/* ftrace_enabled is a method to turn ftrace on or off */ int ftrace_enabled __read_mostly; staticint __maybe_unused last_ftrace_enabled;
/* Current function tracing op */ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end; /* What to set function_trace_op to */ staticstruct ftrace_ops *set_function_trace_op;
/* * ftrace_disabled is set when an anomaly is discovered. * ftrace_disabled is much stronger than ftrace_enabled.
*/ staticint ftrace_disabled __read_mostly;
/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */ void ftrace_ops_list_func(unsignedlong ip, unsignedlong parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs);
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS /* * Stub used to invoke the list ops without requiring a separate trampoline.
*/ conststruct ftrace_ops ftrace_list_ops = {
.func = ftrace_ops_list_func,
.flags = FTRACE_OPS_FL_STUB,
};
/* * Stub used when a call site is disabled. May be called transiently by threads * which have made it into ftrace_caller but haven't yet recovered the ops at * the point the call site is disabled.
*/ conststruct ftrace_ops ftrace_nop_ops = {
.func = ftrace_ops_nop_func,
.flags = FTRACE_OPS_FL_STUB,
}; #endif
/* Call this function for when a callback filters on set_ftrace_pid */ staticvoid ftrace_pid_func(unsignedlong ip, unsignedlong parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs)
{ struct trace_array *tr = op->private; int pid;
if (tr) {
pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid); if (pid == FTRACE_PID_IGNORE) return; if (pid != FTRACE_PID_TRACE &&
pid != current->pid) return;
}
op->saved_func(ip, parent_ip, op, fregs);
}
void ftrace_sync_ipi(void *data)
{ /* Probably not needed, but do it anyway */
smp_rmb();
}
static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
{ /* * If this is a dynamic or RCU ops, or we force list func, * then it needs to call the list anyway.
*/ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
FTRACE_FORCE_LIST_FUNC) return ftrace_ops_list_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 = rcu_dereference_protected(ftrace_ops_list,
lockdep_is_held(&ftrace_lock));
/* If there's no ftrace_ops registered, just call the stub function */ if (set_function_trace_op == &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.
*/
} elseif (rcu_dereference_protected(ftrace_ops_list->next,
lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
func = ftrace_ops_get_list_func(ftrace_ops_list);
} else { /* Just use the default ftrace_ops */
set_function_trace_op = &ftrace_list_end;
func = ftrace_ops_list_func;
}
/* If there's no change, then do nothing more here */ if (ftrace_trace_function == func) return;
/* * If we are using the list function, it doesn't care * about the function_trace_ops.
*/ if (func == ftrace_ops_list_func) {
ftrace_trace_function = func; /* * Don't even bother setting function_trace_ops, * it would be racy to do so anyway.
*/ return;
}
#ifndef CONFIG_DYNAMIC_FTRACE /* * For static tracing, we need to be a bit more careful. * The function change takes affect immediately. Thus, * we need to coordinate the setting of the function_trace_ops * with the setting of the ftrace_trace_function. * * Set the function to the list ops, which will call the * function we want, albeit indirectly, but it handles the * ftrace_ops and doesn't depend on function_trace_op.
*/
ftrace_trace_function = ftrace_ops_list_func; /* * Make sure all CPUs see this. Yes this is slow, but static * tracing is slow and nasty to have enabled.
*/
synchronize_rcu_tasks_rude(); /* Now all cpus are using the list ops. */
function_trace_op = set_function_trace_op; /* Make sure the function_trace_op is visible on all CPUs */
smp_wmb(); /* Nasty way to force a rmb on all cpus */
smp_call_function(ftrace_sync_ipi, NULL, 1); /* OK, we are all set to update the ftrace_trace_function now! */ #endif/* !CONFIG_DYNAMIC_FTRACE */
/* * We are entering ops into the list but another * CPU might be walking that list. We need to make sure * the ops->next pointer is valid before another CPU sees * the ops pointer included into the list.
*/
rcu_assign_pointer(*list, ops);
}
/* * If we are removing the last function, then simply point * to the ftrace_stub.
*/ if (rcu_dereference_protected(*list,
lockdep_is_held(&ftrace_lock)) == ops &&
rcu_dereference_protected(ops->next,
lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
rcu_assign_pointer(*list, &ftrace_list_end); return 0;
}
for (p = list; *p != &ftrace_list_end; p = &(*p)->next) if (*p == ops) break;
int __register_ftrace_function(struct ftrace_ops *ops)
{ if (ops->flags & FTRACE_OPS_FL_DELETED) return -EINVAL;
if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EBUSY;
#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* * If the ftrace_ops specifies SAVE_REGS, then it only can be used * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set. * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
*/ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
!(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)) return -EINVAL;
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
ops->flags |= FTRACE_OPS_FL_SAVE_REGS; #endif if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT)) return -EBUSY;
if (!is_kernel_core_data((unsignedlong)ops))
ops->flags |= FTRACE_OPS_FL_DYNAMIC;
add_ftrace_ops(&ftrace_ops_list, ops);
/* Always save the function, and reset at unregistering */
ops->saved_func = ops->func;
if (ftrace_pids_enabled(ops))
ops->func = ftrace_pid_func;
ftrace_update_trampoline(ops);
if (ftrace_enabled)
update_ftrace_function();
return 0;
}
int __unregister_ftrace_function(struct ftrace_ops *ops)
{ int ret;
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED))) return -EBUSY;
staticint ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
{ struct ftrace_profile_page *pg; int functions; int pages; int i;
/* If we already allocated, do nothing */ if (stat->pages) return 0;
stat->pages = (void *)get_zeroed_page(GFP_KERNEL); if (!stat->pages) return -ENOMEM;
#ifdef CONFIG_DYNAMIC_FTRACE
functions = ftrace_update_tot_cnt; #else /* * We do not know the number of functions that exist because * dynamic tracing is what counts them. With past experience * we have around 20K functions. That should be more than enough. * It is highly unlikely we will execute every function in * the kernel.
*/
functions = 20000; #endif
staticint ftrace_profile_init_cpu(int cpu)
{ struct ftrace_profile_stat *stat; int size;
stat = &per_cpu(ftrace_profile_stats, cpu);
if (stat->hash) { /* If the profile is already created, simply reset it */
ftrace_profile_reset(stat); return 0;
}
/* * We are profiling all functions, but usually only a few thousand * functions are hit. We'll make a hash of 1024 items.
*/
size = FTRACE_PROFILE_HASH_SIZE;
/* * The memory is already allocated, this simply finds a new record to use.
*/ staticstruct ftrace_profile *
ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsignedlong ip)
{ struct ftrace_profile *rec = NULL;
/* If the calltime was zero'd ignore it */ if (!profile_data || !profile_data->calltime) return;
calltime = rettime - profile_data->calltime;
if (!fgraph_sleep_time) { if (current->ftrace_sleeptime)
calltime -= current->ftrace_sleeptime - profile_data->sleeptime;
}
if (!fgraph_graph_time) { struct profile_fgraph_data *parent_data;
/* Append this call time to the parent time to subtract */
parent_data = fgraph_retrieve_parent_data(gops->idx, &size, 1); if (parent_data)
parent_data->subtime += calltime;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret;
val = !!val;
guard(mutex)(&ftrace_profile_lock); if (ftrace_profile_enabled ^ val) { if (val) {
ret = ftrace_profile_init(); if (ret < 0) return ret;
ret = register_ftrace_profiler(); if (ret < 0) return ret;
ftrace_profile_enabled = 1;
} else {
ftrace_profile_enabled = 0; /* * unregister_ftrace_profiler calls stop_machine * so this acts like an synchronize_rcu.
*/
unregister_ftrace_profiler();
}
}
*ppos += cnt;
return cnt;
}
static ssize_t
ftrace_profile_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{ char buf[64]; /* big enough to hold a number */ int r;
/* used to initialize the real stat files */ staticstruct tracer_stat function_stats __initdata = {
.name = "functions",
.stat_start = function_stat_start,
.stat_next = function_stat_next,
.stat_cmp = function_stat_cmp,
.stat_headers = function_stat_headers,
.stat_show = function_stat_show
};
static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
{ struct ftrace_profile_stat *stat; char *name; int ret; int cpu;
for_each_possible_cpu(cpu) {
stat = &per_cpu(ftrace_profile_stats, cpu);
name = kasprintf(GFP_KERNEL, "function%d", cpu); if (!name) { /* * The files created are permanent, if something happens * we still do not free memory.
*/
WARN(1, "Could not allocate stat file for cpu %d\n",
cpu); return;
}
stat->stat = function_stats;
stat->stat.name = name;
ret = register_stat_tracer(&stat->stat); if (ret) {
WARN(1, "Could not register function stat for cpu %d\n",
cpu);
kfree(name); return;
}
}
/* * Set when doing a global update, like enabling all recs or disabling them. * It is not set when just updating a single ftrace_ops.
*/ staticbool update_all_ops;
/* * We make these constant because no one should touch them, * but they are used as the default "empty hash", to avoid allocating * it all the time. These are in a read only section such that if * anyone does try to modify it, it will cause an exception.
*/ staticconststruct hlist_head empty_buckets[1]; staticconststruct ftrace_hash empty_hash = {
.buckets = (struct hlist_head *)empty_buckets,
}; #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
/* * Used by the stack unwinder to know about dynamic ftrace trampolines.
*/ struct ftrace_ops *ftrace_ops_trampoline(unsignedlong addr)
{ struct ftrace_ops *op = NULL;
/* * Some of the ops may be dynamically allocated, * they are freed after a synchronize_rcu().
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) { /* * This is to check for dynamically allocated trampolines. * Trampolines that are in kernel text will have * core_kernel_text() return true.
*/ if (op->trampoline && op->trampoline_size) if (addr >= op->trampoline &&
addr < op->trampoline + op->trampoline_size) {
preempt_enable_notrace(); return op;
}
} while_for_each_ftrace_op(op);
preempt_enable_notrace();
return NULL;
}
/* * This is used by __kernel_text_address() to return true if the * address is on a dynamically allocated trampoline that would * not return true for either core_kernel_text() or * is_module_text_address().
*/ bool is_ftrace_trampoline(unsignedlong addr)
{ return ftrace_ops_trampoline(addr) != NULL;
}
struct ftrace_page { struct ftrace_page *next; struct dyn_ftrace *records; int index; int order;
};
/* Only use this function if ftrace_hash_empty() has already been tested */ static __always_inline struct ftrace_func_entry *
__ftrace_lookup_ip(struct ftrace_hash *hash, unsignedlong ip)
{ unsignedlong key; struct ftrace_func_entry *entry; struct hlist_head *hhd;
/** * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash * @hash: The hash to look at * @ip: The instruction pointer to test * * Search a given @hash to see if a given instruction pointer (@ip) * exists in it. * * Returns: the entry that holds the @ip if found. NULL otherwise.
*/ struct ftrace_func_entry *
ftrace_lookup_ip(struct ftrace_hash *hash, unsignedlong ip)
{ if (ftrace_hash_empty(hash)) return NULL;
/* * Allocate a new hash and remove entries from @src and move them to the new hash. * On success, the @src hash will be empty and should be freed.
*/ staticstruct ftrace_hash *__move_hash(struct ftrace_hash *src, int size)
{ struct ftrace_func_entry *entry; struct ftrace_hash *new_hash; struct hlist_head *hhd; struct hlist_node *tn; int bits = 0; int i;
/* * Use around half the size (max bit of it), but * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
*/
bits = fls(size / 2);
/* Don't allocate too much */ if (bits > FTRACE_HASH_MAX_BITS)
bits = FTRACE_HASH_MAX_BITS;
new_hash = alloc_ftrace_hash(bits); if (!new_hash) return NULL;
/* Move the @src entries to a newly allocated hash */ staticstruct ftrace_hash *
__ftrace_hash_move(struct ftrace_hash *src)
{ int size = src->count;
/* * If the new source is empty, just return the empty_hash.
*/ if (ftrace_hash_empty(src)) return EMPTY_HASH;
return __move_hash(src, size);
}
/** * ftrace_hash_move - move a new hash to a filter and do updates * @ops: The ops with the hash that @dst points to * @enable: True if for the filter hash, false for the notrace hash * @dst: Points to the @ops hash that should be updated * @src: The hash to update @dst with * * This is called when an ftrace_ops hash is being updated and the * the kernel needs to reflect this. Note, this only updates the kernel * function callbacks if the @ops is enabled (not to be confused with * @enable above). If the @ops is enabled, its hash determines what * callbacks get called. This function gets called when the @ops hash * is updated and it requires new callbacks. * * On success the elements of @src is moved to @dst, and @dst is updated * properly, as well as the functions determined by the @ops hashes * are now calling the @ops callback function. * * Regardless of return type, @src should be freed with free_ftrace_hash().
*/ staticint
ftrace_hash_move(struct ftrace_ops *ops, int enable, struct ftrace_hash **dst, struct ftrace_hash *src)
{ struct ftrace_hash *new_hash; int ret;
/* Reject setting notrace hash on IPMODIFY ftrace_ops */ if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable) return -EINVAL;
new_hash = __ftrace_hash_move(src); if (!new_hash) return -ENOMEM;
/* Make sure this can be applied if it is IPMODIFY ftrace_ops */ if (enable) { /* IPMODIFY should be updated only when filter_hash updating */
ret = ftrace_hash_ipmodify_update(ops, new_hash); if (ret < 0) {
free_ftrace_hash(new_hash); return ret;
}
}
/* * Remove the current set, update the hash and add * them back.
