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-rw-r--r--kernel/marker.c192
1 files changed, 127 insertions, 65 deletions
diff --git a/kernel/marker.c b/kernel/marker.c
index e9c6b2b..ea54f26 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -43,6 +43,7 @@ static DEFINE_MUTEX(markers_mutex);
*/
#define MARKER_HASH_BITS 6
#define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
+static struct hlist_head marker_table[MARKER_TABLE_SIZE];
/*
* Note about RCU :
@@ -64,11 +65,10 @@ struct marker_entry {
void *oldptr;
int rcu_pending;
unsigned char ptype:1;
+ unsigned char format_allocated:1;
char name[0]; /* Contains name'\0'format'\0' */
};
-static struct hlist_head marker_table[MARKER_TABLE_SIZE];
-
/**
* __mark_empty_function - Empty probe callback
* @probe_private: probe private data
@@ -81,7 +81,7 @@ static struct hlist_head marker_table[MARKER_TABLE_SIZE];
* though the function pointer change and the marker enabling are two distinct
* operations that modifies the execution flow of preemptible code.
*/
-void __mark_empty_function(void *probe_private, void *call_private,
+notrace void __mark_empty_function(void *probe_private, void *call_private,
const char *fmt, va_list *args)
{
}
@@ -97,7 +97,8 @@ EXPORT_SYMBOL_GPL(__mark_empty_function);
* need to put a full smp_rmb() in this branch. This is why we do not use
* rcu_dereference() for the pointer read.
*/
-void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
+notrace void marker_probe_cb(const struct marker *mdata,
+ void *call_private, ...)
{
va_list args;
char ptype;
@@ -107,7 +108,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
* sure the teardown of the callbacks can be done correctly when they
* are in modules and they insure RCU read coherency.
*/
- rcu_read_lock_sched();
+ rcu_read_lock_sched_notrace();
ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
@@ -145,7 +146,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
va_end(args);
}
}
- rcu_read_unlock_sched();
+ rcu_read_unlock_sched_notrace();
}
EXPORT_SYMBOL_GPL(marker_probe_cb);
@@ -157,12 +158,13 @@ EXPORT_SYMBOL_GPL(marker_probe_cb);
*
* Should be connected to markers "MARK_NOARGS".
*/
-void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
+static notrace void marker_probe_cb_noarg(const struct marker *mdata,
+ void *call_private, ...)
{
va_list args; /* not initialized */
char ptype;
- rcu_read_lock_sched();
+ rcu_read_lock_sched_notrace();
ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
@@ -195,9 +197,8 @@ void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
multi[i].func(multi[i].probe_private, call_private,
mdata->format, &args);
}
- rcu_read_unlock_sched();
+ rcu_read_unlock_sched_notrace();
}
-EXPORT_SYMBOL_GPL(marker_probe_cb_noarg);
static void free_old_closure(struct rcu_head *head)
{
@@ -416,6 +417,7 @@ static struct marker_entry *add_marker(const char *name, const char *format)
e->single.probe_private = NULL;
e->multi = NULL;
e->ptype = 0;
+ e->format_allocated = 0;
e->refcount = 0;
e->rcu_pending = 0;
hlist_add_head(&e->hlist, head);
@@ -447,6 +449,8 @@ static int remove_marker(const char *name)
if (e->single.func != __mark_empty_function)
return -EBUSY;
hlist_del(&e->hlist);
+ if (e->format_allocated)
+ kfree(e->format);
/* Make sure the call_rcu has been executed */
if (e->rcu_pending)
rcu_barrier_sched();
@@ -457,57 +461,34 @@ static int remove_marker(const char *name)
/*
* Set the mark_entry format to the format found in the element.
