static struct ftrace_ops global_ops;
static struct ftrace_ops control_ops;
+static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct pt_regs *regs);
+
#if ARCH_SUPPORTS_FTRACE_OPS
static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs);
{
ftrace_func_t func;
+ /*
+ * Prepare the ftrace_ops that the arch callback will use.
+ * If there's only one ftrace_ops registered, the ftrace_ops_list
+ * will point to the ops we want.
+ */
+ set_function_trace_op = ftrace_ops_list;
+
+ /* If there's no ftrace_ops registered, just call the stub function */
+ if (ftrace_ops_list == &ftrace_list_end) {
+ func = ftrace_stub;
+
/*
* If we are at the end of the list and this ops is
* recursion safe and not dynamic and the arch supports passing ops,
* then have the mcount trampoline call the function directly.
*/
- if (ftrace_ops_list == &ftrace_list_end ||
- (ftrace_ops_list->next == &ftrace_list_end &&
- !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
- (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
- !FTRACE_FORCE_LIST_FUNC)) {
- /* Set the ftrace_ops that the arch callback uses */
- set_function_trace_op = ftrace_ops_list;
- func = ftrace_ops_list->func;
+ } else if (ftrace_ops_list->next == &ftrace_list_end) {
+ func = ftrace_ops_get_func(ftrace_ops_list);
+
} else {
/* Just use the default ftrace_ops */
set_function_trace_op = &ftrace_list_end;
static struct ftrace_ops *removed_ops;
+/*
+ * Set when doing a global update, like enabling all recs or disabling them.
+ * It is not set when just updating a single ftrace_ops.
+ */
+static bool update_all_ops;
+
#ifndef CONFIG_FTRACE_MCOUNT_RECORD
# error Dynamic ftrace depends on MCOUNT_RECORD
#endif
struct ftrace_func_entry *entry;
struct hlist_node *tn;
struct hlist_head *hhd;
- struct ftrace_hash *old_hash;
struct ftrace_hash *new_hash;
int size = src->count;
int bits = 0;
*/
ftrace_hash_rec_disable_modify(ops, enable);
- old_hash = *dst;
rcu_assign_pointer(*dst, new_hash);
- free_ftrace_hash_rcu(old_hash);
ftrace_hash_rec_enable_modify(ops, enable);
return 0;
}
+static bool hash_contains_ip(unsigned long ip,
+ struct ftrace_ops_hash *hash)
+{
+ /*
+ * The function record is a match if it exists in the filter
+ * hash and not in the notrace hash. Note, an emty hash is
+ * considered a match for the filter hash, but an empty
+ * notrace hash is considered not in the notrace hash.
+ */
+ return (ftrace_hash_empty(hash->filter_hash) ||
+ ftrace_lookup_ip(hash->filter_hash, ip)) &&
+ (ftrace_hash_empty(hash->notrace_hash) ||
+ !ftrace_lookup_ip(hash->notrace_hash, ip));
+}
+
/*
* Test the hashes for this ops to see if we want to call
* the ops->func or not.
static int
ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
{
- struct ftrace_hash *filter_hash;
- struct ftrace_hash *notrace_hash;
+ struct ftrace_ops_hash hash;
int ret;
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
return 0;
#endif
- filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
- notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
+ hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
+ hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
- if ((ftrace_hash_empty(filter_hash) ||
- ftrace_lookup_ip(filter_hash, ip)) &&
- (ftrace_hash_empty(notrace_hash) ||
- !ftrace_lookup_ip(notrace_hash, ip)))
+ if (hash_contains_ip(ip, &hash))
ret = 1;
else
ret = 0;
return keep_regs;
}
-static void ftrace_remove_tramp(struct ftrace_ops *ops,
- struct dyn_ftrace *rec)
-{
- /* If TRAMP is not set, no ops should have a trampoline for this */
- if (!(rec->flags & FTRACE_FL_TRAMP))
- return;
-
- rec->flags &= ~FTRACE_FL_TRAMP;
-
- if ((!ftrace_hash_empty(ops->func_hash->filter_hash) &&
- !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip)) ||
- ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
- return;
- /*
- * The tramp_hash entry will be removed at time
- * of update.
