1fec56f58SAlexei Starovoitov // SPDX-License-Identifier: GPL-2.0-only 2fec56f58SAlexei Starovoitov /* Copyright (c) 2019 Facebook */ 3fec56f58SAlexei Starovoitov #include <linux/hash.h> 4fec56f58SAlexei Starovoitov #include <linux/bpf.h> 5fec56f58SAlexei Starovoitov #include <linux/filter.h> 6b91e014fSAlexei Starovoitov #include <linux/ftrace.h> 7e9b4e606SJiri Olsa #include <linux/rbtree_latch.h> 8a108f7dcSJiri Olsa #include <linux/perf_event.h> 99e4e01dfSKP Singh #include <linux/btf.h> 101e6c62a8SAlexei Starovoitov #include <linux/rcupdate_trace.h> 111e6c62a8SAlexei Starovoitov #include <linux/rcupdate_wait.h> 12856c02dbSSong Liu #include <linux/static_call.h> 1369fd337aSStanislav Fomichev #include <linux/bpf_verifier.h> 1469fd337aSStanislav Fomichev #include <linux/bpf_lsm.h> 1500963a2eSSong Liu #include <linux/delay.h> 16fec56f58SAlexei Starovoitov 17be8704ffSAlexei Starovoitov /* dummy _ops. The verifier will operate on target program's ops. */ 18be8704ffSAlexei Starovoitov const struct bpf_verifier_ops bpf_extension_verifier_ops = { 19be8704ffSAlexei Starovoitov }; 20be8704ffSAlexei Starovoitov const struct bpf_prog_ops bpf_extension_prog_ops = { 21be8704ffSAlexei Starovoitov }; 22be8704ffSAlexei Starovoitov 23fec56f58SAlexei Starovoitov /* btf_vmlinux has ~22k attachable functions. 1k htab is enough. */ 24fec56f58SAlexei Starovoitov #define TRAMPOLINE_HASH_BITS 10 25fec56f58SAlexei Starovoitov #define TRAMPOLINE_TABLE_SIZE (1 << TRAMPOLINE_HASH_BITS) 26fec56f58SAlexei Starovoitov 27fec56f58SAlexei Starovoitov static struct hlist_head trampoline_table[TRAMPOLINE_TABLE_SIZE]; 28fec56f58SAlexei Starovoitov 297ac88ebaSJiri Olsa /* serializes access to trampoline_table */ 30fec56f58SAlexei Starovoitov static DEFINE_MUTEX(trampoline_mutex); 31fec56f58SAlexei Starovoitov 3200963a2eSSong Liu #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 3300963a2eSSong Liu static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex); 3400963a2eSSong Liu 3500963a2eSSong Liu static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, enum ftrace_ops_cmd cmd) 3600963a2eSSong Liu { 3700963a2eSSong Liu struct bpf_trampoline *tr = ops->private; 3800963a2eSSong Liu int ret = 0; 3900963a2eSSong Liu 4000963a2eSSong Liu if (cmd == FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF) { 4100963a2eSSong Liu /* This is called inside register_ftrace_direct_multi(), so 4200963a2eSSong Liu * tr->mutex is already locked. 4300963a2eSSong Liu */ 4400963a2eSSong Liu lockdep_assert_held_once(&tr->mutex); 4500963a2eSSong Liu 4600963a2eSSong Liu /* Instead of updating the trampoline here, we propagate 47da8bdfbdSFlorent Revest * -EAGAIN to register_ftrace_direct(). Then we can 48da8bdfbdSFlorent Revest * retry register_ftrace_direct() after updating the 4900963a2eSSong Liu * trampoline. 5000963a2eSSong Liu */ 5100963a2eSSong Liu if ((tr->flags & BPF_TRAMP_F_CALL_ORIG) && 5200963a2eSSong Liu !(tr->flags & BPF_TRAMP_F_ORIG_STACK)) { 5300963a2eSSong Liu if (WARN_ON_ONCE(tr->flags & BPF_TRAMP_F_SHARE_IPMODIFY)) 5400963a2eSSong Liu return -EBUSY; 5500963a2eSSong Liu 5600963a2eSSong Liu tr->flags |= BPF_TRAMP_F_SHARE_IPMODIFY; 5700963a2eSSong Liu return -EAGAIN; 5800963a2eSSong Liu } 5900963a2eSSong Liu 6000963a2eSSong Liu return 0; 6100963a2eSSong Liu } 6200963a2eSSong Liu 6300963a2eSSong Liu /* The normal locking order is 6400963a2eSSong Liu * tr->mutex => direct_mutex (ftrace.c) => ftrace_lock (ftrace.c) 6500963a2eSSong Liu * 6600963a2eSSong Liu * The following two commands are called from 6700963a2eSSong Liu * 6800963a2eSSong Liu * prepare_direct_functions_for_ipmodify 6900963a2eSSong Liu * cleanup_direct_functions_after_ipmodify 7000963a2eSSong Liu * 7100963a2eSSong Liu * In both cases, direct_mutex is already locked. Use 7200963a2eSSong Liu * mutex_trylock(&tr->mutex) to avoid deadlock in race condition 7300963a2eSSong Liu * (something else is making changes to this same trampoline). 7400963a2eSSong Liu */ 7500963a2eSSong Liu if (!mutex_trylock(&tr->mutex)) { 7600963a2eSSong Liu /* sleep 1 ms to make sure whatever holding tr->mutex makes 7700963a2eSSong Liu * some progress. 7800963a2eSSong Liu */ 7900963a2eSSong Liu msleep(1); 8000963a2eSSong Liu return -EAGAIN; 8100963a2eSSong Liu } 8200963a2eSSong Liu 8300963a2eSSong Liu switch (cmd) { 8400963a2eSSong Liu case FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER: 8500963a2eSSong Liu tr->flags |= BPF_TRAMP_F_SHARE_IPMODIFY; 8600963a2eSSong Liu 8700963a2eSSong Liu if ((tr->flags & BPF_TRAMP_F_CALL_ORIG) && 8800963a2eSSong Liu !(tr->flags & BPF_TRAMP_F_ORIG_STACK)) 8900963a2eSSong Liu ret = bpf_trampoline_update(tr, false /* lock_direct_mutex */); 9000963a2eSSong Liu break; 9100963a2eSSong Liu case FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER: 9200963a2eSSong Liu tr->flags &= ~BPF_TRAMP_F_SHARE_IPMODIFY; 9300963a2eSSong Liu 9400963a2eSSong Liu if (tr->flags & BPF_TRAMP_F_ORIG_STACK) 9500963a2eSSong Liu ret = bpf_trampoline_update(tr, false /* lock_direct_mutex */); 9600963a2eSSong Liu break; 9700963a2eSSong Liu default: 9800963a2eSSong Liu ret = -EINVAL; 9900963a2eSSong Liu break; 10014250fa4SYang Li } 10100963a2eSSong Liu 10200963a2eSSong Liu mutex_unlock(&tr->mutex); 10300963a2eSSong Liu return ret; 10400963a2eSSong Liu } 10500963a2eSSong Liu #endif 10600963a2eSSong Liu 107f92c1e18SJiri Olsa bool bpf_prog_has_trampoline(const struct bpf_prog *prog) 108f92c1e18SJiri Olsa { 109f92c1e18SJiri Olsa enum bpf_attach_type eatype = prog->expected_attach_type; 1102fcc8241SKui-Feng Lee enum bpf_prog_type ptype = prog->type; 111f92c1e18SJiri Olsa 1122fcc8241SKui-Feng Lee return (ptype == BPF_PROG_TYPE_TRACING && 1132fcc8241SKui-Feng Lee (eatype == BPF_TRACE_FENTRY || eatype == BPF_TRACE_FEXIT || 1142fcc8241SKui-Feng Lee eatype == BPF_MODIFY_RETURN)) || 1152fcc8241SKui-Feng Lee (ptype == BPF_PROG_TYPE_LSM && eatype == BPF_LSM_MAC); 116f92c1e18SJiri Olsa } 117f92c1e18SJiri Olsa 11826ef208cSSong Liu void bpf_image_ksym_add(void *data, unsigned int size, struct bpf_ksym *ksym) 119a108f7dcSJiri Olsa { 120a108f7dcSJiri Olsa ksym->start = (unsigned long) data; 12126ef208cSSong Liu ksym->end = ksym->start + size; 122a108f7dcSJiri Olsa bpf_ksym_add(ksym); 123a108f7dcSJiri Olsa perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start, 1247ac88ebaSJiri Olsa PAGE_SIZE, false, ksym->name); 125a108f7dcSJiri Olsa } 126a108f7dcSJiri Olsa 127a108f7dcSJiri Olsa void bpf_image_ksym_del(struct bpf_ksym *ksym) 128a108f7dcSJiri Olsa { 129a108f7dcSJiri Olsa bpf_ksym_del(ksym); 130a108f7dcSJiri Olsa perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start, 1317ac88ebaSJiri Olsa PAGE_SIZE, true, ksym->name); 132a108f7dcSJiri Olsa } 133a108f7dcSJiri Olsa 134f7b12b6fSToke Høiland-Jørgensen static struct bpf_trampoline *bpf_trampoline_lookup(u64 key) 135fec56f58SAlexei Starovoitov { 136fec56f58SAlexei Starovoitov struct bpf_trampoline *tr; 137fec56f58SAlexei Starovoitov struct hlist_head *head; 138fec56f58SAlexei Starovoitov int i; 139fec56f58SAlexei Starovoitov 140fec56f58SAlexei Starovoitov mutex_lock(&trampoline_mutex); 141fec56f58SAlexei Starovoitov head = &trampoline_table[hash_64(key, TRAMPOLINE_HASH_BITS)]; 142fec56f58SAlexei Starovoitov hlist_for_each_entry(tr, head, hlist) { 143fec56f58SAlexei Starovoitov if (tr->key == key) { 144fec56f58SAlexei Starovoitov refcount_inc(&tr->refcnt); 145fec56f58SAlexei Starovoitov goto out; 146fec56f58SAlexei Starovoitov } 147fec56f58SAlexei Starovoitov } 148fec56f58SAlexei Starovoitov tr = kzalloc(sizeof(*tr), GFP_KERNEL); 149fec56f58SAlexei Starovoitov if (!tr) 150fec56f58SAlexei Starovoitov goto out; 15100963a2eSSong Liu #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 15200963a2eSSong Liu tr->fops = kzalloc(sizeof(struct ftrace_ops), GFP_KERNEL); 15300963a2eSSong Liu if (!tr->fops) { 15400963a2eSSong Liu kfree(tr); 15500963a2eSSong Liu tr = NULL; 15600963a2eSSong Liu goto out; 15700963a2eSSong Liu } 15800963a2eSSong Liu tr->fops->private = tr; 15900963a2eSSong Liu tr->fops->ops_func = bpf_tramp_ftrace_ops_func; 16000963a2eSSong Liu #endif 161fec56f58SAlexei Starovoitov 162fec56f58SAlexei Starovoitov tr->key = key; 163fec56f58SAlexei Starovoitov INIT_HLIST_NODE(&tr->hlist); 164fec56f58SAlexei Starovoitov hlist_add_head(&tr->hlist, head); 165fec56f58SAlexei Starovoitov refcount_set(&tr->refcnt, 1); 166fec56f58SAlexei Starovoitov mutex_init(&tr->mutex); 167fec56f58SAlexei Starovoitov for (i = 0; i < BPF_TRAMP_MAX; i++) 168fec56f58SAlexei Starovoitov INIT_HLIST_HEAD(&tr->progs_hlist[i]); 169fec56f58SAlexei Starovoitov out: 170fec56f58SAlexei Starovoitov mutex_unlock(&trampoline_mutex); 171fec56f58SAlexei Starovoitov return tr; 172fec56f58SAlexei Starovoitov } 173fec56f58SAlexei Starovoitov 174b91e014fSAlexei Starovoitov static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr) 175b91e014fSAlexei Starovoitov { 176b91e014fSAlexei Starovoitov void *ip = tr->func.addr; 177b91e014fSAlexei Starovoitov int ret; 178b91e014fSAlexei Starovoitov 179b91e014fSAlexei Starovoitov if (tr->func.ftrace_managed) 180da8bdfbdSFlorent Revest ret = unregister_ftrace_direct(tr->fops, (long)old_addr, false); 181b91e014fSAlexei Starovoitov else 182b91e014fSAlexei Starovoitov ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, NULL); 183861de02eSJiri Olsa 184b91e014fSAlexei Starovoitov return ret; 185b91e014fSAlexei Starovoitov } 186b91e014fSAlexei Starovoitov 18700963a2eSSong Liu static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_addr, 18800963a2eSSong Liu bool lock_direct_mutex) 189b91e014fSAlexei Starovoitov { 190b91e014fSAlexei Starovoitov void *ip = tr->func.addr; 191b91e014fSAlexei Starovoitov int ret; 192b91e014fSAlexei Starovoitov 19300963a2eSSong Liu if (tr->func.ftrace_managed) { 19400963a2eSSong Liu if (lock_direct_mutex) 195da8bdfbdSFlorent Revest ret = modify_ftrace_direct(tr->fops, (long)new_addr); 196b91e014fSAlexei Starovoitov else 197da8bdfbdSFlorent Revest ret = modify_ftrace_direct_nolock(tr->fops, (long)new_addr); 19800963a2eSSong Liu } else { 199b91e014fSAlexei Starovoitov ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, new_addr); 20000963a2eSSong Liu } 201b91e014fSAlexei Starovoitov return ret; 202b91e014fSAlexei Starovoitov } 203b91e014fSAlexei Starovoitov 204b91e014fSAlexei Starovoitov /* first time registering */ 205b91e014fSAlexei Starovoitov static int register_fentry(struct bpf_trampoline *tr, void *new_addr) 206b91e014fSAlexei Starovoitov { 207b91e014fSAlexei Starovoitov void *ip = tr->func.addr; 208aebfd125SPeter Zijlstra unsigned long faddr; 209b91e014fSAlexei Starovoitov int ret; 210b91e014fSAlexei Starovoitov 211aebfd125SPeter Zijlstra faddr = ftrace_location((unsigned long)ip); 2123b317abcSXu Kuohai if (faddr) { 2133b317abcSXu Kuohai if (!tr->fops) 2143b317abcSXu Kuohai return -ENOTSUPP; 215aebfd125SPeter Zijlstra tr->func.ftrace_managed = true; 2163b317abcSXu Kuohai } 217b91e014fSAlexei Starovoitov 21800963a2eSSong Liu if (tr->func.ftrace_managed) { 219dc81f8d1SSong Liu ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 1); 220da8bdfbdSFlorent Revest ret = register_ftrace_direct(tr->fops, (long)new_addr); 22100963a2eSSong Liu } else { 222b91e014fSAlexei Starovoitov ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, NULL, new_addr); 22300963a2eSSong Liu } 224861de02eSJiri Olsa 225b91e014fSAlexei Starovoitov return ret; 226b91e014fSAlexei Starovoitov } 227b91e014fSAlexei Starovoitov 228f7e0beafSKui-Feng Lee static struct bpf_tramp_links * 2291e37392cSJiri Olsa bpf_trampoline_get_progs(const struct bpf_trampoline *tr, int *total, bool *ip_arg) 23088fd9e53SKP Singh { 231f7e0beafSKui-Feng Lee struct bpf_tramp_link *link; 232f7e0beafSKui-Feng Lee struct bpf_tramp_links *tlinks; 233f7e0beafSKui-Feng Lee struct bpf_tramp_link **links; 23488fd9e53SKP Singh int kind; 23588fd9e53SKP Singh 23688fd9e53SKP Singh *total = 0; 237f7e0beafSKui-Feng Lee tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL); 238f7e0beafSKui-Feng Lee if (!tlinks) 23988fd9e53SKP Singh return ERR_PTR(-ENOMEM); 24088fd9e53SKP Singh 24188fd9e53SKP Singh for (kind = 0; kind < BPF_TRAMP_MAX; kind++) { 242f7e0beafSKui-Feng Lee tlinks[kind].nr_links = tr->progs_cnt[kind]; 24388fd9e53SKP Singh *total += tr->progs_cnt[kind]; 244f7e0beafSKui-Feng Lee links = tlinks[kind].links; 24588fd9e53SKP Singh 246f7e0beafSKui-Feng Lee hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) { 247f7e0beafSKui-Feng Lee *ip_arg |= link->link.prog->call_get_func_ip; 248f7e0beafSKui-Feng Lee *links++ = link; 24988fd9e53SKP Singh } 2501e37392cSJiri Olsa } 251f7e0beafSKui-Feng Lee return tlinks; 25288fd9e53SKP Singh } 253fec56f58SAlexei Starovoitov 254108598c3SYafang Shao static void bpf_tramp_image_free(struct bpf_tramp_image *im) 255e21aa341SAlexei Starovoitov { 256e21aa341SAlexei Starovoitov bpf_image_ksym_del(&im->ksym); 25726ef208cSSong Liu arch_free_bpf_trampoline(im->image, im->size); 25826ef208cSSong Liu bpf_jit_uncharge_modmem(im->size); 259e21aa341SAlexei Starovoitov percpu_ref_exit(&im->pcref); 260e21aa341SAlexei Starovoitov kfree_rcu(im, rcu); 261e21aa341SAlexei Starovoitov } 262e21aa341SAlexei Starovoitov 263108598c3SYafang Shao static void __bpf_tramp_image_put_deferred(struct work_struct *work) 264108598c3SYafang Shao { 265108598c3SYafang Shao struct bpf_tramp_image *im; 266108598c3SYafang Shao 267108598c3SYafang Shao im = container_of(work, struct