#include <errno.h>
#include <stdint.h>
#include <stddef.h>
+#include <stdio.h>
#include <urcu/arch.h>
#include <urcu-bp.h>
#include <urcu/hlist.h>
#include <urcu/uatomic.h>
#include <urcu/compiler.h>
+#include <urcu/system.h>
#include <lttng/tracepoint.h>
#include <lttng/ust-abi.h> /* for LTTNG_UST_SYM_NAME_LEN */
#include <helper.h>
#include "tracepoint-internal.h"
-#include "ltt-tracer-core.h"
+#include "lttng-tracer-core.h"
#include "jhash.h"
#include "error.h"
/* Set to 1 to enable tracepoint debug output */
static const int tracepoint_debug;
static int initialized;
-static void (*new_tracepoint_cb)(struct tracepoint *);
+static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *);
/*
* tracepoint_mutex nests inside UST mutex.
* Tracepoint hash table, containing the active tracepoints.
* Protected by tracepoint mutex.
*/
-#define TRACEPOINT_HASH_BITS 6
+#define TRACEPOINT_HASH_BITS 12
#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
*/
struct tracepoint_entry {
struct cds_hlist_node hlist;
- struct tracepoint_probe *probes;
+ struct lttng_ust_tracepoint_probe *probes;
int refcount; /* Number of times armed. 0 if disarmed. */
+ int callsite_refcount; /* how many libs use this tracepoint */
const char *signature;
char name[0];
};
/* Field below only used for call_rcu scheme */
/* struct rcu_head head; */
} u;
- struct tracepoint_probe probes[0];
+ struct lttng_ust_tracepoint_probe probes[0];
};
+/*
+ * Callsite hash table, containing the tracepoint call sites.
+ * Protected by tracepoint mutex.
+ */
+#define CALLSITE_HASH_BITS 12
+#define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS)
+static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE];
+
+struct callsite_entry {
+ struct cds_hlist_node hlist; /* hash table node */
+ struct cds_list_head node; /* lib list of callsites node */
+ struct lttng_ust_tracepoint *tp;
+};
+
+/* coverity[+alloc] */
static void *allocate_probes(int count)
{
- struct tp_probes *p = zmalloc(count * sizeof(struct tracepoint_probe)
- + sizeof(struct tp_probes));
+ struct tp_probes *p =
+ zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe)
+ + sizeof(struct tp_probes));
return p == NULL ? NULL : p->probes;
}
+/* coverity[+free : arg-0] */
static void release_probes(void *old)
{
if (old) {
static void *
tracepoint_entry_add_probe(struct tracepoint_entry *entry,
- void *probe, void *data)
+ void (*probe)(void), void *data)
{
int nr_probes = 0;
- struct tracepoint_probe *old, *new;
-
- WARN_ON(!probe);
+ struct lttng_ust_tracepoint_probe *old, *new;
+ if (!probe) {
+ WARN_ON(1);
+ return ERR_PTR(-EINVAL);
+ }
debug_print_probes(entry);
old = entry->probes;
if (old) {
if (new == NULL)
return ERR_PTR(-ENOMEM);
if (old)
- memcpy(new, old, nr_probes * sizeof(struct tracepoint_probe));
+ memcpy(new, old,
+ nr_probes * sizeof(struct lttng_ust_tracepoint_probe));
new[nr_probes].func = probe;
new[nr_probes].data = data;
new[nr_probes + 1].func = NULL;
}
static void *
-tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe,
- void *data)
+tracepoint_entry_remove_probe(struct tracepoint_entry *entry,
+ void (*probe)(void), void *data)
{
int nr_probes = 0, nr_del = 0, i;
- struct tracepoint_probe *old, *new;
+ struct lttng_ust_tracepoint_probe *old, *new;
old = entry->probes;
debug_print_probes(entry);
/* (N -> M), (N > 1, M >= 0) probes */
- for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
- if (!probe ||
- (old[nr_probes].func == probe &&
- old[nr_probes].data == data))
- nr_del++;
+ if (probe) {
+ for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
+ if (old[nr_probes].func == probe &&
+ old[nr_probes].data == data)
+ nr_del++;
+ }
}
if (nr_probes - nr_del == 0) {
if (new == NULL)
return ERR_PTR(-ENOMEM);
for (i = 0; old[i].func; i++)
- if (probe &&
- (old[i].func != probe || old[i].data != data))
+ if (old[i].func != probe || old[i].data != data)
new[j++] = old[i];
new[nr_probes - nr_del].func = NULL;
entry->refcount = nr_probes - nr_del;
e->name[name_len] = '\0';
e->probes = NULL;
e->refcount = 0;
+ e->callsite_refcount = 0;
e->signature = signature;
cds_hlist_add_head(&e->hlist, head);
return e;
* Sets the probe callback corresponding to one tracepoint.
