Adding register_ftrace_direct_hash function that registers all entries (ip -> direct) provided in hash argument.
The difference to current register_ftrace_direct is - hash argument that allows to register multiple ip -> direct entries at once - we can call register_ftrace_direct_hash multiple times on the same ftrace_ops object, becase after first registration with register_ftrace_function_nolock, it uses ftrace_update_ops to update the ftrace_ops object This change will allow us to have simple ftrace_ops for all bpf direct interface users in following changes. Signed-off-by: Jiri Olsa <[email protected]> --- include/linux/ftrace.h | 7 +++ kernel/trace/ftrace.c | 110 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 117 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 7ded7df6e9b5..2705c292341a 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -526,6 +526,8 @@ int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); +int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash); + void ftrace_stub_direct_tramp(void); #else @@ -552,6 +554,11 @@ static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned l return -ENODEV; } +int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + return -ENODEV; +} + /* * This must be implemented by the architecture. * It is the way the ftrace direct_ops helper, when called diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a45556257963..06528af2281f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6219,6 +6219,116 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) return err; } EXPORT_SYMBOL_GPL(modify_ftrace_direct); + +static unsigned long hash_count(struct ftrace_hash *hash) +{ + return hash ? hash->count : 0; +} + +/** + * hash_add - adds two struct ftrace_hash and returns the result + * @a: struct ftrace_hash object + * @b: struct ftrace_hash object + * + * Returns struct ftrace_hash object on success, NULL on error. + */ +static struct ftrace_hash *hash_add(struct ftrace_hash *a, struct ftrace_hash *b) +{ + struct ftrace_func_entry *entry; + struct ftrace_hash *add; + int size, i; + + size = hash_count(a) + hash_count(b); + if (size > 32) + size = 32; + + add = alloc_and_copy_ftrace_hash(fls(size), a); + if (!add) + goto error; + + size = 1 << b->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + if (add_hash_entry_direct(add, entry->ip, entry->direct) == NULL) + goto error; + } + } + return add; + + error: + free_ftrace_hash(add); + return NULL; +} + +int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + struct ftrace_hash *filter_hash = NULL, *new_hash = NULL, *free_hash = NULL; + struct ftrace_func_entry *entry; + int i, size, err = -EINVAL; + bool reg; + + if (!hash_count(hash)) + return 0; + + 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_lookup_ip(direct_functions, entry->ip)) + goto out_unlock; + } + } + + filter_hash = ops->func_hash ? ops->func_hash->filter_hash : NULL; + + /* If there's nothing in filter_hash we need to register the ops. */ + reg = hash_count(filter_hash) == 0; + if (reg) { + if (ops->func || ops->trampoline) + goto out_unlock; + if (ops->flags & FTRACE_OPS_FL_ENABLED) + goto out_unlock; + } + + err = -ENOMEM; + filter_hash = hash_add(filter_hash, hash); + if (!filter_hash) + goto out_unlock; + + new_hash = hash_add(direct_functions, hash); + if (!new_hash) + goto out_unlock; + + free_hash = direct_functions; + rcu_assign_pointer(direct_functions, new_hash); + + if (reg) { + ops->func = call_direct_funcs; + ops->flags = MULTI_FLAGS; + ops->trampoline = FTRACE_REGS_ADDR; + ops->local_hash.filter_hash = filter_hash; + + err = register_ftrace_function_nolock(ops); + if (!err) + filter_hash = NULL; + } else { + err = ftrace_update_ops(ops, filter_hash, EMPTY_HASH); + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (free_hash && free_hash != EMPTY_HASH) + call_rcu_tasks(&free_hash->rcu, register_ftrace_direct_cb); + if (filter_hash) + free_ftrace_hash(filter_hash); + + return err; +} +EXPORT_SYMBOL_GPL(register_ftrace_direct_hash); + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** -- 2.51.0