*/
ftrace_hash_rec_disable_modify(ops);
rcu_assign_pointer(*dst, new_hash);
ftrace_hash_rec_enable_modify(ops);
return 0;
}
staticbool hash_contains_ip(unsignedlong 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 empty 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. * * It's a match if the ip is in the ops->filter_hash or * the filter_hash does not exist or is empty, * AND * the ip is not in the ops->notrace_hash. * * This needs to be called with preemption disabled as * the hashes are freed with call_rcu().
*/ int
ftrace_ops_test(struct ftrace_ops *ops, unsignedlong ip, void *regs)
{ struct ftrace_ops_hash hash; int ret;
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* * There's a small race when adding ops that the ftrace handler * that wants regs, may be called without them. We can not * allow that handler to be called if regs is NULL.
*/ if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS)) return 0; #endif
if (hash_contains_ip(ip, &hash))
ret = 1; else
ret = 0;
return ret;
}
/* * This is a double for. Do not use 'break' to break out of the loop, * you must use a goto.
*/ #define do_for_each_ftrace_rec(pg, rec) \ for (pg = ftrace_pages_start; pg; pg = pg->next) { \ int _____i; \ for (_____i = 0; _____i < pg->index; _____i++) { \
rec = &pg->records[_____i];
/** * ftrace_location_range - return the first address of a traced location * if it touches the given ip range * @start: start of range to search. * @end: end of range to search (inclusive). @end points to the last byte * to check. * * Returns: rec->ip if the related ftrace location is a least partly within * the given address range. That is, the first address of the instruction * that is either a NOP or call to the function tracer. It checks the ftrace * internal tables to determine if the address belongs or not.
*/ unsignedlong ftrace_location_range(unsignedlong start, unsignedlong end)
{ struct dyn_ftrace *rec; unsignedlong ip = 0;
rcu_read_lock();
rec = lookup_rec(start, end); if (rec)
ip = rec->ip;
rcu_read_unlock();
return ip;
}
/** * ftrace_location - return the ftrace location * @ip: the instruction pointer to check * * Returns: * * If @ip matches the ftrace location, return @ip. * * If @ip matches sym+0, return sym's ftrace location. * * Otherwise, return 0.
*/ unsignedlong ftrace_location(unsignedlong ip)
{ unsignedlong loc; unsignedlong offset; unsignedlong size;
loc = ftrace_location_range(ip, ip); if (!loc) { if (!kallsyms_lookup_size_offset(ip, &size, &offset)) return 0;
/* map sym+0 to __fentry__ */ if (!offset)
loc = ftrace_location_range(ip, ip + size - 1);
} return loc;
}
/** * ftrace_text_reserved - return true if range contains an ftrace location * @start: start of range to search * @end: end of range to search (inclusive). @end points to the last byte to check. * * Returns: 1 if @start and @end contains a ftrace location. * That is, the instruction that is either a NOP or call to * the function tracer. It checks the ftrace internal tables to * determine if the address belongs or not.
*/ int ftrace_text_reserved(constvoid *start, constvoid *end)
{ unsignedlong ret;
ret = ftrace_location_range((unsignedlong)start,
(unsignedlong)end);
return (int)!!ret;
}
/* Test if ops registered to this rec needs regs */ staticbool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
{ struct ftrace_ops *ops; bool keep_regs = false;
for (ops = ftrace_ops_list;
ops != &ftrace_list_end; ops = ops->next) { /* pass rec in as regs to have non-NULL val */ if (ftrace_ops_test(ops, rec->ip, rec)) { if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
keep_regs = true; break;
}
}
}
staticbool skip_record(struct dyn_ftrace *rec)
{ /* * At boot up, weak functions are set to disable. Function tracing * can be enabled before they are, and they still need to be disabled now. * If the record is disabled, still continue if it is marked as already * enabled (this is needed to keep the accounting working).
*/ return rec->flags & FTRACE_FL_DISABLED &&
!(rec->flags & FTRACE_FL_ENABLED);
}
/* * This is the main engine to the ftrace updates to the dyn_ftrace records. * * It will iterate through all the available ftrace functions * (the ones that ftrace can have callbacks to) and set the flags * in the associated dyn_ftrace records. * * @inc: If true, the functions associated to @ops are added to * the dyn_ftrace records, otherwise they are removed.
*/ staticbool __ftrace_hash_rec_update(struct ftrace_ops *ops, bool inc)
{ struct ftrace_hash *hash; struct ftrace_hash *notrace_hash; struct ftrace_page *pg; struct dyn_ftrace *rec; bool update = false; int count = 0; int all = false;
/* Only update if the ops has been registered */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) returnfalse;
/* * If the count is zero, we update all records. * Otherwise we just update the items in the hash.
*/
hash = ops->func_hash->filter_hash;
notrace_hash = ops->func_hash->notrace_hash; if (ftrace_hash_empty(hash))
all = true;
do_for_each_ftrace_rec(pg, rec) { int in_notrace_hash = 0; int in_hash = 0; int match = 0;
if (skip_record(rec)) continue;
if (all) { /* * Only the filter_hash affects all records. * Update if the record is not in the notrace hash.
*/ if (!notrace_hash || !ftrace_lookup_ip(notrace_hash, rec->ip))
match = 1;
} else {
in_hash = !!ftrace_lookup_ip(hash, rec->ip);
in_notrace_hash = !!ftrace_lookup_ip(notrace_hash, rec->ip);
/* * We want to match all functions that are in the hash but * not in the other hash.
*/ if (in_hash && !in_notrace_hash)
match = 1;
} if (!match) continue;
if (inc) {
rec->flags++; if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) returnfalse;
if (ops->flags & FTRACE_OPS_FL_DIRECT)
rec->flags |= FTRACE_FL_DIRECT;
/* * If there's only a single callback registered to a * function, and the ops has a trampoline registered * for it, then we can call it directly.
*/ if (ftrace_rec_count(rec) == 1 && ops->trampoline)
rec->flags |= FTRACE_FL_TRAMP; 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.
*/
rec->flags &= ~FTRACE_FL_TRAMP;
/* * If any ops wants regs saved for this function * then all ops will get saved regs.
*/ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
rec->flags |= FTRACE_FL_REGS;
} else { if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) returnfalse;
rec->flags--;
/* * Only the internal direct_ops should have the * DIRECT flag set. Thus, if it is removing a * function, then that function should no longer * be direct.
*/ if (ops->flags & FTRACE_OPS_FL_DIRECT)
rec->flags &= ~FTRACE_FL_DIRECT;
/* * If the rec had REGS enabled and the ops that is * being removed had REGS set, then see if there is * still any ops for this record that wants regs. * If not, we can stop recording them.
*/ if (ftrace_rec_count(rec) > 0 &&
rec->flags & FTRACE_FL_REGS &&
ops->flags & FTRACE_OPS_FL_SAVE_REGS) { if (!test_rec_ops_needs_regs(rec))
rec->flags &= ~FTRACE_FL_REGS;
}
/* * The TRAMP needs to be set only if rec count * is decremented to one, and the ops that is * left has a trampoline. As TRAMP can only be * enabled if there is only a single ops attached * to it.
*/ if (ftrace_rec_count(rec) == 1 &&
ftrace_find_tramp_ops_any_other(rec, ops))
rec->flags |= FTRACE_FL_TRAMP; else
rec->flags &= ~FTRACE_FL_TRAMP;
/* * flags will be cleared in ftrace_check_record() * if rec count is zero.
*/
}
/* * If the rec has a single associated ops, and ops->func can be * called directly, allow the call site to call via the ops.
*/ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
ftrace_rec_count(rec) == 1 &&
ftrace_ops_get_func(ops) == ops->func)
rec->flags |= FTRACE_FL_CALL_OPS; else
rec->flags &= ~FTRACE_FL_CALL_OPS;
count++;
/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
/* Shortcut, if we handled all records, we are done. */ if (!all && count == hash->count) return update;
} while_for_each_ftrace_rec();
return update;
}
/* * This is called when an ops is removed from tracing. It will decrement * the counters of the dyn_ftrace records for all the functions that * the @ops attached to.
*/ staticbool ftrace_hash_rec_disable(struct ftrace_ops *ops)
{ return __ftrace_hash_rec_update(ops, false);
}
/* * This is called when an ops is added to tracing. It will increment * the counters of the dyn_ftrace records for all the functions that * the @ops attached to.
*/ staticbool ftrace_hash_rec_enable(struct ftrace_ops *ops)
{ return __ftrace_hash_rec_update(ops, true);
}
/* * This function will update what functions @ops traces when its filter * changes. * * The @inc states if the @ops callbacks are going to be added or removed. * When one of the @ops hashes are updated to a "new_hash" the dyn_ftrace * records are update via: * * ftrace_hash_rec_disable_modify(ops); * ops->hash = new_hash * ftrace_hash_rec_enable_modify(ops); * * Where the @ops is removed from all the records it is tracing using * its old hash. The @ops hash is updated to the new hash, and then * the @ops is added back to the records so that it is tracing all * the new functions.
*/ staticvoid ftrace_hash_rec_update_modify(struct ftrace_ops *ops, bool inc)
{ struct ftrace_ops *op;
__ftrace_hash_rec_update(ops, inc);
if (ops->func_hash != &global_ops.local_hash) return;
/* * If the ops shares the global_ops hash, then we need to update * all ops that are enabled and use this hash.
*/
do_for_each_ftrace_op(op, ftrace_ops_list) { /* Already done */ if (op == ops) continue; if (op->func_hash == &global_ops.local_hash)
__ftrace_hash_rec_update(op, inc);
} while_for_each_ftrace_op(op);
}
/* * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK * or no-needed to update, -EBUSY if it detects a conflict of the flag * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs. * Note that old_hash and new_hash has below meanings * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected) * - If the hash is EMPTY_HASH, it hits nothing * - Anything else hits the recs which match the hash entries. * * DIRECT ops does not have IPMODIFY flag, but we still need to check it * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate * the return value to the caller and eventually to the owner of the DIRECT * ops.
*/ staticint __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, struct ftrace_hash *old_hash, struct ftrace_hash *new_hash)
{ struct ftrace_page *pg; struct dyn_ftrace *rec, *end = NULL; int in_old, in_new; bool is_ipmodify, is_direct;
/* Only update if the ops has been registered */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return 0;
/* neither IPMODIFY nor DIRECT, skip */ if (!is_ipmodify && !is_direct) return 0;
if (WARN_ON_ONCE(is_ipmodify && is_direct)) return 0;
/* * Since the IPMODIFY and DIRECT are very address sensitive * actions, we do not allow ftrace_ops to set all functions to new * hash.
*/ if (!new_hash || !old_hash) return -EINVAL;
/* We need to update only differences of filter_hash */
in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
in_new = !!ftrace_lookup_ip(new_hash, rec->ip); if (in_old == in_new) continue;
if (in_new) { if (rec->flags & FTRACE_FL_IPMODIFY) { int ret;
/* Cannot have two ipmodify on same rec */ if (is_ipmodify) goto rollback;
FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
/* * Another ops with IPMODIFY is already * attached. We are now attaching a direct * ops. Run SHARE_IPMODIFY_SELF, to check * whether sharing is supported.
*/ if (!ops->ops_func) return -EBUSY;
ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF); if (ret) return ret;
} elseif (is_ipmodify) {
rec->flags |= FTRACE_FL_IPMODIFY;
}
} elseif (is_ipmodify) {
rec->flags &= ~FTRACE_FL_IPMODIFY;
}
} while_for_each_ftrace_rec();
return 0;
rollback:
end = rec;
/* Roll back what we did above */
do_for_each_ftrace_rec(pg, rec) {
staticvoid print_bug_type(void)
{ switch (ftrace_bug_type) { case FTRACE_BUG_UNKNOWN: break; case FTRACE_BUG_INIT:
pr_info("Initializing ftrace call sites\n"); break; case FTRACE_BUG_NOP:
pr_info("Setting ftrace call site to NOP\n"); break; case FTRACE_BUG_CALL:
pr_info("Setting ftrace call site to call ftrace function\n"); break; case FTRACE_BUG_UPDATE:
pr_info("Updating ftrace call site to call a different ftrace function\n"); break;
}
}
/** * ftrace_bug - report and shutdown function tracer * @failed: The failed type (EFAULT, EINVAL, EPERM) * @rec: The record that failed * * The arch code that enables or disables the function tracing * can call ftrace_bug() when it has detected a problem in * modifying the code. @failed should be one of either: * EFAULT - if the problem happens on reading the @ip address * EINVAL - if what is read at @ip is not what was expected * EPERM - if the problem happens on writing to the @ip address
*/ void ftrace_bug(int failed, struct dyn_ftrace *rec)
{ unsignedlong ip = rec ? rec->ip : 0;
if (skip_record(rec)) return FTRACE_UPDATE_IGNORE;
/* * If we are updating calls: * * If the record has a ref count, then we need to enable it * because someone is using it. * * Otherwise we make sure its disabled. * * If we are disabling calls, then disable all records that * are enabled.
