mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 05:48:40 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
a staging driver; fix included. Greg KH said he'd take the patch but hadn't as the merge window opened, so it's included here to avoid breaking build. Cheers, Rusty. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) iQIcBAABAgAGBQJTQMH9AAoJENkgDmzRrbjxo4UP/jwlenP44v+RFpo/dn8Z8E2n SREQscU5ZZKvuyFD6kUdvOz8YC/nTrJvXoVkMUF05GVbuvb8/8UPtT9ECVemd0rW xNy4aFfv9rbrqRLBLpLK9LAgTuhwlbTgGxgL78zRn3hWmf1hBZWCY+cEvKM8l/+9 oEQdORL0sUpZh7iryAeGqbOrXT4gqJEvSLOFwiYTSo6ryzWIilmdXSUAh6s8MIEX PR1+oH9J8B6J29lcXKMf8/sDI1EBUeSLdBmMCuN5Y7xpYxsQLroVx94kPbdBY+XK ZRoYuUGSUJfGRZY46cFKApIGeF07z1DGoyXghbSWEQrI+23TMUmrKUg47LSukE4Y yCUf8HAtqIA3gVc9GKDdSp/2UpkAhTTv5ogKgnIzs1InWtOIBdDRSVUQXDosFEXw 6ZZe1pQs2zfXyXxO4j0Wq36K4RgI0aqOVw+dcC+w5BidjVylgnYRV0PSDd72tid7 bIfnjDbUBo+o4LanPNGYK474KyO7AslgTE50w6zwbJzgdwCQ36hCpKqScBZzm60a 42LrgTVoIHHWAL1tDzWL/LzWflZGdJAezzNje0/f2Q3bGMiNHWoljAvUphkTZ7qt E8+jWqmM+riH3e8Y5wKpO1BKt7NGHISEy//bUlnqTwisjIzVILZ6VjfugQ1AI+0x llTXPBotFvfvXqxunBg7 =yzUO -----END PGP SIGNATURE----- Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull module updates from Rusty Russell: "Nothing major: the stricter permissions checking for sysfs broke a staging driver; fix included. Greg KH said he'd take the patch but hadn't as the merge window opened, so it's included here to avoid breaking build" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: staging: fix up speakup kobject mode Use 'E' instead of 'X' for unsigned module taint flag. VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms. kallsyms: fix percpu vars on x86-64 with relocation. kallsyms: generalize address range checking module: LLVMLinux: Remove unused function warning from __param_check macro Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE module: remove MODULE_GENERIC_TABLE module: allow multiple calls to MODULE_DEVICE_TABLE() per module module: use pr_cont
592 lines
16 KiB
C
592 lines
16 KiB
C
/*
|
|
* Copyright (C) 2008 Mathieu Desnoyers
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/types.h>
|
|
#include <linux/jhash.h>
|
|
#include <linux/list.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/tracepoint.h>
|
|
#include <linux/err.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/static_key.h>
|
|
|
|
extern struct tracepoint * const __start___tracepoints_ptrs[];
|
|
extern struct tracepoint * const __stop___tracepoints_ptrs[];
|
|
|
|
/* Set to 1 to enable tracepoint debug output */
|
|
static const int tracepoint_debug;
|
|
|
|
/*
|
|
* Tracepoints mutex protects the builtin and module tracepoints and the hash
|
|
* table, as well as the local module list.
|
|
*/
|
|
static DEFINE_MUTEX(tracepoints_mutex);
|
|
|
|
#ifdef CONFIG_MODULES
|
|
/* Local list of struct module */
|
|
static LIST_HEAD(tracepoint_module_list);
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
/*
|
|
* Tracepoint hash table, containing the active tracepoints.
|
|
* Protected by tracepoints_mutex.
|
|
*/
|
|
#define TRACEPOINT_HASH_BITS 6
|
|
#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
|
|
static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
|
|
|
|
/*
|
|
* Note about RCU :
|
|
* It is used to delay the free of multiple probes array until a quiescent
|
|
* state is reached.
|
|
* Tracepoint entries modifications are protected by the tracepoints_mutex.
