arm64: idmap: Use "awx" flags for .idmap.text .pushsection directives

[mirror_ubuntu-artful-kernel.git] / kernel / trace / Kconfig

#
# Architectures that offer an FUNCTION_TRACER implementation should
#  select HAVE_FUNCTION_TRACER:
#

config USER_STACKTRACE_SUPPORT
        bool

config NOP_TRACER
        bool

config HAVE_FTRACE_NMI_ENTER
        bool
        help
          See Documentation/trace/ftrace-design.txt

config HAVE_FUNCTION_TRACER
        bool
        help
          See Documentation/trace/ftrace-design.txt

config HAVE_FUNCTION_GRAPH_TRACER
        bool
        help
          See Documentation/trace/ftrace-design.txt

config HAVE_DYNAMIC_FTRACE
        bool
        help
          See Documentation/trace/ftrace-design.txt

config HAVE_DYNAMIC_FTRACE_WITH_REGS
        bool

config HAVE_FTRACE_MCOUNT_RECORD
        bool
        help
          See Documentation/trace/ftrace-design.txt

config HAVE_SYSCALL_TRACEPOINTS
        bool
        help
          See Documentation/trace/ftrace-design.txt

config HAVE_FENTRY
        bool
        help
          Arch supports the gcc options -pg with -mfentry

config HAVE_C_RECORDMCOUNT
        bool
        help
          C version of recordmcount available?

config TRACER_MAX_TRACE
        bool

config TRACE_CLOCK
        bool

config RING_BUFFER
        bool
        select TRACE_CLOCK
        select IRQ_WORK

config FTRACE_NMI_ENTER
       bool
       depends on HAVE_FTRACE_NMI_ENTER
       default y

config EVENT_TRACING
        select CONTEXT_SWITCH_TRACER
        select GLOB
        bool

config CONTEXT_SWITCH_TRACER
        bool

config RING_BUFFER_ALLOW_SWAP
        bool
        help
         Allow the use of ring_buffer_swap_cpu.
         Adds a very slight overhead to tracing when enabled.

# All tracer options should select GENERIC_TRACER. For those options that are
# enabled by all tracers (context switch and event tracer) they select TRACING.
# This allows those options to appear when no other tracer is selected. But the
# options do not appear when something else selects it. We need the two options
# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
# hiding of the automatic options.

config TRACING
        bool
        select DEBUG_FS
        select RING_BUFFER
        select STACKTRACE if STACKTRACE_SUPPORT
        select TRACEPOINTS
        select NOP_TRACER
        select BINARY_PRINTF
        select EVENT_TRACING
        select TRACE_CLOCK

config GENERIC_TRACER
        bool
        select TRACING

#
# Minimum requirements an architecture has to meet for us to
# be able to offer generic tracing facilities:
#
config TRACING_SUPPORT
        bool
        # PPC32 has no irqflags tracing support, but it can use most of the
        # tracers anyway, they were tested to build and work. Note that new
        # exceptions to this list aren't welcomed, better implement the
        # irqflags tracing for your architecture.
        depends on TRACE_IRQFLAGS_SUPPORT || PPC32
        depends on STACKTRACE_SUPPORT
        default y

if TRACING_SUPPORT

menuconfig FTRACE
        bool "Tracers"
        default y if DEBUG_KERNEL
        help
          Enable the kernel tracing infrastructure.

if FTRACE

config FUNCTION_TRACER
        bool "Kernel Function Tracer"
        depends on HAVE_FUNCTION_TRACER
        select KALLSYMS
        select GENERIC_TRACER
        select CONTEXT_SWITCH_TRACER
        select GLOB
        select TASKS_RCU if PREEMPT
        help
          Enable the kernel to trace every kernel function. This is done
          by using a compiler feature to insert a small, 5-byte No-Operation
          instruction at the beginning of every kernel function, which NOP
          sequence is then dynamically patched into a tracer call when
          tracing is enabled by the administrator. If it's runtime disabled
          (the bootup default), then the overhead of the instructions is very
          small and not measurable even in micro-benchmarks.

config FUNCTION_GRAPH_TRACER
        bool "Kernel Function Graph Tracer"
        depends on HAVE_FUNCTION_GRAPH_TRACER
        depends on FUNCTION_TRACER
        depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
        default y
        help
          Enable the kernel to trace a function at both its return
          and its entry.
          Its first purpose is to trace the duration of functions and
          draw a call graph for each thread with some information like
          the return value. This is done by setting the current return
          address on the current task structure into a stack of calls.


config IRQSOFF_TRACER
        bool "Interrupts-off Latency Tracer"
        default n
        depends on TRACE_IRQFLAGS_SUPPORT
        depends on !ARCH_USES_GETTIMEOFFSET
        select TRACE_IRQFLAGS
        select GENERIC_TRACER
        select TRACER_MAX_TRACE
        select RING_BUFFER_ALLOW_SWAP
        select TRACER_SNAPSHOT
        select TRACER_SNAPSHOT_PER_CPU_SWAP
        help
          This option measures the time spent in irqs-off critical
          sections, with microsecond accuracy.