*/
static void set_tracepoint(struct tracepoint_entry **entry,
- struct tracepoint *elem, int active)
+ struct lttng_ust_tracepoint *elem, int active)
{
WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0);
/*
* is used.
*/
rcu_assign_pointer(elem->probes, (*entry)->probes);
- elem->state = active;
+ CMM_STORE_SHARED(elem->state, active);
}
/*
* function insures that the original callback is not used anymore. This insured
* by preempt_disable around the call site.
*/
-static void disable_tracepoint(struct tracepoint *elem)
+static void disable_tracepoint(struct lttng_ust_tracepoint *elem)
{
- elem->state = 0;
+ CMM_STORE_SHARED(elem->state, 0);
rcu_assign_pointer(elem->probes, NULL);
}
+/*
+ * Add the callsite to the callsite hash table. Must be called with
+ * tracepoint mutex held.
+ */
+static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp)
+{
+ struct cds_hlist_head *head;
+ struct callsite_entry *e;
+ const char *name = tp->name;
+ size_t name_len = strlen(name);
+ uint32_t hash;
+ struct tracepoint_entry *tp_entry;
+
+ if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) {
+ WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1);
+ name_len = LTTNG_UST_SYM_NAME_LEN - 1;
+ }
+ hash = jhash(name, name_len, 0);
+ head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)];
+ e = zmalloc(sizeof(struct callsite_entry));
+ if (!e) {
+ PERROR("Unable to add callsite for tracepoint \"%s\"", name);
+ return;
+ }
+ cds_hlist_add_head(&e->hlist, head);
+ e->tp = tp;
+ cds_list_add(&e->node, &lib->callsites);
+
+ tp_entry = get_tracepoint(name);
+ if (!tp_entry)
+ return;
+ tp_entry->callsite_refcount++;
+}
+
+/*
+ * Remove the callsite from the callsite hash table and from lib
+ * callsite list. Must be called with tracepoint mutex held.
+ */
+static void remove_callsite(struct callsite_entry *e)
+{
+ struct tracepoint_entry *tp_entry;
+
+ tp_entry = get_tracepoint(e->tp->name);
+ if (tp_entry) {
+ tp_entry->callsite_refcount--;
+ if (tp_entry->callsite_refcount == 0)
+ disable_tracepoint(e->tp);
+ }
+ cds_hlist_del(&e->hlist);
+ cds_list_del(&e->node);
+ free(e);
+}
+
+/*
+ * Enable/disable all callsites based on the state of a specific
+ * tracepoint entry.
+ * Must be called with tracepoint mutex held.
+ */
+static void tracepoint_sync_callsites(const char *name)
+{
+ struct cds_hlist_head *head;
+ struct cds_hlist_node *node;
+ struct callsite_entry *e;
+ size_t name_len = strlen(name);
+ uint32_t hash;
+ struct tracepoint_entry *tp_entry;
+
+ tp_entry = get_tracepoint(name);
+ if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) {
+ WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1);
+ name_len = LTTNG_UST_SYM_NAME_LEN - 1;
+ }
+ hash = jhash(name, name_len, 0);
+ head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)];
+ cds_hlist_for_each_entry(e, node, head, hlist) {
+ struct lttng_ust_tracepoint *tp = e->tp;
+
+ if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1))
+ continue;
+ if (tp_entry) {
+ set_tracepoint(&tp_entry, tp,
+ !!tp_entry->refcount);
+ } else {
+ disable_tracepoint(tp);
+ }
+ }
+}
+
/**
* tracepoint_update_probe_range - Update a probe range
* @begin: beginning of the range
* Updates the probe callback corresponding to a range of tracepoints.