|
|
*/
|
|
struct tracepoint_entry {
|
|
struct hlist_node hlist;
|
|
struct tracepoint_func *funcs;
|
|
int refcount; /* Number of times armed. 0 if disarmed. */
|
|
int enabled; /* Tracepoint enabled */
|
|
char name[0];
|
|
};
|
|
|
|
struct tp_probes {
|
|
struct rcu_head rcu;
|
|
struct tracepoint_func probes[0];
|
|
};
|
|
|
|
static inline void *allocate_probes(int count)
|
|
{
|
|
struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func)
|
|
+ sizeof(struct tp_probes), GFP_KERNEL);
|
|
return p == NULL ? NULL : p->probes;
|
|
}
|
|
|
|
static void rcu_free_old_probes(struct rcu_head *head)
|
|
{
|
|
kfree(container_of(head, struct tp_probes, rcu));
|
|
}
|
|
|
|
static inline void release_probes(struct tracepoint_func *old)
|
|
{
|
|
if (old) {
|
|
struct tp_probes *tp_probes = container_of(old,
|
|
struct tp_probes, probes[0]);
|
|
call_rcu_sched(&tp_probes->rcu, rcu_free_old_probes);
|
|
}
|
|
}
|
|
|
|
static void debug_print_probes(struct tracepoint_entry *entry)
|
|
{
|
|
int i;
|
|
|
|
if (!tracepoint_debug || !entry->funcs)
|
|
return;
|
|
|
|
for (i = 0; entry->funcs[i].func; i++)
|
|
printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i].func);
|
|
}
|
|
|
|
static struct tracepoint_func *
|
|
tracepoint_entry_add_probe(struct tracepoint_entry *entry,
|
|
void *probe, void *data)
|
|
{
|
|
int nr_probes = 0;
|
|
struct tracepoint_func *old, *new;
|
|
|
|
if (WARN_ON(!probe))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
debug_print_probes(entry);
|
|
old = entry->funcs;
|
|
if (old) {
|
|
/* (N -> N+1), (N != 0, 1) probes */
|
|
for (nr_probes = 0; old[nr_probes].func; nr_probes++)
|
|
if (old[nr_probes].func == probe &&
|
|
old[nr_probes].data == data)
|
|
return ERR_PTR(-EEXIST);
|
|
}
|
|
/* + 2 : one for new probe, one for NULL func */
|
|
new = allocate_probes(nr_probes + 2);
|
|
if (new == NULL)
|
|
return ERR_PTR(-ENOMEM);
|
|
if (old)
|
|
memcpy(new, old, nr_probes * sizeof(struct tracepoint_func));
|
|
new[nr_probes].func = probe;
|
|
new[nr_probes].data = data;
|
|
new[nr_probes + 1].func = NULL;
|
|
entry->refcount = nr_probes + 1;
|
|
entry->funcs = new;
|
|
debug_print_probes(entry);
|
|
return old;
|
|
}
|
|
|
|
static void *
|
|
tracepoint_entry_remove_probe(struct tracepoint_entry *entry,
|
|
void *probe, void *data)
|
|
{
|
|
int nr_probes = 0, nr_del = 0, i;
|
|
struct tracepoint_func *old, *new;
|
|
|
|
old = entry->funcs;
|
|
|
|
if (!old)
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
debug_print_probes(entry);
|
|
/* (N -> M), (N > 1, M >= 0) probes */
|
|
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 probe is NULL, then nr_probes = nr_del = 0, and then the
|
|
* entire entry will be removed.
|
|
*/
|
|
if (nr_probes - nr_del == 0) {
|
|
/* N -> 0, (N > 1) */
|
|
entry->funcs = NULL;
|
|
entry->refcount = 0;
|
|
debug_print_probes(entry);
|
|
return old;
|
|
} else {
|
|
int j = 0;
|
|
/* N -> M, (N > 1, M > 0) */
|
|
/* + 1 for NULL */
|
|
new = allocate_probes(nr_probes - nr_del + 1);
|
|
if (new == NULL)
|
|
return ERR_PTR(-ENOMEM);
|
|
for (i = 0; old[i].func; i++)
|
|
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;
|
|
entry->funcs = new;
|
|
}
|
|
debug_print_probes(entry);
|
|
return old;
|
|
}
|
|
|
|
/*
|
|
* Get tracepoint if the tracepoint is present in the tracepoint hash table.
|
|
* Must be called with tracepoints_mutex held.
|
|
* Returns NULL if not present.
|
|
*/
|
|
static struct tracepoint_entry *get_tracepoint(const char *name)
|
|
{
|
|
struct hlist_head *head;
|
|
struct tracepoint_entry *e;
|
|
u32 hash = jhash(name, strlen(name), 0);
|
|
|
|
head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
|
|
hlist_for_each_entry(e, head, hlist) {
|
|
if (!strcmp(name, e->name))
|
|
return e;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Add the tracepoint to the tracepoint hash table. Must be called with
|
|
* tracepoints_mutex held.
