROBE_EVENTS_BTF_ARGS 269 default y 270 help 271 If supported with function argument access API and BTF, then 272 the function tracer and function graph tracer will support printing 273 of function arguments. This feature is off by default, and can be 274 enabled via the trace option func-args (for the function tracer) and 275 funcgraph-args (for the function graph tracer) 276 277config DYNAMIC_FTRACE 278 bool "enable/disable function tracing dynamically" 279 depends on FUNCTION_TRACER 280 depends on HAVE_DYNAMIC_FTRACE 281 default y 282 help 283 This option will modify all the calls to function tracing 284 dynamically (will patch them out of the binary image and 285 replace them with a No-Op instruction) on boot up. During 286 compile time, a table is made of all the locations that ftrace 287 can function trace, and this table is linked into the kernel 288 image. When this is enabled, functions can be individually 289 enabled, and the functions not enabled will not affect 290 performance of the system. 291 292 See the files in /sys/kernel/tracing: 293 available_filter_functions 294 set_ftrace_filter 295 set_ftrace_notrace 296 297 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 298 otherwise has native performance as long as no tracing is active. 299 300config DYNAMIC_FTRACE_WITH_REGS 301 def_bool y 302 depends on DYNAMIC_FTRACE 303 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS 304 305config DYNAMIC_FTRACE_WITH_DIRECT_CALLS 306 def_bool y 307 depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS 308 depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 309 310config DYNAMIC_FTRACE_WITH_CALL_OPS 311 def_bool y 312 depends on HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS 313 314config DYNAMIC_FTRACE_WITH_ARGS 315 def_bool y 316 depends on DYNAMIC_FTRACE 317 depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS 318 319config FPROBE 320 bool "Kernel Function Probe (fprobe)" 321 depends on HAVE_FUNCTION_GRAPH_FREGS && HAVE_FTRACE_GRAPH_FUNC 322 depends on DYNAMIC_FTRACE_WITH_ARGS 323 select FUNCTION_GRAPH_TRACER 324 default n 325 help 326 This option enables kernel function probe (fprobe) based on ftrace. 327 The fprobe is similar to kprobes, but probes only for kernel function 328 entries and exits. This also can probe multiple functions by one 329 fprobe. 330 331 If unsure, say N. 332 333config FUNCTION_PROFILER 334 bool "Kernel function profiler" 335 depends on FUNCTION_TRACER 336 default n 337 help 338 This option enables the kernel function profiler. A file is created 339 in debugfs called function_profile_enabled which defaults to zero. 340 When a 1 is echoed into this file profiling begins, and when a 341 zero is entered, profiling stops. A "functions" file is created in 342 the trace_stat directory; this file shows the list of functions that 343 have been hit and their counters. 344 345 If in doubt, say N. 346 347config STACK_TRACER 348 bool "Trace max stack" 349 depends on HAVE_FUNCTION_TRACER 350 select FUNCTION_TRACER 351 select STACKTRACE 352 select KALLSYMS 353 help 354 This special tracer records the maximum stack footprint of the 355 kernel and displays it in /sys/kernel/tracing/stack_trace. 356 357 This tracer works by hooking into every function call that the 358 kernel executes, and keeping a maximum stack depth value and 359 stack-trace saved. If this is configured with DYNAMIC_FTRACE 360 then it will not have any overhead while the stack tracer 361 is disabled. 362 363 To enable the stack tracer on bootup, pass in 'stacktrace' 364 on the kernel command line. 365 366 The stack tracer can also be enabled or disabled via the 367 sysctl kernel.stack_tracer_enabled 368 369 Say N if unsure. 370 371config TRACE_PREEMPT_TOGGLE 372 bool 373 help 374 Enables hooks which will be called when preemption is first disabled, 375 and last enabled. 376 377config IRQSOFF_TRACER 378 bool "Interrupts-off Latency Tracer" 379 default n 380 depends on TRACE_IRQFLAGS_SUPPORT 381 select TRACE_IRQFLAGS 382 select GENERIC_TRACER 383 select TRACER_MAX_TRACE 384 select RING_BUFFER_ALLOW_SWAP 385 select TRACER_SNAPSHOT 386 select TRACER_SNAPSHOT_PER_CPU_SWAP 387 help 388 This option measures the time spent in irqs-off critical 389 sections, with microsecond accuracy. 390 391 The default measurement method is a maximum search, which is 392 disabled by default and can be runtime (re-)started 393 via: 394 395 echo 0 > /sys/kernel/tracing/tracing_max_latency 396 397 (Note that kernel size and overhead increase with this option 398 enabled. This option and the preempt-off timing option can be 399 used together or separately.) 