a0bca6a59e
Impact: new API. Allow markers to be used only for declaration, without function call associated. Useful to create specialized probes. The problem we had is that two function calls were required when one wanted to put a marker in a tracepoint probe. Now the marker can be used simply for trace data type declaration, leaving the trace write work within the tracepoint probe without any additional function call. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
220 lines
6.9 KiB
C
220 lines
6.9 KiB
C
#ifndef _LINUX_MARKER_H
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#define _LINUX_MARKER_H
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/*
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* Code markup for dynamic and static tracing.
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*
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* See Documentation/marker.txt.
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*
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* (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
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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 <stdarg.h>
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#include <linux/types.h>
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struct module;
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struct marker;
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/**
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* marker_probe_func - Type of a marker probe function
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* @probe_private: probe private data
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* @call_private: call site private data
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* @fmt: format string
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* @args: variable argument list pointer. Use a pointer to overcome C's
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* inability to pass this around as a pointer in a portable manner in
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* the callee otherwise.
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*
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* Type of marker probe functions. They receive the mdata and need to parse the
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* format string to recover the variable argument list.
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*/
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typedef void marker_probe_func(void *probe_private, void *call_private,
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const char *fmt, va_list *args);
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struct marker_probe_closure {
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marker_probe_func *func; /* Callback */
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void *probe_private; /* Private probe data */
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};
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struct marker {
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const char *name; /* Marker name */
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const char *format; /* Marker format string, describing the
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* variable argument list.
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*/
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char state; /* Marker state. */
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char ptype; /* probe type : 0 : single, 1 : multi */
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/* Probe wrapper */
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void (*call)(const struct marker *mdata, void *call_private, ...);
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struct marker_probe_closure single;
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struct marker_probe_closure *multi;
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const char *tp_name; /* Optional tracepoint name */
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void *tp_cb; /* Optional tracepoint callback */
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} __attribute__((aligned(8)));
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#ifdef CONFIG_MARKERS
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#define _DEFINE_MARKER(name, tp_name_str, tp_cb, format) \
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static const char __mstrtab_##name[] \
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__attribute__((section("__markers_strings"))) \
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= #name "\0" format; \
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static struct marker __mark_##name \
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__attribute__((section("__markers"), aligned(8))) = \
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{ __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \
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0, 0, marker_probe_cb, { __mark_empty_function, NULL},\
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NULL, tp_name_str, tp_cb }
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#define DEFINE_MARKER(name, format) \
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_DEFINE_MARKER(name, NULL, NULL, format)
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#define DEFINE_MARKER_TP(name, tp_name, tp_cb, format) \
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_DEFINE_MARKER(name, #tp_name, tp_cb, format)
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/*
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* Note : the empty asm volatile with read constraint is used here instead of a
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* "used" attribute to fix a gcc 4.1.x bug.
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* Make sure the alignment of the structure in the __markers 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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* The "generic" argument controls which marker enabling mechanism must be used.
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* If generic is true, a variable read is used.
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* If generic is false, immediate values are used.
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*/
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#define __trace_mark(generic, name, call_private, format, args...) \
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do { \
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DEFINE_MARKER(name, format); \
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__mark_check_format(format, ## args); \
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if (unlikely(__mark_##name.state)) { \
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(*__mark_##name.call) \
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(&__mark_##name, call_private, ## args);\
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} \
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} while (0)
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#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
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do { \
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void __check_tp_type(void) \
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{ \
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register_trace_##tp_name(tp_cb); \
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} \
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DEFINE_MARKER_TP(name, tp_name, tp_cb, format); \
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__mark_check_format(format, ## args); \
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(*__mark_##name.call)(&__mark_##name, call_private, \
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## args); \
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} while (0)
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extern void marker_update_probe_range(struct marker *begin,
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struct marker *end);
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#define GET_MARKER(name) (__mark_##name)
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#else /* !CONFIG_MARKERS */
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#define DEFINE_MARKER(name, tp_name, tp_cb, format)
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#define __trace_mark(generic, name, call_private, format, args...) \
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__mark_check_format(format, ## args)
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#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
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do { \
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void __check_tp_type(void) \
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{ \
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register_trace_##tp_name(tp_cb); \
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} \
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__mark_check_format(format, ## args); \
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} while (0)
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static inline void marker_update_probe_range(struct marker *begin,
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struct marker *end)
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{ }
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#define GET_MARKER(name)
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#endif /* CONFIG_MARKERS */
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/**
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* trace_mark - Marker using code patching
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* @name: marker name, not quoted.
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* @format: format string
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* @args...: variable argument list
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*
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* Places a marker using optimized code patching technique (imv_read())
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* to be enabled when immediate values are present.
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*/
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#define trace_mark(name, format, args...) \
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__trace_mark(0, name, NULL, format, ## args)
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/**
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* _trace_mark - Marker using variable read
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* @name: marker name, not quoted.
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* @format: format string
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* @args...: variable argument list
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*
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* Places a marker using a standard memory read (_imv_read()) to be
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* enabled. Should be used for markers in code paths where instruction
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* modification based enabling is not welcome. (__init and __exit functions,
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* lockdep, some traps, printk).
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*/
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#define _trace_mark(name, format, args...) \
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__trace_mark(1, name, NULL, format, ## args)
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/**
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* trace_mark_tp - Marker in a tracepoint callback
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* @name: marker name, not quoted.
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* @tp_name: tracepoint name, not quoted.
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* @tp_cb: tracepoint callback. Should have an associated global symbol so it
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* is not optimized away by the compiler (should not be static).
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* @format: format string
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* @args...: variable argument list
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*
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* Places a marker in a tracepoint callback.
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*/
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#define trace_mark_tp(name, tp_name, tp_cb, format, args...) \
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__trace_mark_tp(name, NULL, tp_name, tp_cb, format, ## args)
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/**
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* MARK_NOARGS - Format string for a marker with no argument.
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*/
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#define MARK_NOARGS " "
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/* To be used for string format validity checking with gcc */
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static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
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{
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}
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#define __mark_check_format(format, args...) \
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do { \
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if (0) \
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___mark_check_format(format, ## args); \
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} while (0)
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extern marker_probe_func __mark_empty_function;
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extern void marker_probe_cb(const struct marker *mdata,
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void *call_private, ...);
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/*
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* Connect a probe to a marker.
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* private data pointer must be a valid allocated memory address, or NULL.
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*/
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extern int marker_probe_register(const char *name, const char *format,
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marker_probe_func *probe, void *probe_private);
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/*
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* Returns the private data given to marker_probe_register.
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*/
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extern int marker_probe_unregister(const char *name,
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marker_probe_func *probe, void *probe_private);
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/*
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* Unregister a marker by providing the registered private data.
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*/
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extern int marker_probe_unregister_private_data(marker_probe_func *probe,
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void *probe_private);
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extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
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int num);
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/*
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* marker_synchronize_unregister must be called between the last marker probe
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* unregistration and the end of module exit to make sure there is no caller
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* executing a probe when it is freed.
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*/
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#define marker_synchronize_unregister() synchronize_sched()
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#endif
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