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2541517c32
BPF programs, attached to kprobes, provide a safe way to execute
user-defined BPF byte-code programs without being able to crash or
hang the kernel in any way. The BPF engine makes sure that such
programs have a finite execution time and that they cannot break
out of their sandbox.
The user interface is to attach to a kprobe via the perf syscall:
struct perf_event_attr attr = {
.type = PERF_TYPE_TRACEPOINT,
.config = event_id,
...
};
event_fd = perf_event_open(&attr,...);
ioctl(event_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
'prog_fd' is a file descriptor associated with BPF program
previously loaded.
'event_id' is an ID of the kprobe created.
Closing 'event_fd':
close(event_fd);
... automatically detaches BPF program from it.
BPF programs can call in-kernel helper functions to:
- lookup/update/delete elements in maps
- probe_read - wraper of probe_kernel_read() used to access any
kernel data structures
BPF programs receive 'struct pt_regs *' as an input ('struct pt_regs' is
architecture dependent) and return 0 to ignore the event and 1 to store
kprobe event into the ring buffer.
Note, kprobes are a fundamentally _not_ a stable kernel ABI,
so BPF programs attached to kprobes must be recompiled for
every kernel version and user must supply correct LINUX_VERSION_CODE
in attr.kern_version during bpf_prog_load() call.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1427312966-8434-4-git-send-email-ast@plumgrid.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
71 lines
2.3 KiB
Makefile
71 lines
2.3 KiB
Makefile
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# Do not instrument the tracer itself:
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ifdef CONFIG_FUNCTION_TRACER
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ORIG_CFLAGS := $(KBUILD_CFLAGS)
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KBUILD_CFLAGS = $(subst $(CC_FLAGS_FTRACE),,$(ORIG_CFLAGS))
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ifdef CONFIG_FTRACE_SELFTEST
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# selftest needs instrumentation
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CFLAGS_trace_selftest_dynamic.o = $(CC_FLAGS_FTRACE)
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obj-y += trace_selftest_dynamic.o
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endif
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endif
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# If unlikely tracing is enabled, do not trace these files
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ifdef CONFIG_TRACING_BRANCHES
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KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
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endif
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CFLAGS_trace_benchmark.o := -I$(src)
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CFLAGS_trace_events_filter.o := -I$(src)
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obj-$(CONFIG_TRACE_CLOCK) += trace_clock.o
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obj-$(CONFIG_FUNCTION_TRACER) += libftrace.o
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obj-$(CONFIG_RING_BUFFER) += ring_buffer.o
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obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
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obj-$(CONFIG_TRACING) += trace.o
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obj-$(CONFIG_TRACING) += trace_output.o
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obj-$(CONFIG_TRACING) += trace_seq.o
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obj-$(CONFIG_TRACING) += trace_stat.o
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obj-$(CONFIG_TRACING) += trace_printk.o
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obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
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obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
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obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
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obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
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obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
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obj-$(CONFIG_NOP_TRACER) += trace_nop.o
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obj-$(CONFIG_STACK_TRACER) += trace_stack.o
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obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
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obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
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obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
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obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
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ifeq ($(CONFIG_BLOCK),y)
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obj-$(CONFIG_EVENT_TRACING) += blktrace.o
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endif
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obj-$(CONFIG_EVENT_TRACING) += trace_events.o
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obj-$(CONFIG_EVENT_TRACING) += trace_export.o
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obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
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ifeq ($(CONFIG_PERF_EVENTS),y)
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obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o
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endif
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obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
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obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o
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obj-$(CONFIG_BPF_SYSCALL) += bpf_trace.o
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obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o
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obj-$(CONFIG_TRACEPOINTS) += power-traces.o
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ifeq ($(CONFIG_PM),y)
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obj-$(CONFIG_TRACEPOINTS) += rpm-traces.o
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endif
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ifeq ($(CONFIG_TRACING),y)
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obj-$(CONFIG_KGDB_KDB) += trace_kdb.o
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endif
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obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
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obj-$(CONFIG_UPROBE_EVENT) += trace_uprobe.o
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obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o
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libftrace-y := ftrace.o
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