2 * Copyright (C) 2007 Mathieu Desnoyers
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include <urcu/rculist.h>
24 #include <urcu/hlist.h>
27 #include <ust/marker.h>
28 #include <ust/tracepoint.h>
32 #include "tracercore.h"
35 __thread
long ust_reg_stack
[500];
36 volatile __thread
long *ust_reg_stack_ptr
= (long *) 0;
38 extern struct marker __start___markers
[] __attribute__((visibility("hidden")));
39 extern struct marker __stop___markers
[] __attribute__((visibility("hidden")));
41 /* Set to 1 to enable marker debug output */
42 static const int marker_debug
;
45 * markers_mutex nests inside module_mutex. Markers mutex protects the builtin
46 * and module markers and the hash table.
48 static DEFINE_MUTEX(markers_mutex
);
50 static CDS_LIST_HEAD(libs
);
53 void lock_markers(void)
55 pthread_mutex_lock(&markers_mutex
);
58 void unlock_markers(void)
60 pthread_mutex_unlock(&markers_mutex
);
64 * Marker hash table, containing the active markers.
65 * Protected by module_mutex.
67 #define MARKER_HASH_BITS 6
68 #define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
69 static struct cds_hlist_head marker_table
[MARKER_TABLE_SIZE
];
73 * It is used to make sure every handler has finished using its private data
74 * between two consecutive operation (add or remove) on a given marker. It is
75 * also used to delay the free of multiple probes array until a quiescent state
77 * marker entries modifications are protected by the markers_mutex.
80 struct cds_hlist_node hlist
;
84 void (*call
)(const struct marker
*mdata
, void *call_private
, struct registers
*regs
, ...);
85 struct marker_probe_closure single
;
86 struct marker_probe_closure
*multi
;
87 int refcount
; /* Number of times armed. 0 if disarmed. */
93 unsigned char ptype
:1;
94 unsigned char format_allocated
:1;
95 char channel
[0]; /* Contains channel'\0'name'\0'format'\0' */
98 #ifdef CONFIG_MARKERS_USERSPACE
99 static void marker_update_processes(void);
101 static void marker_update_processes(void)
107 * __mark_empty_function - Empty probe callback
108 * @mdata: marker data
109 * @probe_private: probe private data
110 * @call_private: call site private data
111 * @fmt: format string
112 * @...: variable argument list
114 * Empty callback provided as a probe to the markers. By providing this to a
115 * disabled marker, we make sure the execution flow is always valid even
116 * though the function pointer change and the marker enabling are two distinct
117 * operations that modifies the execution flow of preemptible code.
119 notrace
void __mark_empty_function(const struct marker
*mdata
,
120 void *probe_private
, struct registers
*regs
, void *call_private
, const char *fmt
, va_list *args
)
123 //ust// EXPORT_SYMBOL_GPL(__mark_empty_function);
126 * marker_probe_cb Callback that prepares the variable argument list for probes.
127 * @mdata: pointer of type struct marker
128 * @call_private: caller site private data
129 * @...: Variable argument list.
131 * Since we do not use "typical" pointer based RCU in the 1 argument case, we
132 * need to put a full cmm_smp_rmb() in this branch. This is why we do not use
133 * rcu_dereference() for the pointer read.
135 notrace
void marker_probe_cb(const struct marker
*mdata
,
136 void *call_private
, struct registers
*regs
, ...)
142 * rcu_read_lock_sched does two things : disabling preemption to make
143 * sure the teardown of the callbacks can be done correctly when they
144 * are in modules and they insure RCU read coherency.
146 //ust// rcu_read_lock_sched_notrace();
147 ptype
= mdata
->ptype
;
148 if (likely(!ptype
)) {
149 marker_probe_func
*func
;
150 /* Must read the ptype before ptr. They are not data dependant,
151 * so we put an explicit cmm_smp_rmb() here. */
153 func
= mdata
->single
.func
;
154 /* Must read the ptr before private data. They are not data
155 * dependant, so we put an explicit cmm_smp_rmb() here. */
157 va_start(args
, regs
);
158 func(mdata
, mdata
->single
.probe_private
, regs
, call_private
,
159 mdata
->format
, &args
);
162 struct marker_probe_closure
*multi
;
165 * Read mdata->ptype before mdata->multi.
168 multi
= mdata
->multi
;
170 * multi points to an array, therefore accessing the array
171 * depends on reading multi. However, even in this case,
172 * we must insure that the pointer is read _before_ the array
173 * data. Same as rcu_dereference, but we need a full cmm_smp_rmb()
174 * in the fast path, so put the explicit cmm_barrier here.
176 cmm_smp_read_barrier_depends();
177 for (i
= 0; multi
[i
].func
; i
++) {
178 va_start(args
, regs
);
179 multi
[i
].func(mdata
, multi
[i
].probe_private
,
180 regs
, call_private
, mdata
->format
, &args
);
184 //ust// rcu_read_unlock_sched_notrace();
186 //ust// EXPORT_SYMBOL_GPL(marker_probe_cb);
189 * marker_probe_cb Callback that does not prepare the variable argument list.
190 * @mdata: pointer of type struct marker
191 * @call_private: caller site private data
192 * @...: Variable argument list.
194 * Should be connected to markers "MARK_NOARGS".
