From de5ba9bca9900c553c9eded3b315f4b518f68a90 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:13:54 +0100 Subject: [PATCH 1/9] ftrace,bpf: Remove FTRACE_OPS_FL_JMP ftrace_ops flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit At the moment the we allow the jmp attach only for ftrace_ops that has FTRACE_OPS_FL_JMP set. This conflicts with following changes where we use single ftrace_ops object for all direct call sites, so all could be be attached via just call or jmp. We already limit the jmp attach support with config option and bit (LSB) set on the trampoline address. It turns out that's actually enough to limit the jmp attach for architecture and only for chosen addresses (with LSB bit set). Each user of register_ftrace_direct or modify_ftrace_direct can set the trampoline bit (LSB) to indicate it has to be attached by jmp. The bpf trampoline generation code uses trampoline flags to generate jmp-attach specific code and ftrace inner code uses the trampoline bit (LSB) to handle return from jmp attachment, so there's no harm to remove the FTRACE_OPS_FL_JMP bit. The fexit/fmodret performance stays the same (did not drop), current code: fentry : 77.904 ± 0.546M/s fexit : 62.430 ± 0.554M/s fmodret : 66.503 ± 0.902M/s with this change: fentry : 80.472 ± 0.061M/s fexit : 63.995 ± 0.127M/s fmodret : 67.362 ± 0.175M/s Fixes: 25e4e3565d45 ("ftrace: Introduce FTRACE_OPS_FL_JMP") Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 1 - kernel/bpf/trampoline.c | 32 ++++++++++++++------------------ kernel/trace/ftrace.c | 14 -------------- 3 files changed, 14 insertions(+), 33 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 770f0dc993ccf..41c9bb08d4e43 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -359,7 +359,6 @@ enum { FTRACE_OPS_FL_DIRECT = BIT(17), FTRACE_OPS_FL_SUBOP = BIT(18), FTRACE_OPS_FL_GRAPH = BIT(19), - FTRACE_OPS_FL_JMP = BIT(20), }; #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 976d89011b157..b9a358d7a78f1 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -214,10 +214,15 @@ static int modify_fentry(struct bpf_trampoline *tr, u32 orig_flags, int ret; if (tr->func.ftrace_managed) { + unsigned long addr = (unsigned long) new_addr; + + if (bpf_trampoline_use_jmp(tr->flags)) + addr = ftrace_jmp_set(addr); + if (lock_direct_mutex) - ret = modify_ftrace_direct(tr->fops, (long)new_addr); + ret = modify_ftrace_direct(tr->fops, addr); else - ret = modify_ftrace_direct_nolock(tr->fops, (long)new_addr); + ret = modify_ftrace_direct_nolock(tr->fops, addr); } else { ret = bpf_trampoline_update_fentry(tr, orig_flags, old_addr, new_addr); @@ -240,10 +245,15 @@ static int register_fentry(struct bpf_trampoline *tr, void *new_addr) } if (tr->func.ftrace_managed) { + unsigned long addr = (unsigned long) new_addr; + + if (bpf_trampoline_use_jmp(tr->flags)) + addr = ftrace_jmp_set(addr); + ret = ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 1); if (ret) return ret; - ret = register_ftrace_direct(tr->fops, (long)new_addr); + ret = register_ftrace_direct(tr->fops, addr); } else { ret = bpf_trampoline_update_fentry(tr, 0, NULL, new_addr); } @@ -499,13 +509,6 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut if (err) goto out_free; -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_JMP - if (bpf_trampoline_use_jmp(tr->flags)) - tr->fops->flags |= FTRACE_OPS_FL_JMP; - else - tr->fops->flags &= ~FTRACE_OPS_FL_JMP; -#endif - WARN_ON(tr->cur_image && total == 0); if (tr->cur_image) /* progs already running at this address */ @@ -533,15 +536,8 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut tr->cur_image = im; out: /* If any error happens, restore previous flags */ - if (err) { + if (err) tr->flags = orig_flags; -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_JMP - if (bpf_trampoline_use_jmp(tr->flags)) - tr->fops->flags |= FTRACE_OPS_FL_JMP; - else - tr->fops->flags &= ~FTRACE_OPS_FL_JMP; -#endif - } kfree(tlinks); return err; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3ec2033c07743..f5f042ea079eb 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6043,15 +6043,8 @@ int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) if (ftrace_hash_empty(hash)) return -EINVAL; - /* This is a "raw" address, and this should never happen. */ - if (WARN_ON_ONCE(ftrace_is_jmp(addr))) - return -EINVAL; - mutex_lock(&direct_mutex); - if (ops->flags & FTRACE_OPS_FL_JMP) - addr = ftrace_jmp_set(addr); - /* Make sure requested entries are not already registered.. */ size = 1 << hash->size_bits; for (i = 0; i < size; i++) { @@ -6172,13 +6165,6 @@ __modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) lockdep_assert_held_once(&direct_mutex); - /* This is a "raw" address, and this should never happen. */ - if (WARN_ON_ONCE(ftrace_is_jmp(addr))) - return -EINVAL; - - if (ops->flags & FTRACE_OPS_FL_JMP) - addr = ftrace_jmp_set(addr); - /* 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; From 60e584d56f5b61e607206a3969edb3834abc81d5 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:13:55 +0100 Subject: [PATCH 2/9] ftrace: Make alloc_and_copy_ftrace_hash direct friendly Make alloc_and_copy_ftrace_hash to copy also direct address for each hash entry. Signed-off-by: Jiri Olsa --- kernel/trace/ftrace.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index f5f042ea079eb..409271aa8dad4 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1212,7 +1212,7 @@ static void __add_hash_entry(struct ftrace_hash *hash, } static struct ftrace_func_entry * -add_hash_entry(struct ftrace_hash *hash, unsigned long ip) +add_hash_entry_direct(struct ftrace_hash *hash, unsigned long ip, unsigned long direct) { struct ftrace_func_entry *entry; @@ -1221,11 +1221,18 @@ add_hash_entry(struct ftrace_hash *hash, unsigned long ip) return NULL; entry->ip = ip; + entry->direct = direct; __add_hash_entry(hash, entry); return entry; } +static struct ftrace_func_entry * +add_hash_entry(struct ftrace_hash *hash, unsigned long ip) +{ + return add_hash_entry_direct(hash, ip, 0); +} + static void free_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) @@ -1398,7 +1405,7 @@ alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash) size = 1 << hash->size_bits; for (i = 0; i < size; i++) { hlist_for_each_entry(entry, &hash->buckets[i], hlist) { - if (add_hash_entry(new_hash, entry->ip) == NULL) + if (add_hash_entry_direct(new_hash, entry->ip, entry->direct) == NULL) goto free_hash; } } From 7583bb67566ddae48c3b28215f49443e76021b48 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:13:56 +0100 Subject: [PATCH 3/9] ftrace: Export some of hash related functions We are going to use these functions in following changes. Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 9 +++++++++ kernel/trace/ftrace.c | 7 +++---- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 41c9bb08d4e43..958dccc578142 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -82,6 +82,7 @@ static inline void early_trace_init(void) { } struct module; struct ftrace_hash; +struct ftrace_func_entry; #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \ defined(CONFIG_DYNAMIC_FTRACE) @@ -405,6 +406,14 @@ enum ftrace_ops_cmd { typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd); #ifdef CONFIG_DYNAMIC_FTRACE + +#define FTRACE_HASH_DEFAULT_BITS 10 + +struct ftrace_hash *alloc_ftrace_hash(int size_bits); +void free_ftrace_hash(struct ftrace_hash *hash); +struct ftrace_func_entry *add_hash_entry_direct(struct ftrace_hash *hash, + unsigned long ip, unsigned long direct); + /* The hash used to know what functions callbacks trace */ struct ftrace_ops_hash { struct ftrace_hash __rcu *notrace_hash; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 409271aa8dad4..46544788d7659 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -68,7 +68,6 @@ }) /* hash bits for specific function selection */ -#define FTRACE_HASH_DEFAULT_BITS 10 #define FTRACE_HASH_MAX_BITS 12 #ifdef CONFIG_DYNAMIC_FTRACE @@ -1211,7 +1210,7 @@ static void __add_hash_entry(struct ftrace_hash *hash, hash->count++; } -static struct ftrace_func_entry * +struct ftrace_func_entry * add_hash_entry_direct(struct ftrace_hash *hash, unsigned long ip, unsigned long direct) { struct ftrace_func_entry *entry; @@ -1291,7 +1290,7 @@ static void clear_ftrace_mod_list(struct list_head *head) mutex_unlock(&ftrace_lock); } -static void free_ftrace_hash(struct ftrace_hash *hash) +void free_ftrace_hash(struct ftrace_hash *hash) { if (!hash || hash == EMPTY_HASH) return; @@ -1331,7 +1330,7 @@ void ftrace_free_filter(struct ftrace_ops *ops) } EXPORT_SYMBOL_GPL(ftrace_free_filter); -static struct ftrace_hash *alloc_ftrace_hash(int size_bits) +struct ftrace_hash *alloc_ftrace_hash(int size_bits) { struct ftrace_hash *hash; int size; From 580fa00004c8b60aae5cb6d1c843827a9174aaa3 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:13:57 +0100 Subject: [PATCH 4/9] ftrace: Add update_ftrace_direct_add function Adding update_ftrace_direct_add function that adds all entries (ip -> addr) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current register_ftrace_direct is - hash argument that allows to register multiple ip -> direct entries at once - we can call update_ftrace_direct_add 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 --- include/linux/ftrace.h | 7 +++ kernel/trace/ftrace.c | 128 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 135 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 958dccc578142..0e45e910403bb 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -543,6 +543,8 @@ 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 update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash); + void ftrace_stub_direct_tramp(void); #else @@ -569,6 +571,11 @@ static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned l return -ENODEV; } +static inline int update_ftrace_direct_add(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 46544788d7659..3558dffe5f553 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6275,6 +6275,134 @@ 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 update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + struct ftrace_hash *old_direct_functions = NULL, *new_direct_functions; + struct ftrace_hash *old_filter_hash, *new_filter_hash = NULL; + struct ftrace_func_entry *entry; + int i, size, err = -EINVAL; + bool reg; + + if (!hash_count(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_lookup_ip(direct_functions, entry->ip)) + goto out_unlock; + } + } + + old_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(old_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; + new_filter_hash = hash_add(old_filter_hash, hash); + if (!new_filter_hash) + goto out_unlock; + + new_direct_functions = hash_add(direct_functions, hash); + if (!new_direct_functions) + goto out_unlock; + + old_direct_functions = direct_functions; + rcu_assign_pointer(direct_functions, new_direct_functions); + + if (reg) { + ops->func = call_direct_funcs; + ops->flags |= MULTI_FLAGS; + ops->trampoline = FTRACE_REGS_ADDR; + ops->local_hash.filter_hash = new_filter_hash; + + err = register_ftrace_function_nolock(ops); + if (err) { + /* restore old filter on error */ + ops->local_hash.filter_hash = old_filter_hash; + + /* cleanup for possible another register call */ + ops->func = NULL; + ops->trampoline = 0; + } else { + new_filter_hash = old_filter_hash; + } + } else { + err = ftrace_update_ops(ops, new_filter_hash, EMPTY_HASH); + /* + * new_filter_hash is dup-ed, so we need to release it anyway, + * old_filter_hash either stays on error or is already released + */ + } + + if (err) { + /* reset direct_functions and free the new one */ + rcu_assign_pointer(direct_functions, old_direct_functions); + old_direct_functions = new_direct_functions; + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (old_direct_functions && old_direct_functions != EMPTY_HASH) + call_rcu_tasks(&old_direct_functions->rcu, register_ftrace_direct_cb); + if (new_filter_hash) + free_ftrace_hash(new_filter_hash); + + return err; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** From 3014c7cfeb7fc4f738cf945f4daba8269bfbd1ab Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:13:58 +0100 Subject: [PATCH 5/9] ftrace: Add update_ftrace_direct_del function Adding update_ftrace_direct_del function that removes all entries (ip -> addr) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current unregister_ftrace_direct is - hash argument that allows to unregister multiple ip -> direct entries at once - we can call update_ftrace_direct_del multiple times on the same ftrace_ops object, becase we do not need to unregister all entries at once, we can do it gradualy with the help of ftrace_update_ops function This change will allow us to have simple ftrace_ops for all bpf direct interface users in following changes. Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 6 +++ kernel/trace/ftrace.c | 112 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 118 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 0e45e910403bb..62139c0cb43d2 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -544,6 +544,7 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash); +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash); void ftrace_stub_direct_tramp(void); @@ -576,6 +577,11 @@ static inline int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace return -ENODEV; } +static inline int update_ftrace_direct_del(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 3558dffe5f553..7e51688d78255 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6403,6 +6403,118 @@ int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) return err; } +/** + * hash_sub - substracts @b from @a 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_sub(struct ftrace_hash *a, struct ftrace_hash *b) +{ + struct ftrace_func_entry *entry, *del; + struct ftrace_hash *sub; + int size, i; + + sub = alloc_and_copy_ftrace_hash(a->size_bits, a); + if (!sub) + goto error; + + size = 1 << b->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + del = __ftrace_lookup_ip(sub, entry->ip); + if (WARN_ON_ONCE(!del)) + goto error; + remove_hash_entry(sub, del); + kfree(del); + } + } + return sub; + + error: + free_ftrace_hash(sub); + return NULL; +} + +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + struct ftrace_hash *old_direct_functions = NULL, *new_direct_functions; + struct ftrace_hash *old_filter_hash, *new_filter_hash = NULL; + struct ftrace_func_entry *del, *entry; + unsigned long size, i; + int err = -EINVAL; + + if (!hash_count(hash)) + return -EINVAL; + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + if (direct_functions == EMPTY_HASH) + return -EINVAL; + + mutex_lock(&direct_mutex); + + old_filter_hash = ops->func_hash ? ops->func_hash->filter_hash : NULL; + + if (!hash_count(old_filter_hash)) + goto out_unlock; + + /* Make sure requested entries are already registered. */ + size = 1 << hash->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + del = __ftrace_lookup_ip(direct_functions, entry->ip); + if (!del || del->direct != entry->direct) + goto out_unlock; + } + } + + err = -ENOMEM; + new_filter_hash = hash_sub(old_filter_hash, hash); + if (!new_filter_hash) + goto out_unlock; + + new_direct_functions = hash_sub(direct_functions, hash); + if (!new_direct_functions) + goto out_unlock; + + /* If there's nothing left, we need to unregister the ops. */ + if (ftrace_hash_empty(new_filter_hash)) { + err = unregister_ftrace_function(ops); + if (!err) { + /* cleanup for possible another register call */ + ops->func = NULL; + ops->trampoline = 0; + ftrace_free_filter(ops); + ops->func_hash->filter_hash = NULL; + } + } else { + err = ftrace_update_ops(ops, new_filter_hash, EMPTY_HASH); + /* + * new_filter_hash is dup-ed, so we need to release it anyway, + * old_filter_hash either stays on error or is already released + */ + } + + if (err) { + /* free the new_direct_functions */ + old_direct_functions = new_direct_functions; + } else { + rcu_assign_pointer(direct_functions, new_direct_functions); + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (old_direct_functions && old_direct_functions != EMPTY_HASH) + call_rcu_tasks(&old_direct_functions->rcu, register_ftrace_direct_cb); + free_ftrace_hash(new_filter_hash); + + return err; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** From 17b6964ba9f509fb0f978d64a2423e8a370742bd Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:13:59 +0100 Subject: [PATCH 6/9] ftrace: Add update_ftrace_direct_mod function Adding update_ftrace_direct_mod function that modifies all entries (ip -> direct) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current modify_ftrace_direct is: - hash argument that allows to modify multiple ip -> direct entries at once This change will allow us to have simple ftrace_ops for all bpf direct interface users in following changes. Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 6 ++++ kernel/trace/ftrace.c | 72 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 78 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 62139c0cb43d2..d4bb5d3e01f12 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -545,6 +545,7 @@ int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash); int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash); +int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock); void ftrace_stub_direct_tramp(void); @@ -582,6 +583,11 @@ static inline int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace return -ENODEV; } +static inline int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock) +{ + 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 