*/
static
-void tracepoint_update_probe_range(struct tracepoint * const *begin,
- struct tracepoint * const *end)
+void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin,
+ struct lttng_ust_tracepoint * const *end)
{
- struct tracepoint * const *iter;
+ struct lttng_ust_tracepoint * const *iter;
struct tracepoint_entry *mark_entry;
for (iter = begin; iter < end; iter++) {
}
}
-static void lib_update_tracepoints(void)
+static void lib_update_tracepoints(struct tracepoint_lib *lib)
{
- struct tracepoint_lib *lib;
+ tracepoint_update_probe_range(lib->tracepoints_start,
+ lib->tracepoints_start + lib->tracepoints_count);
+}
- cds_list_for_each_entry(lib, &libs, list) {
- tracepoint_update_probe_range(lib->tracepoints_start,
- lib->tracepoints_start + lib->tracepoints_count);
+static void lib_register_callsites(struct tracepoint_lib *lib)
+{
+ struct lttng_ust_tracepoint * const *begin;
+ struct lttng_ust_tracepoint * const *end;
+ struct lttng_ust_tracepoint * const *iter;
+
+ begin = lib->tracepoints_start;
+ end = lib->tracepoints_start + lib->tracepoints_count;
+
+ for (iter = begin; iter < end; iter++) {
+ if (!*iter)
+ continue; /* skip dummy */
+ if (!(*iter)->name) {
+ continue;
+ }
+ add_callsite(lib, *iter);
}
}
+static void lib_unregister_callsites(struct tracepoint_lib *lib)
+{
+ struct callsite_entry *callsite, *tmp;
+
+ cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node)
+ remove_callsite(callsite);
+}
+
/*
* Update probes, removing the faulty probes.
*/
static void tracepoint_update_probes(void)
{
+ struct tracepoint_lib *lib;
+
/* tracepoints registered from libraries and executable. */
- lib_update_tracepoints();
+ cds_list_for_each_entry(lib, &libs, list)
+ lib_update_tracepoints(lib);
}
-static struct tracepoint_probe *
-tracepoint_add_probe(const char *name, void *probe, void *data,
+static struct lttng_ust_tracepoint_probe *
+tracepoint_add_probe(const char *name, void (*probe)(void), void *data,
const char *signature)
{
struct tracepoint_entry *entry;
- struct tracepoint_probe *old;
+ struct lttng_ust_tracepoint_probe *old;
entry = get_tracepoint(name);
if (!entry) {
entry = add_tracepoint(name, signature);
if (IS_ERR(entry))
- return (struct tracepoint_probe *)entry;
+ return (struct lttng_ust_tracepoint_probe *)entry;
}
old = tracepoint_entry_add_probe(entry, probe, data);
if (IS_ERR(old) && !entry->refcount)
* The probe address must at least be aligned on the architecture pointer size.
* Called with the tracepoint mutex held.
*/
-int __tracepoint_probe_register(const char *name, void *probe, void *data,
- const char *signature)
+int __tracepoint_probe_register(const char *name, void (*probe)(void),
+ void *data, const char *signature)
{
void *old;
int ret = 0;
goto end;
}
- tracepoint_update_probes(); /* may update entry */
+ tracepoint_sync_callsites(name);
release_probes(old);
end:
pthread_mutex_unlock(&tracepoint_mutex);
return ret;
}
-static void *tracepoint_remove_probe(const char *name, void *probe, void *data)
+static void *tracepoint_remove_probe(const char *name, void (*probe)(void),
+ void *data)
{
struct tracepoint_entry *entry;
void *old;
* @probe: probe function pointer
* @probe: probe data pointer
*/
-int __tracepoint_probe_unregister(const char *name, void *probe, void *data)
+int __tracepoint_probe_unregister(const char *name, void (*probe)(void),
+ void *data)
{
void *old;
int ret = 0;
ret = PTR_ERR(old);
goto end;
}
- tracepoint_update_probes(); /* may update entry */
+ tracepoint_sync_callsites(name);
release_probes(old);
end:
pthread_mutex_unlock(&tracepoint_mutex);
*
* caller must call tracepoint_probe_update_all()
*/
-int tracepoint_probe_register_noupdate(const char *name, void *probe,
+int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void),
void *data, const char *signature)
{
void *old;
* caller must call tracepoint_probe_update_all()
* Called with the tracepoint mutex held.