196 static notrace
void marker_probe_cb_noarg(const struct marker
*mdata
,
197 void *call_private
, struct registers
*regs
, ...)
199 va_list args
; /* not initialized */
202 //ust// rcu_read_lock_sched_notrace();
203 ptype
= mdata
->ptype
;
204 if (likely(!ptype
)) {
205 marker_probe_func
*func
;
206 /* Must read the ptype before ptr. They are not data dependant,
207 * so we put an explicit cmm_smp_rmb() here. */
209 func
= mdata
->single
.func
;
210 /* Must read the ptr before private data. They are not data
211 * dependant, so we put an explicit cmm_smp_rmb() here. */
213 func(mdata
, mdata
->single
.probe_private
, regs
, call_private
,
214 mdata
->format
, &args
);
216 struct marker_probe_closure
*multi
;
219 * Read mdata->ptype before mdata->multi.
222 multi
= mdata
->multi
;
224 * multi points to an array, therefore accessing the array
225 * depends on reading multi. However, even in this case,
226 * we must insure that the pointer is read _before_ the array
227 * data. Same as rcu_dereference, but we need a full cmm_smp_rmb()
228 * in the fast path, so put the explicit cmm_barrier here.
230 cmm_smp_read_barrier_depends();
231 for (i
= 0; multi
[i
].func
; i
++)
232 multi
[i
].func(mdata
, multi
[i
].probe_private
, regs
,
233 call_private
, mdata
->format
, &args
);
235 //ust// rcu_read_unlock_sched_notrace();
238 static void free_old_closure(struct rcu_head
*head
)
240 struct marker_entry
*entry
= _ust_container_of(head
,
241 struct marker_entry
, rcu
);
243 /* Make sure we free the data before setting the pending flag to 0 */
245 entry
->rcu_pending
= 0;
248 static void debug_print_probes(struct marker_entry
*entry
)
256 DBG("Single probe : %p %p",
258 entry
->single
.probe_private
);
260 for (i
= 0; entry
->multi
[i
].func
; i
++)
261 DBG("Multi probe %d : %p %p", i
,
262 entry
->multi
[i
].func
,
263 entry
->multi
[i
].probe_private
);
267 static struct marker_probe_closure
*
268 marker_entry_add_probe(struct marker_entry
*entry
,
269 marker_probe_func
*probe
, void *probe_private
)
272 struct marker_probe_closure
*old
, *new;
276 debug_print_probes(entry
);
279 if (entry
->single
.func
== probe
&&
280 entry
->single
.probe_private
== probe_private
)
281 return ERR_PTR(-EBUSY
);
282 if (entry
->single
.func
== __mark_empty_function
) {
284 entry
->single
.func
= probe
;
285 entry
->single
.probe_private
= probe_private
;
288 debug_print_probes(entry
);
296 /* (N -> N+1), (N != 0, 1) probes */
297 for (nr_probes
= 0; old
[nr_probes
].func
; nr_probes
++)
298 if (old
[nr_probes
].func
== probe
299 && old
[nr_probes
].probe_private
301 return ERR_PTR(-EBUSY
);
303 /* + 2 : one for new probe, one for NULL func */
304 new = zmalloc((nr_probes
+ 2) * sizeof(struct marker_probe_closure
));
306 return ERR_PTR(-ENOMEM
);
308 new[0] = entry
->single
;
311 nr_probes
* sizeof(struct marker_probe_closure
));
312 new[nr_probes
].func
= probe
;
313 new[nr_probes
].probe_private
= probe_private
;
314 entry
->refcount
= nr_probes
+ 1;
317 debug_print_probes(entry
);
321 static struct marker_probe_closure
*
322 marker_entry_remove_probe(struct marker_entry
*entry
,
323 marker_probe_func
*probe
, void *probe_private
)
325 int nr_probes
= 0, nr_del
= 0, i
;
326 struct marker_probe_closure
*old
, *new;
330 debug_print_probes(entry
);
332 /* 0 -> N is an error */
333 WARN_ON(entry
->single
.func
== __mark_empty_function
);
335 WARN_ON(probe
&& entry
->single
.func
!= probe
);
336 WARN_ON(entry
->single
.probe_private
!= probe_private
);
337 entry
->single
.func
= __mark_empty_function
;
340 debug_print_probes(entry
);
343 /* (N -> M), (N > 1, M >= 0) probes */
344 for (nr_probes
= 0; old
[nr_probes
].func
; nr_probes
++) {
345 if ((!probe
|| old
[nr_probes
].func
== probe
)
346 && old
[nr_probes
].probe_private
352 if (nr_probes
- nr_del
== 0) {
353 /* N -> 0, (N > 1) */
354 entry
->single
.func
= __mark_empty_function
;
357 } else if (nr_probes
- nr_del
== 1) {
358 /* N -> 1, (N > 1) */
359 for (i
= 0; old
[i
].func
; i
++)
360 if ((probe
&& old
[i
].func
!= probe
) ||
361 old
[i
].probe_private
!= probe_private
)
362 entry
->single
= old
[i
];
367 /* N -> M, (N > 1, M > 1) */
369 new = zmalloc((nr_probes
- nr_del
+ 1) * sizeof(struct marker_probe_closure
));
371 return ERR_PTR(-ENOMEM
);
372 for (i
= 0; old
[i
].func
; i
++)
373 if ((probe
&& old
[i
].func
!= probe
) ||
374 old
[i
].probe_private
!= probe_private
)
376 entry
->refcount
= nr_probes
- nr_del
;
380 debug_print_probes(entry
);
385 * Get marker if the marker is present in the marker hash table.