7e51688d78255..da6087fe07d3a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6515,6 +6515,78 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) return err; } +int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock) +{ + struct ftrace_func_entry *entry, *tmp; + static struct ftrace_ops tmp_ops = { + .func = ftrace_stub, + .flags = FTRACE_OPS_FL_STUB, + }; + struct ftrace_hash *orig_hash; + unsigned long size, i; + int err = -EINVAL; + + if (!hash_count(hash)) + return -EINVAL; + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + if (direct_functions == EMPTY_HASH) + return -EINVAL; + + if (do_direct_lock) + mutex_lock(&direct_mutex); + + orig_hash = ops->func_hash ? ops->func_hash->filter_hash : NULL; + if (!orig_hash) + goto unlock; + + /* 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; + + err = register_ftrace_function_nolock(&tmp_ops); + if (err) + goto unlock; + + /* + * Call __ftrace_hash_update_ipmodify() here, so that we can call + * ops->ops_func for the ops. This is needed because the above + * register_ftrace_function_nolock() worked on tmp_ops. + */ + err = __ftrace_hash_update_ipmodify(ops, orig_hash, orig_hash, true); + if (err) + goto out; + + /* + * 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); + + size = 1 << hash->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + tmp = __ftrace_lookup_ip(direct_functions, entry->ip); + if (!tmp) + continue; + tmp->direct = entry->direct; + } + } + + mutex_unlock(&ftrace_lock); + +out: + /* Removing the tmp_ops will add the updated direct callers to the functions */ + unregister_ftrace_function(&tmp_ops); + +unlock: + if (do_direct_lock) + mutex_unlock(&direct_mutex); + return err; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** From 27170c86a67cae9010f9ac34c961d8d154c7a21c Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:14:00 +0100 Subject: [PATCH 7/9] bpf: Add trampoline ip hash table Following changes need to lookup trampoline based on its ip address, adding hash table for that. Signed-off-by: Jiri Olsa --- include/linux/bpf.h | 7 +++++-- kernel/bpf/trampoline.c | 30 +++++++++++++++++++----------- 2 files changed, 24 insertions(+), 13 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index bb3847caeae11..b2295fd708603 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1309,14 +1309,17 @@ struct bpf_tramp_image { }; struct bpf_trampoline { - /* hlist for trampoline_table */ - struct hlist_node hlist; + /* hlist for trampoline_key_table */ + struct hlist_node hlist_key; + /* hlist for trampoline_ip_table */ + struct hlist_node hlist_ip; struct ftrace_ops *fops; /* serializes access to fields of this trampoline */ struct mutex mutex; refcount_t refcnt; u32 flags; u64 key; + unsigned long ip; struct { struct btf_func_model model; void *addr; diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index b9a358d7a78f1..f298bafab76e3 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -24,9 +24,10 @@ const struct bpf_prog_ops bpf_extension_prog_ops = { #define TRAMPOLINE_HASH_BITS 10 #define TRAMPOLINE_TABLE_SIZE (1 << TRAMPOLINE_HASH_BITS) -static struct hlist_head trampoline_table[TRAMPOLINE_TABLE_SIZE]; +static struct hlist_head trampoline_key_table[TRAMPOLINE_TABLE_SIZE]; +static struct hlist_head trampoline_ip_table[TRAMPOLINE_TABLE_SIZE]; -/* serializes access to trampoline_table */ +/* serializes access to trampoline tables */ static DEFINE_MUTEX(trampoline_mutex); #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS @@ -135,15 +136,15 @@ void bpf_image_ksym_del(struct bpf_ksym *ksym) PAGE_SIZE, true, ksym->name); } -static struct bpf_trampoline *bpf_trampoline_lookup(u64 key) +static struct bpf_trampoline *bpf_trampoline_lookup(u64 key, unsigned long ip) { struct bpf_trampoline *tr; struct hlist_head *head; int i; mutex_lock(&trampoline_mutex); - head = &trampoline_table[hash_64(key, TRAMPOLINE_HASH_BITS)]; - hlist_for_each_entry(tr, head, hlist) { + head = &trampoline_key_table[hash_64(key, TRAMPOLINE_HASH_BITS)]; + hlist_for_each_entry(tr, head, hlist_key) { if (tr->key == key) { refcount_inc(&tr->refcnt); goto out; @@ -164,8 +165,12 @@ static struct bpf_trampoline *bpf_trampoline_lookup(u64 key) #endif tr->key = key; - INIT_HLIST_NODE(&tr->hlist); - hlist_add_head(&tr->hlist, head); + tr->ip = ftrace_location(ip); + INIT_HLIST_NODE(&tr->hlist_key); + INIT_HLIST_NODE(&tr->hlist_ip); + hlist_add_head(&tr->hlist_key, head); + head = &trampoline_ip_table[hash_64(tr->ip, TRAMPOLINE_HASH_BITS)]; + hlist_add_head(&tr->hlist_ip, head); refcount_set(&tr->refcnt, 1); mutex_init(&tr->mutex); for (i = 0; i < BPF_TRAMP_MAX; i++) @@ -846,7 +851,7 @@ void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog) prog->aux->attach_btf_id); bpf_lsm_find_cgroup_shim(prog, &bpf_func); - tr = bpf_trampoline_lookup(key); + tr = bpf_trampoline_lookup(key, 0); if (WARN_ON_ONCE(!tr)) return; @@ -866,7 +871,7 @@ struct bpf_trampoline *bpf_trampoline_get(u64 key, { struct bpf_trampoline *tr; - tr = bpf_trampoline_lookup(key); + tr = bpf_trampoline_lookup(key, tgt_info->tgt_addr); if (!tr) return NULL; @@ -902,7 +907,8 @@ void bpf_trampoline_put(struct bpf_trampoline *tr) * fexit progs. The fentry-only trampoline will be freed via * multiple rcu callbacks. */ - hlist_del(&tr->hlist); + hlist_del(&tr->hlist_key); + hlist_del(&tr->hlist_ip); if (tr->fops) { ftrace_free_filter(tr->fops); kfree(tr->fops); @@ -1175,7 +1181,9 @@ static int __init init_trampolines(void) int i; for (i = 0; i < TRAMPOLINE_TABLE_SIZE; i++) - INIT_HLIST_HEAD(&trampoline_table[i]); + INIT_HLIST_HEAD(&trampoline_key_table[i]); + for (i = 0; i < TRAMPOLINE_TABLE_SIZE; i++) + INIT_HLIST_HEAD(&trampoline_ip_table[i]); return 0; } late_initcall(init_trampolines); From 8859ac653abb62ef4123e714868dafb38589c544 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:14:01 +0100 Subject: [PATCH 8/9] ftrace: Factor ftrace_ops ops_func interface We are going to remove "ftrace_ops->private == bpf_trampoline" setup in following changes. Adding ip argument to ftrace_ops_func_t callback function, so we can use it to look up the trampoline. Signed-off-by: Jiri Olsa Acked-by: Steven Rostedt (Google) --- include/linux/ftrace.h | 2 +- kernel/bpf/trampoline.c | 3 ++- kernel/trace/ftrace.c | 6 +++--- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index d4bb5d3e01f12..9f19a3a2d7e01 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -403,7 +403,7 @@ enum ftrace_ops_cmd { * Negative on failure. The return value is dependent on the * callback. */ -typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd); +typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, unsigned long ip, enum ftrace_ops_cmd cmd); #ifdef CONFIG_DYNAMIC_FTRACE diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index f298bafab76e3..17af2aad83825 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -33,7 +33,8 @@ static DEFINE_MUTEX(trampoline_mutex); #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex); -static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, enum ftrace_ops_cmd cmd) +static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, unsigned long ip, + enum ftrace_ops_cmd cmd) { struct bpf_trampoline *tr = ops->private; int ret = 0; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index da6087fe07d3a..b6d195796d4b0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2075,7 +2075,7 @@ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, */ if (!ops->ops_func) return -EBUSY; - ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF); + ret = ops->ops_func(ops, rec->ip, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF); if (ret) return ret; } else if (is_ipmodify) { @@ -9009,7 +9009,7 @@ static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops) if (!op->ops_func) return -EBUSY; - ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER); + ret = op->ops_func(op, ip, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER); if (ret) return ret; } @@ -9056,7 +9056,7 @@ static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops) /* The cleanup is optional, ignore any errors */ if (found_op && op->ops_func) - op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER); + op->ops_func(op, ip, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER); } } mutex_unlock(&direct_mutex); From b0a551b3472d3f4a1a25882493f30c995aaf7dad Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 15 Dec 2025 22:14:02 +0100 Subject: [PATCH 9/9] bpf,x86: Use single ftrace_ops for direct calls Using single ftrace_ops for direct calls update instead of allocating ftrace_ops object for each trampoline. With single ftrace_ops object we can use update_ftrace_direct_* api that allows multiple ip sites updates on single ftrace_ops object. Adding HAVE_SINGLE_FTRACE_DIRECT_OPS config option to be enabled on each arch that supports this. At the moment we can enable this only