|
|
*/
|
|
static struct tracepoint_entry *add_tracepoint(const char *name)
|
|
{
|
|
struct hlist_head *head;
|
|
struct tracepoint_entry *e;
|
|
size_t name_len = strlen(name) + 1;
|
|
u32 hash = jhash(name, name_len-1, 0);
|
|
|
|
head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
|
|
hlist_for_each_entry(e, head, hlist) {
|
|
if (!strcmp(name, e->name)) {
|
|
printk(KERN_NOTICE
|
|
"tracepoint %s busy\n", name);
|
|
return ERR_PTR(-EEXIST); /* Already there */
|
|
}
|
|
}
|
|
/*
|
|
* Using kmalloc here to allocate a variable length element. Could
|
|
* cause some memory fragmentation if overused.
|
|
*/
|
|
e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
|
|
if (!e)
|
|
return ERR_PTR(-ENOMEM);
|
|
memcpy(&e->name[0], name, name_len);
|
|
e->funcs = NULL;
|
|
e->refcount = 0;
|
|
e->enabled = 0;
|
|
hlist_add_head(&e->hlist, head);
|
|
return e;
|
|
}
|
|
|
|
/*
|
|
* Remove the tracepoint from the tracepoint hash table. Must be called with
|
|
* mutex_lock held.
|
|
*/
|
|
static inline void remove_tracepoint(struct tracepoint_entry *e)
|
|
{
|
|
hlist_del(&e->hlist);
|
|
kfree(e);
|
|
}
|
|
|
|
/*
|
|
* Sets the probe callback corresponding to one tracepoint.
|
|
*/
|
|
static void set_tracepoint(struct tracepoint_entry **entry,
|
|
struct tracepoint *elem, int active)
|
|
{
|
|
WARN_ON(strcmp((*entry)->name, elem->name) != 0);
|
|
|
|
if (elem->regfunc && !static_key_enabled(&elem->key) && active)
|
|
elem->regfunc();
|
|
else if (elem->unregfunc && static_key_enabled(&elem->key) && !active)
|
|
elem->unregfunc();
|
|
|
|
/*
|
|
* rcu_assign_pointer has a smp_wmb() which makes sure that the new
|
|
* probe callbacks array is consistent before setting a pointer to it.
|
|
* This array is referenced by __DO_TRACE from
|
|
* include/linux/tracepoints.h. A matching smp_read_barrier_depends()
|
|
* is used.
|
|
*/
|
|
rcu_assign_pointer(elem->funcs, (*entry)->funcs);
|
|
if (active && !static_key_enabled(&elem->key))
|
|
static_key_slow_inc(&elem->key);
|
|
else if (!active && static_key_enabled(&elem->key))
|
|
static_key_slow_dec(&elem->key);
|
|
}
|
|
|
|
/*
|
|
* Disable a tracepoint and its probe callback.
|
|
* Note: only waiting an RCU period after setting elem->call to the empty
|
|
* 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)
|
|
{
|
|
if (elem->unregfunc && static_key_enabled(&elem->key))
|
|
elem->unregfunc();
|
|
|
|
if (static_key_enabled(&elem->key))
|
|
static_key_slow_dec(&elem->key);
|
|
rcu_assign_pointer(elem->funcs, NULL);
|
|
}
|
|
|
|
/**
|
|
* tracepoint_update_probe_range - Update a probe range
|
|
* @begin: beginning of the range
|
|
* @end: end of the range
|
|
*
|
|
* Updates the probe callback corresponding to a range of tracepoints.
|
|
* Called with tracepoints_mutex held.
|
|
*/
|
|
static void tracepoint_update_probe_range(struct tracepoint * const *begin,
|
|
struct tracepoint * const *end)
|
|
{
|
|
struct tracepoint * const *iter;
|
|
struct tracepoint_entry *mark_entry;
|
|
|
|
if (!begin)
|
|
return;
|
|
|
|
for (iter = begin; iter < end; iter++) {
|
|
mark_entry = get_tracepoint((*iter)->name);
|
|
if (mark_entry) {
|
|
set_tracepoint(&mark_entry, *iter,
|
|
!!mark_entry->refcount);
|
|
mark_entry->enabled = !!mark_entry->refcount;
|
|
} else {
|
|
disable_tracepoint(*iter);
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
void module_update_tracepoints(void)
|
|
{
|
|
struct tp_module *tp_mod;
|
|
|
|
list_for_each_entry(tp_mod, &tracepoint_module_list, list)
|
|
tracepoint_update_probe_range(tp_mod->tracepoints_ptrs,
|
|
tp_mod->tracepoints_ptrs + tp_mod->num_tracepoints);
|
|
}
|
|
#else /* CONFIG_MODULES */
|
|
void module_update_tracepoints(void)
|
|
{
|
|
}
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
|
|
/*
|
|
* Update probes, removing the faulty probes.