386 * Must be called with markers_mutex held.
387 * Returns NULL if not present.
389 static struct marker_entry
*get_marker(const char *channel
, const char *name
)
391 struct cds_hlist_head
*head
;
392 struct cds_hlist_node
*node
;
393 struct marker_entry
*e
;
394 size_t channel_len
= strlen(channel
) + 1;
395 size_t name_len
= strlen(name
) + 1;
398 hash
= jhash(channel
, channel_len
-1, 0) ^ jhash(name
, name_len
-1, 0);
399 head
= &marker_table
[hash
& ((1 << MARKER_HASH_BITS
)-1)];
400 cds_hlist_for_each_entry(e
, node
, head
, hlist
) {
401 if (!strcmp(channel
, e
->channel
) && !strcmp(name
, e
->name
))
408 * Add the marker to the marker hash table. Must be called with markers_mutex
411 static struct marker_entry
*add_marker(const char *channel
, const char *name
,
414 struct cds_hlist_head
*head
;
415 struct cds_hlist_node
*node
;
416 struct marker_entry
*e
;
417 size_t channel_len
= strlen(channel
) + 1;
418 size_t name_len
= strlen(name
) + 1;
419 size_t format_len
= 0;
422 hash
= jhash(channel
, channel_len
-1, 0) ^ jhash(name
, name_len
-1, 0);
424 format_len
= strlen(format
) + 1;
425 head
= &marker_table
[hash
& ((1 << MARKER_HASH_BITS
)-1)];
426 cds_hlist_for_each_entry(e
, node
, head
, hlist
) {
427 if (!strcmp(channel
, e
->channel
) && !strcmp(name
, e
->name
)) {
428 DBG("Marker %s.%s busy", channel
, name
);
429 return ERR_PTR(-EBUSY
); /* Already there */
433 * Using zmalloc here to allocate a variable length element. Could
434 * cause some memory fragmentation if overused.
436 e
= zmalloc(sizeof(struct marker_entry
)
437 + channel_len
+ name_len
+ format_len
);
439 return ERR_PTR(-ENOMEM
);
440 memcpy(e
->channel
, channel
, channel_len
);
441 e
->name
= &e
->channel
[channel_len
];
442 memcpy(e
->name
, name
, name_len
);
444 e
->format
= &e
->name
[name_len
];
445 memcpy(e
->format
, format
, format_len
);
446 if (strcmp(e
->format
, MARK_NOARGS
) == 0)
447 e
->call
= marker_probe_cb_noarg
;
449 e
->call
= marker_probe_cb
;
450 trace_mark(metadata
, core_marker_format
,
451 "channel %s name %s format %s",
452 e
->channel
, e
->name
, e
->format
);
455 e
->call
= marker_probe_cb
;
457 e
->single
.func
= __mark_empty_function
;
458 e
->single
.probe_private
= NULL
;
461 e
->format_allocated
= 0;
464 cds_hlist_add_head(&e
->hlist
, head
);
469 * Remove the marker from the marker hash table. Must be called with mutex_lock
472 static int remove_marker(const char *channel
, const char *name
)
474 struct cds_hlist_head
*head
;
475 struct cds_hlist_node
*node
;
476 struct marker_entry
*e
;
478 size_t channel_len
= strlen(channel
) + 1;
479 size_t name_len
= strlen(name
) + 1;
483 hash
= jhash(channel
, channel_len
-1, 0) ^ jhash(name
, name_len
-1, 0);
484 head
= &marker_table
[hash
& ((1 << MARKER_HASH_BITS
)-1)];
485 cds_hlist_for_each_entry(e
, node
, head
, hlist
) {
486 if (!strcmp(channel
, e
->channel
) && !strcmp(name
, e
->name
)) {
493 if (e
->single
.func
!= __mark_empty_function
)
495 cds_hlist_del(&e
->hlist
);
496 if (e
->format_allocated
)
498 ret
= ltt_channels_unregister(e
->channel
);
500 /* Make sure the call_rcu has been executed */
501 //ust// if (e->rcu_pending)
502 //ust// rcu_cmm_barrier_sched();
508 * Set the mark_entry format to the format found in the element.
510 static int marker_set_format(struct marker_entry
*entry
, const char *format
)
512 entry
->format
= strdup(format
);
515 entry
->format_allocated
= 1;
517 trace_mark(metadata
, core_marker_format
,
518 "channel %s name %s format %s",
519 entry
->channel
, entry
->name
, entry
->format
);
524 * Sets the probe callback corresponding to one marker.
526 static int set_marker(struct marker_entry
*entry
, struct marker
*elem
,
530 WARN_ON(strcmp(entry
->name
, elem
->name
) != 0);
533 if (strcmp(entry
->format
, elem
->format
) != 0) {
534 ERR("Format mismatch for probe %s (%s), marker (%s)",
541 ret
= marker_set_format(entry
, elem
->format
);
547 * probe_cb setup (statically known) is done here. It is
548 * asynchronous with the rest of execution, therefore we only
549 * pass from a "safe" callback (with argument) to an "unsafe"
550 * callback (does not set arguments).