          The default measurement method is a maximum search, which is
          disabled by default and can be runtime (re-)started
          via:

              echo 0 > /sys/kernel/debug/tracing/tracing_max_latency

          (Note that kernel size and overhead increase with this option
          enabled. This option and the preempt-off timing option can be
          used together or separately.)

config PREEMPT_TRACER
        bool "Preemption-off Latency Tracer"
        default n
        depends on !ARCH_USES_GETTIMEOFFSET
        depends on PREEMPT
        select GENERIC_TRACER
        select TRACER_MAX_TRACE
        select RING_BUFFER_ALLOW_SWAP
        select TRACER_SNAPSHOT
        select TRACER_SNAPSHOT_PER_CPU_SWAP
        help
          This option measures the time spent in preemption-off critical
          sections, with microsecond accuracy.

          The default measurement method is a maximum search, which is
          disabled by default and can be runtime (re-)started
          via:

              echo 0 > /sys/kernel/debug/tracing/tracing_max_latency

          (Note that kernel size and overhead increase with this option
          enabled. This option and the irqs-off timing option can be
          used together or separately.)

config SCHED_TRACER
        bool "Scheduling Latency Tracer"
        select GENERIC_TRACER
        select CONTEXT_SWITCH_TRACER
        select TRACER_MAX_TRACE
        select TRACER_SNAPSHOT
        help
          This tracer tracks the latency of the highest priority task
          to be scheduled in, starting from the point it has woken up.

config HWLAT_TRACER
        bool "Tracer to detect hardware latencies (like SMIs)"
        select GENERIC_TRACER
        help
         This tracer, when enabled will create one or more kernel threads,
         depening on what the cpumask file is set to, which each thread
         spinning in a loop looking for interruptions caused by
         something other than the kernel. For example, if a
         System Management Interrupt (SMI) takes a noticeable amount of
         time, this tracer will detect it. This is useful for testing
         if a system is reliable for Real Time tasks.

         Some files are created in the tracing directory when this
         is enabled:

           hwlat_detector/width   - time in usecs for how long to spin for
           hwlat_detector/window  - time in usecs between the start of each
                                     iteration

         A kernel thread is created that will spin with interrupts disabled
         for "width" microseconds in every "widow" cycle. It will not spin
         for "window - width" microseconds, where the system can
         continue to operate.

         The output will appear in the trace and trace_pipe files.

         When the tracer is not running, it has no affect on the system,
         but when it is running, it can cause the system to be
         periodically non responsive. Do not run this tracer on a
         production system.

         To enable this tracer, echo in "hwlat" into the current_tracer
         file. Every time a latency is greater than tracing_thresh, it will
         be recorded into the ring buffer.

config ENABLE_DEFAULT_TRACERS
        bool "Trace process context switches and events"
        depends on !GENERIC_TRACER
        select TRACING
        help
          This tracer hooks to various trace points in the kernel,
          allowing the user to pick and choose which trace point they
          want to trace. It also includes the sched_switch tracer plugin.

config FTRACE_SYSCALLS
        bool "Trace syscalls"
        depends on HAVE_SYSCALL_TRACEPOINTS
        select GENERIC_TRACER
        select KALLSYMS
        help
          Basic tracer to catch the syscall entry and exit events.

config TRACER_SNAPSHOT
        bool "Create a snapshot trace buffer"
        select TRACER_MAX_TRACE
        help
          Allow tracing users to take snapshot of the current buffer using the
          ftrace interface, e.g.:

              echo 1 > /sys/kernel/debug/tracing/snapshot
              cat snapshot

config TRACER_SNAPSHOT_PER_CPU_SWAP
        bool "Allow snapshot to swap per CPU"
        depends on TRACER_SNAPSHOT
        select RING_BUFFER_ALLOW_SWAP
        help
          Allow doing a snapshot of a single CPU buffer instead of a
          full swap (all buffers). If this is set, then the following is
          allowed:

              echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot

          After which, only the tracing buffer for CPU 2 was swapped with
          the main tracing buffer, and the other CPU buffers remain the same.