400 401config PREEMPT_TRACER 402 bool "Preemption-off Latency Tracer" 403 default n 404 depends on PREEMPTION 405 select GENERIC_TRACER 406 select TRACER_MAX_TRACE 407 select RING_BUFFER_ALLOW_SWAP 408 select TRACER_SNAPSHOT 409 select TRACER_SNAPSHOT_PER_CPU_SWAP 410 select TRACE_PREEMPT_TOGGLE 411 help 412 This option measures the time spent in preemption-off critical 413 sections, with microsecond accuracy. 414 415 The default measurement method is a maximum search, which is 416 disabled by default and can be runtime (re-)started 417 via: 418 419 echo 0 > /sys/kernel/tracing/tracing_max_latency 420 421 (Note that kernel size and overhead increase with this option 422 enabled. This option and the irqs-off timing option can be 423 used together or separately.) 424 425config SCHED_TRACER 426 bool "Scheduling Latency Tracer" 427 select GENERIC_TRACER 428 select CONTEXT_SWITCH_TRACER 429 select TRACER_MAX_TRACE 430 select TRACER_SNAPSHOT 431 help 432 This tracer tracks the latency of the highest priority task 433 to be scheduled in, starting from the point it has woken up. 434 435config HWLAT_TRACER 436 bool "Tracer to detect hardware latencies (like SMIs)" 437 select GENERIC_TRACER 438 select TRACER_MAX_TRACE 439 help 440 This tracer, when enabled will create one or more kernel threads, 441 depending on what the cpumask file is set to, which each thread 442 spinning in a loop looking for interruptions caused by 443 something other than the kernel. For example, if a 444 System Management Interrupt (SMI) takes a noticeable amount of 445 time, this tracer will detect it. This is useful for testing 446 if a system is reliable for Real Time tasks. 447 448 Some files are created in the tracing directory when this 449 is enabled: 450 451 hwlat_detector/width - time in usecs for how long to spin for 452 hwlat_detector/window - time in usecs between the start of each 453 iteration 454 455 A kernel thread is created that will spin with interrupts disabled 456 for "width" microseconds in every "window" cycle. It will not spin 457 for "window - width" microseconds, where the system can 458 continue to operate. 459 460 The output will appear in the trace and trace_pipe files. 461 462 When the tracer is not running, it has no affect on the system, 463 but when it is running, it can cause the system to be 464 periodically non responsive. Do not run this tracer on a 465 production system. 466 467 To enable this tracer, echo in "hwlat" into the current_tracer 468 file. Every time a latency is greater than tracing_thresh, it will 469 be recorded into the ring buffer. 470 471config OSNOISE_TRACER 472 bool "OS Noise tracer" 473 select GENERIC_TRACER 474 select TRACER_MAX_TRACE 475 help 476 In the context of high-performance computing (HPC), the Operating 477 System Noise (osnoise) refers to the interference experienced by an 478 application due to activities inside the operating system. In the 479 context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread 480 can cause noise to the system. Moreover, hardware-related jobs can 481 also cause noise, for example, via SMIs. 482 483 The osnoise tracer leverages the hwlat_detector by running a similar 484 loop with preemption, SoftIRQs and IRQs enabled, thus allowing all 485 the sources of osnoise during its execution. The osnoise tracer takes 486 note of the entry and exit point of any source of interferences, 487 increasing a per-cpu interference counter. It saves an interference 488 counter for each source of interference. The interference counter for 489 NMI, IRQs, SoftIRQs, and threads is increased anytime the tool 490 observes these interferences' entry events. When a noise happens 491 without any interference from the operating system level, the 492 hardware noise counter increases, pointing to a hardware-related 493 noise. In this way, osnoise can account for any source of 494 interference. At the end of the period, the osnoise tracer prints 495 the sum of all noise, the max single noise, the percentage of CPU 496 available for the thread, and the counters for the noise sources. 497 498 In addition to the tracer, a set of tracepoints were added to 499 facilitate the identification of the osnoise source. 500 501 The output will appear in the trace and trace_pipe files. 