552 elem
->call
= entry
->call
;
553 elem
->channel_id
= entry
->channel_id
;
554 elem
->event_id
= entry
->event_id
;
557 * We only update the single probe private data when the ptr is
558 * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
560 WARN_ON(elem
->single
.func
!= __mark_empty_function
561 && elem
->single
.probe_private
!= entry
->single
.probe_private
563 elem
->single
.probe_private
= entry
->single
.probe_private
;
565 * Make sure the private data is valid when we update the
569 elem
->single
.func
= entry
->single
.func
;
571 * We also make sure that the new probe callbacks array is consistent
572 * before setting a pointer to it.
574 rcu_assign_pointer(elem
->multi
, entry
->multi
);
576 * Update the function or multi probe array pointer before setting the
580 elem
->ptype
= entry
->ptype
;
582 if (elem
->tp_name
&& (active
^ _imv_read(elem
->state
))) {
583 WARN_ON(!elem
->tp_cb
);
585 * It is ok to directly call the probe registration because type
586 * checking has been done in the __trace_mark_tp() macro.
591 * try_module_get should always succeed because we hold
592 * markers_mutex to get the tp_cb address.
594 //ust// ret = try_module_get(__module_text_address(
595 //ust// (unsigned long)elem->tp_cb));
596 //ust// BUG_ON(!ret);
597 ret
= tracepoint_probe_register_noupdate(
601 ret
= tracepoint_probe_unregister_noupdate(
605 * tracepoint_probe_update_all() must be called
606 * before the module containing tp_cb is unloaded.
608 //ust// module_put(__module_text_address(
609 //ust// (unsigned long)elem->tp_cb));
612 elem
->state__imv
= active
;
618 * Disable a marker and its probe callback.
619 * Note: only waiting an RCU period after setting elem->call to the empty
620 * function insures that the original callback is not used anymore. This insured
621 * by rcu_read_lock_sched around the call site.
623 static void disable_marker(struct marker
*elem
)
627 /* leave "call" as is. It is known statically. */
628 if (elem
->tp_name
&& _imv_read(elem
->state
)) {
629 WARN_ON(!elem
->tp_cb
);
631 * It is ok to directly call the probe registration because type
632 * checking has been done in the __trace_mark_tp() macro.
634 ret
= tracepoint_probe_unregister_noupdate(elem
->tp_name
,
638 * tracepoint_probe_update_all() must be called
639 * before the module containing tp_cb is unloaded.
641 //ust// module_put(__module_text_address((unsigned long)elem->tp_cb));
643 elem
->state__imv
= 0;
644 elem
->single
.func
= __mark_empty_function
;
645 /* Update the function before setting the ptype */
647 elem
->ptype
= 0; /* single probe */
649 * Leave the private data and channel_id/event_id there, because removal
650 * is racy and should be done only after an RCU period. These are never
651 * used until the next initialization anyway.
656 * is_marker_enabled - Check if a marker is enabled
657 * @channel: channel name
660 * Returns 1 if the marker is enabled, 0 if disabled.
662 int is_marker_enabled(const char *channel
, const char *name
)
664 struct marker_entry
*entry
;
666 pthread_mutex_lock(&markers_mutex
);
667 entry
= get_marker(channel
, name
);
668 pthread_mutex_unlock(&markers_mutex
);
670 return entry
&& !!entry
->refcount
;
674 * marker_update_probe_range - Update a probe range
675 * @begin: beginning of the range
676 * @end: end of the range
678 * Updates the probe callback corresponding to a range of markers.
680 void marker_update_probe_range(struct marker
*begin
,
684 struct marker_entry
*mark_entry
;
686 pthread_mutex_lock(&markers_mutex
);
687 for (iter
= begin
; iter
< end
; iter
++) {
688 mark_entry
= get_marker(iter
->channel
, iter
->name
);
690 set_marker(mark_entry
, iter
, !!mark_entry
->refcount
);
692 * ignore error, continue
695 /* This is added for UST. We emit a core_marker_id event
696 * for markers that are already registered to a probe
697 * upon library load. Otherwise, no core_marker_id will
698 * be generated for these markers. Is this the right thing
701 trace_mark(metadata
, core_marker_id
,
702 "channel %s name %s event_id %hu "
703 "int #1u%zu long #1u%zu pointer #1u%zu "
704 "size_t #1u%zu alignment #1u%u",
705 iter
->channel
, iter
->name
, mark_entry
->event_id
,
706 sizeof(int), sizeof(long), sizeof(void *),
707 sizeof(size_t), ltt_get_alignment());
709 disable_marker(iter
);
712 pthread_mutex_unlock(&markers_mutex
);
715 static void lib_update_markers(void)
719 /* FIXME: we should probably take a mutex here on libs */
720 //ust// pthread_mutex_lock(&module_mutex);
721 cds_list_for_each_entry(lib
, &libs
, list
)
722 marker_update_probe_range(lib
->markers_start
,
723 lib
->markers_start
+ lib
->markers_count
);
724 //ust// pthread_mutex_unlock(&module_mutex);
728 * Update probes, removing the faulty probes.