*/ if (enable && ftrace_rec_count(rec))
flag = FTRACE_FL_ENABLED;
/* * If enabling and the REGS flag does not match the REGS_EN, or * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore * this record. Set flags to fail the compare against ENABLED. * Same for direct calls.
*/ if (flag) { if (!(rec->flags & FTRACE_FL_REGS) !=
!(rec->flags & FTRACE_FL_REGS_EN))
flag |= FTRACE_FL_REGS;
if (!(rec->flags & FTRACE_FL_TRAMP) !=
!(rec->flags & FTRACE_FL_TRAMP_EN))
flag |= FTRACE_FL_TRAMP;
/* * Direct calls are special, as count matters. * We must test the record for direct, if the * DIRECT and DIRECT_EN do not match, but only * if the count is 1. That's because, if the * count is something other than one, we do not * want the direct enabled (it will be done via the * direct helper). But if DIRECT_EN is set, and * the count is not one, we need to clear it. *
*/ if (ftrace_rec_count(rec) == 1) { if (!(rec->flags & FTRACE_FL_DIRECT) !=
!(rec->flags & FTRACE_FL_DIRECT_EN))
flag |= FTRACE_FL_DIRECT;
} elseif (rec->flags & FTRACE_FL_DIRECT_EN) {
flag |= FTRACE_FL_DIRECT;
}
/* * Ops calls are special, as count matters. * As with direct calls, they must only be enabled when count * is one, otherwise they'll be handled via the list ops.
*/ if (ftrace_rec_count(rec) == 1) { if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
!(rec->flags & FTRACE_FL_CALL_OPS_EN))
flag |= FTRACE_FL_CALL_OPS;
} elseif (rec->flags & FTRACE_FL_CALL_OPS_EN) {
flag |= FTRACE_FL_CALL_OPS;
}
}
/* If the state of this record hasn't changed, then do nothing */ if ((rec->flags & FTRACE_FL_ENABLED) == flag) return FTRACE_UPDATE_IGNORE;
if (flag) { /* Save off if rec is being enabled (for return value) */
flag ^= rec->flags & FTRACE_FL_ENABLED;
if (update) {
rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED; if (flag & FTRACE_FL_REGS) { if (rec->flags & FTRACE_FL_REGS)
rec->flags |= FTRACE_FL_REGS_EN; else
rec->flags &= ~FTRACE_FL_REGS_EN;
} if (flag & FTRACE_FL_TRAMP) { if (rec->flags & FTRACE_FL_TRAMP)
rec->flags |= FTRACE_FL_TRAMP_EN; else
rec->flags &= ~FTRACE_FL_TRAMP_EN;
}
/* Keep track of anything that modifies the function */ if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
rec->flags |= FTRACE_FL_MODIFIED;
if (flag & FTRACE_FL_DIRECT) { /* * If there's only one user (direct_ops helper) * then we can call the direct function * directly (no ftrace trampoline).
*/ if (ftrace_rec_count(rec) == 1) { if (rec->flags & FTRACE_FL_DIRECT)
rec->flags |= FTRACE_FL_DIRECT_EN; else
rec->flags &= ~FTRACE_FL_DIRECT_EN;
} else { /* * Can only call directly if there's * only one callback to the function.
*/
rec->flags &= ~FTRACE_FL_DIRECT_EN;
}
}
if (flag & FTRACE_FL_CALL_OPS) { if (ftrace_rec_count(rec) == 1) { if (rec->flags & FTRACE_FL_CALL_OPS)
rec->flags |= FTRACE_FL_CALL_OPS_EN; else
rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
} else { /* * Can only call directly if there's * only one set of associated ops.
*/
rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
}
}
}
/* * If this record is being updated from a nop, then * return UPDATE_MAKE_CALL. * Otherwise, * return UPDATE_MODIFY_CALL to tell the caller to convert * from the save regs, to a non-save regs function or * vice versa, or from a trampoline call.
*/ if (flag & FTRACE_FL_ENABLED) {
ftrace_bug_type = FTRACE_BUG_CALL; return FTRACE_UPDATE_MAKE_CALL;
}
if (update) { /* If there's no more users, clear all flags */ if (!ftrace_rec_count(rec))
rec->flags &= FTRACE_NOCLEAR_FLAGS; else /* * Just disable the record, but keep the ops TRAMP * and REGS states. The _EN flags must be disabled though.
*/
rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
FTRACE_FL_CALL_OPS_EN);
}
/** * ftrace_update_record - set a record that now is tracing or not * @rec: the record to update * @enable: set to true if the record is tracing, false to force disable * * The records that represent all functions that can be traced need * to be updated when tracing has been enabled.
*/ int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
{ return ftrace_check_record(rec, enable, true);
}
/** * ftrace_test_record - check if the record has been enabled or not * @rec: the record to test * @enable: set to true to check if enabled, false if it is disabled * * The arch code may need to test if a record is already set to * tracing to determine how to modify the function code that it * represents.
*/ int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
{ return ftrace_check_record(rec, enable, false);
}
/* * 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. * * If an ops is being modified (hooking to different functions) * then we don't care about the new functions that are being * added, just the old ones (that are probably being removed). * * If we are adding an ops to a function that already is using * a trampoline, it needs to be removed (trampolines are only * for single ops connected), then an ops that is not being * modified also needs to be checked.
*/
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (!op->trampoline) continue;
/* * 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 being modified and is in the old * hash, then it is probably being removed from this * function.
*/ if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
hash_contains_ip(ip, &op->old_hash)) return op; /* * If the ops is not being added or modified, and it's * in its normal filter hash, then this must be the one * we want!
*/ if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
hash_contains_ip(ip, op->func_hash)) return op;
do_for_each_ftrace_op(op, ftrace_ops_list) { /* pass rec in as regs to have non-NULL val */ if (hash_contains_ip(ip, op->func_hash)) return op;
} while_for_each_ftrace_op(op);
if (hash_contains_ip(ip, op->func_hash)) { if (found) return NULL;
found = op;
}
} while_for_each_ftrace_op(op);
return found;
}
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS /* Protected by rcu_tasks for reading, and direct_mutex for writing */ staticstruct ftrace_hash __rcu *direct_functions = EMPTY_HASH; static DEFINE_MUTEX(direct_mutex);
/* * Search the direct_functions hash to see if the given instruction pointer * has a direct caller attached to it.
*/ unsignedlong ftrace_find_rec_direct(unsignedlong ip)
{ struct ftrace_func_entry *entry;
entry = __ftrace_lookup_ip(direct_functions, ip); if (!entry) return 0;
/** * ftrace_get_addr_new - Get the call address to set to * @rec: The ftrace record descriptor * * If the record has the FTRACE_FL_REGS set, that means that it * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS * is not set, then it wants to convert to the normal callback. * * Returns: the address of the trampoline to set to
*/ unsignedlong ftrace_get_addr_new(struct dyn_ftrace *rec)
{ struct ftrace_ops *ops; unsignedlong addr;
if ((rec->flags & FTRACE_FL_DIRECT) &&
(ftrace_rec_count(rec) == 1)) {
addr = ftrace_find_rec_direct(rec->ip); if (addr) return addr;
WARN_ON_ONCE(1);
}
/* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP) {
ops = ftrace_find_tramp_ops_new(rec); if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
(void *)rec->ip, (void *)rec->ip, rec->flags); /* Ftrace is shutting down, return anything */ return (unsignedlong)FTRACE_ADDR;
} return ops->trampoline;
}
if (rec->flags & FTRACE_FL_REGS) return (unsignedlong)FTRACE_REGS_ADDR; else return (unsignedlong)FTRACE_ADDR;
}
/** * ftrace_get_addr_curr - Get the call address that is already there * @rec: The ftrace record descriptor * * The FTRACE_FL_REGS_EN is set when the record already points to * a function that saves all the regs. Basically the '_EN' version * represents the current state of the function. * * Returns: the address of the trampoline that is currently being called
*/ unsignedlong ftrace_get_addr_curr(struct dyn_ftrace *rec)
{ struct ftrace_ops *ops; unsignedlong addr;
/* Direct calls take precedence over trampolines */ if (rec->flags & FTRACE_FL_DIRECT_EN) {
addr = ftrace_find_rec_direct(rec->ip); if (addr) return addr;
WARN_ON_ONCE(1);
}
/* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP_EN) {
ops = ftrace_find_tramp_ops_curr(rec); if (FTRACE_WARN_ON(!ops)) {
pr_warn("Bad trampoline accounting at: %p (%pS)\n",
(void *)rec->ip, (void *)rec->ip); /* Ftrace is shutting down, return anything */ return (unsignedlong)FTRACE_ADDR;
} return ops->trampoline;
}
if (rec->flags & FTRACE_FL_REGS_EN) return (unsignedlong)FTRACE_REGS_ADDR; else return (unsignedlong)FTRACE_ADDR;
}
struct ftrace_rec_iter { struct ftrace_page *pg; int index;
};
/** * ftrace_rec_iter_start - start up iterating over traced functions * * Returns: an iterator handle that is used to iterate over all * the records that represent address locations where functions * are traced. * * May return NULL if no records are available.
*/ struct ftrace_rec_iter *ftrace_rec_iter_start(void)
{ /* * We only use a single iterator. * Protected by the ftrace_lock mutex.
*/ staticstruct ftrace_rec_iter ftrace_rec_iter; struct ftrace_rec_iter *iter = &ftrace_rec_iter;
iter->pg = ftrace_pages_start;
iter->index = 0;
/* Could have empty pages */ while (iter->pg && !iter->pg->index)
iter->pg = iter->pg->next;
if (!iter->pg) return NULL;
return iter;
}
/** * ftrace_rec_iter_next - get the next record to process. * @iter: The handle to the iterator. * * Returns: the next iterator after the given iterator @iter.
*/ struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
{
iter->index++;
/* Could have empty pages */ while (iter->pg && !iter->pg->index)
iter->pg = iter->pg->next;
}
if (!iter->pg) return NULL;
return iter;
}
/** * ftrace_rec_iter_record - get the record at the iterator location * @iter: The current iterator location * * Returns: the record that the current @iter is at.
*/ struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
{ return &iter->pg->records[iter->index];
}
staticint
ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
{ int ret;
if (unlikely(ftrace_disabled)) return 0;
ret = ftrace_init_nop(mod, rec); if (ret) {
ftrace_bug_type = FTRACE_BUG_INIT;
ftrace_bug(ret, rec); return 0;
} return 1;
}
/* * archs can override this function if they must do something * before the modifying code is performed.
*/ void __weak ftrace_arch_code_modify_prepare(void)
{
}
/* * archs can override this function if they must do something * after the modifying code is performed.
*/ void __weak ftrace_arch_code_modify_post_process(void)
{
}
/* Avoid updating if it hasn't changed */ if (func == save_func) return 0;
save_func = func;
return ftrace_update_ftrace_func(func);
}
void ftrace_modify_all_code(int command)
{ int update = command & FTRACE_UPDATE_TRACE_FUNC; int mod_flags = 0; int err = 0;
if (command & FTRACE_MAY_SLEEP)
mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
/* * If the ftrace_caller calls a ftrace_ops func directly, * we need to make sure that it only traces functions it * expects to trace. When doing the switch of functions, * we need to update to the ftrace_ops_list_func first * before the transition between old and new calls are set, * as the ftrace_ops_list_func will check the ops hashes * to make sure the ops are having the right functions * traced.
*/ if (update) {
err = update_ftrace_func(ftrace_ops_list_func); if (FTRACE_WARN_ON(err)) return;
}
if (update && ftrace_trace_function != ftrace_ops_list_func) {
function_trace_op = set_function_trace_op;
smp_wmb(); /* If irqs are disabled, we are in stop machine */ if (!irqs_disabled())
smp_call_function(ftrace_sync_ipi, NULL, 1);
err = update_ftrace_func(ftrace_trace_function); if (FTRACE_WARN_ON(err)) return;
}
staticint __ftrace_modify_code(void *data)
{ int *command = data;
ftrace_modify_all_code(*command);
return 0;
}
/** * ftrace_run_stop_machine - go back to the stop machine method * @command: The command to tell ftrace what to do * * If an arch needs to fall back to the stop machine method, the * it can call this function.
*/ void ftrace_run_stop_machine(int command)
{
stop_machine(__ftrace_modify_code, &command, NULL);
}
/** * arch_ftrace_update_code - modify the code to trace or not trace * @command: The command that needs to be done * * Archs can override this function if it does not need to * run stop_machine() to modify code.
*/ void __weak arch_ftrace_update_code(int command)
{
ftrace_run_stop_machine(command);
}
/* * By default we use stop_machine() to modify the code. * But archs can do what ever they want as long as it * is safe. The stop_machine() is the safest, but also * produces the most overhead.
*/
arch_ftrace_update_code(command);
/* * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is * not a module.
*/ #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace" #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
staticvoid ftrace_trampoline_free(struct ftrace_ops *ops)
{ if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
ops->trampoline) { /* * Record the text poke event before the ksymbol unregister * event.