502 503 To enable this tracer, echo in "osnoise" into the current_tracer 504 file. 505 506config TIMERLAT_TRACER 507 bool "Timerlat tracer" 508 select OSNOISE_TRACER 509 select GENERIC_TRACER 510 help 511 The timerlat tracer aims to help the preemptive kernel developers 512 to find sources of wakeup latencies of real-time threads. 513 514 The tracer creates a per-cpu kernel thread with real-time priority. 515 The tracer thread sets a periodic timer to wakeup itself, and goes 516 to sleep waiting for the timer to fire. At the wakeup, the thread 517 then computes a wakeup latency value as the difference between 518 the current time and the absolute time that the timer was set 519 to expire. 520 521 The tracer prints two lines at every activation. The first is the 522 timer latency observed at the hardirq context before the 523 activation of the thread. The second is the timer latency observed 524 by the thread, which is the same level that cyclictest reports. The 525 ACTIVATION ID field serves to relate the irq execution to its 526 respective thread execution. 527 528 The tracer is build on top of osnoise tracer, and the osnoise: 529 events can be used to trace the source of interference from NMI, 530 IRQs and other threads. It also enables the capture of the 531 stacktrace at the IRQ context, which helps to identify the code 532 path that can cause thread delay. 533 534config MMIOTRACE 535 bool "Memory mapped IO tracing" 536 depends on HAVE_MMIOTRACE_SUPPORT && PCI 537 select GENERIC_TRACER 538 help 539 Mmiotrace traces Memory Mapped I/O access and is meant for 540 debugging and reverse engineering. It is called from the ioremap 541 implementation and works via page faults. Tracing is disabled by 542 default and can be enabled at run-time. 543 544 See Documentation/trace/mmiotrace.rst. 545 If you are not helping to develop drivers, say N. 546 547config ENABLE_DEFAULT_TRACERS 548 bool "Trace process context switches and events" 549 depends on !GENERIC_TRACER 550 select TRACING 551 help 552 This tracer hooks to various trace points in the kernel, 553 allowing the user to pick and choose which trace point they 554 want to trace. It also includes the sched_switch tracer plugin. 555 556config FTRACE_SYSCALLS 557 bool "Trace syscalls" 558 depends on HAVE_SYSCALL_TRACEPOINTS 559 select GENERIC_TRACER 560 select KALLSYMS 561 help 562 Basic tracer to catch the syscall entry and exit events. 563 564config TRACER_SNAPSHOT 565 bool "Create a snapshot trace buffer" 566 select TRACER_MAX_TRACE 567 help 568 Allow tracing users to take snapshot of the current buffer using the 569 ftrace interface, e.g.: 570 571 echo 1 > /sys/kernel/tracing/snapshot 572 cat snapshot 573 574config TRACER_SNAPSHOT_PER_CPU_SWAP 575 bool "Allow snapshot to swap per CPU" 576 depends on TRACER_SNAPSHOT 577 select RING_BUFFER_ALLOW_SWAP 578 help 579 Allow doing a snapshot of a single CPU buffer instead of a 580 full swap (all buffers). If this is set, then the following is 581 allowed: 582 583 echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot 584 585 After which, only the tracing buffer for CPU 2 was swapped with 586 the main tracing buffer, and the other CPU buffers remain the same. 587 588 When this is enabled, this adds a little more overhead to the 589 trace recording, as it needs to add some checks to synchronize 590 recording with swaps. But this does not affect the performance 591 of the overall system. This is enabled by default when the preempt 592 or irq latency tracers are enabled, as those need to swap as well 593 and already adds the overhead (plus a lot more). 594 595config TRACE_BRANCH_PROFILING 596 bool 597 select GENERIC_TRACER 598 599choice 600 prompt "Branch Profiling" 601 default BRANCH_PROFILE_NONE 602 help 603 The branch profiling is a software profiler. It will add hooks 604 into the C conditionals to test which path a branch takes. 605 606 The likely/unlikely profiler only looks at the conditions that 607 are annotated with a likely or unlikely macro. 608 609 The "all branch" profiler will profile every if-statement in the 610 kernel. This profiler will also enable the likely/unlikely 611 profiler. 612 613 Either of the above profilers adds a bit of overhead to the system. 614 If unsure, choose "No branch profiling". 615 616config BRANCH_PROFILE_NONE 617 bool "No branch profiling" 618 help 619 No branch profiling. Branch profiling adds a bit of overhead. 