- */
- ops->nr_trampolines--;
-}
-
-static void ftrace_clear_tramps(struct dyn_ftrace *rec, struct ftrace_ops *ops)
-{
- struct ftrace_ops *op;
-
- /* If TRAMP is not set, no ops should have a trampoline for this */
- if (!(rec->flags & FTRACE_FL_TRAMP))
- return;
-
- do_for_each_ftrace_op(op, ftrace_ops_list) {
- /*
- * This function is called to clear other tramps
- * not the one that is being updated.
- */
- if (op == ops)
- continue;
- if (op->nr_trampolines)
- ftrace_remove_tramp(op, rec);
- } while_for_each_ftrace_op(op);
-}
-
static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
int filter_hash,
bool inc)
* function, and the ops has a trampoline registered
* for it, then we can call it directly.
*/
- if (ftrace_rec_count(rec) == 1 && ops->trampoline) {
+ if (ftrace_rec_count(rec) == 1 && ops->trampoline)
rec->flags |= FTRACE_FL_TRAMP;
- ops->nr_trampolines++;
- } else {
+ else
/*
* If we are adding another function callback
* to this function, and the previous had a
* custom trampoline in use, then we need to go
* back to the default trampoline.
*/
- ftrace_clear_tramps(rec, ops);
- }
+ rec->flags &= ~FTRACE_FL_TRAMP;
/*
* If any ops wants regs saved for this function
return;
rec->flags--;
- if (ops->trampoline && !ftrace_rec_count(rec))
- ftrace_remove_tramp(ops, rec);
-
/*
* If the rec had REGS enabled and the ops that is
* being removed had REGS set, then see if there is
rec->flags &= ~FTRACE_FL_REGS;
}
+ /*
+ * If the rec had TRAMP enabled, then it needs to
+ * be cleared. As TRAMP can only be enabled iff
+ * there is only a single ops attached to it.
+ * In otherwords, always disable it on decrementing.
+ * In the future, we may set it if rec count is
+ * decremented to one, and the ops that is left
+ * has a trampoline.
+ */
+ rec->flags &= ~FTRACE_FL_TRAMP;
+
/*
* flags will be cleared in ftrace_check_record()
* if rec count is zero.
return ftrace_check_record(rec, enable, 0);
}
+static struct ftrace_ops *
+ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
+{
+ struct ftrace_ops *op;
+ unsigned long ip = rec->ip;
+
+ do_for_each_ftrace_op(op, ftrace_ops_list) {
+
+ if (!op->trampoline)
+ continue;
+
+ if (hash_contains_ip(ip, op->func_hash))
+ return op;
+ } while_for_each_ftrace_op(op);
+
+ return NULL;
+}
+
static struct ftrace_ops *
ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
{
struct ftrace_ops *op;
+ unsigned long ip = rec->ip;
- /* Removed ops need to be tested first */
- if (removed_ops && removed_ops->tramp_hash) {
- if (ftrace_lookup_ip(removed_ops->tramp_hash, rec->ip))
+ /*
+ * Need to check removed ops first.
+ * If they are being removed, and this rec has a tramp,
+ * and this rec is in the ops list, then it would be the
+ * one with the tramp.
+ */
+ if (removed_ops) {
+ if (hash_contains_ip(ip, &removed_ops->old_hash))
return removed_ops;
}
+ /*
+ * Need to find the current trampoline for a rec.
+ * Now, a trampoline is only attached to a rec if there
+ * was a single 'ops' attached to it. But this can be called
+ * when we are adding another op to the rec or removing the
+ * current one. Thus, if the op is being added, we can
+ * ignore it because it hasn't attached itself to the rec
+ * yet. That means we just need to find the op that has a
+ * trampoline and is not beeing added.