*/
perf_event_text_poke((void *)ops->trampoline,
(void *)ops->trampoline,
ops->trampoline_size, NULL, 0);
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
ops->trampoline, ops->trampoline_size, true, FTRACE_TRAMPOLINE_SYM); /* Remove from kallsyms after the perf events */
ftrace_remove_trampoline_from_kallsyms(ops);
}
int ftrace_startup(struct ftrace_ops *ops, int command)
{ int ret;
if (unlikely(ftrace_disabled)) return -ENODEV;
ret = __register_ftrace_function(ops); if (ret) return ret;
ftrace_start_up++;
/* * 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;
ret = ftrace_hash_ipmodify_enable(ops); if (ret < 0) { /* Rollback registration process */
__unregister_ftrace_function(ops);
ftrace_start_up--;
ops->flags &= ~FTRACE_OPS_FL_ENABLED; if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
ftrace_trampoline_free(ops); return ret;
}
if (ftrace_hash_rec_enable(ops))
command |= FTRACE_UPDATE_CALLS;
ftrace_startup_enable(command);
/* * If ftrace is in an undefined state, we just remove ops from list * to prevent the NULL pointer, instead of totally rolling it back and * free trampoline, because those actions could cause further damage.
*/ if (unlikely(ftrace_disabled)) {
__unregister_ftrace_function(ops); return -ENODEV;
}
ops->flags &= ~FTRACE_OPS_FL_ADDING;
return 0;
}
int ftrace_shutdown(struct ftrace_ops *ops, int command)
{ int ret;
if (unlikely(ftrace_disabled)) return -ENODEV;
ret = __unregister_ftrace_function(ops); if (ret) return ret;
ftrace_start_up--; /* * Just warn in case of unbalance, no need to kill ftrace, it's not * critical but the ftrace_call callers may be never nopped again after * further ftrace uses.
*/
WARN_ON_ONCE(ftrace_start_up < 0);
/* Disabling ipmodify never fails */
ftrace_hash_ipmodify_disable(ops);
if (ftrace_hash_rec_disable(ops))
command |= FTRACE_UPDATE_CALLS;
/* * 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 (rcu_dereference_protected(ftrace_ops_list,
lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { struct ftrace_page *pg; struct dyn_ftrace *rec;
out: /* * Dynamic ops may be freed, we must make sure that all * callers are done before leaving this function.
*/ if (ops->flags & FTRACE_OPS_FL_DYNAMIC) { /* * We need to do a hard force of sched synchronization. * This is because we use preempt_disable() to do RCU, but * the function tracers can be called where RCU is not watching * (like before user_exit()). We can not rely on the RCU * infrastructure to do the synchronization, thus we must do it * ourselves.
*/
synchronize_rcu_tasks_rude();
/* * When the kernel is preemptive, tasks can be preempted * while on a ftrace trampoline. Just scheduling a task on * a CPU is not good enough to flush them. Calling * synchronize_rcu_tasks() will wait for those tasks to * execute and either schedule voluntarily or enter user space.
*/
synchronize_rcu_tasks();
ftrace_trampoline_free(ops);
}
return 0;
}
/* Simply make a copy of @src and return it */ staticstruct ftrace_hash *copy_hash(struct ftrace_hash *src)
{ if (ftrace_hash_empty(src)) return EMPTY_HASH;
/* * Append @new_hash entries to @hash: * * If @hash is the EMPTY_HASH then it traces all functions and nothing * needs to be done. * * If @new_hash is the EMPTY_HASH, then make *hash the EMPTY_HASH so * that it traces everything. * * Otherwise, go through all of @new_hash and add anything that @hash * doesn't already have, to @hash. * * The filter_hash updates uses just the append_hash() function * and the notrace_hash does not.
*/ staticint append_hash(struct ftrace_hash **hash, struct ftrace_hash *new_hash, int size_bits)
{ struct ftrace_func_entry *entry; int size; int i;
if (*hash) { /* An empty hash does everything */ if (ftrace_hash_empty(*hash)) return 0;
} else {
*hash = alloc_ftrace_hash(size_bits); if (!*hash) return -ENOMEM;
}
/* If new_hash has everything make hash have everything */ if (ftrace_hash_empty(new_hash)) {
free_ftrace_hash(*hash);
*hash = EMPTY_HASH; return 0;
}
size = 1 << new_hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &new_hash->buckets[i], hlist) { /* Only add if not already in hash */ if (!__ftrace_lookup_ip(*hash, entry->ip) &&
add_hash_entry(*hash, entry->ip) == NULL) return -ENOMEM;
}
} return 0;
}
/* * Remove functions from @hash that are in @notrace_hash
*/ staticvoid remove_hash(struct ftrace_hash *hash, struct ftrace_hash *notrace_hash)
{ struct ftrace_func_entry *entry; struct hlist_node *tmp; int size; int i;
/* If the notrace hash is empty, there's nothing to do */ if (ftrace_hash_empty(notrace_hash)) return;
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) { if (!__ftrace_lookup_ip(notrace_hash, entry->ip)) continue;
remove_hash_entry(hash, entry);
kfree(entry);
}
}
}
/* * Add to @hash only those that are in both @new_hash1 and @new_hash2 * * The notrace_hash updates uses just the intersect_hash() function * and the filter_hash does not.
*/ staticint intersect_hash(struct ftrace_hash **hash, struct ftrace_hash *new_hash1, struct ftrace_hash *new_hash2)
{ struct ftrace_func_entry *entry; int size; int i;
/* * If new_hash1 or new_hash2 is the EMPTY_HASH then make the hash * empty as well as empty for notrace means none are notraced.
*/ if (ftrace_hash_empty(new_hash1) || ftrace_hash_empty(new_hash2)) {
free_ftrace_hash(*hash);
*hash = EMPTY_HASH; return 0;
}
size = 1 << new_hash1->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &new_hash1->buckets[i], hlist) { /* Only add if in both @new_hash1 and @new_hash2 */ if (__ftrace_lookup_ip(new_hash2, entry->ip) &&
add_hash_entry(*hash, entry->ip) == NULL) return -ENOMEM;
}
} /* If nothing intersects, make it the empty set */ if (ftrace_hash_empty(*hash)) {
free_ftrace_hash(*hash);
*hash = EMPTY_HASH;
} return 0;
}
staticbool ops_equal(struct ftrace_hash *A, struct ftrace_hash *B)
{ struct ftrace_func_entry *entry; int size; int i;
if (ftrace_hash_empty(A)) return ftrace_hash_empty(B);
if (ftrace_hash_empty(B)) return ftrace_hash_empty(A);
if (A->count != B->count) returnfalse;
size = 1 << A->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &A->buckets[i], hlist) { if (!__ftrace_lookup_ip(B, entry->ip)) returnfalse;
}
}
if (!ops_equal(filter_hash, ops->func_hash->filter_hash)) {
ret = __ftrace_hash_move_and_update_ops(ops, &ops->func_hash->filter_hash,
filter_hash, 1); if (ret < 0) return ret;
}
if (!ops_equal(notrace_hash, ops->func_hash->notrace_hash)) {
ret = __ftrace_hash_move_and_update_ops(ops, &ops->func_hash->notrace_hash,
notrace_hash, 0); if (ret < 0) return ret;
}
return 0;
}
staticint add_first_hash(struct ftrace_hash **filter_hash, struct ftrace_hash **notrace_hash, struct ftrace_ops_hash *func_hash)
{ /* If the filter hash is not empty, simply remove the nohash from it */ if (!ftrace_hash_empty(func_hash->filter_hash)) {
*filter_hash = copy_hash(func_hash->filter_hash); if (!*filter_hash) return -ENOMEM;
remove_hash(*filter_hash, func_hash->notrace_hash);
*notrace_hash = EMPTY_HASH;
staticint add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash **notrace_hash, struct ftrace_ops_hash *ops_hash, struct ftrace_ops_hash *subops_hash)
{ int size_bits; int ret;
/* If the subops trace all functions so must the main ops */ if (ftrace_hash_empty(ops_hash->filter_hash) ||
ftrace_hash_empty(subops_hash->filter_hash)) {
*filter_hash = EMPTY_HASH;
} else { /* * The main ops filter hash is not empty, so its * notrace_hash had better be, as the notrace hash * is only used for empty main filter hashes.
*/
WARN_ON_ONCE(!ftrace_hash_empty(ops_hash->notrace_hash));
/* Copy the subops hash */
*filter_hash = alloc_and_copy_ftrace_hash(size_bits, subops_hash->filter_hash); if (!*filter_hash) return -ENOMEM; /* Remove any notrace functions from the copy */
remove_hash(*filter_hash, subops_hash->notrace_hash);
ret = append_hash(filter_hash, ops_hash->filter_hash,
size_bits); if (ret < 0) {
free_ftrace_hash(*filter_hash);
*filter_hash = EMPTY_HASH; return ret;
}
}
/* * Only process notrace hashes if the main filter hash is empty * (tracing all functions), otherwise the filter hash will just * remove the notrace hash functions, and the notrace hash is * not needed.
*/ if (ftrace_hash_empty(*filter_hash)) { /* * Intersect the notrace functions. That is, if two * subops are not tracing a set of functions, the * main ops will only not trace the functions that are * in both subops, but has to trace the functions that * are only notrace in one of the subops, for the other * subops to be able to trace them.
*/
size_bits = max(ops_hash->notrace_hash->size_bits,
subops_hash->notrace_hash->size_bits);
*notrace_hash = alloc_ftrace_hash(size_bits); if (!*notrace_hash) return -ENOMEM;
/** * ftrace_startup_subops - enable tracing for subops of an ops * @ops: Manager ops (used to pick all the functions of its subops) * @subops: A new ops to add to @ops * @command: Extra commands to use to enable tracing * * The @ops is a manager @ops that has the filter that includes all the functions * that its list of subops are tracing. Adding a new @subops will add the * functions of @subops to @ops.
*/ int ftrace_startup_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command)
{ struct ftrace_hash *filter_hash = EMPTY_HASH; struct ftrace_hash *notrace_hash = EMPTY_HASH; struct ftrace_hash *save_filter_hash; struct ftrace_hash *save_notrace_hash; int ret;
if (unlikely(ftrace_disabled)) return -ENODEV;
ftrace_ops_init(ops);
ftrace_ops_init(subops);
if (WARN_ON_ONCE(subops->flags & FTRACE_OPS_FL_ENABLED)) return -EBUSY;
/* Make everything canonical (Just in case!) */ if (!ops->func_hash->filter_hash)
ops->func_hash->filter_hash = EMPTY_HASH; if (!ops->func_hash->notrace_hash)
ops->func_hash->notrace_hash = EMPTY_HASH; if (!subops->func_hash->filter_hash)
subops->func_hash->filter_hash = EMPTY_HASH; if (!subops->func_hash->notrace_hash)
subops->func_hash->notrace_hash = EMPTY_HASH;
/* For the first subops to ops just enable it normally */ if (list_empty(&ops->subop_list)) {
/* The ops was empty, should have empty hashes */
WARN_ON_ONCE(!ftrace_hash_empty(ops->func_hash->filter_hash));
WARN_ON_ONCE(!ftrace_hash_empty(ops->func_hash->notrace_hash));
ret = add_first_hash(&filter_hash, ¬race_hash, subops->func_hash); if (ret < 0) return ret;
/* * Here there's already something attached. Here are the rules: * If the new subops and main ops filter hashes are not empty: * o Make a copy of the subops filter hash * o Remove all functions in the nohash from it. * o Add in the main hash filter functions * o Remove any of these functions from the main notrace hash
*/
ret = add_next_hash(&filter_hash, ¬race_hash, ops->func_hash, subops->func_hash); if (ret < 0) return ret;
/** * ftrace_shutdown_subops - Remove a subops from a manager ops * @ops: A manager ops to remove @subops from * @subops: The subops to remove from @ops * @command: Any extra command flags to add to modifying the text * * Removes the functions being traced by the @subops from @ops. Note, it * will not affect functions that are being traced by other subops that * still exist in @ops. * * If the last subops is removed from @ops, then @ops is shutdown normally.
*/ int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command)
{ struct ftrace_hash *filter_hash = EMPTY_HASH; struct ftrace_hash *notrace_hash = EMPTY_HASH; int ret;
if (unlikely(ftrace_disabled)) return -ENODEV;
if (WARN_ON_ONCE(!(subops->flags & FTRACE_OPS_FL_ENABLED))) return -EINVAL;
list_del(&subops->list);
if (list_empty(&ops->subop_list)) { /* Last one, just disable the current ops */
ret = ftrace_shutdown(ops, command); if (ret < 0) {
list_add(&subops->list, &ops->subop_list); return ret;
}
/* Manager ops can not be subops (yet) */ if (WARN_ON_ONCE(!ops || ops->flags & FTRACE_OPS_FL_SUBOP)) return -EINVAL;
/* Move the new hash over to the subops hash */
save_hash = *orig_subhash;
*orig_subhash = __ftrace_hash_move(hash); if (!*orig_subhash) {
*orig_subhash = save_hash; return -ENOMEM;
}
ret = rebuild_hashes(&filter_hash, ¬race_hash, ops); if (!ret) {
ret = ftrace_update_ops(ops, filter_hash, notrace_hash);
free_ftrace_hash(filter_hash);
free_ftrace_hash(notrace_hash);
}
if (ret) { /* Put back the original hash */
new_hash = *orig_subhash;
*orig_subhash = save_hash;
free_ftrace_hash_rcu(new_hash);
} else {
free_ftrace_hash_rcu(save_hash);
} return ret;
}
staticinlineint ops_traces_mod(struct ftrace_ops *ops)
{ /* * Filter_hash being empty will default to trace module. * But notrace hash requires a test of individual module functions.