730 * Internal callback only changed before the first probe is connected to it.
731 * Single probe private data can only be changed on 0 -> 1 and 2 -> 1
732 * transitions. All other transitions will leave the old private data valid.
733 * This makes the non-atomicity of the callback/private data updates valid.
735 * "special case" updates :
740 * Other updates all behave the same, just like the 2 -> 3 or 3 -> 2 updates.
741 * Site effect : marker_set_format may delete the marker entry (creating a
744 static void marker_update_probes(void)
746 /* Core kernel markers */
747 //ust// marker_update_probe_range(__start___markers, __stop___markers);
748 /* Markers in modules. */
749 //ust// module_update_markers();
750 lib_update_markers();
751 tracepoint_probe_update_all();
752 /* Update immediate values */
754 //ust// module_imv_update(); /* FIXME: need to port for libs? */
755 marker_update_processes();
759 * marker_probe_register - Connect a probe to a marker
760 * @channel: marker channel
762 * @format: format string
763 * @probe: probe handler
764 * @probe_private: probe private data
766 * private data must be a valid allocated memory address, or NULL.
767 * Returns 0 if ok, error value on error.
768 * The probe address must at least be aligned on the architecture pointer size.
770 int marker_probe_register(const char *channel
, const char *name
,
771 const char *format
, marker_probe_func
*probe
,
774 struct marker_entry
*entry
;
775 int ret
= 0, ret_err
;
776 struct marker_probe_closure
*old
;
779 pthread_mutex_lock(&markers_mutex
);
780 entry
= get_marker(channel
, name
);
783 entry
= add_marker(channel
, name
, format
);
785 ret
= PTR_ERR(entry
);
788 ret
= ltt_channels_register(channel
);
790 goto error_remove_marker
;
791 ret
= ltt_channels_get_index_from_name(channel
);
793 goto error_unregister_channel
;
794 entry
->channel_id
= ret
;
795 ret
= ltt_channels_get_event_id(channel
, name
);
797 goto error_unregister_channel
;
798 entry
->event_id
= ret
;
800 trace_mark(metadata
, core_marker_id
,
801 "channel %s name %s event_id %hu "
802 "int #1u%zu long #1u%zu pointer #1u%zu "
803 "size_t #1u%zu alignment #1u%u",
804 channel
, name
, entry
->event_id
,
805 sizeof(int), sizeof(long), sizeof(void *),
806 sizeof(size_t), ltt_get_alignment());
809 ret
= marker_set_format(entry
, format
);
810 else if (strcmp(entry
->format
, format
))
817 * If we detect that a call_rcu is pending for this marker,
818 * make sure it's executed now.
820 //ust// if (entry->rcu_pending)
821 //ust// rcu_cmm_barrier_sched();
822 old
= marker_entry_add_probe(entry
, probe
, probe_private
);
826 goto error_unregister_channel
;
830 pthread_mutex_unlock(&markers_mutex
);
832 /* Activate marker if necessary */
833 marker_update_probes();
835 pthread_mutex_lock(&markers_mutex
);
836 entry
= get_marker(channel
, name
);
839 //ust// if (entry->rcu_pending)
840 //ust// rcu_cmm_barrier_sched();
842 entry
->rcu_pending
= 1;
843 /* write rcu_pending before calling the RCU callback */
845 //ust// call_rcu_sched(&entry->rcu, free_old_closure);
846 synchronize_rcu(); free_old_closure(&entry
->rcu
);
849 error_unregister_channel
:
850 ret_err
= ltt_channels_unregister(channel
);
853 ret_err
= remove_marker(channel
, name
);
856 pthread_mutex_unlock(&markers_mutex
);
859 //ust// EXPORT_SYMBOL_GPL(marker_probe_register);
862 * marker_probe_unregister - Disconnect a probe from a marker
863 * @channel: marker channel
865 * @probe: probe function pointer
866 * @probe_private: probe private data
868 * Returns the private data given to marker_probe_register, or an ERR_PTR().
869 * We do not need to call a synchronize_sched to make sure the probes have
870 * finished running before doing a module unload, because the module unload
871 * itself uses stop_machine(), which insures that every preempt disabled section
874 int marker_probe_unregister(const char *channel
, const char *name
,
875 marker_probe_func
*probe
, void *probe_private
)
877 struct marker_entry
*entry
;
878 struct marker_probe_closure
*old
;
881 pthread_mutex_lock(&markers_mutex
);
882 entry
= get_marker(channel
, name
);
885 //ust// if (entry->rcu_pending)
886 //ust// rcu_cmm_barrier_sched();
887 old
= marker_entry_remove_probe(entry
, probe
, probe_private
);
888 pthread_mutex_unlock(&markers_mutex
);
890 marker_update_probes();
892 pthread_mutex_lock(&markers_mutex
);
893 entry
= get_marker(channel
, name
);
896 //ust// if (entry->rcu_pending)
897 //ust// rcu_cmm_barrier_sched();
899 entry
->rcu_pending
= 1;
900 /* write rcu_pending before calling the RCU callback */
902 //ust// call_rcu_sched(&entry->rcu, free_old_closure);
903 synchronize_rcu(); free_old_closure(&entry
->rcu
);
904 remove_marker(channel
, name
); /* Ignore busy error message */
907 pthread_mutex_unlock(&markers_mutex
);
910 //ust// EXPORT_SYMBOL_GPL(marker_probe_unregister);
912 static struct marker_entry
*
913 get_marker_from_private_data(marker_probe_func
*probe
, void *probe_private
)
915 struct marker_entry
*entry
;
917 struct cds_hlist_head
*head
;
918 struct cds_hlist_node
*node
;
920 for (i
= 0; i
< MARKER_TABLE_SIZE
; i
++) {
921 head
= &marker_table
[i
];
922 cds_hlist_for_each_entry(entry
, node
, head
, hlist
) {
924 if (entry
->single
.func
== probe
925 && entry
->single
.probe_private
929 struct marker_probe_closure
*closure
;
930 closure
= entry
->multi
;
931 for (i
= 0; closure
[i
].func
; i
++) {
932 if (closure
[i
].func
== probe
&&
933 closure
[i
].probe_private
944 * marker_probe_unregister_private_data - Disconnect a probe from a marker
945 * @probe: probe function
946 * @probe_private: probe private data
948 * Unregister a probe by providing the registered private data.