bpf_tramp_image, work); 268108598c3SYafang Shao bpf_tramp_image_free(im); 269108598c3SYafang Shao } 270108598c3SYafang Shao 271e21aa341SAlexei Starovoitov /* callback, fexit step 3 or fentry step 2 */ 272e21aa341SAlexei Starovoitov static void __bpf_tramp_image_put_rcu(struct rcu_head *rcu) 273e21aa341SAlexei Starovoitov { 274e21aa341SAlexei Starovoitov struct bpf_tramp_image *im; 275e21aa341SAlexei Starovoitov 276e21aa341SAlexei Starovoitov im = container_of(rcu, struct bpf_tramp_image, rcu); 277e21aa341SAlexei Starovoitov INIT_WORK(&im->work, __bpf_tramp_image_put_deferred); 278e21aa341SAlexei Starovoitov schedule_work(&im->work); 279e21aa341SAlexei Starovoitov } 280e21aa341SAlexei Starovoitov 281e21aa341SAlexei Starovoitov /* callback, fexit step 2. Called after percpu_ref_kill confirms. */ 282e21aa341SAlexei Starovoitov static void __bpf_tramp_image_release(struct percpu_ref *pcref) 283e21aa341SAlexei Starovoitov { 284e21aa341SAlexei Starovoitov struct bpf_tramp_image *im; 285e21aa341SAlexei Starovoitov 286e21aa341SAlexei Starovoitov im = container_of(pcref, struct bpf_tramp_image, pcref); 287e21aa341SAlexei Starovoitov call_rcu_tasks(&im->rcu, __bpf_tramp_image_put_rcu); 288e21aa341SAlexei Starovoitov } 289e21aa341SAlexei Starovoitov 290e21aa341SAlexei Starovoitov /* callback, fexit or fentry step 1 */ 291e21aa341SAlexei Starovoitov static void __bpf_tramp_image_put_rcu_tasks(struct rcu_head *rcu) 292e21aa341SAlexei Starovoitov { 293e21aa341SAlexei Starovoitov struct bpf_tramp_image *im; 294e21aa341SAlexei Starovoitov 295e21aa341SAlexei Starovoitov im = container_of(rcu, struct bpf_tramp_image, rcu); 296e21aa341SAlexei Starovoitov if (im->ip_after_call) 297e21aa341SAlexei Starovoitov /* the case of fmod_ret/fexit trampoline and CONFIG_PREEMPTION=y */ 298e21aa341SAlexei Starovoitov percpu_ref_kill(&im->pcref); 299e21aa341SAlexei Starovoitov else 300e21aa341SAlexei Starovoitov /* the case of fentry trampoline */ 301e21aa341SAlexei Starovoitov call_rcu_tasks(&im->rcu, __bpf_tramp_image_put_rcu); 302e21aa341SAlexei Starovoitov } 303e21aa341SAlexei Starovoitov 304e21aa341SAlexei Starovoitov static void bpf_tramp_image_put(struct bpf_tramp_image *im) 305e21aa341SAlexei Starovoitov { 306e21aa341SAlexei Starovoitov /* The trampoline image that calls original function is using: 307e21aa341SAlexei Starovoitov * rcu_read_lock_trace to protect sleepable bpf progs 308e21aa341SAlexei Starovoitov * rcu_read_lock to protect normal bpf progs 309e21aa341SAlexei Starovoitov * percpu_ref to protect trampoline itself 310e21aa341SAlexei Starovoitov * rcu tasks to protect trampoline asm not covered by percpu_ref 311e21aa341SAlexei Starovoitov * (which are few asm insns before __bpf_tramp_enter and 312e21aa341SAlexei Starovoitov * after __bpf_tramp_exit) 313e21aa341SAlexei Starovoitov * 314e21aa341SAlexei Starovoitov * The trampoline is unreachable before bpf_tramp_image_put(). 315e21aa341SAlexei Starovoitov * 316e21aa341SAlexei Starovoitov * First, patch the trampoline to avoid calling into fexit progs. 317e21aa341SAlexei Starovoitov * The progs will be freed even if the original function is still 318e21aa341SAlexei Starovoitov * executing or sleeping. 319e21aa341SAlexei Starovoitov * In case of CONFIG_PREEMPT=y use call_rcu_tasks() to wait on 320e21aa341SAlexei Starovoitov * first few asm instructions to execute and call into 321e21aa341SAlexei Starovoitov * __bpf_tramp_enter->percpu_ref_get. 322e21aa341SAlexei Starovoitov * Then use percpu_ref_kill to wait for the trampoline and the original 323e21aa341SAlexei Starovoitov * function to finish. 324e21aa341SAlexei Starovoitov * Then use call_rcu_tasks() to make sure few asm insns in 325e21aa341SAlexei Starovoitov * the trampoline epilogue are done as well. 326e21aa341SAlexei Starovoitov * 327e21aa341SAlexei Starovoitov * In !PREEMPT case the task that got interrupted in the first asm 328e21aa341SAlexei Starovoitov * insns won't go through an RCU quiescent state which the 329e21aa341SAlexei Starovoitov * percpu_ref_kill will be waiting for. Hence the first 330e21aa341SAlexei Starovoitov * call_rcu_tasks() is not necessary. 331e21aa341SAlexei Starovoitov */ 332e21aa341SAlexei Starovoitov if (im->ip_after_call) { 333e21aa341SAlexei Starovoitov int err = bpf_arch_text_poke(im->ip_after_call, BPF_MOD_JUMP, 334e21aa341SAlexei Starovoitov NULL, im->ip_epilogue); 335e21aa341SAlexei Starovoitov WARN_ON(err); 336e21aa341SAlexei Starovoitov if (IS_ENABLED(CONFIG_PREEMPTION)) 337e21aa341SAlexei Starovoitov call_rcu_tasks(&im->rcu, __bpf_tramp_image_put_rcu_tasks); 338e21aa341SAlexei Starovoitov else 339e21aa341SAlexei Starovoitov percpu_ref_kill(&im->pcref); 340e21aa341SAlexei Starovoitov return; 341e21aa341SAlexei Starovoitov } 342e21aa341SAlexei Starovoitov 343e21aa341SAlexei Starovoitov /* The trampoline without fexit and fmod_ret progs doesn't call original 344e21aa341SAlexei Starovoitov * function and doesn't use percpu_ref. 345e21aa341SAlexei Starovoitov * Use call_rcu_tasks_trace() to wait for sleepable progs to finish. 346e21aa341SAlexei Starovoitov * Then use call_rcu_tasks() to wait for the rest of trampoline asm 347e21aa341SAlexei Starovoitov * and normal progs. 348e21aa341SAlexei Starovoitov */ 349e21aa341SAlexei Starovoitov call_rcu_tasks_trace(&im->rcu, __bpf_tramp_image_put_rcu_tasks); 350e21aa341SAlexei Starovoitov } 351e21aa341SAlexei Starovoitov 35226ef208cSSong Liu static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, int size) 353e21aa341SAlexei Starovoitov { 354e21aa341SAlexei Starovoitov struct bpf_tramp_image *im; 355e21aa341SAlexei Starovoitov struct bpf_ksym *ksym; 356e21aa341SAlexei Starovoitov void *image; 357e21aa341SAlexei Starovoitov int err = -ENOMEM; 358e21aa341SAlexei Starovoitov 359e21aa341SAlexei Starovoitov im = kzalloc(sizeof(*im), GFP_KERNEL); 360e21aa341SAlexei Starovoitov if (!im) 361e21aa341SAlexei Starovoitov goto out; 362e21aa341SAlexei Starovoitov 36326ef208cSSong Liu err = bpf_jit_charge_modmem(size); 364e21aa341SAlexei Starovoitov if (err) 365e21aa341SAlexei Starovoitov goto out_free_im; 36626ef208cSSong Liu im->size = size; 367e21aa341SAlexei Starovoitov 368e21aa341SAlexei Starovoitov err = -ENOMEM; 36926ef208cSSong Liu im->image = image = arch_alloc_bpf_trampoline(size); 370e21aa341SAlexei Starovoitov if (!image) 371e21aa341SAlexei Starovoitov goto out_uncharge; 372e21aa341SAlexei Starovoitov 373e21aa341SAlexei Starovoitov err = percpu_ref_init(&im->pcref, __bpf_tramp_image_release, 0, GFP_KERNEL); 374e21aa341SAlexei Starovoitov if (err) 375e21aa341SAlexei Starovoitov goto out_free_image; 376e21aa341SAlexei Starovoitov 377e21aa341SAlexei Starovoitov ksym = &im->ksym; 378e21aa341SAlexei Starovoitov INIT_LIST_HEAD_RCU(&ksym->lnode); 37947e79cbeSYafang Shao snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu", key); 38026ef208cSSong Liu bpf_image_ksym_add(image, size, ksym); 381e21aa341SAlexei Starovoitov return im; 382e21aa341SAlexei Starovoitov 383e21aa341SAlexei Starovoitov out_free_image: 38426ef208cSSong Liu arch_free_bpf_trampoline(im->image, im->size); 385e21aa341SAlexei Starovoitov out_uncharge: 38626ef208cSSong Liu bpf_jit_uncharge_modmem(size); 387e21aa341SAlexei Starovoitov out_free_im: 388e21aa341SAlexei Starovoitov kfree(im); 389e21aa341SAlexei Starovoitov out: 390e21aa341SAlexei Starovoitov return ERR_PTR(err); 391e21aa341SAlexei Starovoitov } 392e21aa341SAlexei Starovoitov 39300963a2eSSong Liu static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex) 394fec56f58SAlexei Starovoitov { 395e21aa341SAlexei Starovoitov struct bpf_tramp_image *im; 396f7e0beafSKui-Feng Lee struct bpf_tramp_links *tlinks; 39700963a2eSSong Liu u32 orig_flags = tr->flags; 3981e37392cSJiri Olsa bool ip_arg = false; 39926ef208cSSong Liu int err, total, size; 400fec56f58SAlexei Starovoitov 401f7e0beafSKui-Feng Lee tlinks = bpf_trampoline_get_progs(tr, &total, &ip_arg); 402f7e0beafSKui-Feng Lee if (IS_ERR(tlinks)) 403f7e0beafSKui-Feng Lee return PTR_ERR(tlinks); 40488fd9e53SKP Singh 40588fd9e53SKP Singh if (total == 0) { 406e21aa341SAlexei Starovoitov err = unregister_fentry(tr, tr->cur_image->image); 407e21aa341SAlexei Starovoitov bpf_tramp_image_put(tr->cur_image); 408e21aa341SAlexei Starovoitov tr->cur_image = NULL; 409fec56f58SAlexei Starovoitov goto out; 410fec56f58SAlexei Starovoitov } 411fec56f58SAlexei Starovoitov 4122b5dcb31SLeon Hwang /* clear all bits except SHARE_IPMODIFY and TAIL_CALL_CTX */ 4132b5dcb31SLeon Hwang tr->flags &= (BPF_TRAMP_F_SHARE_IPMODIFY | BPF_TRAMP_F_TAIL_CALL_CTX); 41400963a2eSSong Liu 415f7e0beafSKui-Feng Lee if (tlinks[BPF_TRAMP_FEXIT].nr_links || 41600963a2eSSong Liu tlinks[BPF_TRAMP_MODIFY_RETURN].nr_links) { 417535a57a7SXu Kuohai /* NOTE: BPF_TRAMP_F_RESTORE_REGS and BPF_TRAMP_F_SKIP_FRAME 418535a57a7SXu Kuohai * should not be set together. 419535a57a7SXu Kuohai */ 42000963a2eSSong Liu tr->flags |= BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME; 42100963a2eSSong Liu } else { 42200963a2eSSong Liu tr->flags |= BPF_TRAMP_F_RESTORE_REGS; 42300963a2eSSong Liu } 424fec56f58SAlexei Starovoitov 4251e37392cSJiri Olsa if (ip_arg) 42600963a2eSSong Liu tr->flags |= BPF_TRAMP_F_IP_ARG; 42700963a2eSSong Liu 42800963a2eSSong Liu #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 42900963a2eSSong Liu again: 43000963a2eSSong Liu if ((tr->flags & BPF_TRAMP_F_SHARE_IPMODIFY) && 43100963a2eSSong Liu (tr->flags & BPF_TRAMP_F_CALL_ORIG)) 43200963a2eSSong Liu tr->flags |= BPF_TRAMP_F_ORIG_STACK; 43300963a2eSSong Liu #endif 4341e37392cSJiri Olsa 43526ef208cSSong Liu size = arch_bpf_trampoline_size(&tr->func.model, tr->flags, 43626ef208cSSong Liu tlinks, tr->func.addr); 43726ef208cSSong Liu if (size < 0) { 43826ef208cSSong Liu err = size; 43926ef208cSSong Liu goto out; 44026ef208cSSong Liu } 44126ef208cSSong Liu 44226ef208cSSong Liu if (size > PAGE_SIZE) { 44326ef208cSSong Liu err = -E2BIG; 44426ef208cSSong Liu goto out; 44526ef208cSSong Liu } 44626ef208cSSong Liu 44726ef208cSSong Liu im = bpf_tramp_image_alloc(tr->key, size); 44826ef208cSSong Liu if (IS_ERR(im)) { 44926ef208cSSong Liu err = PTR_ERR(im); 45026ef208cSSong Liu goto out; 45126ef208cSSong Liu } 45226ef208cSSong Liu 45326ef208cSSong Liu err = arch_prepare_bpf_trampoline(im, im->image, im->image + size, 45400963a2eSSong Liu &tr->func.model, tr->flags, tlinks, 455fec56f58SAlexei Starovoitov tr->func.addr); 45685d33df3SMartin KaFai Lau if (err < 0) 457108598c3SYafang Shao goto out_free; 458fec56f58SAlexei Starovoitov 45926ef208cSSong Liu arch_protect_bpf_trampoline(im->image, im->size); 4605b0d1c7bSSong Liu 46147e79cbeSYafang Shao WARN_ON(tr->cur_image && total == 0); 462e21aa341SAlexei Starovoitov if (tr->cur_image) 463fec56f58SAlexei Starovoitov /* progs already running at this address */ 46400963a2eSSong Liu err = modify_fentry(tr, tr->cur_image->image, im->image, lock_direct_mutex); 465fec56f58SAlexei Starovoitov else 466fec56f58SAlexei Starovoitov /* first time registering */ 467e21aa341SAlexei Starovoitov err = register_fentry(tr, im->image); 46800963a2eSSong Liu 46900963a2eSSong Liu #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 47000963a2eSSong Liu if (err == -EAGAIN) { 47100963a2eSSong Liu /* -EAGAIN from bpf_tramp_ftrace_ops_func. Now 47200963a2eSSong Liu * BPF_TRAMP_F_SHARE_IPMODIFY is set, we can generate the 47300963a2eSSong Liu * trampoline again, and retry register. 47400963a2eSSong Liu */ 47500963a2eSSong Liu /* reset fops->func and fops->trampoline for re-register */ 47600963a2eSSong Liu tr->fops->func = NULL; 47700963a2eSSong Liu tr->fops->trampoline = 0; 4789ed1d9aeSChuang Wang 47926ef208cSSong Liu /* free im memory and reallocate later */ 48026ef208cSSong Liu bpf_tramp_image_free(im); 48100963a2eSSong Liu goto again; 48200963a2eSSong Liu } 48300963a2eSSong Liu #endif 484fec56f58SAlexei Starovoitov if (err) 485108598c3SYafang Shao goto out_free; 48600963a2eSSong Liu 487e21aa341SAlexei Starovoitov if (tr->cur_image) 488e21aa341SAlexei Starovoitov bpf_tramp_image_put(tr->cur_image); 489e21aa341SAlexei Starovoitov tr->cur_image = im; 490fec56f58SAlexei Starovoitov out: 49100963a2eSSong Liu /* If any error happens, restore previous flags */ 49200963a2eSSong Liu if (err) 49300963a2eSSong Liu tr->flags = orig_flags; 494f7e0beafSKui-Feng Lee kfree(tlinks); 495fec56f58SAlexei Starovoitov return err; 496108598c3SYafang Shao 497108598c3SYafang Shao out_free: 498108598c3SYafang Shao bpf_tramp_image_free(im); 499108598c3SYafang Shao goto out; 500fec56f58SAlexei Starovoitov } 501fec56f58SAlexei Starovoitov 5029e4e01dfSKP Singh static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog) 503fec56f58SAlexei Starovoitov { 5049e4e01dfSKP Singh switch (prog->expected_attach_type) { 505fec56f58SAlexei Starovoitov case BPF_TRACE_FENTRY: 506fec56f58SAlexei Starovoitov return BPF_TRAMP_FENTRY; 507ae240823SKP Singh case BPF_MODIFY_RETURN: 508ae240823SKP Singh return BPF_TRAMP_MODIFY_RETURN; 509be8704ffSAlexei Starovoitov case BPF_TRACE_FEXIT: 510fec56f58SAlexei Starovoitov return BPF_TRAMP_FEXIT; 5119e4e01dfSKP Singh case BPF_LSM_MAC: 5129e4e01dfSKP Singh if (!prog->aux->attach_func_proto->type) 5139e4e01dfSKP Singh /* The function returns void, we cannot modify its 5149e4e01dfSKP Singh * return value. 