f2461fc82a
Create tracepoint_synchronize_unregister() which must be called before the end of exit() to make sure every probe callers have exited the non preemptible section and thus are not executing the probe code anymore. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
135 lines
3.8 KiB
C
135 lines
3.8 KiB
C
#ifndef _LINUX_TRACEPOINT_H
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#define _LINUX_TRACEPOINT_H
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/*
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* Kernel Tracepoint API.
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*
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* See Documentation/tracepoint.txt.
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*
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* (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
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*
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* Heavily inspired from the Linux Kernel Markers.
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*
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* This file is released under the GPLv2.
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* See the file COPYING for more details.
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*/
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#include <linux/types.h>
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#include <linux/rcupdate.h>
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struct module;
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struct tracepoint;
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struct tracepoint {
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const char *name; /* Tracepoint name */
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int state; /* State. */
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void **funcs;
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} __attribute__((aligned(8)));
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#define TPPROTO(args...) args
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#define TPARGS(args...) args
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#ifdef CONFIG_TRACEPOINTS
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/*
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* it_func[0] is never NULL because there is at least one element in the array
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* when the array itself is non NULL.
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*/
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#define __DO_TRACE(tp, proto, args) \
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do { \
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void **it_func; \
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\
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rcu_read_lock_sched(); \
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it_func = rcu_dereference((tp)->funcs); \
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if (it_func) { \
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do { \
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((void(*)(proto))(*it_func))(args); \
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} while (*(++it_func)); \
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} \
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rcu_read_unlock_sched(); \
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} while (0)
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/*
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* Make sure the alignment of the structure in the __tracepoints section will
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* not add unwanted padding between the beginning of the section and the
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* structure. Force alignment to the same alignment as the section start.
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*/
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#define DEFINE_TRACE(name, proto, args) \
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static inline void trace_##name(proto) \
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{ \
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static const char __tpstrtab_##name[] \
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__attribute__((section("__tracepoints_strings"))) \
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= #name ":" #proto; \
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static struct tracepoint __tracepoint_##name \
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__attribute__((section("__tracepoints"), aligned(8))) = \
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{ __tpstrtab_##name, 0, NULL }; \
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if (unlikely(__tracepoint_##name.state)) \
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__DO_TRACE(&__tracepoint_##name, \
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TPPROTO(proto), TPARGS(args)); \
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} \
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static inline int register_trace_##name(void (*probe)(proto)) \
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{ \
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return tracepoint_probe_register(#name ":" #proto, \
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(void *)probe); \
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} \
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static inline void unregister_trace_##name(void (*probe)(proto))\
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{ \
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tracepoint_probe_unregister(#name ":" #proto, \
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(void *)probe); \
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}
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extern void tracepoint_update_probe_range(struct tracepoint *begin,
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struct tracepoint *end);
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#else /* !CONFIG_TRACEPOINTS */
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#define DEFINE_TRACE(name, proto, args) \
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static inline void _do_trace_##name(struct tracepoint *tp, proto) \
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{ } \
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static inline void trace_##name(proto) \
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{ } \
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static inline int register_trace_##name(void (*probe)(proto)) \
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{ \
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return -ENOSYS; \
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} \
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static inline void unregister_trace_##name(void (*probe)(proto))\
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{ }
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static inline void tracepoint_update_probe_range(struct tracepoint *begin,
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struct tracepoint *end)
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{ }
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#endif /* CONFIG_TRACEPOINTS */
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/*
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* Connect a probe to a tracepoint.
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* Internal API, should not be used directly.
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*/
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extern int tracepoint_probe_register(const char *name, void *probe);
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/*
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* Disconnect a probe from a tracepoint.
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* Internal API, should not be used directly.
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*/
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extern int tracepoint_probe_unregister(const char *name, void *probe);
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struct tracepoint_iter {
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struct module *module;
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struct tracepoint *tracepoint;
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};
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extern void tracepoint_iter_start(struct tracepoint_iter *iter);
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extern void tracepoint_iter_next(struct tracepoint_iter *iter);
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extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
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extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
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extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
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struct tracepoint *begin, struct tracepoint *end);
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/*
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* tracepoint_synchronize_unregister must be called between the last tracepoint
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* probe unregistration and the end of module exit to make sure there is no
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* caller executing a probe when it is freed.
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*/
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#define tracepoint_synchronize_unregister() synchronize_sched()
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#endif
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