620 Only enable it if you want to analyse the branching behavior. 621 Otherwise keep it disabled. 622 623config PROFILE_ANNOTATED_BRANCHES 624 bool "Trace likely/unlikely profiler" 625 select TRACE_BRANCH_PROFILING 626 help 627 This tracer profiles all likely and unlikely macros 628 in the kernel. It will display the results in: 629 630 /sys/kernel/tracing/trace_stat/branch_annotated 631 632 Note: this will add a significant overhead; only turn this 633 on if you need to profile the system's use of these macros. 634 635config PROFILE_ALL_BRANCHES 636 bool "Profile all if conditionals" if !FORTIFY_SOURCE 637 select TRACE_BRANCH_PROFILING 638 help 639 This tracer profiles all branch conditions. Every if () 640 taken in the kernel is recorded whether it hit or miss. 641 The results will be displayed in: 642 643 /sys/kernel/tracing/trace_stat/branch_all 644 645 This option also enables the likely/unlikely profiler. 646 647 This configuration, when enabled, will impose a great overhead 648 on the system. This should only be enabled when the system 649 is to be analyzed in much detail. 650endchoice 651 652config TRACING_BRANCHES 653 bool 654 help 655 Selected by tracers that will trace the likely and unlikely 656 conditions. This prevents the tracers themselves from being 657 profiled. Profiling the tracing infrastructure can only happen 658 when the likelys and unlikelys are not being traced. 659 660config BRANCH_TRACER 661 bool "Trace likely/unlikely instances" 662 depends on TRACE_BRANCH_PROFILING 663 select TRACING_BRANCHES 664 help 665 This traces the events of likely and unlikely condition 666 calls in the kernel. The difference between this and the 667 "Trace likely/unlikely profiler" is that this is not a 668 histogram of the callers, but actually places the calling 669 events into a running trace buffer to see when and where the 670 events happened, as well as their results. 671 672 Say N if unsure. 673 674config BLK_DEV_IO_TRACE 675 bool "Support for tracing block IO actions" 676 depends on SYSFS 677 depends on BLOCK 678 select RELAY 679 select DEBUG_FS 680 select TRACEPOINTS 681 select GENERIC_TRACER 682 select STACKTRACE 683 help 684 Say Y here if you want to be able to trace the block layer actions 685 on a given queue. Tracing allows you to see any traffic happening 686 on a block device queue. For more information (and the userspace 687 support tools needed), fetch the blktrace tools from: 688 689 git://git.kernel.dk/blktrace.git 690 691 Tracing also is possible using the ftrace interface, e.g.: 692 693 echo 1 > /sys/block/sda/sda1/trace/enable 694 echo blk > /sys/kernel/tracing/current_tracer 695 cat /sys/kernel/tracing/trace_pipe 696 697 If unsure, say N. 698 699config FPROBE_EVENTS 700 depends on FPROBE 701 depends on HAVE_REGS_AND_STACK_ACCESS_API 702 bool "Enable fprobe-based dynamic events" 703 select TRACING 704 select PROBE_EVENTS 705 select DYNAMIC_EVENTS 706 default y 707 help 708 This allows user to add tracing events on the function entry and 709 exit via ftrace interface. The syntax is same as the kprobe events 710 and the kprobe events on function entry and exit will be 711 transparently converted to this fprobe events. 712 713config PROBE_EVENTS_BTF_ARGS 714 depends on HAVE_FUNCTION_ARG_ACCESS_API 715 depends on FPROBE_EVENTS || KPROBE_EVENTS 716 depends on DEBUG_INFO_BTF && BPF_SYSCALL 717 bool "Support BTF function arguments for probe events" 718 default y 719 help 720 The user can specify the arguments of the probe event using the names 721 of the arguments of the probed function, when the probe location is a 722 kernel function entry or a tracepoint. 723 This is available only if BTF (BPF Type Format) support is enabled. 724 725config KPROBE_EVENTS 726 depends on KPROBES 727 depends on HAVE_REGS_AND_STACK_ACCESS_API 728 bool "Enable kprobes-based dynamic events" 729 select TRACING 730 select PROBE_EVENTS 731 select DYNAMIC_EVENTS 732 default y 733 help 734 This allows the user to add tracing events (similar to tracepoints) 735 on the fly via the ftrace interface. See 736 Documentation/trace/kprobetrace.rst for more details. 737 738 Those events can be inserted wherever kprobes can probe, and record 739 various register and memory values. 740 741 This option is also required by perf-probe subcommand of perf tools. 742 If you want to use perf tools, this option is strongly recommended. 