          When this is enabled, this adds a little more overhead to the
          trace recording, as it needs to add some checks to synchronize
          recording with swaps. But this does not affect the performance
          of the overall system. This is enabled by default when the preempt
          or irq latency tracers are enabled, as those need to swap as well
          and already adds the overhead (plus a lot more).

config TRACE_BRANCH_PROFILING
        bool
        select GENERIC_TRACER

choice
        prompt "Branch Profiling"
        default BRANCH_PROFILE_NONE
        help
         The branch profiling is a software profiler. It will add hooks
         into the C conditionals to test which path a branch takes.

         The likely/unlikely profiler only looks at the conditions that
         are annotated with a likely or unlikely macro.

         The "all branch" profiler will profile every if-statement in the
         kernel. This profiler will also enable the likely/unlikely
         profiler.

         Either of the above profilers adds a bit of overhead to the system.
         If unsure, choose "No branch profiling".

config BRANCH_PROFILE_NONE
        bool "No branch profiling"
        help
          No branch profiling. Branch profiling adds a bit of overhead.
          Only enable it if you want to analyse the branching behavior.
          Otherwise keep it disabled.

config PROFILE_ANNOTATED_BRANCHES
        bool "Trace likely/unlikely profiler"
        select TRACE_BRANCH_PROFILING
        help
          This tracer profiles all likely and unlikely macros
          in the kernel. It will display the results in:

          /sys/kernel/debug/tracing/trace_stat/branch_annotated

          Note: this will add a significant overhead; only turn this
          on if you need to profile the system's use of these macros.

config PROFILE_ALL_BRANCHES
        bool "Profile all if conditionals"
        select TRACE_BRANCH_PROFILING
        help
          This tracer profiles all branch conditions. Every if ()
          taken in the kernel is recorded whether it hit or miss.
          The results will be displayed in:

          /sys/kernel/debug/tracing/trace_stat/branch_all

          This option also enables the likely/unlikely profiler.

          This configuration, when enabled, will impose a great overhead
          on the system. This should only be enabled when the system
          is to be analyzed in much detail.
endchoice

config TRACING_BRANCHES
        bool
        help
          Selected by tracers that will trace the likely and unlikely
          conditions. This prevents the tracers themselves from being
          profiled. Profiling the tracing infrastructure can only happen
          when the likelys and unlikelys are not being traced.

config BRANCH_TRACER
        bool "Trace likely/unlikely instances"
        depends on TRACE_BRANCH_PROFILING
        select TRACING_BRANCHES
        help
          This traces the events of likely and unlikely condition
          calls in the kernel.  The difference between this and the
          "Trace likely/unlikely profiler" is that this is not a
          histogram of the callers, but actually places the calling
          events into a running trace buffer to see when and where the
          events happened, as well as their results.

          Say N if unsure.

config STACK_TRACER
        bool "Trace max stack"
        depends on HAVE_FUNCTION_TRACER
        select FUNCTION_TRACER
        select STACKTRACE
        select KALLSYMS
        help
          This special tracer records the maximum stack footprint of the
          kernel and displays it in /sys/kernel/debug/tracing/stack_trace.

          This tracer works by hooking into every function call that the
          kernel executes, and keeping a maximum stack depth value and
          stack-trace saved.  If this is configured with DYNAMIC_FTRACE
          then it will not have any overhead while the stack tracer
          is disabled.

          To enable the stack tracer on bootup, pass in 'stacktrace'
          on the kernel command line.

          The stack tracer can also be enabled or disabled via the
          sysctl kernel.stack_tracer_enabled

          Say N if unsure.

config BLK_DEV_IO_TRACE
        bool "Support for tracing block IO actions"
        depends on SYSFS
        depends on BLOCK
        select RELAY
        select DEBUG_FS
        select TRACEPOINTS
        select GENERIC_TRACER
        select STACKTRACE
        help
          Say Y here if you want to be able to trace the block layer actions
          on a given queue. Tracing allows you to see any traffic happening
          on a block device queue. For more information (and the userspace
          support tools needed), fetch the blktrace tools from:

          git://git.kernel.dk/blktrace.git

          Tracing also is possible using the ftrace interface, e.g.:

            echo 1 > /sys/block/sda/sda1/trace/enable
            echo blk > /sys/kernel/debug/tracing/current_tracer
            cat /sys/kernel/debug/tracing/trace_pipe

          If unsure, say N.

config KPROBE_EVENTS
        depends on KPROBES
        depends on HAVE_REGS_AND_STACK_ACCESS_API
        bool "Enable kprobes-based dynamic events"
        select TRACING
        select PROBE_EVENTS
        default y
        help
          This allows the user to add tracing events (similar to tracepoints)
          on the fly via the ftrace interface. See
          Documentation/trace/kprobetrace.txt for more details.