949 * Only removes the first marker found in hash table.
950 * Return 0 on success or error value.
951 * We do not need to call a synchronize_sched to make sure the probes have
952 * finished running before doing a module unload, because the module unload
953 * itself uses stop_machine(), which insures that every preempt disabled section
956 int marker_probe_unregister_private_data(marker_probe_func
*probe
,
959 struct marker_entry
*entry
;
961 struct marker_probe_closure
*old
;
962 char *channel
= NULL
, *name
= NULL
;
964 pthread_mutex_lock(&markers_mutex
);
965 entry
= get_marker_from_private_data(probe
, probe_private
);
970 //ust// if (entry->rcu_pending)
971 //ust// rcu_cmm_barrier_sched();
972 old
= marker_entry_remove_probe(entry
, NULL
, probe_private
);
973 channel
= strdup(entry
->channel
);
974 name
= strdup(entry
->name
);
975 pthread_mutex_unlock(&markers_mutex
);
977 marker_update_probes();
979 pthread_mutex_lock(&markers_mutex
);
980 entry
= get_marker(channel
, name
);
983 //ust// if (entry->rcu_pending)
984 //ust// rcu_cmm_barrier_sched();
986 entry
->rcu_pending
= 1;
987 /* write rcu_pending before calling the RCU callback */
989 //ust// call_rcu_sched(&entry->rcu, free_old_closure);
990 synchronize_rcu(); free_old_closure(&entry
->rcu
);
991 /* Ignore busy error message */
992 remove_marker(channel
, name
);
994 pthread_mutex_unlock(&markers_mutex
);
999 //ust// EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data);
1002 * marker_get_private_data - Get a marker's probe private data
1003 * @channel: marker channel
1004 * @name: marker name
1005 * @probe: probe to match
1006 * @num: get the nth matching probe's private data
1008 * Returns the nth private data pointer (starting from 0) matching, or an
1010 * Returns the private data pointer, or an ERR_PTR.
1011 * The private data pointer should _only_ be dereferenced if the caller is the
1012 * owner of the data, or its content could vanish. This is mostly used to
1013 * confirm that a caller is the owner of a registered probe.
1015 void *marker_get_private_data(const char *channel
, const char *name
,
1016 marker_probe_func
*probe
, int num
)
1018 struct cds_hlist_head
*head
;
1019 struct cds_hlist_node
*node
;
1020 struct marker_entry
*e
;
1021 size_t channel_len
= strlen(channel
) + 1;
1022 size_t name_len
= strlen(name
) + 1;
1026 hash
= jhash(channel
, channel_len
-1, 0) ^ jhash(name
, name_len
-1, 0);
1027 head
= &marker_table
[hash
& ((1 << MARKER_HASH_BITS
)-1)];
1028 cds_hlist_for_each_entry(e
, node
, head
, hlist
) {
1029 if (!strcmp(channel
, e
->channel
) && !strcmp(name
, e
->name
)) {
1031 if (num
== 0 && e
->single
.func
== probe
)
1032 return e
->single
.probe_private
;
1034 struct marker_probe_closure
*closure
;
1037 for (i
= 0; closure
[i
].func
; i
++) {
1038 if (closure
[i
].func
!= probe
)
1041 return closure
[i
].probe_private
;
1047 return ERR_PTR(-ENOENT
);
1049 //ust// EXPORT_SYMBOL_GPL(marker_get_private_data);
1052 * markers_compact_event_ids - Compact markers event IDs and reassign channels
1054 * Called when no channel users are active by the channel infrastructure.
1055 * Called with lock_markers() and channel mutex held.
1057 //ust// void markers_compact_event_ids(void)
1059 //ust// struct marker_entry *entry;
1060 //ust// unsigned int i;
1061 //ust// struct hlist_head *head;
1062 //ust// struct hlist_node *node;
1065 //ust// for (i = 0; i < MARKER_TABLE_SIZE; i++) {
1066 //ust// head = &marker_table[i];
1067 //ust// hlist_for_each_entry(entry, node, head, hlist) {
1068 //ust// ret = ltt_channels_get_index_from_name(entry->channel);
1069 //ust// WARN_ON(ret < 0);
1070 //ust// entry->channel_id = ret;
1071 //ust// ret = _ltt_channels_get_event_id(entry->channel,
1072 //ust// entry->name);
1073 //ust// WARN_ON(ret < 0);
1074 //ust// entry->event_id = ret;
1079 //ust//#ifdef CONFIG_MODULES
1082 * Returns 0 if current not found.