|
|
* Called with tracepoints_mutex held.
|
|
*/
|
|
static void tracepoint_update_probes(void)
|
|
{
|
|
/* Core kernel tracepoints */
|
|
tracepoint_update_probe_range(__start___tracepoints_ptrs,
|
|
__stop___tracepoints_ptrs);
|
|
/* tracepoints in modules. */
|
|
module_update_tracepoints();
|
|
}
|
|
|
|
static struct tracepoint_func *
|
|
tracepoint_add_probe(const char *name, void *probe, void *data)
|
|
{
|
|
struct tracepoint_entry *entry;
|
|
struct tracepoint_func *old;
|
|
|
|
entry = get_tracepoint(name);
|
|
if (!entry) {
|
|
entry = add_tracepoint(name);
|
|
if (IS_ERR(entry))
|
|
return (struct tracepoint_func *)entry;
|
|
}
|
|
old = tracepoint_entry_add_probe(entry, probe, data);
|
|
if (IS_ERR(old) && !entry->refcount)
|
|
remove_tracepoint(entry);
|
|
return old;
|
|
}
|
|
|
|
/**
|
|
* tracepoint_probe_register - Connect a probe to a tracepoint
|
|
* @name: tracepoint name
|
|
* @probe: probe handler
|
|
* @data: probe private data
|
|
*
|
|
* Returns:
|
|
* - 0 if the probe was successfully registered, and tracepoint
|
|
* callsites are currently loaded for that probe,
|
|
* - -ENODEV if the probe was successfully registered, but no tracepoint
|
|
* callsite is currently loaded for that probe,
|
|
* - other negative error value on error.
|
|
*
|
|
* When tracepoint_probe_register() returns either 0 or -ENODEV,
|
|
* parameters @name, @probe, and @data may be used by the tracepoint
|
|
* infrastructure until the probe is unregistered.
|
|
*
|
|
* The probe address must at least be aligned on the architecture pointer size.
|
|
*/
|
|
int tracepoint_probe_register(const char *name, void *probe, void *data)
|
|
{
|
|
struct tracepoint_func *old;
|
|
struct tracepoint_entry *entry;
|
|
int ret = 0;
|
|
|
|
mutex_lock(&tracepoints_mutex);
|
|
old = tracepoint_add_probe(name, probe, data);
|
|
if (IS_ERR(old)) {
|
|
mutex_unlock(&tracepoints_mutex);
|
|
return PTR_ERR(old);
|
|
}
|
|
tracepoint_update_probes(); /* may update entry */
|
|
entry = get_tracepoint(name);
|
|
/* Make sure the entry was enabled */
|
|
if (!entry || !entry->enabled)
|
|
ret = -ENODEV;
|
|
mutex_unlock(&tracepoints_mutex);
|
|
release_probes(old);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
|
|
|
|
static struct tracepoint_func *
|
|
tracepoint_remove_probe(const char *name, void *probe, void *data)
|
|
{
|
|
struct tracepoint_entry *entry;
|
|
struct tracepoint_func *old;
|
|
|
|
entry = get_tracepoint(name);
|
|
if (!entry)
|
|
return ERR_PTR(-ENOENT);
|
|
old = tracepoint_entry_remove_probe(entry, probe, data);
|
|
if (IS_ERR(old))
|
|
return old;
|
|
if (!entry->refcount)
|
|
remove_tracepoint(entry);
|
|
return old;
|
|
}
|
|
|
|
/**
|
|
* tracepoint_probe_unregister - Disconnect a probe from a tracepoint
|
|
* @name: tracepoint name
|
|
* @probe: probe function pointer
|
|
* @data: probe private data
|
|
*
|
|
* We do not need to call a synchronize_sched to make sure the probes have
|
|
* finished running before doing a module unload, because the module unload
|
|
* itself uses stop_machine(), which insures that every preempt disabled section
|
|
* have finished.