*/
-int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
+int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void),
void *data)
{
void *old;
pthread_mutex_unlock(&tracepoint_mutex);
}
-void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *))
+void tracepoint_set_new_tracepoint_cb(void (*cb)(struct lttng_ust_tracepoint *))
{
new_tracepoint_cb = cb;
}
-static void new_tracepoints(struct tracepoint * const *start, struct tracepoint * const *end)
+static void new_tracepoints(struct lttng_ust_tracepoint * const *start,
+ struct lttng_ust_tracepoint * const *end)
{
if (new_tracepoint_cb) {
- struct tracepoint * const *t;
+ struct lttng_ust_tracepoint * const *t;
for (t = start; t < end; t++) {
if (*t)
}
}
-static
-void lib_disable_tracepoints(struct tracepoint * const *begin,
- struct tracepoint * const *end)
-{
- struct tracepoint * const *iter;
-
- for (iter = begin; iter < end; iter++) {
- if (!*iter)
- continue; /* skip dummy */
- disable_tracepoint(*iter);
- }
-
-}
-
-int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
+int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start,
int tracepoints_count)
{
struct tracepoint_lib *pl, *iter;
init_tracepoint();
pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib));
-
+ if (!pl) {
+ PERROR("Unable to register tracepoint lib");
+ return -1;
+ }
pl->tracepoints_start = tracepoints_start;
pl->tracepoints_count = tracepoints_count;
+ CDS_INIT_LIST_HEAD(&pl->callsites);
pthread_mutex_lock(&tracepoint_mutex);
/*
cds_list_add(&pl->list, &libs);
lib_added:
new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
-
- /* TODO: update just the loaded lib */
- lib_update_tracepoints();
+ lib_register_callsites(pl);
+ lib_update_tracepoints(pl);
pthread_mutex_unlock(&tracepoint_mutex);
DBG("just registered a tracepoints section from %p and having %d tracepoints",
return 0;
}
-int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start)
+int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start)
{
struct tracepoint_lib *lib;
- int tracepoints_count;
pthread_mutex_lock(&tracepoint_mutex);
cds_list_for_each_entry(lib, &libs, list) {
- if (lib->tracepoints_start == tracepoints_start) {
- struct tracepoint_lib *lib2free = lib;
+ if (lib->tracepoints_start != tracepoints_start)
+ continue;
- cds_list_del(&lib->list);
- tracepoints_count = lib->tracepoints_count;
- free(lib2free);
- goto found;
- }
+ cds_list_del(&lib->list);
+ /*
+ * Unregistering a callsite also decreases the
+ * callsite reference count of the corresponding
+ * tracepoint, and disables the tracepoint if
+ * the reference count drops to zero.
+ */
+ lib_unregister_callsites(lib);
+ DBG("just unregistered a tracepoints section from %p",
+ lib->tracepoints_start);
+ free(lib);
+ break;
}
- goto end;
-found:
- /*
- * Force tracepoint disarm for all tracepoints of this lib.
- * This takes care of destructor of library that would leave a
- * LD_PRELOAD wrapper override function enabled for tracing, but
- * the session teardown would not be able to reach the
- * tracepoint anymore to disable it.
- */
- lib_disable_tracepoints(tracepoints_start,
- tracepoints_start + tracepoints_count);
- DBG("just unregistered a tracepoints section from %p",
- tracepoints_start);
-end:
pthread_mutex_unlock(&tracepoint_mutex);
return 0;
}
projects / lttng-ust.git / blobdiff