1083 * Returns 1 if current found.
1085 int lib_get_iter_markers(struct marker_iter
*iter
)
1087 struct lib
*iter_lib
;
1090 //ust// pthread_mutex_lock(&module_mutex);
1091 cds_list_for_each_entry(iter_lib
, &libs
, list
) {
1092 if (iter_lib
< iter
->lib
)
1094 else if (iter_lib
> iter
->lib
)
1095 iter
->marker
= NULL
;
1096 found
= marker_get_iter_range(&iter
->marker
,
1097 iter_lib
->markers_start
,
1098 iter_lib
->markers_start
+ iter_lib
->markers_count
);
1100 iter
->lib
= iter_lib
;
1104 //ust// pthread_mutex_unlock(&module_mutex);
1109 * marker_get_iter_range - Get a next marker iterator given a range.
1110 * @marker: current markers (in), next marker (out)
1111 * @begin: beginning of the range
1112 * @end: end of the range
1114 * Returns whether a next marker has been found (1) or not (0).
1115 * Will return the first marker in the range if the input marker is NULL.
1117 int marker_get_iter_range(struct marker
**marker
, struct marker
*begin
,
1120 if (!*marker
&& begin
!= end
) {
1124 if (*marker
>= begin
&& *marker
< end
)
1128 //ust// EXPORT_SYMBOL_GPL(marker_get_iter_range);
1130 static void marker_get_iter(struct marker_iter
*iter
)
1134 /* Core kernel markers */
1136 /* ust FIXME: how come we cannot disable the following line? we shouldn't need core stuff */
1137 found
= marker_get_iter_range(&iter
->marker
,
1138 __start___markers
, __stop___markers
);
1142 /* Markers in modules. */
1143 found
= lib_get_iter_markers(iter
);
1146 marker_iter_reset(iter
);
1149 void marker_iter_start(struct marker_iter
*iter
)
1151 marker_get_iter(iter
);
1153 //ust// EXPORT_SYMBOL_GPL(marker_iter_start);
1155 void marker_iter_next(struct marker_iter
*iter
)
1159 * iter->marker may be invalid because we blindly incremented it.
1160 * Make sure it is valid by marshalling on the markers, getting the
1161 * markers from following modules if necessary.
1163 marker_get_iter(iter
);
1165 //ust// EXPORT_SYMBOL_GPL(marker_iter_next);
1167 void marker_iter_stop(struct marker_iter
*iter
)
1170 //ust// EXPORT_SYMBOL_GPL(marker_iter_stop);
1172 void marker_iter_reset(struct marker_iter
*iter
)
1175 iter
->marker
= NULL
;
1177 //ust// EXPORT_SYMBOL_GPL(marker_iter_reset);
1179 #ifdef CONFIG_MARKERS_USERSPACE
1181 * must be called with current->user_markers_mutex held
1183 static void free_user_marker(char __user
*state
, struct cds_hlist_head
*head
)
1185 struct user_marker
*umark
;
1186 struct cds_hlist_node
*pos
, *n
;
1188 cds_hlist_for_each_entry_safe(umark
, pos
, n
, head
, hlist
) {
1189 if (umark
->state
== state
) {
1190 cds_hlist_del(&umark
->hlist
);
1197 * Update current process.
1198 * Note that we have to wait a whole scheduler period before we are sure that
1199 * every running userspace threads have their markers updated.
1200 * (synchronize_sched() can be used to insure this).
1202 //ust// void marker_update_process(void)
1204 //ust// struct user_marker *umark;
1205 //ust// struct hlist_node *pos;
1206 //ust// struct marker_entry *entry;
1208 //ust// pthread_mutex_lock(&markers_mutex);
1209 //ust// pthread_mutex_lock(¤t->group_leader->user_markers_mutex);
1210 //ust// if (strcmp(current->comm, "testprog") == 0)
1211 //ust// DBG("do update pending for testprog");
1212 //ust// hlist_for_each_entry(umark, pos,
1213 //ust// ¤t->group_leader->user_markers, hlist) {
1214 //ust// DBG("Updating marker %s in %s", umark->name, current->comm);
1215 //ust// entry = get_marker("userspace", umark->name);
1216 //ust// if (entry) {
1217 //ust// if (entry->format &&
1218 //ust// strcmp(entry->format, umark->format) != 0) {
1219 //ust// WARN("error, wrong format in process %s",
1220 //ust// current->comm);
1223 //ust// if (put_user(!!entry->refcount, umark->state)) {
1224 //ust// WARN("Marker in %s caused a fault",
1225 //ust// current->comm);
1229 //ust// if (put_user(0, umark->state)) {
1230 //ust// WARN("Marker in %s caused a fault", current->comm);
1235 //ust// clear_thread_flag(TIF_MARKER_PENDING);
1236 //ust// pthread_mutex_unlock(¤t->group_leader->user_markers_mutex);
1237 //ust// pthread_mutex_unlock(&markers_mutex);
1241 * Called at process exit and upon do_execve().