          Those events can be inserted wherever kprobes can probe, and record
          various register and memory values.

          This option is also required by perf-probe subcommand of perf tools.
          If you want to use perf tools, this option is strongly recommended.

config UPROBE_EVENTS
        bool "Enable uprobes-based dynamic events"
        depends on ARCH_SUPPORTS_UPROBES
        depends on MMU
        depends on PERF_EVENTS
        select UPROBES
        select PROBE_EVENTS
        select TRACING
        default y
        help
          This allows the user to add tracing events on top of userspace
          dynamic events (similar to tracepoints) on the fly via the trace
          events interface. Those events can be inserted wherever uprobes
          can probe, and record various registers.
          This option is required if you plan to use perf-probe subcommand
          of perf tools on user space applications.

config BPF_EVENTS
        depends on BPF_SYSCALL
        depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
        bool
        default y
        help
          This allows the user to attach BPF programs to kprobe events.

config PROBE_EVENTS
        def_bool n

config DYNAMIC_FTRACE
        bool "enable/disable function tracing dynamically"
        depends on FUNCTION_TRACER
        depends on HAVE_DYNAMIC_FTRACE
        default y
        help
          This option will modify all the calls to function tracing
          dynamically (will patch them out of the binary image and
          replace them with a No-Op instruction) on boot up. During
          compile time, a table is made of all the locations that ftrace
          can function trace, and this table is linked into the kernel
          image. When this is enabled, functions can be individually
          enabled, and the functions not enabled will not affect
          performance of the system.

          See the files in /sys/kernel/debug/tracing:
            available_filter_functions
            set_ftrace_filter
            set_ftrace_notrace

          This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
          otherwise has native performance as long as no tracing is active.

config DYNAMIC_FTRACE_WITH_REGS
        def_bool y
        depends on DYNAMIC_FTRACE
        depends on HAVE_DYNAMIC_FTRACE_WITH_REGS

config FUNCTION_PROFILER
        bool "Kernel function profiler"
        depends on FUNCTION_TRACER
        default n
        help
          This option enables the kernel function profiler. A file is created
          in debugfs called function_profile_enabled which defaults to zero.
          When a 1 is echoed into this file profiling begins, and when a
          zero is entered, profiling stops. A "functions" file is created in
          the trace_stats directory; this file shows the list of functions that
          have been hit and their counters.

          If in doubt, say N.

config FTRACE_MCOUNT_RECORD
        def_bool y
        depends on DYNAMIC_FTRACE
        depends on HAVE_FTRACE_MCOUNT_RECORD

config FTRACE_SELFTEST
        bool

config FTRACE_STARTUP_TEST
        bool "Perform a startup test on ftrace"
        depends on GENERIC_TRACER
        select FTRACE_SELFTEST
        help
          This option performs a series of startup tests on ftrace. On bootup
          a series of tests are made to verify that the tracer is
          functioning properly. It will do tests on all the configured
          tracers of ftrace.

config EVENT_TRACE_TEST_SYSCALLS
        bool "Run selftest on syscall events"
        depends on FTRACE_STARTUP_TEST
        help
         This option will also enable testing every syscall event.
         It only enables the event and disables it and runs various loads
         with the event enabled. This adds a bit more time for kernel boot
         up since it runs this on every system call defined.

         TBD - enable a way to actually call the syscalls as we test their
               events

config MMIOTRACE
        bool "Memory mapped IO tracing"
        depends on HAVE_MMIOTRACE_SUPPORT && PCI
        select GENERIC_TRACER
        help
          Mmiotrace traces Memory Mapped I/O access and is meant for
          debugging and reverse engineering. It is called from the ioremap
          implementation and works via page faults. Tracing is disabled by
          default and can be enabled at run-time.