*/ return ftrace_hash_empty(ops->func_hash->filter_hash) &&
ftrace_hash_empty(ops->func_hash->notrace_hash);
}
/* * When a module is loaded, this function is called to convert * the calls to mcount in its text to nops, and also to create * an entry in the ftrace data. Now, if ftrace is activated * after this call, but before the module sets its text to * read-only, the modification of enabling ftrace can fail if * the read-only is done while ftrace is converting the calls. * To prevent this, the module's records are set as disabled * and will be enabled after the call to set the module's text * to read-only.
*/ if (mod)
rec_flags |= FTRACE_FL_DISABLED;
for (pg = new_pgs; pg; pg = pg->next) {
for (i = 0; i < pg->index; i++) {
/* If something went wrong, bail without enabling anything */ if (unlikely(ftrace_disabled)) return -1;
p = &pg->records[i];
p->flags = rec_flags;
/* * Do the initial record conversion from mcount jump * to the NOP instructions.
*/ if (init_nop && !ftrace_nop_initialize(mod, p)) break;
start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL); if (!pg) return NULL;
/* * Try to allocate as much as possible in one continues * location that fills in all of the space. We want to * waste as little space as possible.
*/ for (;;) {
cnt = ftrace_allocate_records(pg, num_to_init); if (cnt < 0) goto free_pages;
num_to_init -= cnt; if (!num_to_init) break;
pg->next = kzalloc(sizeof(*pg), GFP_KERNEL); if (!pg->next) goto free_pages;
pg = pg->next;
}
return start_pg;
free_pages:
ftrace_free_pages(start_pg);
pr_info("ftrace: FAILED to allocate memory for functions\n"); return NULL;
}
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
func_probes = &tr->func_probes; if (list_empty(func_probes)) return NULL;
if (!iter->probe) {
next = func_probes->next;
iter->probe = list_entry(next, struct ftrace_func_probe, list);
}
if (iter->probe_entry)
hnd = &iter->probe_entry->hlist;
hash = iter->probe->ops.func_hash->filter_hash;
/* * A probe being registered may temporarily have an empty hash * and it's at the end of the func_probes list.
*/ if (!hash || hash == EMPTY_HASH) return NULL;
/* * If an lseek was done, then reset and start from beginning.
*/ if (*pos < iter->pos)
reset_iter_read(iter);
/* * For set_ftrace_filter reading, if we have the filter * off, we can short cut and just print out that all * functions are enabled.
*/ if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
ftrace_hash_empty(iter->hash)) {
iter->func_pos = 1; /* Account for the message */ if (*pos > 0) return t_mod_start(m, pos);
iter->flags |= FTRACE_ITER_PRINTALL; /* reset in case of seek/pread */
iter->flags &= ~FTRACE_ITER_PROBE; return iter;
}
if (iter->flags & FTRACE_ITER_MOD) return t_mod_start(m, pos);
/* * Unfortunately, we need to restart at ftrace_pages_start * every time we let go of the ftrace_mutex. This is because * those pointers can change without the lock.
*/
iter->pg = ftrace_pages_start;
iter->idx = 0; for (l = 0; l <= *pos; ) {
p = t_func_next(m, &l); if (!p) break;
}
#ifdef FTRACE_MCOUNT_MAX_OFFSET /* * Weak functions can still have an mcount/fentry that is saved in * the __mcount_loc section. These can be detected by having a * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the * symbol found by kallsyms is not the function that the mcount/fentry * is part of. The offset is much greater in these cases. * * Test the record to make sure that the ip points to a valid kallsyms * and if not, mark it disabled.
*/ staticint test_for_valid_rec(struct dyn_ftrace *rec)
{ char str[KSYM_SYMBOL_LEN]; unsignedlong offset; constchar *ret;
ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
/* Weak functions can cause invalid addresses */ if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
rec->flags |= FTRACE_FL_DISABLED; return 0;
} return 1;
}
/* * Scan all the mcount/fentry entries to make sure they are valid.
*/ static __init void ftrace_check_work_func(struct work_struct *work)
{ struct ftrace_page *pg; struct dyn_ftrace *rec;
staticint __init ftrace_check_sync(void)
{ /* Make sure the ftrace_check updates are finished */ if (ftrace_check_wq)
destroy_workqueue(ftrace_check_wq); return 0;
}
if (iter->flags & FTRACE_ITER_PROBE) return t_probe_show(m, iter);
if (iter->flags & FTRACE_ITER_MOD) return t_mod_show(m, iter);
if (iter->flags & FTRACE_ITER_PRINTALL) { if (iter->flags & FTRACE_ITER_NOTRACE)
seq_puts(m, "#### no functions disabled ####\n"); else
seq_puts(m, "#### all functions enabled ####\n"); return 0;
}
rec = iter->func;
if (!rec) return 0;
if (iter->flags & FTRACE_ITER_ADDRS)
seq_printf(m, "%lx ", rec->ip);
if (print_rec(m, rec->ip)) { /* This should only happen when a rec is disabled */
WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
seq_putc(m, '\n'); return 0;
}
if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) { struct ftrace_ops *ops;
/* * This shows us what functions are currently being * traced and by what. Not sure if we want lockdown * to hide such critical information for an admin. * Although, perhaps it can show information we don't * want people to see, but if something is tracing * something, we probably want to know about it.
*/
iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); if (!iter) return -ENOMEM;
/* * This shows us what functions have ever been enabled * (traced, direct, patched, etc). Not sure if we want lockdown * to hide such critical information for an admin. * Although, perhaps it can show information we don't * want people to see, but if something had traced * something, we probably want to know about it.
*/
iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); if (!iter) return -ENOMEM;
/** * ftrace_regex_open - initialize function tracer filter files * @ops: The ftrace_ops that hold the hash filters * @flag: The type of filter to process * @inode: The inode, usually passed in to your open routine * @file: The file, usually passed in to your open routine * * ftrace_regex_open() initializes the filter files for the * @ops. Depending on @flag it may process the filter hash or * the notrace hash of @ops. With this called from the open * routine, you can use ftrace_filter_write() for the write * routine if @flag has FTRACE_ITER_FILTER set, or * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set. * tracing_lseek() should be used as the lseek routine, and * release must call ftrace_regex_release(). * * Returns: 0 on success or a negative errno value on failure
*/ int
ftrace_regex_open(struct ftrace_ops *ops, int flag, struct inode *inode, struct file *file)
{ struct ftrace_iterator *iter; struct ftrace_hash *hash; struct list_head *mod_head; struct trace_array *tr = ops->private; int ret = -ENOMEM;
ftrace_ops_init(ops);
if (unlikely(ftrace_disabled)) return -ENODEV;
if (tracing_check_open_get_tr(tr)) return -ENODEV;
iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) goto out;
if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) goto out;
/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */ struct ftrace_glob { char *search; unsigned len; int type;
};
/* * If symbols in an architecture don't correspond exactly to the user-visible * name of what they represent, it is possible to define this function to * perform the necessary adjustments.
*/ char * __weak arch_ftrace_match_adjust(char *str, constchar *search)
{ return str;
}
staticint ftrace_match(char *str, struct ftrace_glob *g)
{ int matched = 0; int slen;
str = arch_ftrace_match_adjust(str, g->search);
switch (g->type) { case MATCH_FULL: if (strcmp(str, g->search) == 0)
matched = 1; break; case MATCH_FRONT_ONLY: if (strncmp(str, g->search, g->len) == 0)
matched = 1; break; case MATCH_MIDDLE_ONLY: if (strstr(str, g->search))
matched = 1; break; case MATCH_END_ONLY:
slen = strlen(str); if (slen >= g->len &&
memcmp(str + slen - g->len, g->search, g->len) == 0)
matched = 1; break; case MATCH_GLOB: if (glob_match(g->search, str))
matched = 1; break;
}
return matched;
}
staticint
enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
{ struct ftrace_func_entry *entry; int ret = 0;
entry = ftrace_lookup_ip(hash, rec->ip); if (clear_filter) { /* Do nothing if it doesn't exist */ if (!entry) return 0;
free_hash_entry(hash, entry);
} else { /* Do nothing if it exists */ if (entry) return 0; if (add_hash_entry(hash, rec->ip) == NULL)
ret = -ENOMEM;
} return ret;
}
staticint
add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g, int clear_filter)
{ long index; struct ftrace_page *pg; struct dyn_ftrace *rec;
/* The index starts at 1 */ if (kstrtoul(func_g->search, 0, &index) || --index < 0) return 0;
do_for_each_ftrace_rec(pg, rec) { if (pg->index <= index) {
index -= pg->index; /* this is a double loop, break goes to the next page */ break;
}
rec = &pg->records[index];
enter_record(hash, rec, clear_filter); return 1;
} while_for_each_ftrace_rec(); return 0;
}
if (lookup_ip(rec->ip, &modname, str)) { /* This should only happen when a rec is disabled */
WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
!(rec->flags & FTRACE_FL_DISABLED)); return 0;
}
if (mod_g) { int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
/* blank module name to match all modules */ if (!mod_g->len) { /* blank module globbing: modname xor exclude_mod */ if (!exclude_mod != !modname) goto func_match; return 0;
}
/* * exclude_mod is set to trace everything but the given * module. If it is set and the module matches, then * return 0. If it is not set, and the module doesn't match * also return 0. Otherwise, check the function to see if * that matches.
*/ if (!mod_matches == !exclude_mod) return 0;
func_match: /* blank search means to match all funcs in the mod */ if (!func_g->len) return 1;
}
return ftrace_match(str, func_g);
}
staticint
match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
{ struct ftrace_page *pg; struct dyn_ftrace *rec; struct ftrace_glob func_g = { .type = MATCH_FULL }; struct ftrace_glob mod_g = { .type = MATCH_FULL }; struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL; int exclude_mod = 0; int found = 0; int ret; int clear_filter = 0;
if (ops->flags & FTRACE_OPS_FL_ENABLED) {
ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash); return;
}
/* * If this is the shared global_ops filter, then we need to * check if there is another ops that shares it, is enabled. * If so, we still need to run the modify code.
*/ if (ops->func_hash != &global_ops.local_hash) return;
do_for_each_ftrace_op(op, ftrace_ops_list) { if (op->func_hash == &global_ops.local_hash &&
op->flags & FTRACE_OPS_FL_ENABLED) {
ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash); /* Only need to do this once */ return;
}
} while_for_each_ftrace_op(op);
}
/* * If this ops is not enabled, it could be sharing its filters * with a subop. If that's the case, update the subop instead of * this ops. Shared filters are only allowed to have one ops set * at a time, and if we update the ops that is not enabled, * it will not affect subops that share it.
*/ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) { struct ftrace_ops *op;
/* Check if any other manager subops maps to this hash */
do_for_each_ftrace_op(op, ftrace_ops_list) { struct ftrace_ops *subops;
mod = kstrdup(mod_name, GFP_KERNEL); if (!mod) return;
mutex_lock(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (!list_empty(&tr->mod_trace))
process_mod_list(&tr->mod_trace, tr->ops, mod, true); if (!list_empty(&tr->mod_notrace))
process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
}
mutex_unlock(&trace_types_lock);
kfree(mod);
} #endif
/* * We register the module command as a template to show others how * to register the a command as well.
*/
staticint
ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash, char *func_orig, char *cmd, char *module, int enable)
{ char *func; int ret;
if (!tr) return -ENODEV;
/* match_records() modifies func, and we need the original */
func = kstrdup(func_orig, GFP_KERNEL); if (!func) return -ENOMEM;
/* * cmd == 'mod' because we only registered this func * for the 'mod' ftrace_func_command. * But if you register one func with multiple commands, * you can tell which command was used by the cmd * parameter.
*/
ret = match_records(hash, func, strlen(func), module);
kfree(func);
if (!ret) return cache_mod(tr, func_orig, module, enable); if (ret < 0) return ret; return 0;
}
/* * Disable preemption for these calls to prevent a RCU grace * period. This syncs the hash iteration and freeing of items * on the hash. rcu_read_lock is too dangerous here.
*/
preempt_disable_notrace();
probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
preempt_enable_notrace();
}
/* * Note, ftrace_func_mapper is freed by free_ftrace_hash(&mapper->hash). * The hash field must be the first field.
*/ struct ftrace_func_mapper { struct ftrace_hash hash; /* Must be first! */
};
/** * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper * * Returns: a ftrace_func_mapper descriptor that can be used to map ips to data.
*/ struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
{ struct ftrace_hash *hash;
/* * The mapper is simply a ftrace_hash, but since the entries * in the hash are not ftrace_func_entry type, we define it * as a separate structure.
*/
hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); return (struct ftrace_func_mapper *)hash;
}
/** * ftrace_func_mapper_find_ip - Find some data mapped to an ip * @mapper: The mapper that has the ip maps * @ip: the instruction pointer to find the data for * * Returns: the data mapped to @ip if found otherwise NULL. The return * is actually the address of the mapper data pointer. The address is * returned for use cases where the data is no bigger than a long, and * the user can use the data pointer as its data instead of having to * allocate more memory for the reference.
*/ void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper, unsignedlong ip)
{ struct ftrace_func_entry *entry; struct ftrace_func_map *map;
entry = ftrace_lookup_ip(&mapper->hash, ip); if (!entry) return NULL;
/** * ftrace_func_mapper_add_ip - Map some data to an ip * @mapper: The mapper that has the ip maps * @ip: The instruction pointer address to map @data to * @data: The data to map to @ip * * Returns: 0 on success otherwise an error.