+ */
do_for_each_ftrace_op(op, ftrace_ops_list) {
- if (!op->tramp_hash)
+
+ if (!op->trampoline)
continue;
- if (ftrace_lookup_ip(op->tramp_hash, rec->ip))
+ /*
+ * If the ops is being added, it hasn't gotten to
+ * the point to be removed from this tree yet.
+ */
+ if (op->flags & FTRACE_OPS_FL_ADDING)
+ continue;
+
+ /*
+ * If the ops is not being added and has a trampoline,
+ * then it must be the one that we want!
+ */
+ if (hash_contains_ip(ip, op->func_hash))
+ return op;
+
+ /* If the ops is being modified, it may be in the old hash. */
+ if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
+ hash_contains_ip(ip, &op->old_hash))
return op;
} while_for_each_ftrace_op(op);
ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
{
struct ftrace_ops *op;
+ unsigned long ip = rec->ip;
do_for_each_ftrace_op(op, ftrace_ops_list) {
/* pass rec in as regs to have non-NULL val */
- if (ftrace_ops_test(op, rec->ip, rec))
+ if (hash_contains_ip(ip, op->func_hash))
return op;
} while_for_each_ftrace_op(op);
ftrace_run_stop_machine(command);
}
-static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops)
-{
- struct ftrace_page *pg;
- struct dyn_ftrace *rec;
- int size, bits;
- int ret;
-
- size = ops->nr_trampolines;
- bits = 0;
- /*
- * Make the hash size about 1/2 the # found
- */
- for (size /= 2; size; size >>= 1)
- bits++;
-
- ops->tramp_hash = alloc_ftrace_hash(bits);
- /*
- * TODO: a failed allocation is going to screw up
- * the accounting of what needs to be modified
- * and not. For now, we kill ftrace if we fail
- * to allocate here. But there are ways around this,
- * but that will take a little more work.
- */
- if (!ops->tramp_hash)
- return -ENOMEM;
-
- do_for_each_ftrace_rec(pg, rec) {
- if (ftrace_rec_count(rec) == 1 &&
- ftrace_ops_test(ops, rec->ip, rec)) {
-
- /*
- * If another ops adds to a rec, the rec will
- * lose its trampoline and never get it back
- * until all ops are off of it.
- */
- if (!(rec->flags & FTRACE_FL_TRAMP))
- continue;
-
- /* This record had better have a trampoline */
- if (FTRACE_WARN_ON(!(rec->flags & FTRACE_FL_TRAMP_EN)))
- return -1;
-
- ret = add_hash_entry(ops->tramp_hash, rec->ip);
- if (ret < 0)
- return ret;
- }
- } while_for_each_ftrace_rec();
-
- /* The number of recs in the hash must match nr_trampolines */
- if (FTRACE_WARN_ON(ops->tramp_hash->count != ops->nr_trampolines))
- pr_warn("count=%ld trampolines=%d\n",
- ops->tramp_hash->count,
- ops->nr_trampolines);
-
- return 0;
-}
-
-static int ftrace_save_tramp_hashes(void)
-{
- struct ftrace_ops *op;
- int ret;
-
- /*
- * Now that any trampoline is being used, we need to save the
- * hashes for the ops that have them. This allows the mapping
- * back from the record to the ops that has the trampoline to
- * know what code is being replaced. Modifying code must always
- * verify what it is changing.
