#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 "jhash.h"
#include "error.h"
+/* Test compiler support for weak symbols with hidden visibility. */
+int __tracepoint_test_symbol1 __attribute__((weak, visibility("hidden")));
+void *__tracepoint_test_symbol2 __attribute__((weak, visibility("hidden")));
+struct {
+ char a[24];
+} __tracepoint_test_symbol3 __attribute__((weak, visibility("hidden")));
+
/* 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.
*/
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];
};
/*
struct callsite_entry {
struct cds_hlist_node hlist; /* hash table node */
struct cds_list_head node; /* lib list of callsites node */
- struct tracepoint *tp;
+ 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;
}
void (*probe)(void), void *data)
{
int nr_probes = 0;
- struct tracepoint_probe *old, *new;
+ struct lttng_ust_tracepoint_probe *old, *new;
if (!probe) {
WARN_ON(1);
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;
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;
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;
free(e);
}
-/*
- * Add the callsite to the callsite hash table. Must be called with
- * tracepoint mutex held.
- */
-static void add_callsite(struct 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;
-
- 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));
- assert(e);
- cds_hlist_add_head(&e->hlist, head);
- e->tp = tp;
-}
-
-/*
- * 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)
-{
- cds_hlist_del(&e->hlist);
- cds_list_del(&e->node);
- free(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.
hash = jhash(name, name_len, 0);
head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)];
cds_hlist_for_each_entry(e, node, head, hlist) {
- struct tracepoint *tp = e->tp;
+ struct lttng_ust_tracepoint *tp = e->tp;
if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1))
continue;
* 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_register_callsites(struct tracepoint_lib *lib)
{
- struct tracepoint * const *begin;
- struct tracepoint * const *end;
- struct tracepoint * const *iter;
+ 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;
if (!(*iter)->name) {
continue;
}
- add_callsite(*iter);
+ add_callsite(lib, *iter);
}
}
lib_update_tracepoints(lib);
}
-static struct tracepoint_probe *
+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)
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_lib *lib)
-{
- struct tracepoint * const *begin;
- struct tracepoint * const *end;
- struct 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 */
- 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);
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;
cds_list_del(&lib->list);
/*
- * 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.
+ * 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_disable_tracepoints(lib);
lib_unregister_callsites(lib);
DBG("just unregistered a tracepoints section from %p",
lib->tracepoints_start);
return 0;
}
+/*
+ * Report in debug message whether the compiler correctly supports weak
+ * hidden symbols. This test checks that the address associated with two
+ * weak symbols with hidden visibility is the same when declared within
+ * two compile units part of the same module.
+ */
+static void check_weak_hidden(void)
+{
+ DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.",
+ &__tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ?
+ "SAME address" :
+ "DIFFERENT addresses");
+ DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.",
+ &__tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ?
+ "SAME address" :
+ "DIFFERENT addresses");
+ DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.",
+ &__tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ?
+ "SAME address" :
+ "DIFFERENT addresses");
+}
+
void init_tracepoint(void)
{
if (uatomic_xchg(&initialized, 1) == 1)
return;
init_usterr();
+ check_weak_hidden();
}
void exit_tracepoint(void)
projects / lttng-ust.git / blobdiff