on x86 arch, because arm relies on ftrace_ops object representing just single trampoline image (stored in ftrace_ops::direct_call). Ach that do not support this will continue to use *_ftrace_direct api. Signed-off-by: Jiri Olsa --- arch/x86/Kconfig | 1 + kernel/bpf/trampoline.c | 195 ++++++++++++++++++++++++++++++++++------ kernel/trace/Kconfig | 3 + kernel/trace/ftrace.c | 7 +- 4 files changed, 177 insertions(+), 29 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 80527299f859a..53bf2cf7ff6ff 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -336,6 +336,7 @@ config X86 select SCHED_SMT if SMP select ARCH_SUPPORTS_SCHED_CLUSTER if SMP select ARCH_SUPPORTS_SCHED_MC if SMP + select HAVE_SINGLE_FTRACE_DIRECT_OPS if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS config INSTRUCTION_DECODER def_bool y diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 17af2aad83825..02371db3db3ed 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -33,12 +33,40 @@ static DEFINE_MUTEX(trampoline_mutex); #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex); +#ifdef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS +static struct bpf_trampoline *direct_ops_ip_lookup(struct ftrace_ops *ops, unsigned long ip) +{ + struct hlist_head *head_ip; + struct bpf_trampoline *tr; + + mutex_lock(&trampoline_mutex); + head_ip = &trampoline_ip_table[hash_64(ip, TRAMPOLINE_HASH_BITS)]; + hlist_for_each_entry(tr, head_ip, hlist_ip) { + if (tr->ip == ip) + goto out; + } + tr = NULL; +out: + mutex_unlock(&trampoline_mutex); + return tr; +} +#else +static struct bpf_trampoline *direct_ops_ip_lookup(struct ftrace_ops *ops, unsigned long ip) +{ + return ops->private; +} +#endif /* CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS */ + static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, unsigned long ip, enum ftrace_ops_cmd cmd) { - struct bpf_trampoline *tr = ops->private; + struct bpf_trampoline *tr; int ret = 0; + tr = direct_ops_ip_lookup(ops, ip); + if (!tr) + return -EINVAL; + if (cmd == FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF) { /* This is called inside register_ftrace_direct_multi(), so * tr->mutex is already locked. @@ -137,6 +165,139 @@ void bpf_image_ksym_del(struct bpf_ksym *ksym) PAGE_SIZE, true, ksym->name); } +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +#ifdef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS +/* + * We have only single direct_ops which contains all the direct call + * sites and is the only global ftrace_ops for all trampolines. + * + * We use 'update_ftrace_direct_*' api for attachment. + */ +struct ftrace_ops direct_ops = { + .ops_func = bpf_tramp_ftrace_ops_func, +}; + +static int direct_ops_alloc(struct bpf_trampoline *tr) +{ + tr->fops = &direct_ops; + return 0; +} + +static void direct_ops_free(struct bpf_trampoline *tr) { } + +static struct ftrace_hash *hash_from_ip(struct bpf_trampoline *tr, void *ptr) +{ + unsigned long ip, addr = (unsigned long) ptr; + struct ftrace_hash *hash; + + ip = ftrace_location(tr->ip); + if (!ip) + return NULL; + hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); + if (!hash) + return NULL; + if (bpf_trampoline_use_jmp(tr->flags)) + addr = ftrace_jmp_set(addr); + if (!add_hash_entry_direct(hash, ip, addr)) { + free_ftrace_hash(hash); + return NULL; + } + return hash; +} + +static int direct_ops_add(struct bpf_trampoline *tr, void *addr) +{ + struct ftrace_hash *hash = hash_from_ip(tr, addr); + int err = -ENOMEM; + + if (hash) + err = update_ftrace_direct_add(tr->fops, hash); + free_ftrace_hash(hash); + return err; +} + +static int direct_ops_del(struct bpf_trampoline *tr, void *addr) +{ + struct ftrace_hash *hash = hash_from_ip(tr, addr); + int err = -ENOMEM; + + if (hash) + err = update_ftrace_direct_del(tr->fops, hash); + free_ftrace_hash(hash); + return err; +} + +static int direct_ops_mod(struct bpf_trampoline *tr, void *addr, bool lock_direct_mutex) +{ + struct ftrace_hash *hash = hash_from_ip(tr, addr); + int err = -ENOMEM; + + if (hash) + err = update_ftrace_direct_mod(tr->fops, hash, lock_direct_mutex); + free_ftrace_hash(hash); + return err; +} +#else +/* + * We allocate ftrace_ops object for each trampoline and it contains + * call site specific for that trampoline. + * + * We use *_ftrace_direct api for attachment. + */ +static int direct_ops_alloc(struct bpf_trampoline *tr) +{ + tr->fops = kzalloc(sizeof(struct