5159e4e01dfSKP Singh */ 5169e4e01dfSKP Singh return BPF_TRAMP_FEXIT; 5179e4e01dfSKP Singh else 5189e4e01dfSKP Singh return BPF_TRAMP_MODIFY_RETURN; 519be8704ffSAlexei Starovoitov default: 520be8704ffSAlexei Starovoitov return BPF_TRAMP_REPLACE; 521fec56f58SAlexei Starovoitov } 522fec56f58SAlexei Starovoitov } 523fec56f58SAlexei Starovoitov 524af3f4134SStanislav Fomichev static int __bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) 525fec56f58SAlexei Starovoitov { 526fec56f58SAlexei Starovoitov enum bpf_tramp_prog_type kind; 527f7e0beafSKui-Feng Lee struct bpf_tramp_link *link_exiting; 528fec56f58SAlexei Starovoitov int err = 0; 529a2aa95b7SYuntao Wang int cnt = 0, i; 530fec56f58SAlexei Starovoitov 531f7e0beafSKui-Feng Lee kind = bpf_attach_type_to_tramp(link->link.prog); 532af3f4134SStanislav Fomichev if (tr->extension_prog) 533be8704ffSAlexei Starovoitov /* cannot attach fentry/fexit if extension prog is attached. 534be8704ffSAlexei Starovoitov * cannot overwrite extension prog either. 535be8704ffSAlexei Starovoitov */ 536af3f4134SStanislav Fomichev return -EBUSY; 537a2aa95b7SYuntao Wang 538a2aa95b7SYuntao Wang for (i = 0; i < BPF_TRAMP_MAX; i++) 539a2aa95b7SYuntao Wang cnt += tr->progs_cnt[i]; 540a2aa95b7SYuntao Wang 541be8704ffSAlexei Starovoitov if (kind == BPF_TRAMP_REPLACE) { 542be8704ffSAlexei Starovoitov /* Cannot attach extension if fentry/fexit are in use. */ 543af3f4134SStanislav Fomichev if (cnt) 544af3f4134SStanislav Fomichev return -EBUSY; 545f7e0beafSKui-Feng Lee tr->extension_prog = link->link.prog; 546af3f4134SStanislav Fomichev return bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL, 547f7e0beafSKui-Feng Lee link->link.prog->bpf_func); 548be8704ffSAlexei Starovoitov } 549af3f4134SStanislav Fomichev if (cnt >= BPF_MAX_TRAMP_LINKS) 550af3f4134SStanislav Fomichev return -E2BIG; 551af3f4134SStanislav Fomichev if (!hlist_unhashed(&link->tramp_hlist)) 552fec56f58SAlexei Starovoitov /* prog already linked */ 553af3f4134SStanislav Fomichev return -EBUSY; 554f7e0beafSKui-Feng Lee hlist_for_each_entry(link_exiting, &tr->progs_hlist[kind], tramp_hlist) { 555f7e0beafSKui-Feng Lee if (link_exiting->link.prog != link->link.prog) 556f7e0beafSKui-Feng Lee continue; 557f7e0beafSKui-Feng Lee /* prog already linked */ 558af3f4134SStanislav Fomichev return -EBUSY; 559f7e0beafSKui-Feng Lee } 560f7e0beafSKui-Feng Lee 561f7e0beafSKui-Feng Lee hlist_add_head(&link->tramp_hlist, &tr->progs_hlist[kind]); 562fec56f58SAlexei Starovoitov tr->progs_cnt[kind]++; 56300963a2eSSong Liu err = bpf_trampoline_update(tr, true /* lock_direct_mutex */); 564fec56f58SAlexei Starovoitov if (err) { 565f7e0beafSKui-Feng Lee hlist_del_init(&link->tramp_hlist); 566fec56f58SAlexei Starovoitov tr->progs_cnt[kind]--; 567fec56f58SAlexei Starovoitov } 568af3f4134SStanislav Fomichev return err; 569af3f4134SStanislav Fomichev } 570af3f4134SStanislav Fomichev 571af3f4134SStanislav Fomichev int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) 572af3f4134SStanislav Fomichev { 573af3f4134SStanislav Fomichev int err; 574af3f4134SStanislav Fomichev 575af3f4134SStanislav Fomichev mutex_lock(&tr->mutex); 576af3f4134SStanislav Fomichev err = __bpf_trampoline_link_prog(link, tr); 577fec56f58SAlexei Starovoitov mutex_unlock(&tr->mutex); 578fec56f58SAlexei Starovoitov return err; 579fec56f58SAlexei Starovoitov } 580fec56f58SAlexei Starovoitov 581af3f4134SStanislav Fomichev static int __bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) 582fec56f58SAlexei Starovoitov { 583fec56f58SAlexei Starovoitov enum bpf_tramp_prog_type kind; 584fec56f58SAlexei Starovoitov int err; 585fec56f58SAlexei Starovoitov 586f7e0beafSKui-Feng Lee kind = bpf_attach_type_to_tramp(link->link.prog); 587be8704ffSAlexei Starovoitov if (kind == BPF_TRAMP_REPLACE) { 588be8704ffSAlexei Starovoitov WARN_ON_ONCE(!tr->extension_prog); 589be8704ffSAlexei Starovoitov err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, 590be8704ffSAlexei Starovoitov tr->extension_prog->bpf_func, NULL); 591be8704ffSAlexei Starovoitov tr->extension_prog = NULL; 592af3f4134SStanislav Fomichev return err; 593be8704ffSAlexei Starovoitov } 594f7e0beafSKui-Feng Lee hlist_del_init(&link->tramp_hlist); 595fec56f58SAlexei Starovoitov tr->progs_cnt[kind]--; 59600963a2eSSong Liu return bpf_trampoline_update(tr, true /* lock_direct_mutex */); 597af3f4134SStanislav Fomichev } 598af3f4134SStanislav Fomichev 599af3f4134SStanislav Fomichev /* bpf_trampoline_unlink_prog() should never fail. */ 600af3f4134SStanislav Fomichev int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr) 601af3f4134SStanislav Fomichev { 602af3f4134SStanislav Fomichev int err; 603af3f4134SStanislav Fomichev 604af3f4134SStanislav Fomichev mutex_lock(&tr->mutex); 605af3f4134SStanislav Fomichev err = __bpf_trampoline_unlink_prog(link, tr); 606fec56f58SAlexei Starovoitov mutex_unlock(&tr->mutex); 607fec56f58SAlexei Starovoitov return err; 608fec56f58SAlexei Starovoitov } 609fec56f58SAlexei Starovoitov 6103908fcddSStanislav Fomichev #if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM) 61169fd337aSStanislav Fomichev static void bpf_shim_tramp_link_release(struct bpf_link *link) 61269fd337aSStanislav Fomichev { 61369fd337aSStanislav Fomichev struct bpf_shim_tramp_link *shim_link = 61469fd337aSStanislav Fomichev container_of(link, struct bpf_shim_tramp_link, link.link); 61569fd337aSStanislav Fomichev 61669fd337aSStanislav Fomichev /* paired with 'shim_link->trampoline = tr' in bpf_trampoline_link_cgroup_shim */ 61769fd337aSStanislav Fomichev if (!shim_link->trampoline) 61869fd337aSStanislav Fomichev return; 61969fd337aSStanislav Fomichev 62069fd337aSStanislav Fomichev WARN_ON_ONCE(bpf_trampoline_unlink_prog(&shim_link->link, shim_link->trampoline)); 62169fd337aSStanislav Fomichev bpf_trampoline_put(shim_link->trampoline); 62269fd337aSStanislav Fomichev } 62369fd337aSStanislav Fomichev 62469fd337aSStanislav Fomichev static void bpf_shim_tramp_link_dealloc(struct bpf_link *link) 62569fd337aSStanislav Fomichev { 62669fd337aSStanislav Fomichev struct bpf_shim_tramp_link *shim_link = 62769fd337aSStanislav Fomichev container_of(link, struct bpf_shim_tramp_link, link.link); 62869fd337aSStanislav Fomichev 62969fd337aSStanislav Fomichev kfree(shim_link); 63069fd337aSStanislav Fomichev } 63169fd337aSStanislav Fomichev 63269fd337aSStanislav Fomichev static const struct bpf_link_ops bpf_shim_tramp_link_lops = { 63369fd337aSStanislav Fomichev .release = bpf_shim_tramp_link_release, 63469fd337aSStanislav Fomichev .dealloc = bpf_shim_tramp_link_dealloc, 63569fd337aSStanislav Fomichev }; 63669fd337aSStanislav Fomichev 63769fd337aSStanislav Fomichev static struct bpf_shim_tramp_link *cgroup_shim_alloc(const struct bpf_prog *prog, 63869fd337aSStanislav Fomichev bpf_func_t bpf_func, 63969fd337aSStanislav