- */
- do_for_each_ftrace_op(op, ftrace_ops_list) {
-
- /* The tramp_hash is recreated each time. */
- free_ftrace_hash(op->tramp_hash);
- op->tramp_hash = NULL;
-
- if (op->nr_trampolines) {
- ret = ftrace_save_ops_tramp_hash(op);
- if (ret)
- return ret;
- }
-
- } while_for_each_ftrace_op(op);
-
- return 0;
-}
-
static void ftrace_run_update_code(int command)
{
int ret;
ret = ftrace_arch_code_modify_post_process();
FTRACE_WARN_ON(ret);
+}
- ret = ftrace_save_tramp_hashes();
- FTRACE_WARN_ON(ret);
+static void ftrace_run_modify_code(struct ftrace_ops *ops, int command)
+{
+ ops->flags |= FTRACE_OPS_FL_MODIFYING;
+ ftrace_run_update_code(command);
+ ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
}
static ftrace_func_t saved_ftrace_func;
ftrace_run_update_code(command);
}
+static void ftrace_startup_all(int command)
+{
+ update_all_ops = true;
+ ftrace_startup_enable(command);
+ update_all_ops = false;
+}
+
static int ftrace_startup(struct ftrace_ops *ops, int command)
{
int ret;
ftrace_start_up++;
command |= FTRACE_UPDATE_CALLS;
- ops->flags |= FTRACE_OPS_FL_ENABLED;
+ /*
+ * Note that ftrace probes uses this to start up
+ * and modify functions it will probe. But we still
+ * set the ADDING flag for modification, as probes
+ * do not have trampolines. If they add them in the
+ * future, then the probes will need to distinguish
+ * between adding and updating probes.
+ */
+ ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
ftrace_hash_rec_enable(ops, 1);
ftrace_startup_enable(command);
+ ops->flags &= ~FTRACE_OPS_FL_ADDING;
+
return 0;
}
* If the ops uses a trampoline, then it needs to be
* tested first on update.
*/
+ ops->flags |= FTRACE_OPS_FL_REMOVING;
removed_ops = ops;
+ /* The trampoline logic checks the old hashes */
+ ops->old_hash.filter_hash = ops->func_hash->filter_hash;
+ ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
+
ftrace_run_update_code(command);
+ /*
+ * If there's no more ops registered with ftrace, run a
+ * sanity check to make sure all rec flags are cleared.
+ */
+ if (ftrace_ops_list == &ftrace_list_end) {
+ struct ftrace_page *pg;
+ struct dyn_ftrace *rec;
+
+ do_for_each_ftrace_rec(pg, rec) {
+ if (FTRACE_WARN_ON_ONCE(rec->flags))
+ pr_warn(" %pS flags:%lx\n",
+ (void *)rec->ip, rec->flags);
+ } while_for_each_ftrace_rec();
+ }
+
+ ops->old_hash.filter_hash = NULL;
+ ops->old_hash.notrace_hash = NULL;
+
removed_ops = NULL;
+ ops->flags &= ~FTRACE_OPS_FL_REMOVING;
/*
* Dynamic ops may be freed, we must make sure that all
if (rec->flags & FTRACE_FL_TRAMP_EN) {
struct ftrace_ops *ops;
- ops = ftrace_find_tramp_ops_curr(rec);
- if (ops && ops->trampoline)
+ ops = ftrace_find_tramp_ops_any(rec);
+ if (ops)
seq_printf(m, "\ttramp: %pS",
(void *)ops->trampoline);
else
if (ftrace_probe_registered) {
/* still need to update the function call sites */
if (ftrace_enabled)
- ftrace_run_update_code(FTRACE_UPDATE_CALLS);
+ ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS);
return;
}
{
struct ftrace_func_probe *entry;
struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
+ struct ftrace_hash *old_hash = *orig_hash;
struct ftrace_hash *hash;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
mutex_lock(&trace_probe_ops.func_hash->regex_lock);
- hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+ hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
if (!hash) {
count = -ENOMEM;
goto out;
} while_for_each_ftrace_rec();
ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
- if (ret < 0)
+ if (!ret)
+ free_ftrace_hash_rcu(old_hash);
+ else
count = ret;
__enable_ftrace_function_probe();
struct ftrace_func_probe *entry;
struct ftrace_func_probe *p;
struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
+ struct ftrace_hash *old_hash = *orig_hash;
struct list_head free_list;
struct ftrace_hash *hash;
struct hlist_node *tmp;
int type = MATCH_FULL;
int i, len = 0;
char *search;
+ int ret;
if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
glob = NULL;
* Remove after the disable is called. Otherwise, if the last
* probe is removed, a null hash means *all enabled*.
