diff options
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 34 | ||||
| -rw-r--r-- | kernel/trace/Kconfig | 19 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 6 |
4 files changed, 31 insertions, 30 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 15415243a9a..47aabeebbdf 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -1,26 +1,23 @@ - Kprobe-based Event Tracer - ========================= + Kprobe-based Event Tracing + ========================== Documentation is written by Masami Hiramatsu Overview -------- -This tracer is similar to the events tracer which is based on Tracepoint -infrastructure. Instead of Tracepoint, this tracer is based on kprobes(kprobe -and kretprobe). It probes anywhere where kprobes can probe(this means, all -functions body except for __kprobes functions). +These events are similar to tracepoint based events. Instead of Tracepoint, +this is based on kprobes (kprobe and kretprobe). So it can probe wherever +kprobes can probe (this means, all functions body except for __kprobes +functions). Unlike the Tracepoint based event, this can be added and removed +dynamically, on the fly. -Unlike the function tracer, this tracer can probe instructions inside of -kernel functions. It allows you to check which instruction has been executed. +To enable this feature, build your kernel with CONFIG_KPROBE_TRACING=y. -Unlike the Tracepoint based events tracer, this tracer can add and remove -probe points on the fly. - -Similar to the events tracer, this tracer doesn't need to be activated via -current_tracer, instead of that, just set probe points via -/sys/kernel/debug/tracing/kprobe_events. And you can set filters on each -probe events via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/filter. +Similar to the events tracer, this doesn't need to be activated via +current_tracer. Instead of that, add probe points via +/sys/kernel/debug/tracing/kprobe_events, and enable it via +/sys/kernel/debug/tracing/events/kprobes/<EVENT>/enabled. Synopsis of kprobe_events @@ -55,9 +52,9 @@ Per-Probe Event Filtering ------------------------- Per-probe event filtering feature allows you to set different filter on each probe and gives you what arguments will be shown in trace buffer. If an event -name is specified right after 'p:' or 'r:' in kprobe_events, the tracer adds -an event under tracing/events/kprobes/<EVENT>, at the directory you can see -'id', 'enabled', 'format' and 'filter'. +name is specified right after 'p:' or 'r:' in kprobe_events, it adds an event +under tracing/events/kprobes/<EVENT>, at the directory you can see 'id', +'enabled', 'format' and 'filter'. enabled: You can enable/disable the probe by writing 1 or 0 on it. @@ -71,6 +68,7 @@ filter: id: This shows the id of this probe event. + Event Profiling --------------- You can check the total number of probe hits and probe miss-hits via diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 15372a9f239..f05671609a8 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -428,17 +428,22 @@ config BLK_DEV_IO_TRACE If unsure, say N. -config KPROBE_TRACER +config KPROBE_EVENT depends on KPROBES depends on X86 - bool "Trace kprobes" + bool "Enable kprobes-based dynamic events" select TRACING - select GENERIC_TRACER + default y help - This tracer probes everywhere where kprobes can probe it, and - records various registers and memories specified by user. - This also allows you to trace kprobe probe points as a dynamic - defined events. It provides per-probe event filtering interface. + 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 DYNAMIC_FTRACE bool "enable/disable ftrace tracepoints dynamically" diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index c8cb75d7f28..edc3a3cca1a 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -53,7 +53,7 @@ obj-$(CONFIG_EVENT_TRACING) += trace_export.o obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o obj-$(CONFIG_EVENT_PROFILE) += trace_event_profile.o obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o -obj-$(CONFIG_KPROBE_TRACER) += trace_kprobe.o +obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o obj-$(CONFIG_EVENT_TRACING) += power-traces.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index a86c3ac0df2..cf17a6694f3 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1,5 +1,5 @@ /* - * kprobe based kernel tracer + * Kprobes-based tracing events * * Created by Masami Hiramatsu <mhiramat@redhat.com> * @@ -57,8 +57,6 @@ const char *reserved_field_names[] = { FIELD_STRING_FUNC, }; -/* currently, trace_kprobe only supports X86. */ - struct fetch_func { unsigned long (*func)(struct pt_regs *, void *); void *data; @@ -191,7 +189,7 @@ static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data) } /** - * Kprobe tracer core functions + * Kprobe event core functions */ struct probe_arg { |