743 744config KPROBE_EVENTS_ON_NOTRACE 745 bool "Do NOT protect notrace function from kprobe events" 746 depends on KPROBE_EVENTS 747 depends on DYNAMIC_FTRACE 748 default n 749 help 750 This is only for the developers who want to debug ftrace itself 751 using kprobe events. 752 753 If kprobes can use ftrace instead of breakpoint, ftrace related 754 functions are protected from kprobe-events to prevent an infinite 755 recursion or any unexpected execution path which leads to a kernel 756 crash. 757 758 This option disables such protection and allows you to put kprobe 759 events on ftrace functions for debugging ftrace by itself. 760 Note that this might let you shoot yourself in the foot. 761 762 If unsure, say N. 763 764config UPROBE_EVENTS 765 bool "Enable uprobes-based dynamic events" 766 depends on ARCH_SUPPORTS_UPROBES 767 depends on MMU 768 depends on PERF_EVENTS 769 select UPROBES 770 select PROBE_EVENTS 771 select DYNAMIC_EVENTS 772 select TRACING 773 default y 774 help 775 This allows the user to add tracing events on top of userspace 776 dynamic events (similar to tracepoints) on the fly via the trace 777 events interface. Those events can be inserted wherever uprobes 778 can probe, and record various registers. 779 This option is required if you plan to use perf-probe subcommand 780 of perf tools on user space applications. 781 782config BPF_EVENTS 783 depends on BPF_SYSCALL 784 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS 785 bool 786 default y 787 help 788 This allows the user to attach BPF programs to kprobe, uprobe, and 789 tracepoint events. 790 791config DYNAMIC_EVENTS 792 def_bool n 793 794config PROBE_EVENTS 795 def_bool n 796 797config BPF_KPROBE_OVERRIDE 798 bool "Enable BPF programs to override a kprobed function" 799 depends on BPF_EVENTS 800 depends on FUNCTION_ERROR_INJECTION 801 default n 802 help 803 Allows BPF to override the execution of a probed function and 804 set a different return value. This is used for error injection. 805 806config FTRACE_MCOUNT_RECORD 807 def_bool y 808 depends on DYNAMIC_FTRACE 809 depends on HAVE_FTRACE_MCOUNT_RECORD 810 811config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 812 bool 813 depends on FTRACE_MCOUNT_RECORD 814 815config FTRACE_MCOUNT_USE_CC 816 def_bool y 817 depends on $(cc-option,-mrecord-mcount) 818 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 819 depends on FTRACE_MCOUNT_RECORD 820 821config FTRACE_MCOUNT_USE_OBJTOOL 822 def_bool y 823 depends on HAVE_OBJTOOL_MCOUNT 824 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 825 depends on !FTRACE_MCOUNT_USE_CC 826 depends on FTRACE_MCOUNT_RECORD 827 select OBJTOOL 828 829config FTRACE_MCOUNT_USE_RECORDMCOUNT 830 def_bool y 831 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 832 depends on !FTRACE_MCOUNT_USE_CC 833 depends on !FTRACE_MCOUNT_USE_OBJTOOL 834 depends on FTRACE_MCOUNT_RECORD 835 836config TRACING_MAP 837 bool 838 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 839 help 840 tracing_map is a special-purpose lock-free map for tracing, 841 separated out as a stand-alone facility in order to allow it 842 to be shared between multiple tracers. It isn't meant to be 843 generally used outside of that context, and is normally 844 selected by tracers that use it. 845 846config SYNTH_EVENTS 847 bool "Synthetic trace events" 848 select TRACING 849 select DYNAMIC_EVENTS 850 default n 851 help 852 Synthetic events are user-defined trace events that can be 853 used to combine data from other trace events or in fact any 854 data source. Synthetic events can be generated indirectly 855 via the trace() action of histogram triggers or directly 856 by way of an in-kernel API. 857 858 See Documentation/trace/events.rst or 859 Documentation/trace/histogram.rst for details and examples. 860 861 If in doubt, say N. 862 863config USER_EVENTS 864 bool "User trace events" 865 select TRACING 866 select DYNAMIC_EVENTS 867 help 868 User trace events are user-defined trace events that 869 can be used like an existing kernel trace event. User trace 870 events are generated by writing to a tracefs file. User 871 processes can determine if their tracing events should be 872 generated by registering a value and bit with the kernel 873 that reflects when it is enabled or not. 874 875 See Documentation/trace/user_events.rst. 876 If in doubt, say N. 877 878config HIST_TRIGGERS 879 bool "Histogram triggers" 880 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 881 select TRACING_MAP 882 select TRACING 883 select DYNAMIC_EVENTS 884 select SYNTH_EVENTS 885 default n 886 help 887 Hist triggers allow one or more arbitrary trace event fields 888 to be aggregated into hash tables and dumped to stdout by 889 reading a debugfs/tracefs file. They're useful for 890 gathering quick and dirty (though precise) summaries of 891 event activity as an initial guide for further investigation 892 using more advanced tools. 