ftrace_ops), GFP_KERNEL); + if (!tr->fops) + return -ENOMEM; + tr->fops->private = tr; + tr->fops->ops_func = bpf_tramp_ftrace_ops_func; + return 0; +} + +static void direct_ops_free(struct bpf_trampoline *tr) +{ + if (tr->fops) { + ftrace_free_filter(tr->fops); + kfree(tr->fops); + } +} + +static int direct_ops_add(struct bpf_trampoline *tr, void *ptr) +{ + unsigned long addr = (unsigned long) ptr; + struct ftrace_ops *ops = tr->fops; + int ret; + + if (bpf_trampoline_use_jmp(tr->flags)) + addr = ftrace_jmp_set(addr); + + ret = ftrace_set_filter_ip(ops, tr->ip, 0, 1); + if (ret) + return ret; + return register_ftrace_direct(ops, addr); +} + +static int direct_ops_del(struct bpf_trampoline *tr, void *addr) +{ + return unregister_ftrace_direct(tr->fops, (long)addr, false); +} + +static int direct_ops_mod(struct bpf_trampoline *tr, void *ptr, bool lock_direct_mutex) +{ + unsigned long addr = (unsigned long) ptr; + struct ftrace_ops *ops = tr->fops; + + if (bpf_trampoline_use_jmp(tr->flags)) + addr = ftrace_jmp_set(addr); + if (lock_direct_mutex) + return modify_ftrace_direct(ops, addr); + return modify_ftrace_direct_nolock(ops, addr); +} +#endif /* CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS */ +#else +static void direct_ops_free(struct bpf_trampoline *tr) { } +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ + static struct bpf_trampoline *bpf_trampoline_lookup(u64 key, unsigned long ip) { struct bpf_trampoline *tr; @@ -155,14 +316,11 @@ static struct bpf_trampoline *bpf_trampoline_lookup(u64 key, unsigned long ip) if (!tr) goto out; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS - tr->fops = kzalloc(sizeof(struct ftrace_ops), GFP_KERNEL); - if (!tr->fops) { + if (direct_ops_alloc(tr)) { kfree(tr); tr = NULL; goto out; } - tr->fops->private = tr; - tr->fops->ops_func = bpf_tramp_ftrace_ops_func; #endif tr->key = key; @@ -206,7 +364,7 @@ static int unregister_fentry(struct bpf_trampoline *tr, u32 orig_flags, int ret; if (tr->func.ftrace_managed) - ret = unregister_ftrace_direct(tr->fops, (long)old_addr, false); + ret = direct_ops_del(tr, old_addr); else ret = bpf_trampoline_update_fentry(tr, orig_flags, old_addr, NULL); @@ -220,15 +378,7 @@ static int modify_fentry(struct bpf_trampoline *tr, u32 orig_flags, int ret; if (tr->func.ftrace_managed) { - unsigned long addr = (unsigned long) new_addr; - - if (bpf_trampoline_use_jmp(tr->flags)) - addr = ftrace_jmp_set(addr); - - if (lock_direct_mutex) - ret = modify_ftrace_direct(tr->fops, addr); - else - ret = modify_ftrace_direct_nolock(tr->fops, addr); + ret = direct_ops_mod(tr, new_addr, lock_direct_mutex); } else { ret = bpf_trampoline_update_fentry(tr, orig_flags, old_addr, new_addr); @@ -251,15 +401,7 @@ static int register_fentry(struct bpf_trampoline *tr, void *new_addr) } if (tr->func.ftrace_managed) { - unsigned long addr = (unsigned long) new_addr; - - if (bpf_trampoline_use_jmp(tr->flags)) - addr = ftrace_jmp_set(addr); - - ret = ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 1); - if (ret) - return ret; - ret = register_ftrace_direct(tr->fops, addr); + ret = direct_ops_add(tr, new_addr); } else { ret = bpf_trampoline_update_fentry(tr, 0, NULL, new_addr); } @@ -910,10 +1052,7 @@ void bpf_trampoline_put(struct bpf_trampoline *tr) */ hlist_del(&tr->hlist_key); hlist_del(&tr->hlist_ip); - if (tr->fops) { - ftrace_free_filter(tr->fops); - kfree(tr->fops); - } + direct_ops_free(tr); kfree(tr); out: mutex_unlock(&trampoline_mutex); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index bfa2ec46e0752..d7042a09fe469 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -50,6 +50,9 @@ config HAVE_DYNAMIC_FTRACE_WITH_REGS config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS bool +config HAVE_SINGLE_FTRACE_DIRECT_OPS + bool + config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS bool diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b6d195796d4b0..90790e015f80f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2631,8 +2631,13 @@ unsigned long ftrace_find_rec_direct(unsigned long ip) static void call_direct_funcs(unsigned long ip, unsigned long pip, struct ftrace_ops *ops, struct ftrace_regs *fregs) { - unsigned long addr = READ_ONCE(ops->direct_call); + unsigned long addr; +#ifdef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS + addr = ftrace_find_rec_direct(ip); +#else + addr = READ_ONCE(ops->direct_call); +#endif if (!addr) return;