Fomichev int cgroup_atype) 64069fd337aSStanislav Fomichev { 64169fd337aSStanislav Fomichev struct bpf_shim_tramp_link *shim_link = NULL; 64269fd337aSStanislav Fomichev struct bpf_prog *p; 64369fd337aSStanislav Fomichev 64469fd337aSStanislav Fomichev shim_link = kzalloc(sizeof(*shim_link), GFP_USER); 64569fd337aSStanislav Fomichev if (!shim_link) 64669fd337aSStanislav Fomichev return NULL; 64769fd337aSStanislav Fomichev 64869fd337aSStanislav Fomichev p = bpf_prog_alloc(1, 0); 64969fd337aSStanislav Fomichev if (!p) { 65069fd337aSStanislav Fomichev kfree(shim_link); 65169fd337aSStanislav Fomichev return NULL; 65269fd337aSStanislav Fomichev } 65369fd337aSStanislav Fomichev 65469fd337aSStanislav Fomichev p->jited = false; 65569fd337aSStanislav Fomichev p->bpf_func = bpf_func; 65669fd337aSStanislav Fomichev 65769fd337aSStanislav Fomichev p->aux->cgroup_atype = cgroup_atype; 65869fd337aSStanislav Fomichev p->aux->attach_func_proto = prog->aux->attach_func_proto; 65969fd337aSStanislav Fomichev p->aux->attach_btf_id = prog->aux->attach_btf_id; 66069fd337aSStanislav Fomichev p->aux->attach_btf = prog->aux->attach_btf; 66169fd337aSStanislav Fomichev btf_get(p->aux->attach_btf); 66269fd337aSStanislav Fomichev p->type = BPF_PROG_TYPE_LSM; 66369fd337aSStanislav Fomichev p->expected_attach_type = BPF_LSM_MAC; 66469fd337aSStanislav Fomichev bpf_prog_inc(p); 66569fd337aSStanislav Fomichev bpf_link_init(&shim_link->link.link, BPF_LINK_TYPE_UNSPEC, 66669fd337aSStanislav Fomichev &bpf_shim_tramp_link_lops, p); 667c0e19f2cSStanislav Fomichev bpf_cgroup_atype_get(p->aux->attach_btf_id, cgroup_atype); 66869fd337aSStanislav Fomichev 66969fd337aSStanislav Fomichev return shim_link; 67069fd337aSStanislav Fomichev } 67169fd337aSStanislav Fomichev 67269fd337aSStanislav Fomichev static struct bpf_shim_tramp_link *cgroup_shim_find(struct bpf_trampoline *tr, 67369fd337aSStanislav Fomichev bpf_func_t bpf_func) 67469fd337aSStanislav Fomichev { 67569fd337aSStanislav Fomichev struct bpf_tramp_link *link; 67669fd337aSStanislav Fomichev int kind; 67769fd337aSStanislav Fomichev 67869fd337aSStanislav Fomichev for (kind = 0; kind < BPF_TRAMP_MAX; kind++) { 67969fd337aSStanislav Fomichev hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) { 68069fd337aSStanislav Fomichev struct bpf_prog *p = link->link.prog; 68169fd337aSStanislav Fomichev 68269fd337aSStanislav Fomichev if (p->bpf_func == bpf_func) 68369fd337aSStanislav Fomichev return container_of(link, struct bpf_shim_tramp_link, link); 68469fd337aSStanislav Fomichev } 68569fd337aSStanislav Fomichev } 68669fd337aSStanislav Fomichev 68769fd337aSStanislav Fomichev return NULL; 68869fd337aSStanislav Fomichev } 68969fd337aSStanislav Fomichev 69069fd337aSStanislav Fomichev int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog, 69169fd337aSStanislav Fomichev int cgroup_atype) 69269fd337aSStanislav Fomichev { 69369fd337aSStanislav Fomichev struct bpf_shim_tramp_link *shim_link = NULL; 69469fd337aSStanislav Fomichev struct bpf_attach_target_info tgt_info = {}; 69569fd337aSStanislav Fomichev struct bpf_trampoline *tr; 69669fd337aSStanislav Fomichev bpf_func_t bpf_func; 69769fd337aSStanislav Fomichev u64 key; 69869fd337aSStanislav Fomichev int err; 69969fd337aSStanislav Fomichev 70069fd337aSStanislav Fomichev err = bpf_check_attach_target(NULL, prog, NULL, 70169fd337aSStanislav Fomichev prog->aux->attach_btf_id, 70269fd337aSStanislav Fomichev &tgt_info); 70369fd337aSStanislav Fomichev if (err) 70469fd337aSStanislav Fomichev return err; 70569fd337aSStanislav Fomichev 70669fd337aSStanislav Fomichev key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf, 70769fd337aSStanislav Fomichev prog->aux->attach_btf_id); 70869fd337aSStanislav Fomichev 70969fd337aSStanislav Fomichev bpf_lsm_find_cgroup_shim(prog, &bpf_func); 71069fd337aSStanislav Fomichev tr = bpf_trampoline_get(key, &tgt_info); 71169fd337aSStanislav Fomichev if (!tr) 71269fd337aSStanislav Fomichev return -ENOMEM; 71369fd337aSStanislav Fomichev 71469fd337aSStanislav Fomichev mutex_lock(&tr->mutex); 71569fd337aSStanislav Fomichev 71669fd337aSStanislav Fomichev shim_link = cgroup_shim_find(tr, bpf_func); 71769fd337aSStanislav Fomichev if (shim_link) { 71869fd337aSStanislav Fomichev /* Reusing existing shim attached by the other program. */ 71969fd337aSStanislav Fomichev bpf_link_inc(&shim_link->link.link); 72069fd337aSStanislav Fomichev 72169fd337aSStanislav Fomichev mutex_unlock(&tr->mutex); 72269fd337aSStanislav Fomichev bpf_trampoline_put(tr); /* bpf_trampoline_get above */ 72369fd337aSStanislav Fomichev return 0; 72469fd337aSStanislav Fomichev } 72569fd337aSStanislav Fomichev 72669fd337aSStanislav Fomichev /* Allocate and install new shim. */ 72769fd337aSStanislav Fomichev 72869fd337aSStanislav Fomichev shim_link = cgroup_shim_alloc(prog, bpf_func, cgroup_atype); 72969fd337aSStanislav Fomichev if (!shim_link) { 73069fd337aSStanislav Fomichev err = -ENOMEM; 73169fd337aSStanislav Fomichev goto err; 73269fd337aSStanislav Fomichev } 73369fd337aSStanislav Fomichev 73469fd337aSStanislav Fomichev err = __bpf_trampoline_link_prog(&shim_link->link, tr); 73569fd337aSStanislav Fomichev if (err) 73669fd337aSStanislav Fomichev goto err; 73769fd337aSStanislav Fomichev 73869fd337aSStanislav Fomichev shim_link->trampoline = tr; 73969fd337aSStanislav Fomichev /* note, we're still holding tr refcnt from above */ 74069fd337aSStanislav Fomichev 74169fd337aSStanislav Fomichev mutex_unlock(&tr->mutex); 74269fd337aSStanislav Fomichev 74369fd337aSStanislav Fomichev return 0; 74469fd337aSStanislav Fomichev err: 74569fd337aSStanislav Fomichev mutex_unlock(&tr->mutex); 74669fd337aSStanislav Fomichev 74769fd337aSStanislav Fomichev if (shim_link) 74869fd337aSStanislav Fomichev bpf_link_put(&shim_link->link.link); 74969fd337aSStanislav Fomichev 75069fd337aSStanislav Fomichev /* have to release tr while _not_ holding its mutex */ 75169fd337aSStanislav Fomichev bpf_trampoline_put(tr); /* bpf_trampoline_get above */ 75269fd337aSStanislav Fomichev 75369fd337aSStanislav Fomichev return err; 75469fd337aSStanislav Fomichev } 75569fd337aSStanislav Fomichev 75669fd337aSStanislav Fomichev void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog) 75769fd337aSStanislav Fomichev { 75869fd337aSStanislav Fomichev struct bpf_shim_tramp_link *shim_link = NULL; 75969fd337aSStanislav Fomichev struct bpf_trampoline *tr; 76069fd337aSStanislav Fomichev bpf_func_t bpf_func; 76169fd337aSStanislav Fomichev u64 key; 76269fd337aSStanislav Fomichev 76369fd337aSStanislav Fomichev key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf, 76469fd337aSStanislav Fomichev prog->aux->attach_btf_id); 76569fd337aSStanislav Fomichev 