893 894 Inter-event tracing of quantities such as latencies is also 895 supported using hist triggers under this option. 896 897 See Documentation/trace/histogram.rst. 898 If in doubt, say N. 899 900config TRACE_EVENT_INJECT 901 bool "Trace event injection" 902 depends on TRACING 903 help 904 Allow user-space to inject a specific trace event into the ring 905 buffer. This is mainly used for testing purpose. 906 907 If unsure, say N. 908 909config TRACEPOINT_BENCHMARK 910 bool "Add tracepoint that benchmarks tracepoints" 911 help 912 This option creates the tracepoint "benchmark:benchmark_event". 913 When the tracepoint is enabled, it kicks off a kernel thread that 914 goes into an infinite loop (calling cond_resched() to let other tasks 915 run), and calls the tracepoint. Each iteration will record the time 916 it took to write to the tracepoint and the next iteration that 917 data will be passed to the tracepoint itself. That is, the tracepoint 918 will report the time it took to do the previous tracepoint. 919 The string written to the tracepoint is a static string of 128 bytes 920 to keep the time the same. The initial string is simply a write of 921 "START". The second string records the cold cache time of the first 922 write which is not added to the rest of the calculations. 923 924 As it is a tight loop, it benchmarks as hot cache. That's fine because 925 we care most about hot paths that are probably in cache already. 926 927 An example of the output: 928 929 START 930 first=3672 [COLD CACHED] 931 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712 932 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337 933 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064 934 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411 935 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389 936 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666 937 938 939config RING_BUFFER_BENCHMARK 940 tristate "Ring buffer benchmark stress tester" 941 depends on RING_BUFFER 942 help 943 This option creates a test to stress the ring buffer and benchmark it. 944 It creates its own ring buffer such that it will not interfere with 945 any other users of the ring buffer (such as ftrace). It then creates 946 a producer and consumer that will run for 10 seconds and sleep for 947 10 seconds. Each interval it will print out the number of events 948 it recorded and give a rough estimate of how long each iteration took. 949 950 It does not disable interrupts or raise its priority, so it may be 951 affected by processes that are running. 952 953 If unsure, say N. 954 955config TRACE_EVAL_MAP_FILE 956 bool "Show eval mappings for trace events" 957 depends on TRACING 958 help 959 The "print fmt" of the trace events will show the enum/sizeof names 960 instead of their values. This can cause problems for user space tools 961 that use this string to parse the raw data as user space does not know 962 how to convert the string to its value. 963 964 To fix this, there's a special macro in the kernel that can be used 965 to convert an enum/sizeof into its value. If this macro is used, then 966 the print fmt strings will be converted to their values. 967 968 If something does not get converted properly, this option can be 969 used to show what enums/sizeof the kernel tried to convert. 970 971 This option is for debugging the conversions. A file is created 972 in the tracing directory called "eval_map" that will show the 973 names matched with their values and what trace event system they 974 belong too. 975 976 Normally, the mapping of the strings to values will be freed after 977 boot up or module load. With this option, they will not be freed, as 978 they are needed for the "eval_map" file. Enabling this option will 979 increase the memory footprint of the running kernel. 