*/
- ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
+ ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
synchronize_sched();
+ if (!ret)
+ free_ftrace_hash_rcu(old_hash);
+
list_for_each_entry_safe(entry, p, &free_list, free_list) {
list_del(&entry->free_list);
ftrace_free_entry(entry);
static void ftrace_ops_update_code(struct ftrace_ops *ops)
{
if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
- ftrace_run_update_code(FTRACE_UPDATE_CALLS);
+ ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS);
}
static int
unsigned long ip, int remove, int reset, int enable)
{
struct ftrace_hash **orig_hash;
+ struct ftrace_hash *old_hash;
struct ftrace_hash *hash;
int ret;
}
mutex_lock(&ftrace_lock);
+ old_hash = *orig_hash;
ret = ftrace_hash_move(ops, enable, orig_hash, hash);
- if (!ret)
+ if (!ret) {
ftrace_ops_update_code(ops);
-
+ free_ftrace_hash_rcu(old_hash);
+ }
mutex_unlock(&ftrace_lock);
out_regex_unlock:
struct seq_file *m = (struct seq_file *)file->private_data;
struct ftrace_iterator *iter;
struct ftrace_hash **orig_hash;
+ struct ftrace_hash *old_hash;
struct trace_parser *parser;
int filter_hash;
int ret;
orig_hash = &iter->ops->func_hash->notrace_hash;
mutex_lock(&ftrace_lock);
+ old_hash = *orig_hash;
ret = ftrace_hash_move(iter->ops, filter_hash,
orig_hash, iter->hash);
- if (!ret)
+ if (!ret) {
ftrace_ops_update_code(iter->ops);
-
+ free_ftrace_hash_rcu(old_hash);
+ }
mutex_unlock(&ftrace_lock);
}
static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
static inline void ftrace_startup_enable(int command) { }
+static inline void ftrace_startup_all(int command) { }
/* Keep as macros so we do not need to define the commands */
# define ftrace_startup(ops, command) \
({ \
}
#endif
+/*
+ * If there's only one function registered but it does not support
+ * recursion, this function will be called by the mcount trampoline.
+ * This function will handle recursion protection.
+ */
+static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct pt_regs *regs)
+{
+ int bit;
+
+ bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
+ if (bit < 0)
+ return;
+
+ op->func(ip, parent_ip, op, regs);
+
+ trace_clear_recursion(bit);
+}
+
+/**
+ * ftrace_ops_get_func - get the function a trampoline should call
+ * @ops: the ops to get the function for
+ *
+ * Normally the mcount trampoline will call the ops->func, but there
+ * are times that it should not. For example, if the ops does not
+ * have its own recursion protection, then it should call the
+ * ftrace_ops_recurs_func() instead.
+ *
+ * Returns the function that the trampoline should call for @ops.
+ */
+ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
+{
+ /*
+ * If this is a dynamic ops or we force list func,
+ * then it needs to call the list anyway.
+ */
+ if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC)
+ return ftrace_ops_list_func;
+
+ /*
+ * If the func handles its own recursion, call it directly.
+ * Otherwise call the recursion protected function that
+ * will call the ftrace ops function.
+ */
+ if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE))
+ return ftrace_ops_recurs_func;
+
+ return ops->func;
+}
+
static void clear_ftrace_swapper(void)
{
struct task_struct *p;
set_ftrace_pid_task(pid);
ftrace_update_pid_func();
- ftrace_startup_enable(0);
+
+ ftrace_startup_all(0);
mutex_unlock(&ftrace_lock);
return 0;
}
ftrace_update_pid_func();
- ftrace_startup_enable(0);
+ ftrace_startup_all(0);
mutex_unlock(&ftrace_lock);
}
projects / firefly-linux-kernel-4.4.55.git / blobdiff