*/ int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper, unsignedlong ip, void *data)
{ struct ftrace_func_entry *entry; struct ftrace_func_map *map;
entry = ftrace_lookup_ip(&mapper->hash, ip); if (entry) return -EBUSY;
map = kmalloc(sizeof(*map), GFP_KERNEL); if (!map) return -ENOMEM;
map->entry.ip = ip;
map->data = data;
__add_hash_entry(&mapper->hash, &map->entry);
return 0;
}
/** * ftrace_func_mapper_remove_ip - Remove an ip from the mapping * @mapper: The mapper that has the ip maps * @ip: The instruction pointer address to remove the data from * * Returns: the data if it is found, otherwise NULL. * Note, if the data pointer is used as the data itself, (see * ftrace_func_mapper_find_ip(), then the return value may be meaningless, * if the data pointer was set to zero.
*/ void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper, unsignedlong ip)
{ struct ftrace_func_entry *entry; struct ftrace_func_map *map; void *data;
entry = ftrace_lookup_ip(&mapper->hash, ip); if (!entry) return NULL;
map = (struct ftrace_func_map *)entry;
data = map->data;
/** * free_ftrace_func_mapper - free a mapping of ips and data * @mapper: The mapper that has the ip maps * @free_func: A function to be called on each data item. * * This is used to free the function mapper. The @free_func is optional * and can be used if the data needs to be freed as well.
*/ void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
ftrace_mapper_func free_func)
{ struct ftrace_func_entry *entry; struct ftrace_func_map *map; struct hlist_head *hhd; int size, i;
if (!mapper) return;
if (free_func && mapper->hash.count) {
size = 1 << mapper->hash.size_bits; for (i = 0; i < size; i++) {
hhd = &mapper->hash.buckets[i];
hlist_for_each_entry(entry, hhd, hlist) {
map = (struct ftrace_func_map *)entry;
free_func(map);
}
}
} /* This also frees the mapper itself */
free_ftrace_hash(&mapper->hash);
}
/* Subtract the ref that was used to protect this instance */
probe->ref--;
if (!probe->ref) {
probe_ops = probe->probe_ops; /* * Sending zero as ip tells probe_ops to free * the probe->data itself
*/ if (probe_ops->free)
probe_ops->free(probe_ops, probe->tr, 0, probe->data);
list_del(&probe->list);
kfree(probe);
}
}
staticvoid acquire_probe_locked(struct ftrace_func_probe *probe)
{ /* * Add one ref to keep it from being freed when releasing the * ftrace_lock mutex.
*/
probe->ref++;
}
int
register_ftrace_function_probe(char *glob, struct trace_array *tr, struct ftrace_probe_ops *probe_ops, void *data)
{ struct ftrace_func_probe *probe = NULL, *iter; struct ftrace_func_entry *entry; struct ftrace_hash **orig_hash; struct ftrace_hash *old_hash; struct ftrace_hash *hash; int count = 0; int size; int ret; int i;
if (WARN_ON(!tr)) return -EINVAL;
/* We do not support '!' for function probes */ if (WARN_ON(glob[0] == '!')) return -EINVAL;
mutex_lock(&ftrace_lock); /* Check if the probe_ops is already registered */
list_for_each_entry(iter, &tr->func_probes, list) { if (iter->probe_ops == probe_ops) {
probe = iter; break;
}
} if (!probe) {
probe = kzalloc(sizeof(*probe), GFP_KERNEL); if (!probe) {
mutex_unlock(&ftrace_lock); return -ENOMEM;
}
probe->probe_ops = probe_ops;
probe->ops.func = function_trace_probe_call;
probe->tr = tr;
ftrace_ops_init(&probe->ops);
list_add(&probe->list, &tr->func_probes);
}
acquire_probe_locked(probe);
mutex_unlock(&ftrace_lock);
/* * Note, there's a small window here that the func_hash->filter_hash * may be NULL or empty. Need to be careful when reading the loop.
*/
mutex_lock(&probe->ops.func_hash->regex_lock);
ret = ftrace_match_records(hash, glob, strlen(glob));
/* Nothing found? */ if (!ret)
ret = -EINVAL;
if (ret < 0) goto out;
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) { if (ftrace_lookup_ip(old_hash, entry->ip)) continue; /* * The caller might want to do something special * for each function we find. We call the callback * to give the caller an opportunity to do so.
*/ if (probe_ops->init) {
ret = probe_ops->init(probe_ops, tr,
entry->ip, data,
&probe->data); if (ret < 0) { if (probe_ops->free && count)
probe_ops->free(probe_ops, tr,
0, probe->data);
probe->data = NULL; goto out;
}
}
count++;
}
}
mutex_lock(&ftrace_lock);
if (!count) { /* Nothing was added? */
ret = -EINVAL; goto out_unlock;
}
ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
hash, 1); if (ret < 0) goto err_unlock;
/* One ref for each new function traced */
probe->ref += count;
if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
ret = ftrace_startup(&probe->ops, 0);
out_unlock:
mutex_unlock(&ftrace_lock);
if (!ret)
ret = count;
out:
mutex_unlock(&probe->ops.func_hash->regex_lock);
free_ftrace_hash(hash);
release_probe(probe);
return ret;
err_unlock: if (!probe_ops->free || !count) goto out_unlock;
/* Failed to do the move, need to call the free functions */ for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) { if (ftrace_lookup_ip(old_hash, entry->ip)) continue;
probe_ops->free(probe_ops, tr, entry->ip, probe->data);
}
} goto out_unlock;
}
int
unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr, struct ftrace_probe_ops *probe_ops)
{ struct ftrace_func_probe *probe = NULL, *iter; struct ftrace_ops_hash old_hash_ops; struct ftrace_func_entry *entry; struct ftrace_glob func_g; struct ftrace_hash **orig_hash; struct ftrace_hash *old_hash; struct ftrace_hash *hash = NULL; struct hlist_node *tmp; struct hlist_head hhd; char str[KSYM_SYMBOL_LEN]; int count = 0; int i, ret = -ENODEV; int size;
old_hash_ops.filter_hash = old_hash; /* Probes only have filters */
old_hash_ops.notrace_hash = NULL;
ret = -ENOMEM;
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); if (!hash) goto out_unlock;
INIT_HLIST_HEAD(&hhd);
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
if (func_g.search) {
kallsyms_lookup(entry->ip, NULL, NULL,
NULL, str); if (!ftrace_match(str, &func_g)) continue;
}
count++;
remove_hash_entry(hash, entry);
hlist_add_head(&entry->hlist, &hhd);
}
}
/* Nothing found? */ if (!count) {
ret = -EINVAL; goto out_unlock;
}
mutex_lock(&ftrace_lock);
WARN_ON(probe->ref < count);
probe->ref -= count;
if (ftrace_hash_empty(hash))
ftrace_shutdown(&probe->ops, 0);
ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
hash, 1);
/* still need to update the function call sites */ if (ftrace_enabled && !ftrace_hash_empty(hash))
ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
&old_hash_ops);
synchronize_rcu();
/* * Currently we only register ftrace commands from __init, so mark this * __init too.
*/
__init int register_ftrace_command(struct ftrace_func_command *cmd)
{ struct ftrace_func_command *p;
/* * Currently we only unregister ftrace commands from __init, so mark * this __init too.
*/
__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
{ struct ftrace_func_command *p, *n;
guard(mutex)(&ftrace_cmd_mutex);
list_for_each_entry_safe(p, n, &ftrace_commands, list) { if (strcmp(cmd->name, p->name) == 0) {
list_del_init(&p->list); return 0;
}
}
staticint
ftrace_match_addr(struct ftrace_hash *hash, unsignedlong *ips, unsignedint cnt, int remove)
{ unsignedint i; int err;
for (i = 0; i < cnt; i++) {
err = __ftrace_match_addr(hash, ips[i], remove); if (err) { /* * This expects the @hash is a temporary hash and if this * fails the caller must free the @hash.
*/ return err;
}
} return 0;
}
staticint
ftrace_set_hash(struct ftrace_ops *ops, unsignedchar *buf, int len, unsignedlong *ips, unsignedint cnt, int remove, int reset, int enable, char *mod)
{ struct ftrace_hash **orig_hash; struct ftrace_hash *hash; int ret;
if (unlikely(ftrace_disabled)) return -ENODEV;
mutex_lock(&ops->func_hash->regex_lock);
if (enable)
orig_hash = &ops->func_hash->filter_hash; else
orig_hash = &ops->func_hash->notrace_hash;
if (reset)
hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); else
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
if (!hash) {
ret = -ENOMEM; goto out_regex_unlock;
}
if (buf && !match_records(hash, buf, len, mod)) { /* If this was for a module and nothing was enabled, flag it */ if (mod)
(*orig_hash)->flags |= FTRACE_HASH_FL_MOD;
/* * Even if it is a mod, return error to let caller know * nothing was added
*/
ret = -EINVAL; goto out_regex_unlock;
} if (ips) {
ret = ftrace_match_addr(hash, ips, cnt, remove); if (ret < 0) goto out_regex_unlock;
}
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
mutex_unlock(&ftrace_lock);
/* * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct * call will be jumped from ftrace_regs_caller. Only if the architecture does * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it * jumps from ftrace_caller for multiple ftrace_ops.
*/ #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS) #else #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS) #endif
/* cleanup for possible another register call */
ops->func = NULL;
ops->trampoline = 0;
}
/** * register_ftrace_direct - Call a custom trampoline directly * for multiple functions registered in @ops * @ops: The address of the struct ftrace_ops object * @addr: The address of the trampoline to call at @ops functions * * This is used to connect a direct calls to @addr from the nop locations * of the functions registered in @ops (with by ftrace_set_filter_ip * function). * * The location that it calls (@addr) must be able to handle a direct call, * and save the parameters of the function being traced, and restore them * (or inject new ones if needed), before returning. * * Returns: * 0 on success * -EINVAL - The @ops object was already registered with this call or * when there are no functions in @ops object. * -EBUSY - Another direct function is already attached (there can be only one) * -ENODEV - @ip does not point to a ftrace nop location (or not supported) * -ENOMEM - There was an allocation failure.
*/ int register_ftrace_direct(struct ftrace_ops *ops, unsignedlong addr)
{ struct ftrace_hash *hash, *new_hash = NULL, *free_hash = NULL; struct ftrace_func_entry *entry, *new; int err = -EBUSY, size, i;
if (ops->func || ops->trampoline) return -EINVAL; if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) return -EINVAL; if (ops->flags & FTRACE_OPS_FL_ENABLED) return -EINVAL;
hash = ops->func_hash->filter_hash; if (ftrace_hash_empty(hash)) return -EINVAL;
mutex_lock(&direct_mutex);
/* Make sure requested entries are not already registered.. */
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) { if (ftrace_find_rec_direct(entry->ip)) goto out_unlock;
}
}
err = -ENOMEM;
/* Make a copy hash to place the new and the old entries in */
size = hash->count + direct_functions->count;
size = fls(size); if (size > FTRACE_HASH_MAX_BITS)
size = FTRACE_HASH_MAX_BITS;
new_hash = alloc_ftrace_hash(size); if (!new_hash) goto out_unlock;
/* Now copy over the existing direct entries */
size = 1 << direct_functions->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &direct_functions->buckets[i], hlist) { new = add_hash_entry(new_hash, entry->ip); if (!new) goto out_unlock;
new->direct = entry->direct;
}
}
/* ... and add the new entries */
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) { new = add_hash_entry(new_hash, entry->ip); if (!new) goto out_unlock; /* Update both the copy and the hash entry */
new->direct = addr;
entry->direct = addr;
}
}
/** * unregister_ftrace_direct - Remove calls to custom trampoline * previously registered by register_ftrace_direct for @ops object. * @ops: The address of the struct ftrace_ops object * @addr: The address of the direct function that is called by the @ops functions * @free_filters: Set to true to remove all filters for the ftrace_ops, false otherwise * * This is used to remove a direct calls to @addr from the nop locations * of the functions registered in @ops (with by ftrace_set_filter_ip * function). * * Returns: * 0 on success * -EINVAL - The @ops object was not properly registered.
*/ int unregister_ftrace_direct(struct ftrace_ops *ops, unsignedlong addr, bool free_filters)
{ int err;
if (check_direct_multi(ops)) return -EINVAL; if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EINVAL;
/* Enable the tmp_ops to have the same functions as the direct ops */
ftrace_ops_init(&tmp_ops);
tmp_ops.func_hash = ops->func_hash;
tmp_ops.direct_call = addr;
err = register_ftrace_function_nolock(&tmp_ops); if (err) return err;
/* * Now the ftrace_ops_list_func() is called to do the direct callers. * We can safely change the direct functions attached to each entry.