980 981 If unsure, say N. 982 983config FTRACE_RECORD_RECURSION 984 bool "Record functions that recurse in function tracing" 985 depends on FUNCTION_TRACER 986 help 987 All callbacks that attach to the function tracing have some sort 988 of protection against recursion. Even though the protection exists, 989 it adds overhead. This option will create a file in the tracefs 990 file system called "recursed_functions" that will list the functions 991 that triggered a recursion. 992 993 This will add more overhead to cases that have recursion. 994 995 If unsure, say N 996 997config FTRACE_RECORD_RECURSION_SIZE 998 int "Max number of recursed functions to record" 999 default 128 1000 depends on FTRACE_RECORD_RECURSION 1001 help 1002 This defines the limit of number of functions that can be 1003 listed in the "recursed_functions" file, that lists all 1004 the functions that caused a recursion to happen. 1005 This file can be reset, but the limit can not change in 1006 size at runtime. 1007 1008config FTRACE_VALIDATE_RCU_IS_WATCHING 1009 bool "Validate RCU is on during ftrace execution" 1010 depends on FUNCTION_TRACER 1011 depends on ARCH_WANTS_NO_INSTR 1012 help 1013 All callbacks that attach to the function tracing have some sort of 1014 protection against recursion. This option is only to verify that 1015 ftrace (and other users of ftrace_test_recursion_trylock()) are not 1016 called outside of RCU, as if they are, it can cause a race. But it 1017 also has a noticeable overhead when enabled. 1018 1019 If unsure, say N 1020 1021config RING_BUFFER_RECORD_RECURSION 1022 bool "Record functions that recurse in the ring buffer" 1023 depends on FTRACE_RECORD_RECURSION 1024 # default y, because it is coupled with FTRACE_RECORD_RECURSION 1025 default y 1026 help 1027 The ring buffer has its own internal recursion. Although when 1028 recursion happens it won't cause harm because of the protection, 1029 but it does cause unwanted overhead. Enabling this option will 1030 place where recursion was detected into the ftrace "recursed_functions" 1031 file. 1032 1033 This will add more overhead to cases that have recursion. 1034 1035config GCOV_PROFILE_FTRACE 1036 bool "Enable GCOV profiling on ftrace subsystem" 1037 depends on GCOV_KERNEL 1038 help 1039 Enable GCOV profiling on ftrace subsystem for checking 1040 which functions/lines are tested. 1041 1042 If unsure, say N. 1043 1044 Note that on a kernel compiled with this config, ftrace will 1045 run significantly slower. 1046 1047config FTRACE_SELFTEST 1048 bool 1049 1050config FTRACE_STARTUP_TEST 1051 bool "Perform a startup test on ftrace" 1052 depends on GENERIC_TRACER 1053 select FTRACE_SELFTEST 1054 help 1055 This option performs a series of startup tests on ftrace. On bootup 1056 a series of tests are made to verify that the tracer is 1057 functioning properly. It will do tests on all the configured 1058 tracers of ftrace. 1059 1060config EVENT_TRACE_STARTUP_TEST 1061 bool "Run selftest on trace events" 1062 depends on FTRACE_STARTUP_TEST 1063 default y 1064 help 1065 This option performs a test on all trace events in the system. 1066 It basically just enables each event and runs some code that 1067 will trigger events (not necessarily the event it enables) 1068 This may take some time run as there are a lot of events. 1069 1070config EVENT_TRACE_TEST_SYSCALLS 1071 bool "Run selftest on syscall events" 1072 depends on EVENT_TRACE_STARTUP_TEST 1073 help 1074 This option will also enable testing every syscall event. 1075 It only enables the event and disables it and runs various loads 1076 with the event enabled. This adds a bit more time for kernel boot 1077 up since it runs this on every system call defined. 1078 1079 TBD - enable a way to actually call the syscalls as we test their 1080 events 1081 1082config FTRACE_SORT_STARTUP_TEST 1083 bool "Verify compile time sorting of ftrace functions" 1084 depends on DYNAMIC_FTRACE 1085 depends on BUILDTIME_MCOUNT_SORT 1086 help 1087 Sorting of the mcount_loc sections that is used to find the 1088 where the ftrace knows where to patch functions for tracing 1089 and other callbacks is done at compile time. But if the sort 1090 is not done correctly, it will cause non-deterministic failures. 1091 When this is set, the sorted sections will be verified that they 1092 are in deed sorted and will warn if they are not. 1093 1094 If unsure, say N 1095 1096config RING_BUFFER_STARTUP_TEST 1097 bool "Ring buffer startup self test" 1098 depends on RING_BUFFER 1099 help 1100 Run a simple self test on the ring buffer on boot up. Late in the 1101 kernel boot sequence, the test will start that kicks off 1102 a thread per cpu. Each thread will write various size events 1103 into the ring buffer. Another thread is created to send IPIs 1104 to each of the threads, where the IPI handler will also write 1105 to the ring buffer, to test/stress the nesting ability. 