|
|
*/
|
|
int tracepoint_probe_unregister(const char *name, void *probe, void *data)
|
|
{
|
|
struct tracepoint_func *old;
|
|
|
|
mutex_lock(&tracepoints_mutex);
|
|
old = tracepoint_remove_probe(name, probe, data);
|
|
if (IS_ERR(old)) {
|
|
mutex_unlock(&tracepoints_mutex);
|
|
return PTR_ERR(old);
|
|
}
|
|
tracepoint_update_probes(); /* may update entry */
|
|
mutex_unlock(&tracepoints_mutex);
|
|
release_probes(old);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
|
|
|
|
|
|
#ifdef CONFIG_MODULES
|
|
bool trace_module_has_bad_taint(struct module *mod)
|
|
{
|
|
return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
|
|
(1 << TAINT_UNSIGNED_MODULE));
|
|
}
|
|
|
|
static int tracepoint_module_coming(struct module *mod)
|
|
{
|
|
struct tp_module *tp_mod;
|
|
int ret = 0;
|
|
|
|
if (!mod->num_tracepoints)
|
|
return 0;
|
|
|
|
/*
|
|
* We skip modules that taint the kernel, especially those with different
|
|
* module headers (for forced load), to make sure we don't cause a crash.
|
|
* Staging, out-of-tree, and unsigned GPL modules are fine.
|
|
*/
|
|
if (trace_module_has_bad_taint(mod))
|
|
return 0;
|
|
mutex_lock(&tracepoints_mutex);
|
|
tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);
|
|
if (!tp_mod) {
|
|
ret = -ENOMEM;
|
|
goto end;
|
|
}
|
|
tp_mod->num_tracepoints = mod->num_tracepoints;
|
|
tp_mod->tracepoints_ptrs = mod->tracepoints_ptrs;
|
|
list_add_tail(&tp_mod->list, &tracepoint_module_list);
|
|
tracepoint_update_probe_range(mod->tracepoints_ptrs,
|
|
mod->tracepoints_ptrs + mod->num_tracepoints);
|
|
end:
|
|
mutex_unlock(&tracepoints_mutex);
|
|
return ret;
|
|
}
|
|
|
|
static int tracepoint_module_going(struct module *mod)
|
|
{
|
|
struct tp_module *pos;
|
|
|
|
if (!mod->num_tracepoints)
|
|
return 0;
|
|
|
|
mutex_lock(&tracepoints_mutex);
|
|
tracepoint_update_probe_range(mod->tracepoints_ptrs,
|
|
mod->tracepoints_ptrs + mod->num_tracepoints);
|
|
list_for_each_entry(pos, &tracepoint_module_list, list) {
|
|
if (pos->tracepoints_ptrs == mod->tracepoints_ptrs) {
|
|
list_del(&pos->list);
|
|
kfree(pos);
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* In the case of modules that were tainted at "coming", we'll simply
|
|
* walk through the list without finding it. We cannot use the "tainted"
|
|
* flag on "going", in case a module taints the kernel only after being
|
|
* loaded.
|
|
*/
|
|
mutex_unlock(&tracepoints_mutex);
|
|
return 0;
|
|
}
|
|
|
|
int tracepoint_module_notify(struct notifier_block *self,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct module *mod = data;
|
|
int ret = 0;
|
|
|
|
switch (val) {
|
|
case MODULE_STATE_COMING:
|
|
ret = tracepoint_module_coming(mod);
|
|
break;
|
|
case MODULE_STATE_LIVE:
|
|
break;
|
|
case MODULE_STATE_GOING:
|
|
ret = tracepoint_module_going(mod);
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
struct notifier_block tracepoint_module_nb = {
|
|
.notifier_call = tracepoint_module_notify,
|
|
.priority = 0,
|
|
};
|
|
|
|
static int init_tracepoints(void)
|
|
{
|
|
return register_module_notifier(&tracepoint_module_nb);
|
|
}
|
|
__initcall(init_tracepoints);
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
|
|
|
|
/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
|
|
static int sys_tracepoint_refcount;
|
|
|
|
void syscall_regfunc(void)
|
|
{
|
|
unsigned long flags;
|
|
struct task_struct *g, *t;
|
|
|
|
if (!sys_tracepoint_refcount) {
|
|
read_lock_irqsave(&tasklist_lock, flags);
|
|
do_each_thread(g, t) {
|
|
/* Skip kernel threads. */
|
|
if (t->mm)
|
|
set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
|
|
} while_each_thread(g, t);
|
|
read_unlock_irqrestore(&tasklist_lock, flags);
|
|
}
|
|
sys_tracepoint_refcount++;
|
|
}
|
|
|
|
void syscall_unregfunc(void)
|
|
{
|
|
unsigned long flags;
|
|
struct task_struct *g, *t;
|
|
|
|
sys_tracepoint_refcount--;
|
|
if (!sys_tracepoint_refcount) {
|
|
read_lock_irqsave(&tasklist_lock, flags);
|
|
do_each_thread(g, t) {
|
|
clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
|
|
} while_each_thread(g, t);
|
|
read_unlock_irqrestore(&tasklist_lock, flags);
|
|
}
|
|
}
|
|
#endif
|