*/
mutex_lock(&ftrace_lock);
hash = ops->func_hash->filter_hash;
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
entry = __ftrace_lookup_ip(direct_functions, iter->ip); if (!entry) continue;
entry->direct = addr;
}
} /* Prevent store tearing if a trampoline concurrently accesses the value */
WRITE_ONCE(ops->direct_call, addr);
mutex_unlock(&ftrace_lock);
/* Removing the tmp_ops will add the updated direct callers to the functions */
unregister_ftrace_function(&tmp_ops);
return err;
}
/** * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call * to call something else * @ops: The address of the struct ftrace_ops object * @addr: The address of the new trampoline to call at @ops functions * * This is used to unregister currently registered direct caller and * register new one @addr on functions registered in @ops object. * * Note there's window between ftrace_shutdown and ftrace_startup calls * where there will be no callbacks called. * * Caller should already have direct_mutex locked, so we don't lock * direct_mutex here. * * Returns: zero on success. Non zero on error, which includes: * -EINVAL - The @ops object was not properly registered.
*/ int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsignedlong addr)
{ if (check_direct_multi(ops)) return -EINVAL; if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EINVAL;
/** * modify_ftrace_direct - Modify an existing direct 'multi' call * to call something else * @ops: The address of the struct ftrace_ops object * @addr: The address of the new trampoline to call at @ops functions * * This is used to unregister currently registered direct caller and * register new one @addr on functions registered in @ops object. * * Note there's window between ftrace_shutdown and ftrace_startup calls * where there will be no callbacks called. * * Returns: zero on success. Non zero on error, which includes: * -EINVAL - The @ops object was not properly registered.
*/ int modify_ftrace_direct(struct ftrace_ops *ops, unsignedlong addr)
{ int err;
if (check_direct_multi(ops)) return -EINVAL; if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EINVAL;
/** * ftrace_set_filter_ip - set a function to filter on in ftrace by address * @ops: the ops to set the filter with * @ip: the address to add to or remove from the filter. * @remove: non zero to remove the ip from the filter * @reset: non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled * If @ip is NULL, it fails to update filter. * * This can allocate memory which must be freed before @ops can be freed, * either by removing each filtered addr or by using * ftrace_free_filter(@ops).
*/ int ftrace_set_filter_ip(struct ftrace_ops *ops, unsignedlong ip, int remove, int reset)
{
ftrace_ops_init(ops); return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
/** * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses * @ops: the ops to set the filter with * @ips: the array of addresses to add to or remove from the filter. * @cnt: the number of addresses in @ips * @remove: non zero to remove ips from the filter * @reset: non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled * If @ips array or any ip specified within is NULL , it fails to update filter. * * This can allocate memory which must be freed before @ops can be freed, * either by removing each filtered addr or by using * ftrace_free_filter(@ops).
*/ int ftrace_set_filter_ips(struct ftrace_ops *ops, unsignedlong *ips, unsignedint cnt, int remove, int reset)
{
ftrace_ops_init(ops); return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
/** * ftrace_ops_set_global_filter - setup ops to use global filters * @ops: the ops which will use the global filters * * ftrace users who need global function trace filtering should call this. * It can set the global filter only if ops were not initialized before.
*/ void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
{ if (ops->flags & FTRACE_OPS_FL_INITIALIZED) return;
if (tr && mod && ret < 0) { /* Did tmp fail to allocate? */ if (!tmp) return -ENOMEM;
ret = cache_mod(tr, tmp, mod, enable);
}
return ret;
}
/** * ftrace_set_filter - set a function to filter on in ftrace * @ops: the ops to set the filter with * @buf: the string that holds the function filter text. * @len: the length of the string. * @reset: non-zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. * * This can allocate memory which must be freed before @ops can be freed, * either by removing each filtered addr or by using * ftrace_free_filter(@ops).
*/ int ftrace_set_filter(struct ftrace_ops *ops, unsignedchar *buf, int len, int reset)
{
ftrace_ops_init(ops); return ftrace_set_regex(ops, buf, len, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_filter);
/** * ftrace_set_notrace - set a function to not trace in ftrace * @ops: the ops to set the notrace filter with * @buf: the string that holds the function notrace text. * @len: the length of the string. * @reset: non-zero to reset all filters before applying this filter. * * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. * * This can allocate memory which must be freed before @ops can be freed, * either by removing each filtered addr or by using * ftrace_free_filter(@ops).
*/ int ftrace_set_notrace(struct ftrace_ops *ops, unsignedchar *buf, int len, int reset)
{
ftrace_ops_init(ops); return ftrace_set_regex(ops, buf, len, reset, 0);
}
EXPORT_SYMBOL_GPL(ftrace_set_notrace); /** * ftrace_set_global_filter - set a function to filter on with global tracers * @buf: the string that holds the function filter text. * @len: the length of the string. * @reset: non-zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing.
*/ void ftrace_set_global_filter(unsignedchar *buf, int len, int reset)
{
ftrace_set_regex(&global_ops, buf, len, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
/** * ftrace_set_global_notrace - set a function to not trace with global tracers * @buf: the string that holds the function notrace text. * @len: the length of the string. * @reset: non-zero to reset all filters before applying this filter. * * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing.
*/ void ftrace_set_global_notrace(unsignedchar *buf, int len, int reset)
{
ftrace_set_regex(&global_ops, buf, len, reset, 0);
}
EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
/* * command line interface to allow users to set filters on boot up.
*/ #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE staticchar ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; staticchar ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
/* Used by function selftest to not test if filter is set */ bool ftrace_filter_param __initdata;
staticvoid __init set_ftrace_early_graph(char *buf, int enable)
{ int ret; char *func; struct ftrace_hash *hash;
hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); if (MEM_FAIL(!hash, "Failed to allocate hash\n")) return;
while (buf) {
func = strsep(&buf, ","); /* we allow only one expression at a time */
ret = ftrace_graph_set_hash(hash, func); if (ret)
printk(KERN_DEBUG "ftrace: function %s not " "traceable\n", func);
}
out: if (ret < 0 && file->f_mode & FMODE_WRITE)
trace_parser_put(&fgd->parser);
fgd->new_hash = new_hash;
/* * All uses of fgd->hash must be taken with the graph_lock * held. The graph_lock is going to be released, so force * fgd->hash to be reinitialized when it is taken again.
*/
fgd->hash = NULL;
/* * We need to do a hard force of sched synchronization. * This is because we use preempt_disable() to do RCU, but * the function tracers can be called where RCU is not watching * (like before user_exit()). We can not rely on the RCU * infrastructure to do the synchronization, thus we must do it * ourselves.
*/ if (old_hash != EMPTY_HASH)
synchronize_rcu_tasks_rude();
/* * The name "destroy_filter_files" is really a misnomer. Although * in the future, it may actually delete the files, but this is * really intended to make sure the ops passed in are disabled * and that when this function returns, the caller is free to * free the ops. * * The "destroy" name is only to match the "create" name that this * should be paired with.
*/ void ftrace_destroy_filter_files(struct ftrace_ops *ops)
{
mutex_lock(&ftrace_lock); if (ops->flags & FTRACE_OPS_FL_ENABLED)
ftrace_shutdown(ops, 0);
ops->flags |= FTRACE_OPS_FL_DELETED;
ftrace_free_filter(ops);
mutex_unlock(&ftrace_lock);
}
static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
{
if (*ipa > *ipb) return 1; if (*ipa < *ipb) return -1; return 0;
}
#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST staticvoid test_is_sorted(unsignedlong *start, unsignedlong count)
{ int i;
for (i = 1; i < count; i++) { if (WARN(start[i - 1] > start[i], "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
(void *)start[i - 1], start[i - 1],
(void *)start[i], start[i])) break;
} if (i == count)
pr_info("ftrace section at %px sorted properly\n", start);
} #else staticvoid test_is_sorted(unsignedlong *start, unsignedlong count)
{
} #endif
/* * Sorting mcount in vmlinux at build time depend on * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in * modules can not be sorted at build time.
*/ if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
sort(start, count, sizeof(*start),
ftrace_cmp_ips, NULL);
} else {
test_is_sorted(start, count);
}
start_pg = ftrace_allocate_pages(count); if (!start_pg) return -ENOMEM;
mutex_lock(&ftrace_lock);
/* * Core and each module needs their own pages, as * modules will free them when they are removed. * Force a new page to be allocated for modules.
*/ if (!mod) {
WARN_ON(ftrace_pages || ftrace_pages_start); /* First initialization */
ftrace_pages = ftrace_pages_start = start_pg;
} else { if (!ftrace_pages) goto out;
if (WARN_ON(ftrace_pages->next)) { /* Hmm, we have free pages? */ while (ftrace_pages->next)
ftrace_pages = ftrace_pages->next;
}
ftrace_pages->next = start_pg;
}
p = start;
pg = start_pg; while (p < end) { unsignedlong end_offset;
addr = *p++;
/* * Some architecture linkers will pad between * the different mcount_loc sections of different * object files to satisfy alignments. * Skip any NULL pointers.
*/ if (!addr) {
skipped++; continue;
}
/* * If this is core kernel, make sure the address is in core * or inittext, as weak functions get zeroed and KASLR can * move them to something other than zero. It just will not * move it to an area where kernel text is.
*/ if (!mod && !(is_kernel_text(addr) || is_kernel_inittext(addr))) {
skipped++; continue;
}
addr = ftrace_call_adjust(addr);
end_offset = (pg->index+1) * sizeof(pg->records[0]); if (end_offset > PAGE_SIZE << pg->order) { /* We should have allocated enough */ if (WARN_ON(!pg->next)) break;
pg = pg->next;
}
if (pg->next) {
pg_unuse = pg->next;
pg->next = NULL;
}
/* Assign the last page to ftrace_pages */
ftrace_pages = pg;
/* * We only need to disable interrupts on start up * because we are modifying code that an interrupt * may execute, and the modification is not atomic. * But for modules, nothing runs the code we modify * until we are finished with it, and there's no * reason to cause large interrupt latencies while we do it.
*/ if (!mod)
local_irq_save(flags);
ftrace_update_code(mod, start_pg); if (!mod)
local_irq_restore(flags);
ret = 0;
out:
mutex_unlock(&ftrace_lock);
/* We should have used all pages unless we skipped some */ if (pg_unuse) { unsignedlong pg_remaining, remaining = 0; unsignedlong skip;
/* Count the number of entries unused and compare it to skipped. */
pg_remaining = (ENTRIES_PER_PAGE << pg->order) - pg->index;
if (!WARN(skipped < pg_remaining, "Extra allocated pages for ftrace")) {
/* * Check to see if the number of pages remaining would * just fit the number of entries skipped.
*/
WARN(skip != remaining, "Extra allocated pages for ftrace: %lu with %lu skipped",
remaining, skipped);
} /* Need to synchronize with ftrace_location_range() */
synchronize_rcu();
ftrace_free_pages(pg_unuse);
}
if (!mod) {
count -= skipped;
pr_info("ftrace: allocating %ld entries in %ld pages\n",
count, pages);
}
#ifdefined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES) /* * Check if the current ops references the given ip. * * If the ops traces all functions, then it was already accounted for. * If the ops does not trace the current record function, skip it. * If the ops ignores the function via notrace filter, skip it.
*/ staticbool
ops_references_ip(struct ftrace_ops *ops, unsignedlong ip)
{ /* If ops isn't enabled, ignore it */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) returnfalse;
/* If ops traces all then it includes this function */ if (ops_traces_mod(ops)) returntrue;
/* The function must be in the filter */ if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
!__ftrace_lookup_ip(ops->func_hash->filter_hash, ip)) returnfalse;
/* If in notrace hash, we ignore it too */ if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip)) returnfalse;
for (i = 0; i < pg->index; i++) {
rec = &pg->records[i];
entry = __ftrace_lookup_ip(hash, rec->ip); /* * Do not allow this rec to match again. * Yeah, it may waste some memory, but will be removed * if/when the hash is modified again.
*/ if (entry)
entry->ip = 0;
}
}
/* Clear any records from hashes */ staticvoid clear_mod_from_hashes(struct ftrace_page *pg)
{ struct trace_array *tr;
/* All the contents of mod_map are now not visible to readers */
list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
kfree(mod_func->name);
list_del(&mod_func->list);
kfree(mod_func);
}
/* * To avoid the UAF problem after the module is unloaded, the * 'mod_map' resource needs to be released unconditionally.
*/
list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) { if (mod_map->mod == mod) {
list_del_rcu(&mod_map->list);
call_rcu(&mod_map->rcu, ftrace_free_mod_map); break;
}
}
if (ftrace_disabled) goto out_unlock;
/* * Each module has its own ftrace_pages, remove * them from the list.
*/
last_pg = &ftrace_pages_start; for (pg = ftrace_pages_start; pg; pg = *last_pg) {
rec = &pg->records[0]; if (within_module(rec->ip, mod)) { /* * As core pages are first, the first * page should never be a module page.
*/ if (WARN_ON(pg == ftrace_pages_start)) goto out_unlock;
/* Check if we are deleting the last page */ if (pg == ftrace_pages)
ftrace_pages = next_to_ftrace_page(last_pg);
/* * If the tracing is enabled, go ahead and enable the record. * * The reason not to enable the record immediately is the * inherent check of ftrace_make_nop/ftrace_make_call for * correct previous instructions. Making first the NOP * conversion puts the module to the correct state, thus * passing the ftrace_make_call check. * * We also delay this to after the module code already set the * text to read-only, as we now need to set it back to read-write * so that we can modify the text.
*/ if (ftrace_start_up)
ftrace_arch_code_modify_prepare();
do_for_each_ftrace_rec(pg, rec) { int cnt; /* * do_for_each_ftrace_rec() is a double loop. * module text shares the pg. If a record is * not part of this module, then skip this pg, * which the "break" will do.