*/
-static int marker_set_format(struct marker_entry **entry, const char *format)
+static int marker_set_format(struct marker_entry *entry, const char *format)
{
- struct marker_entry *e;
- size_t name_len = strlen((*entry)->name) + 1;
- size_t format_len = strlen(format) + 1;
-
-
- e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
- GFP_KERNEL);
- if (!e)
+ entry->format = kstrdup(format, GFP_KERNEL);
+ if (!entry->format)
return -ENOMEM;
- memcpy(&e->name[0], (*entry)->name, name_len);
- e->format = &e->name[name_len];
- memcpy(e->format, format, format_len);
- if (strcmp(e->format, MARK_NOARGS) == 0)
- e->call = marker_probe_cb_noarg;
- else
- e->call = marker_probe_cb;
- e->single = (*entry)->single;
- e->multi = (*entry)->multi;
- e->ptype = (*entry)->ptype;
- e->refcount = (*entry)->refcount;
- e->rcu_pending = 0;
- hlist_add_before(&e->hlist, &(*entry)->hlist);
- hlist_del(&(*entry)->hlist);
- /* Make sure the call_rcu has been executed */
- if ((*entry)->rcu_pending)
- rcu_barrier_sched();
- kfree(*entry);
- *entry = e;
+ entry->format_allocated = 1;
+
trace_mark(core_marker_format, "name %s format %s",
- e->name, e->format);
+ entry->name, entry->format);
return 0;
}
/*
* Sets the probe callback corresponding to one marker.
*/
-static int set_marker(struct marker_entry **entry, struct marker *elem,
+static int set_marker(struct marker_entry *entry, struct marker *elem,
int active)
{
- int ret;
- WARN_ON(strcmp((*entry)->name, elem->name) != 0);
+ int ret = 0;
+ WARN_ON(strcmp(entry->name, elem->name) != 0);
- if ((*entry)->format) {
- if (strcmp((*entry)->format, elem->format) != 0) {
+ if (entry->format) {
+ if (strcmp(entry->format, elem->format) != 0) {
printk(KERN_NOTICE
"Format mismatch for probe %s "
"(%s), marker (%s)\n",
- (*entry)->name,
- (*entry)->format,
+ entry->name,
+ entry->format,
elem->format);
return -EPERM;
}
@@ -523,37 +504,67 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
* pass from a "safe" callback (with argument) to an "unsafe"
* callback (does not set arguments).
*/
- elem->call = (*entry)->call;
+ elem->call = entry->call;
/*
* Sanity check :
* We only update the single probe private data when the ptr is
* set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
*/
WARN_ON(elem->single.func != __mark_empty_function
- && elem->single.probe_private
- != (*entry)->single.probe_private &&
- !elem->ptype);
- elem->single.probe_private = (*entry)->single.probe_private;
+ && elem->single.probe_private != entry->single.probe_private
+ && !elem->ptype);
+ elem->single.probe_private = entry->single.probe_private;
/*
* Make sure the private data is valid when we update the
* single probe ptr.
*/
smp_wmb();
- elem->single.func = (*entry)->single.func;
+ elem->single.func = entry->single.func;
/*
* We also make sure that the new probe callbacks array is consistent
* before setting a pointer to it.
*/
- rcu_assign_pointer(elem->multi, (*entry)->multi);
+ rcu_assign_pointer(elem->multi, entry->multi);
/*
* Update the function or multi probe array pointer before setting the
* ptype.
*/
smp_wmb();
- elem->ptype = (*entry)->ptype;
+ elem->ptype = entry->ptype;
+
+ if (elem->tp_name && (active ^ elem->state)) {
+ WARN_ON(!elem->tp_cb);
+ /*
+ * It is ok to directly call the probe registration because type
+ * checking has been done in the __trace_mark_tp() macro.
+ */
+
+ if (active) {
+ /*
+ * try_module_get should always succeed because we hold
+ * lock_module() to get the tp_cb address.
+ */
+ ret = try_module_get(__module_text_address(
+ (unsigned long)elem->tp_cb));
+ BUG_ON(!ret);
+ ret = tracepoint_probe_register_noupdate(
+ elem->tp_name,
+ elem->tp_cb);
+ } else {
+ ret = tracepoint_probe_unregister_noupdate(
+ elem->tp_name,
+ elem->tp_cb);
+ /*
+ * tracepoint_probe_update_all() must be called
+ * before the module containing tp_cb is unloaded.
+ */
+ module_put(__module_text_address(
+ (unsigned long)elem->tp_cb));
+ }
+ }
elem->state = active;
- return 0;
+ return ret;
}
/*
@@ -564,7 +575,24 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
*/
static void disable_marker(struct marker *elem)
{
+ int ret;
+
/* leave "call" as is. It is known statically. */
+ if (elem->tp_name && elem->state) {
+ WARN_ON(!elem->tp_cb);
+ /*
+ * It is ok to directly call the probe registration because type
+ * checking has been done in the __trace_mark_tp() macro.