1242 * We assume that when the leader exits, no more references can be done to the
1243 * leader structure by the other threads.
1245 void exit_user_markers(struct task_struct
*p
)
1247 struct user_marker
*umark
;
1248 struct cds_hlist_node
*pos
, *n
;
1250 if (thread_group_leader(p
)) {
1251 pthread_mutex_lock(&markers_mutex
);
1252 pthread_mutex_lock(&p
->user_markers_mutex
);
1253 cds_hlist_for_each_entry_safe(umark
, pos
, n
, &p
->user_markers
,
1256 INIT_HLIST_HEAD(&p
->user_markers
);
1257 p
->user_markers_sequence
++;
1258 pthread_mutex_unlock(&p
->user_markers_mutex
);
1259 pthread_mutex_unlock(&markers_mutex
);
1263 int is_marker_enabled(const char *channel
, const char *name
)
1265 struct marker_entry
*entry
;
1267 pthread_mutex_lock(&markers_mutex
);
1268 entry
= get_marker(channel
, name
);
1269 pthread_mutex_unlock(&markers_mutex
);
1271 return entry
&& !!entry
->refcount
;
1275 int marker_module_notify(struct notifier_block
*self
,
1276 unsigned long val
, void *data
)
1278 struct module
*mod
= data
;
1281 case MODULE_STATE_COMING
:
1282 marker_update_probe_range(mod
->markers
,
1283 mod
->markers
+ mod
->num_markers
);
1285 case MODULE_STATE_GOING
:
1286 marker_update_probe_range(mod
->markers
,
1287 mod
->markers
+ mod
->num_markers
);
1293 struct notifier_block marker_module_nb
= {
1294 .notifier_call
= marker_module_notify
,
1298 //ust// static int init_markers(void)
1300 //ust// return register_module_notifier(&marker_module_nb);
1302 //ust// __initcall(init_markers);
1303 /* TODO: call marker_module_nb() when a library is linked at runtime (dlopen)? */
1305 #endif /* CONFIG_MODULES */
1307 void ltt_dump_marker_state(struct ust_trace
*trace
)
1309 struct marker_entry
*entry
;
1310 struct ltt_probe_private_data call_data
;
1311 struct cds_hlist_head
*head
;
1312 struct cds_hlist_node
*node
;
1315 pthread_mutex_lock(&markers_mutex
);
1316 call_data
.trace
= trace
;
1317 call_data
.serializer
= NULL
;
1319 for (i
= 0; i
< MARKER_TABLE_SIZE
; i
++) {
1320 head
= &marker_table
[i
];
1321 cds_hlist_for_each_entry(entry
, node
, head
, hlist
) {
1322 __trace_mark(0, metadata
, core_marker_id
,
1324 "channel %s name %s event_id %hu "
1325 "int #1u%zu long #1u%zu pointer #1u%zu "
1326 "size_t #1u%zu alignment #1u%u",
1330 sizeof(int), sizeof(long),
1331 sizeof(void *), sizeof(size_t),
1332 ltt_get_alignment());
1334 __trace_mark(0, metadata
,
1337 "channel %s name %s format %s",
1343 pthread_mutex_unlock(&markers_mutex
);
1345 //ust// EXPORT_SYMBOL_GPL(ltt_dump_marker_state);
1347 static void (*new_marker_cb
)(struct marker
*) = NULL
;
1349 void marker_set_new_marker_cb(void (*cb
)(struct marker
*))
1354 static void new_markers(struct marker
*start
, struct marker
*end
)
1358 for(m
=start
; m
< end
; m
++) {
1364 int marker_register_lib(struct marker
*markers_start
, int markers_count
)
1368 pl
= (struct lib
*) zmalloc(sizeof(struct lib
));
1370 pl
->markers_start
= markers_start
;
1371 pl
->markers_count
= markers_count
;
1373 /* FIXME: maybe protect this with its own mutex? */
1375 cds_list_add(&pl
->list
, &libs
);
1378 new_markers(markers_start
, markers_start
+ markers_count
);
1380 /* FIXME: update just the loaded lib */
1381 lib_update_markers();
1383 DBG("just registered a markers section from %p and having %d markers", markers_start
, markers_count
);
1388 int marker_unregister_lib(struct marker
*markers_start
)
1392 /*FIXME: implement; but before implementing, marker_register_lib must
1393 have appropriate locking. */
1397 /* FIXME: we should probably take a mutex here on libs */
1398 //ust// pthread_mutex_lock(&module_mutex);
1399 cds_list_for_each_entry(lib
, &libs
, list
) {
1400 if(lib
->markers_start
== markers_start
) {
1401 struct lib
*lib2free
= lib
;
1402 cds_list_del(&lib
->list
);
1413 static int initialized
= 0;
1415 void __attribute__((constructor
)) init_markers(void)
1418 marker_register_lib(__start___markers
, (((long)__stop___markers
)-((long)__start___markers
))/sizeof(struct marker
));
1423 void __attribute__((constructor
)) destroy_markers(void)
1425 marker_unregister_lib(__start___markers
);