1106 If any anomalies are discovered, a warning will be displayed 1107 and all ring buffers will be disabled. 1108 1109 The test runs for 10 seconds. This will slow your boot time 1110 by at least 10 more seconds. 1111 1112 At the end of the test, statistics and more checks are done. 1113 It will output the stats of each per cpu buffer: What 1114 was written, the sizes, what was read, what was lost, and 1115 other similar details. 1116 1117 If unsure, say N 1118 1119config RING_BUFFER_VALIDATE_TIME_DELTAS 1120 bool "Verify ring buffer time stamp deltas" 1121 depends on RING_BUFFER 1122 help 1123 This will audit the time stamps on the ring buffer sub 1124 buffer to make sure that all the time deltas for the 1125 events on a sub buffer matches the current time stamp. 1126 This audit is performed for every event that is not 1127 interrupted, or interrupting another event. A check 1128 is also made when traversing sub buffers to make sure 1129 that all the deltas on the previous sub buffer do not 1130 add up to be greater than the current time stamp. 1131 1132 NOTE: This adds significant overhead to recording of events, 1133 and should only be used to test the logic of the ring buffer. 1134 Do not use it on production systems. 1135 1136 Only say Y if you understand what this does, and you 1137 still want it enabled. Otherwise say N 1138 1139config MMIOTRACE_TEST 1140 tristate "Test module for mmiotrace" 1141 depends on MMIOTRACE && m 1142 help 1143 This is a dumb module for testing mmiotrace. It is very dangerous 1144 as it will write garbage to IO memory starting at a given address. 1145 However, it should be safe to use on e.g. unused portion of VRAM. 1146 1147 Say N, unless you absolutely know what you are doing. 1148 1149config PREEMPTIRQ_DELAY_TEST 1150 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers" 1151 depends on m 1152 help 1153 Select this option to build a test module that can help test latency 1154 tracers by executing a preempt or irq disable section with a user 1155 configurable delay. The module busy waits for the duration of the 1156 critical section. 1157 1158 For example, the following invocation generates a burst of three 1159 irq-disabled critical sections for 500us: 1160 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3 1161 1162 What's more, if you want to attach the test on the cpu which the latency 1163 tracer is running on, specify cpu_affinity=cpu_num at the end of the 1164 command. 1165 1166 If unsure, say N 1167 1168config SYNTH_EVENT_GEN_TEST 1169 tristate "Test module for in-kernel synthetic event generation" 1170 depends on SYNTH_EVENTS && m 1171 help 1172 This option creates a test module to check the base 1173 functionality of in-kernel synthetic event definition and 1174 generation. 1175 1176 To test, insert the module, and then check the trace buffer 1177 for the generated sample events. 1178 1179 If unsure, say N. 1180 1181config KPROBE_EVENT_GEN_TEST 1182 tristate "Test module for in-kernel kprobe event generation" 1183 depends on KPROBE_EVENTS && m 1184 help 1185 This option creates a test module to check the base 1186 functionality of in-kernel kprobe event definition. 1187 1188 To test, insert the module, and then check the trace buffer 1189 for the generated kprobe events. 1190 1191 If unsure, say N. 1192 1193config HIST_TRIGGERS_DEBUG 1194 bool "Hist trigger debug support" 1195 depends on HIST_TRIGGERS 1196 help 1197 Add "hist_debug" file for each event, which when read will 1198 dump out a bunch of internal details about the hist triggers 1199 defined on that event. 1200 1201 The hist_debug file serves a couple of purposes: 1202 1203 - Helps developers verify that nothing is broken. 1204 1205 - Provides educational information to support the details 1206 of the hist trigger internals as described by 1207 Documentation/trace/histogram-design.rst. 1208 1209 The hist_debug output only covers the data structures 1210 related to the histogram definitions themselves and doesn't 1211 display the internals of map buckets or variable values of 1212 running histograms. 1213 1214 If unsure, say N. 1215 1216source "kernel/trace/rv/Kconfig" 1217 1218endif # FTRACE 1219