76669fd337aSStanislav Fomichev bpf_lsm_find_cgroup_shim(prog, &bpf_func); 76769fd337aSStanislav Fomichev tr = bpf_trampoline_lookup(key); 76869fd337aSStanislav Fomichev if (WARN_ON_ONCE(!tr)) 76969fd337aSStanislav Fomichev return; 77069fd337aSStanislav Fomichev 77169fd337aSStanislav Fomichev mutex_lock(&tr->mutex); 77269fd337aSStanislav Fomichev shim_link = cgroup_shim_find(tr, bpf_func); 77369fd337aSStanislav Fomichev mutex_unlock(&tr->mutex); 77469fd337aSStanislav Fomichev 77569fd337aSStanislav Fomichev if (shim_link) 77669fd337aSStanislav Fomichev bpf_link_put(&shim_link->link.link); 77769fd337aSStanislav Fomichev 77869fd337aSStanislav Fomichev bpf_trampoline_put(tr); /* bpf_trampoline_lookup above */ 77969fd337aSStanislav Fomichev } 78069fd337aSStanislav Fomichev #endif 78169fd337aSStanislav Fomichev 782f7b12b6fSToke Høiland-Jørgensen struct bpf_trampoline *bpf_trampoline_get(u64 key, 783f7b12b6fSToke Høiland-Jørgensen struct bpf_attach_target_info *tgt_info) 784f7b12b6fSToke Høiland-Jørgensen { 785f7b12b6fSToke Høiland-Jørgensen struct bpf_trampoline *tr; 786f7b12b6fSToke Høiland-Jørgensen 787f7b12b6fSToke Høiland-Jørgensen tr = bpf_trampoline_lookup(key); 788f7b12b6fSToke Høiland-Jørgensen if (!tr) 789f7b12b6fSToke Høiland-Jørgensen return NULL; 790f7b12b6fSToke Høiland-Jørgensen 791f7b12b6fSToke Høiland-Jørgensen mutex_lock(&tr->mutex); 792f7b12b6fSToke Høiland-Jørgensen if (tr->func.addr) 793f7b12b6fSToke Høiland-Jørgensen goto out; 794f7b12b6fSToke Høiland-Jørgensen 795f7b12b6fSToke Høiland-Jørgensen memcpy(&tr->func.model, &tgt_info->fmodel, sizeof(tgt_info->fmodel)); 796f7b12b6fSToke Høiland-Jørgensen tr->func.addr = (void *)tgt_info->tgt_addr; 797f7b12b6fSToke Høiland-Jørgensen out: 798f7b12b6fSToke Høiland-Jørgensen mutex_unlock(&tr->mutex); 799f7b12b6fSToke Høiland-Jørgensen return tr; 800f7b12b6fSToke Høiland-Jørgensen } 801f7b12b6fSToke Høiland-Jørgensen 802fec56f58SAlexei Starovoitov void bpf_trampoline_put(struct bpf_trampoline *tr) 803fec56f58SAlexei Starovoitov { 804a2aa95b7SYuntao Wang int i; 805a2aa95b7SYuntao Wang 806fec56f58SAlexei Starovoitov if (!tr) 807fec56f58SAlexei Starovoitov return; 808fec56f58SAlexei Starovoitov mutex_lock(&trampoline_mutex); 809fec56f58SAlexei Starovoitov if (!refcount_dec_and_test(&tr->refcnt)) 810fec56f58SAlexei Starovoitov goto out; 811fec56f58SAlexei Starovoitov WARN_ON_ONCE(mutex_is_locked(&tr->mutex)); 812a2aa95b7SYuntao Wang 813a2aa95b7SYuntao Wang for (i = 0; i < BPF_TRAMP_MAX; i++) 814a2aa95b7SYuntao Wang if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[i]))) 815fec56f58SAlexei Starovoitov goto out; 816a2aa95b7SYuntao Wang 817e21aa341SAlexei Starovoitov /* This code will be executed even when the last bpf_tramp_image 818e21aa341SAlexei Starovoitov * is alive. All progs are detached from the trampoline and the 819e21aa341SAlexei Starovoitov * trampoline image is patched with jmp into epilogue to skip 820e21aa341SAlexei Starovoitov * fexit progs. The fentry-only trampoline will be freed via 821e21aa341SAlexei Starovoitov * multiple rcu callbacks. 8221e6c62a8SAlexei Starovoitov */ 823fec56f58SAlexei Starovoitov hlist_del(&tr->hlist); 82462d468e5SJiri Olsa if (tr->fops) { 82562d468e5SJiri Olsa ftrace_free_filter(tr->fops); 82600963a2eSSong Liu kfree(tr->fops); 82762d468e5SJiri Olsa } 828fec56f58SAlexei Starovoitov kfree(tr); 829fec56f58SAlexei Starovoitov out: 830fec56f58SAlexei Starovoitov mutex_unlock(&trampoline_mutex); 831fec56f58SAlexei Starovoitov } 832fec56f58SAlexei Starovoitov 833ca06f55bSAlexei Starovoitov #define NO_START_TIME 1 834856c02dbSSong Liu static __always_inline u64 notrace bpf_prog_start_time(void) 835f2dd3b39SAlexei Starovoitov { 836f2dd3b39SAlexei Starovoitov u64 start = NO_START_TIME; 837f2dd3b39SAlexei Starovoitov 838ca06f55bSAlexei Starovoitov if (static_branch_unlikely(&bpf_stats_enabled_key)) { 839f2dd3b39SAlexei Starovoitov start = sched_clock(); 840ca06f55bSAlexei Starovoitov if (unlikely(!start)) 841ca06f55bSAlexei Starovoitov start = NO_START_TIME; 842ca06f55bSAlexei Starovoitov } 843f2dd3b39SAlexei Starovoitov return start; 844f2dd3b39SAlexei Starovoitov } 845f2dd3b39SAlexei Starovoitov 846fb7dd8bcSAndrii Nakryiko /* The logic is similar to bpf_prog_run(), but with an explicit 84702ad0596SDavid Miller * rcu_read_lock() and migrate_disable() which are required 84802ad0596SDavid Miller * for the trampoline. The macro is split into 849f2dd3b39SAlexei Starovoitov * call __bpf_prog_enter 850fec56f58SAlexei Starovoitov * call prog->bpf_func 851fec56f58SAlexei Starovoitov * call __bpf_prog_exit 852ca06f55bSAlexei Starovoitov * 853ca06f55bSAlexei Starovoitov * __bpf_prog_enter returns: 854ca06f55bSAlexei Starovoitov * 0 - skip execution of the bpf prog 855ca06f55bSAlexei Starovoitov * 1 - execute bpf prog 8568fb33b60SZhen Lei * [2..MAX_U64] - execute bpf prog and record execution time. 857ca06f55bSAlexei Starovoitov * This is start time. 858fec56f58SAlexei Starovoitov */ 859271de525SMartin KaFai Lau static u64 notrace __bpf_prog_enter_recur(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx) 860dcce11d5SJules Irenge __acquires(RCU) 861fec56f58SAlexei Starovoitov { 862fec56f58SAlexei Starovoitov rcu_read_lock(); 86302ad0596SDavid Miller migrate_disable(); 864e384c7b7SKui-Feng Lee 865e384c7b7SKui-Feng Lee run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx); 866e384c7b7SKui-Feng Lee 867c89e843aSHou Tao if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) { 86805b24ff9SJiri Olsa bpf_prog_inc_misses_counter(prog); 869ca06f55bSAlexei Starovoitov return 0; 8709ed9e9baSAlexei Starovoitov } 871f2dd3b39SAlexei Starovoitov return bpf_prog_start_time(); 872fec56f58SAlexei Starovoitov } 873fec56f58SAlexei Starovoitov 874f2dd3b39SAlexei Starovoitov static void notrace update_prog_stats(struct bpf_prog *prog, 875f2dd3b39SAlexei Starovoitov u64 start) 876fec56f58SAlexei Starovoitov { 877fec56f58SAlexei Starovoitov struct bpf_prog_stats *stats; 878fec56f58SAlexei Starovoitov 879fec56f58SAlexei Starovoitov if (static_branch_unlikely(&bpf_stats_enabled_key) && 880f2dd3b39SAlexei Starovoitov /* static_key could be enabled in __bpf_prog_enter* 881f2dd3b39SAlexei Starovoitov * and disabled in __bpf_prog_exit*. 882fec56f58SAlexei Starovoitov * And vice versa. 883f2dd3b39SAlexei Starovoitov * Hence check that 'start' is valid. 