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![Yonghong Song](/assets/img/avatar_default.png)
This patch enables multiple bpf attachments for a kprobe/uprobe/tracepoint single trace event. Each trace_event keeps a list of attached perf events. When an event happens, all attached bpf programs will be executed based on the order of attachment. A global bpf_event_mutex lock is introduced to protect prog_array attaching and detaching. An alternative will be introduce a mutex lock in every trace_event_call structure, but it takes a lot of extra memory. So a global bpf_event_mutex lock is a good compromise. The bpf prog detachment involves allocation of memory. If the allocation fails, a dummy do-nothing program will replace to-be-detached program in-place. Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
90 lines
2.5 KiB
C
90 lines
2.5 KiB
C
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#undef TRACE_SYSTEM_VAR
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#ifdef CONFIG_PERF_EVENTS
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#undef __entry
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#define __entry entry
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#undef __get_dynamic_array
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#define __get_dynamic_array(field) \
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((void *)__entry + (__entry->__data_loc_##field & 0xffff))
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#undef __get_dynamic_array_len
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#define __get_dynamic_array_len(field) \
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((__entry->__data_loc_##field >> 16) & 0xffff)
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#undef __get_str
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#define __get_str(field) ((char *)__get_dynamic_array(field))
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#undef __get_bitmask
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#define __get_bitmask(field) (char *)__get_dynamic_array(field)
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#undef __perf_count
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#define __perf_count(c) (__count = (c))
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#undef __perf_task
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#define __perf_task(t) (__task = (t))
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#undef DECLARE_EVENT_CLASS
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#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
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static notrace void \
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perf_trace_##call(void *__data, proto) \
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{ \
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struct trace_event_call *event_call = __data; \
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struct trace_event_data_offsets_##call __maybe_unused __data_offsets;\
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struct trace_event_raw_##call *entry; \
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struct pt_regs *__regs; \
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u64 __count = 1; \
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struct task_struct *__task = NULL; \
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struct hlist_head *head; \
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int __entry_size; \
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int __data_size; \
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int rctx; \
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\
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__data_size = trace_event_get_offsets_##call(&__data_offsets, args); \
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\
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head = this_cpu_ptr(event_call->perf_events); \
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if (!bpf_prog_array_valid(event_call) && \
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__builtin_constant_p(!__task) && !__task && \
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hlist_empty(head)) \
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return; \
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\
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__entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\
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sizeof(u64)); \
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__entry_size -= sizeof(u32); \
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\
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entry = perf_trace_buf_alloc(__entry_size, &__regs, &rctx); \
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if (!entry) \
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return; \
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\
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perf_fetch_caller_regs(__regs); \
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\
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tstruct \
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\
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{ assign; } \
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\
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perf_trace_run_bpf_submit(entry, __entry_size, rctx, \
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event_call, __count, __regs, \
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head, __task); \
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}
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/*
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* This part is compiled out, it is only here as a build time check
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* to make sure that if the tracepoint handling changes, the
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* perf probe will fail to compile unless it too is updated.
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*/
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#undef DEFINE_EVENT
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#define DEFINE_EVENT(template, call, proto, args) \
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static inline void perf_test_probe_##call(void) \
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{ \
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check_trace_callback_type_##call(perf_trace_##template); \
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}
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#undef DEFINE_EVENT_PRINT
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#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
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DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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#endif /* CONFIG_PERF_EVENTS */
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