+ */
+ ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
+ elem->tp_cb);
+ WARN_ON(ret);
+ /*
+ * tracepoint_probe_update_all() must be called
+ * before the module containing tp_cb is unloaded.
+ */
+ module_put(__module_text_address((unsigned long)elem->tp_cb));
+ }
elem->state = 0;
elem->single.func = __mark_empty_function;
/* Update the function before setting the ptype */
@@ -594,8 +622,7 @@ void marker_update_probe_range(struct marker *begin,
for (iter = begin; iter < end; iter++) {
mark_entry = get_marker(iter->name);
if (mark_entry) {
- set_marker(&mark_entry, iter,
- !!mark_entry->refcount);
+ set_marker(mark_entry, iter, !!mark_entry->refcount);
/*
* ignore error, continue
*/
@@ -629,6 +656,7 @@ static void marker_update_probes(void)
marker_update_probe_range(__start___markers, __stop___markers);
/* Markers in modules. */
module_update_markers();
+ tracepoint_probe_update_all();
}
/**
@@ -657,7 +685,7 @@ int marker_probe_register(const char *name, const char *format,
ret = PTR_ERR(entry);
} else if (format) {
if (!entry->format)
- ret = marker_set_format(&entry, format);
+ ret = marker_set_format(entry, format);
else if (strcmp(entry->format, format))
ret = -EPERM;
}
@@ -676,10 +704,11 @@ int marker_probe_register(const char *name, const char *format,
goto end;
}
mutex_unlock(&markers_mutex);
- marker_update_probes(); /* may update entry */
+ marker_update_probes();
mutex_lock(&markers_mutex);
entry = get_marker(name);
- WARN_ON(!entry);
+ if (!entry)
+ goto end;
if (entry->rcu_pending)
rcu_barrier_sched();
entry->oldptr = old;
@@ -720,7 +749,7 @@ int marker_probe_unregister(const char *name,
rcu_barrier_sched();
old = marker_entry_remove_probe(entry, probe, probe_private);
mutex_unlock(&markers_mutex);
- marker_update_probes(); /* may update entry */
+ marker_update_probes();
mutex_lock(&markers_mutex);
entry = get_marker(name);
if (!entry)
@@ -801,10 +830,11 @@ int marker_probe_unregister_private_data(marker_probe_func *probe,
rcu_barrier_sched();
old = marker_entry_remove_probe(entry, NULL, probe_private);
mutex_unlock(&markers_mutex);
- marker_update_probes(); /* may update entry */
+ marker_update_probes();
mutex_lock(&markers_mutex);
entry = get_marker_from_private_data(probe, probe_private);
- WARN_ON(!entry);
+ if (!entry)
+ goto end;
if (entry->rcu_pending)
rcu_barrier_sched();
entry->oldptr = old;
@@ -848,8 +878,6 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe,
if (!e->ptype) {
if (num == 0 && e->single.func == probe)
return e->single.probe_private;
- else
- break;
} else {
struct marker_probe_closure *closure;
int match = 0;
@@ -861,8 +889,42 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe,
return closure[i].probe_private;
}
}
+ break;
}
}
return ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL_GPL(marker_get_private_data);
+
+#ifdef CONFIG_MODULES
+
+int marker_module_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct module *mod = data;
+
+ switch (val) {
+ case MODULE_STATE_COMING:
+ marker_update_probe_range(mod->markers,
+ mod->markers + mod->num_markers);
+ break;
+ case MODULE_STATE_GOING:
+ marker_update_probe_range(mod->markers,
+ mod->markers + mod->num_markers);
+ break;
+ }
+ return 0;
+}
+
+struct notifier_block marker_module_nb = {
+ .notifier_call = marker_module_notify,
+ .priority = 0,
+};
+
+static int init_markers(void)
+{
+ return register_module_notifier(&marker_module_nb);
+}
+__initcall(init_markers);
+
+#endif /* CONFIG_MODULES */
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