          See Documentation/trace/mmiotrace.txt.
          If you are not helping to develop drivers, say N.

config TRACING_MAP
        bool
        depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
        help
          tracing_map is a special-purpose lock-free map for tracing,
          separated out as a stand-alone facility in order to allow it
          to be shared between multiple tracers.  It isn't meant to be
          generally used outside of that context, and is normally
          selected by tracers that use it.

config HIST_TRIGGERS
        bool "Histogram triggers"
        depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
        select TRACING_MAP
        select TRACING
        default n
        help
          Hist triggers allow one or more arbitrary trace event fields
          to be aggregated into hash tables and dumped to stdout by
          reading a debugfs/tracefs file.  They're useful for
          gathering quick and dirty (though precise) summaries of
          event activity as an initial guide for further investigation
          using more advanced tools.

          See Documentation/trace/events.txt.
          If in doubt, say N.

config MMIOTRACE_TEST
        tristate "Test module for mmiotrace"
        depends on MMIOTRACE && m
        help
          This is a dumb module for testing mmiotrace. It is very dangerous
          as it will write garbage to IO memory starting at a given address.
          However, it should be safe to use on e.g. unused portion of VRAM.

          Say N, unless you absolutely know what you are doing.

config TRACEPOINT_BENCHMARK
        bool "Add tracepoint that benchmarks tracepoints"
        help
         This option creates the tracepoint "benchmark:benchmark_event".
         When the tracepoint is enabled, it kicks off a kernel thread that
         goes into an infinite loop (calling cond_sched() to let other tasks
         run), and calls the tracepoint. Each iteration will record the time
         it took to write to the tracepoint and the next iteration that
         data will be passed to the tracepoint itself. That is, the tracepoint
         will report the time it took to do the previous tracepoint.
         The string written to the tracepoint is a static string of 128 bytes
         to keep the time the same. The initial string is simply a write of
         "START". The second string records the cold cache time of the first
         write which is not added to the rest of the calculations.

         As it is a tight loop, it benchmarks as hot cache. That's fine because
         we care most about hot paths that are probably in cache already.

         An example of the output:

              START
              first=3672 [COLD CACHED]
              last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
              last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
              last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
              last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
              last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
              last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666


config RING_BUFFER_BENCHMARK
        tristate "Ring buffer benchmark stress tester"
        depends on RING_BUFFER
        help
          This option creates a test to stress the ring buffer and benchmark it.
          It creates its own ring buffer such that it will not interfere with
          any other users of the ring buffer (such as ftrace). It then creates
          a producer and consumer that will run for 10 seconds and sleep for
          10 seconds. Each interval it will print out the number of events
          it recorded and give a rough estimate of how long each iteration took.

          It does not disable interrupts or raise its priority, so it may be
          affected by processes that are running.

          If unsure, say N.

config RING_BUFFER_STARTUP_TEST
       bool "Ring buffer startup self test"
       depends on RING_BUFFER
       help
         Run a simple self test on the ring buffer on boot up. Late in the
         kernel boot sequence, the test will start that kicks off
         a thread per cpu. Each thread will write various size events
         into the ring buffer. Another thread is created to send IPIs
         to each of the threads, where the IPI handler will also write
         to the ring buffer, to test/stress the nesting ability.
         If any anomalies are discovered, a warning will be displayed
         and all ring buffers will be disabled.

         The test runs for 10 seconds. This will slow your boot time
         by at least 10 more seconds.

         At the end of the test, statics and more checks are done.
         It will output the stats of each per cpu buffer. What
         was written, the sizes, what was read, what was lost, and
         other similar details.

         If unsure, say N

config TRACE_EVAL_MAP_FILE
       bool "Show eval mappings for trace events"
       depends on TRACING
       help
        The "print fmt" of the trace events will show the enum/sizeof names
        instead of their values. This can cause problems for user space tools
        that use this string to parse the raw data as user space does not know
        how to convert the string to its value.

        To fix this, there's a special macro in the kernel that can be used
        to convert an enum/sizeof into its value. If this macro is used, then
        the print fmt strings will be converted to their values.

        If something does not get converted properly, this option can be
        used to show what enums/sizeof the kernel tried to convert.

        This option is for debugging the conversions. A file is created
        in the tracing directory called "eval_map" that will show the
        names matched with their values and what trace event system they
        belong too.

        Normally, the mapping of the strings to values will be freed after
        boot up or module load. With this option, they will not be freed, as
        they are needed for the "eval_map" file. Enabling this option will
        increase the memory footprint of the running kernel.

        If unsure, say N

config TRACING_EVENTS_GPIO
        bool "Trace gpio events"
        depends on GPIOLIB
        default y
        help
          Enable tracing events for gpio subsystem

endif # FTRACE

endif # TRACING_SUPPORT