*/ if (!within_module(rec->ip, mod)) break;
cond_resched();
/* Weak functions should still be ignored */ if (!test_for_valid_rec(rec)) { /* Clear all other flags. Should not be enabled anyway */
rec->flags = FTRACE_FL_DISABLED; continue;
}
cnt = 0;
/* * When adding a module, we need to check if tracers are * currently enabled and if they are, and can trace this record, * we need to enable the module functions as well as update the * reference counts for those function records.
*/ if (ftrace_start_up)
cnt += referenced_filters(rec);
if (ftrace_start_up && cnt) { int failed = __ftrace_replace_code(rec, 1); if (failed) {
ftrace_bug(failed, rec); goto out_loop;
}
}
} while_for_each_ftrace_rec();
out_loop: if (ftrace_start_up)
ftrace_arch_code_modify_post_process();
out_unlock:
mutex_unlock(&ftrace_lock);
process_cached_mods(mod->name);
}
void ftrace_module_init(struct module *mod)
{ int ret;
if (ftrace_disabled || !mod->num_ftrace_callsites) return;
ret = ftrace_process_locs(mod, mod->ftrace_callsites,
mod->ftrace_callsites + mod->num_ftrace_callsites); if (ret)
pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
mod->name);
}
/* Clear any init ips from hashes */ staticvoid
clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
{ struct ftrace_func_entry *entry;
entry = ftrace_lookup_ip(hash, func->ip); /* * Do not allow this rec to match again. * Yeah, it may waste some memory, but will be removed * if/when the hash is modified again.
*/ if (entry)
entry->ip = 0;
}
key.ip = start;
key.flags = end; /* overload flags, as it is unsigned long */
mutex_lock(&ftrace_lock);
/* * If we are freeing module init memory, then check if * any tracer is active. If so, we need to save a mapping of * the module functions being freed with the address.
*/ if (mod && ftrace_ops_list != &ftrace_list_end)
mod_map = allocate_ftrace_mod_map(mod, start, end);
local_irq_save(flags);
ret = ftrace_dyn_arch_init();
local_irq_restore(flags); if (ret) goto failed;
count = __stop_mcount_loc - __start_mcount_loc; if (!count) {
pr_info("ftrace: No functions to be traced?\n"); goto failed;
}
ret = ftrace_process_locs(NULL,
__start_mcount_loc,
__stop_mcount_loc); if (ret) {
pr_warn("ftrace: failed to allocate entries for functions\n"); goto failed;
}
pr_info("ftrace: allocated %ld pages with %ld groups\n",
ftrace_number_of_pages, ftrace_number_of_groups);
last_ftrace_enabled = ftrace_enabled = 1;
set_ftrace_early_filters();
return;
failed:
ftrace_disabled = 1;
}
/* Do nothing if arch does not support this */ void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
{
}
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
{ /* If we filter on pids, update to use the pid function */ if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { if (WARN_ON(tr->ops->func != ftrace_stub))
printk("ftrace ops had %pS for function\n",
tr->ops->func);
}
tr->ops->func = func;
tr->ops->private = tr;
}
/* * The ftrace_test_and_set_recursion() will disable preemption, * which is required since some of the ops may be dynamically * allocated, they must be freed after a synchronize_rcu().
*/
bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START); if (bit < 0) return;
do_for_each_ftrace_op(op, ftrace_ops_list) { /* Stub functions don't need to be called nor tested */ if (op->flags & FTRACE_OPS_FL_STUB) continue; /* * Check the following for each ops before calling their func: * if RCU flag is set, then rcu_is_watching() must be true * Otherwise test if the ip matches the ops filter * * If any of the above fails then the op->func() is not executed.
*/ if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
ftrace_ops_test(op, ip, regs)) { if (FTRACE_WARN_ON(!op->func)) {
pr_warn("op=%p %pS\n", op, op); goto out;
}
op->func(ip, parent_ip, op, fregs);
}
} while_for_each_ftrace_op(op);
out:
trace_clear_recursion(bit);
}
/* * Some archs only support passing ip and parent_ip. Even though * the list function ignores the op parameter, we do not want any * C side effects, where a function is called without the caller * sending a third parameter. * Archs are to support both the regs and ftrace_ops at the same time. * If they support ftrace_ops, it is assumed they support regs. * If call backs want to use regs, they must either check for regs * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS. * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved. * An architecture can pass partial regs with ftrace_ops and still * set the ARCH_SUPPORTS_FTRACE_OPS. * * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be * arch_ftrace_ops_list_func.
*/ #if ARCH_SUPPORTS_FTRACE_OPS void arch_ftrace_ops_list_func(unsignedlong ip, unsignedlong parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs)
{
kmsan_unpoison_memory(fregs, ftrace_regs_size());
__ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
} #else void arch_ftrace_ops_list_func(unsignedlong ip, unsignedlong parent_ip)
{
__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
} #endif
NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
/* * If there's only one function registered but it does not support * recursion, needs RCU protection, then this function will be called * by the mcount trampoline.
*/ staticvoid ftrace_ops_assist_func(unsignedlong ip, unsignedlong parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs)
{ int bit;
bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START); if (bit < 0) return;
if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
op->func(ip, parent_ip, op, fregs);
/** * 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_assist_func() instead. * * Returns: the function that the trampoline should call for @ops.
*/
ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
{ /* * If the function does not handle recursion or needs to be RCU safe, * then we need to call the assist handler.
*/ if (ops->flags & (FTRACE_OPS_FL_RECURSION |
FTRACE_OPS_FL_RCU)) return ftrace_ops_assist_func;
/* Make sure there's something to do */ if (!pid_type_enabled(type, pid_list, no_pid_list)) return;
/* See if the pids still need to be checked after this */ if (!still_need_pid_events(type, pid_list, no_pid_list)) {
unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
for_each_possible_cpu(cpu)
per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
}
if (type & TRACE_PIDS)
rcu_assign_pointer(tr->function_pids, NULL);
if (type & TRACE_NO_PIDS)
rcu_assign_pointer(tr->function_no_pids, NULL);
/* Wait till all users are no longer using pid filtering */
synchronize_rcu();
if ((type & TRACE_PIDS) && pid_list)
trace_pid_list_free(pid_list);
if ((type & TRACE_NO_PIDS) && no_pid_list)
trace_pid_list_free(no_pid_list);
}
/* * This function is called by on_each_cpu() while the * event_mutex is held.
*/
pid_list = rcu_dereference_protected(tr->function_pids,
mutex_is_locked(&ftrace_lock));
no_pid_list = rcu_dereference_protected(tr->function_no_pids,
mutex_is_locked(&ftrace_lock));
if (trace_ignore_this_task(pid_list, no_pid_list, current))
this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
FTRACE_PID_IGNORE); else
this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
current->pid);
}
ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt); if (ret < 0) return ret;
switch (type) { case TRACE_PIDS:
rcu_assign_pointer(tr->function_pids, pid_list); break; case TRACE_NO_PIDS:
rcu_assign_pointer(tr->function_no_pids, pid_list); break;
}
if (filtered_pids) {
synchronize_rcu();
trace_pid_list_free(filtered_pids);
} elseif (pid_list && !other_pids) { /* Register a probe to set whether to ignore the tracing of a task */
register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
}
/* * Ignoring of pids is done at task switch. But we have to * check for those tasks that are currently running. * Always do this in case a pid was appended or removed.
*/
on_each_cpu(ignore_task_cpu, tr, 1);
void __init ftrace_init_tracefs_toplevel(struct trace_array *tr, struct dentry *d_tracer)
{ /* Only the top level directory has the dyn_tracefs and profile */
WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
/** * ftrace_kill - kill ftrace * * This function should be used by panic code. It stops ftrace * but in a not so nice way. If you need to simply kill ftrace * from a non-atomic section, use ftrace_kill.
*/ void ftrace_kill(void)
{
ftrace_disabled = 1;
ftrace_enabled = 0;
ftrace_trace_function = ftrace_stub;
kprobe_ftrace_kill();
}
/** * ftrace_is_dead - Test if ftrace is dead or not. * * Returns: 1 if ftrace is "dead", zero otherwise.
*/ int ftrace_is_dead(void)
{ return ftrace_disabled;
}
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS /* * When registering ftrace_ops with IPMODIFY, it is necessary to make sure * it doesn't conflict with any direct ftrace_ops. If there is existing * direct ftrace_ops on a kernel function being patched, call * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing. * * @ops: ftrace_ops being registered. * * Returns: * 0 on success; * Negative on failure.
*/ staticint prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
{ struct ftrace_func_entry *entry; struct ftrace_hash *hash; struct ftrace_ops *op; int size, i, ret;
lockdep_assert_held_once(&direct_mutex);
if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY)) return 0;
hash = ops->func_hash->filter_hash;
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) { unsignedlong ip = entry->ip; bool found_op = false;
ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER); if (ret) return ret;
}
}
}
return 0;
}
/* * Similar to prepare_direct_functions_for_ipmodify, clean up after ops * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT * ops.
*/ staticvoid cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
{ struct ftrace_func_entry *entry; struct ftrace_hash *hash; struct ftrace_ops *op; int size, i;
if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY)) return;
mutex_lock(&direct_mutex);
hash = ops->func_hash->filter_hash;
size = 1 << hash->size_bits; for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) { unsignedlong ip = entry->ip; bool found_op = false;
/* The cleanup is optional, ignore any errors */ if (found_op && op->ops_func)
op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
}
}
mutex_unlock(&direct_mutex);
}
/* * Similar to register_ftrace_function, except we don't lock direct_mutex.
*/ staticint register_ftrace_function_nolock(struct ftrace_ops *ops)
{ int ret;
ftrace_ops_init(ops);
mutex_lock(&ftrace_lock);
ret = ftrace_startup(ops, 0);
mutex_unlock(&ftrace_lock);
return ret;
}
/** * register_ftrace_function - register a function for profiling * @ops: ops structure that holds the function for profiling. * * Register a function to be called by all functions in the * kernel. * * Note: @ops->func and all the functions it calls must be labeled * with "notrace", otherwise it will go into a * recursive loop.
*/ int register_ftrace_function(struct ftrace_ops *ops)
{ int ret;
lock_direct_mutex();
ret = prepare_direct_functions_for_ipmodify(ops); if (ret < 0) goto out_unlock;
/** * unregister_ftrace_function - unregister a function for profiling. * @ops: ops structure that holds the function to unregister * * Unregister a function that was added to be called by ftrace profiling.
*/ int unregister_ftrace_function(struct ftrace_ops *ops)
{ int ret;
mutex_lock(&ftrace_lock);
ret = ftrace_shutdown(ops, 0);
mutex_unlock(&ftrace_lock);
/* This function gets called for all kernel and module symbols * and returns 1 in case we resolved all the requested symbols, * 0 otherwise.
*/ staticint kallsyms_callback(void *data, constchar *name, unsignedlong addr)
{ struct kallsyms_data *args = data; constchar **sym; int idx;
/** * ftrace_lookup_symbols - Lookup addresses for array of symbols * * @sorted_syms: array of symbols pointers symbols to resolve, * must be alphabetically sorted * @cnt: number of symbols/addresses in @syms/@addrs arrays * @addrs: array for storing resulting addresses * * This function looks up addresses for array of symbols provided in * @syms array (must be alphabetically sorted) and stores them in * @addrs array, which needs to be big enough to store at least @cnt * addresses. * * Returns: 0 if all provided symbols are found, -ESRCH otherwise.
*/ int ftrace_lookup_symbols(constchar **sorted_syms, size_t cnt, unsignedlong *addrs)
{ struct kallsyms_data args; int found_all;
#ifdef CONFIG_DYNAMIC_FTRACE staticvoid ftrace_startup_sysctl(void)
{ int command;
if (unlikely(ftrace_disabled)) return;
/* Force update next time */
saved_ftrace_func = NULL; /* ftrace_start_up is true if we want ftrace running */ if (ftrace_start_up) {
command = FTRACE_UPDATE_CALLS; if (ftrace_graph_active)
command |= FTRACE_START_FUNC_RET;
ftrace_startup_enable(command);
}
}
staticvoid ftrace_shutdown_sysctl(void)
{ int command;
if (unlikely(ftrace_disabled)) return;
/* ftrace_start_up is true if ftrace is running */ if (ftrace_start_up) {
command = FTRACE_DISABLE_CALLS; if (ftrace_graph_active)
command |= FTRACE_STOP_FUNC_RET;
ftrace_run_update_code(command);
}
} #else # define ftrace_startup_sysctl() do { } while (0) # define ftrace_shutdown_sysctl() do { } while (0) #endif/* CONFIG_DYNAMIC_FTRACE */
do_for_each_ftrace_op(op, ftrace_ops_list) { if (op->flags & FTRACE_OPS_FL_PERMANENT) returntrue;
} while_for_each_ftrace_op(op);
returnfalse;
}
staticint
ftrace_enable_sysctl(conststruct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos)
{ int ret;
guard(mutex)(&ftrace_lock);
if (unlikely(ftrace_disabled)) return -ENODEV;
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) return ret;
if (ftrace_enabled) {
/* we are starting ftrace again */ if (rcu_dereference_protected(ftrace_ops_list,
lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
update_ftrace_function();
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