884fec56f58SAlexei Starovoitov */ 885f2dd3b39SAlexei Starovoitov start > NO_START_TIME) { 886d979617aSEric Dumazet unsigned long flags; 887d979617aSEric Dumazet 888700d4796SAlexei Starovoitov stats = this_cpu_ptr(prog->stats); 889d979617aSEric Dumazet flags = u64_stats_update_begin_irqsave(&stats->syncp); 89061a0abaeSEric Dumazet u64_stats_inc(&stats->cnt); 89161a0abaeSEric Dumazet u64_stats_add(&stats->nsecs, sched_clock() - start); 892d979617aSEric Dumazet u64_stats_update_end_irqrestore(&stats->syncp, flags); 893fec56f58SAlexei Starovoitov } 894f2dd3b39SAlexei Starovoitov } 895f2dd3b39SAlexei Starovoitov 896271de525SMartin KaFai Lau static void notrace __bpf_prog_exit_recur(struct bpf_prog *prog, u64 start, 897271de525SMartin KaFai Lau struct bpf_tramp_run_ctx *run_ctx) 898f2dd3b39SAlexei Starovoitov __releases(RCU) 899f2dd3b39SAlexei Starovoitov { 900e384c7b7SKui-Feng Lee bpf_reset_run_ctx(run_ctx->saved_run_ctx); 901e384c7b7SKui-Feng Lee 902f2dd3b39SAlexei Starovoitov update_prog_stats(prog, start); 903c89e843aSHou Tao this_cpu_dec(*(prog->active)); 90402ad0596SDavid Miller migrate_enable(); 905fec56f58SAlexei Starovoitov rcu_read_unlock(); 906fec56f58SAlexei Starovoitov } 907fec56f58SAlexei Starovoitov 908271de525SMartin KaFai Lau static u64 notrace __bpf_prog_enter_lsm_cgroup(struct bpf_prog *prog, 90969fd337aSStanislav Fomichev struct bpf_tramp_run_ctx *run_ctx) 91069fd337aSStanislav Fomichev __acquires(RCU) 91169fd337aSStanislav Fomichev { 91269fd337aSStanislav Fomichev /* Runtime stats are exported via actual BPF_LSM_CGROUP 91369fd337aSStanislav Fomichev * programs, not the shims. 91469fd337aSStanislav Fomichev */ 91569fd337aSStanislav Fomichev rcu_read_lock(); 91669fd337aSStanislav Fomichev migrate_disable(); 91769fd337aSStanislav Fomichev 91869fd337aSStanislav Fomichev run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx); 91969fd337aSStanislav Fomichev 92069fd337aSStanislav Fomichev return NO_START_TIME; 92169fd337aSStanislav Fomichev } 92269fd337aSStanislav Fomichev 923271de525SMartin KaFai Lau static void notrace __bpf_prog_exit_lsm_cgroup(struct bpf_prog *prog, u64 start, 92469fd337aSStanislav Fomichev struct bpf_tramp_run_ctx *run_ctx) 92569fd337aSStanislav Fomichev __releases(RCU) 92669fd337aSStanislav Fomichev { 92769fd337aSStanislav Fomichev bpf_reset_run_ctx(run_ctx->saved_run_ctx); 92869fd337aSStanislav Fomichev 92969fd337aSStanislav Fomichev migrate_enable(); 93069fd337aSStanislav Fomichev rcu_read_unlock(); 93169fd337aSStanislav Fomichev } 93269fd337aSStanislav Fomichev 933271de525SMartin KaFai Lau u64 notrace __bpf_prog_enter_sleepable_recur(struct bpf_prog *prog, 934271de525SMartin KaFai Lau struct bpf_tramp_run_ctx *run_ctx) 9351e6c62a8SAlexei Starovoitov { 9361e6c62a8SAlexei Starovoitov rcu_read_lock_trace(); 937031d6e02SAlexei Starovoitov migrate_disable(); 938f56407faSAlexei Starovoitov might_fault(); 939e384c7b7SKui-Feng Lee 9406764e767SSebastian Andrzej Siewior run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx); 9416764e767SSebastian Andrzej Siewior 942c89e843aSHou Tao if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) { 94305b24ff9SJiri Olsa bpf_prog_inc_misses_counter(prog); 944ca06f55bSAlexei Starovoitov return 0; 9459ed9e9baSAlexei Starovoitov } 946f2dd3b39SAlexei Starovoitov return bpf_prog_start_time(); 9471e6c62a8SAlexei Starovoitov } 9481e6c62a8SAlexei Starovoitov 949271de525SMartin KaFai Lau void notrace __bpf_prog_exit_sleepable_recur(struct bpf_prog *prog, u64 start, 950e384c7b7SKui-Feng Lee struct bpf_tramp_run_ctx *run_ctx) 9511e6c62a8SAlexei Starovoitov { 952e384c7b7SKui-Feng Lee bpf_reset_run_ctx(run_ctx->saved_run_ctx); 953e384c7b7SKui-Feng Lee 954f2dd3b39SAlexei Starovoitov update_prog_stats(prog, start); 955c89e843aSHou Tao this_cpu_dec(*(prog->active)); 956031d6e02SAlexei Starovoitov migrate_enable(); 9571e6c62a8SAlexei Starovoitov rcu_read_unlock_trace(); 9581e6c62a8SAlexei Starovoitov } 9591e6c62a8SAlexei Starovoitov 960271de525SMartin KaFai Lau static u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, 961271de525SMartin KaFai Lau struct bpf_tramp_run_ctx *run_ctx) 962271de525SMartin KaFai Lau { 963271de525SMartin KaFai Lau rcu_read_lock_trace(); 964271de525SMartin KaFai Lau migrate_disable(); 965271de525SMartin KaFai Lau might_fault(); 966271de525SMartin KaFai Lau 967271de525SMartin KaFai Lau run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx); 968271de525SMartin KaFai Lau 969271de525SMartin KaFai Lau return bpf_prog_start_time(); 970271de525SMartin KaFai Lau } 971271de525SMartin KaFai Lau 972271de525SMartin KaFai Lau static void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start, 973271de525SMartin KaFai Lau struct bpf_tramp_run_ctx *run_ctx) 974271de525SMartin KaFai Lau { 975271de525SMartin KaFai Lau bpf_reset_run_ctx(run_ctx->saved_run_ctx); 976271de525SMartin KaFai Lau 977271de525SMartin KaFai Lau update_prog_stats(prog, start); 978271de525SMartin KaFai Lau migrate_enable(); 979271de525SMartin KaFai Lau rcu_read_unlock_trace(); 980271de525SMartin KaFai Lau } 981271de525SMartin KaFai Lau 982271de525SMartin KaFai Lau static u64 notrace __bpf_prog_enter(struct bpf_prog *prog, 98364696c40SMartin KaFai Lau struct bpf_tramp_run_ctx *run_ctx) 98464696c40SMartin KaFai Lau __acquires(RCU) 98564696c40SMartin KaFai Lau { 98664696c40SMartin KaFai Lau rcu_read_lock(); 98764696c40SMartin KaFai Lau migrate_disable(); 98864696c40SMartin KaFai Lau 98964696c40SMartin KaFai Lau run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx); 99064696c40SMartin KaFai Lau 99164696c40SMartin KaFai Lau return bpf_prog_start_time(); 99264696c40SMartin KaFai Lau } 99364696c40SMartin KaFai Lau 994271de525SMartin KaFai Lau static void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, 99564696c40SMartin KaFai Lau struct bpf_tramp_run_ctx *run_ctx) 99664696c40SMartin KaFai Lau __releases(RCU) 99764696c40SMartin KaFai Lau { 99864696c40SMartin KaFai Lau bpf_reset_run_ctx(run_ctx->saved_run_ctx); 99964696c40SMartin KaFai Lau 100064696c40SMartin KaFai Lau update_prog_stats(prog, start); 100164696c40SMartin KaFai Lau migrate_enable(); 100264696c40SMartin KaFai Lau rcu_read_unlock(); 100364696c40SMartin KaFai Lau } 100464696c40SMartin KaFai Lau 1005e21aa341SAlexei Starovoitov void notrace __bpf_tramp_enter(struct bpf_tramp_image *tr) 1006e21aa341SAlexei Starovoitov { 1007e21aa341SAlexei Starovoitov percpu_ref_get(&tr->pcref); 1008e21aa341SAlexei Starovoitov } 1009e21aa341SAlexei Starovoitov 1010e21aa341SAlexei Starovoitov void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr) 1011e21aa341SAlexei Starovoitov { 1012e21aa341SAlexei Starovoitov percpu_ref_put(&tr->pcref); 1013e21aa341SAlexei Starovoitov } 1014e21aa341SAlexei Starovoitov 1015271de525SMartin KaFai Lau bpf_trampoline_enter_t bpf_trampoline_enter(const struct bpf_prog *prog) 1016271de525SMartin KaFai Lau { 1017*66c84731SAndrii Nakryiko bool sleepable = prog->sleepable; 1018271de525SMartin KaFai Lau 1019271de525SMartin KaFai Lau if (bpf_prog_check_recur(prog)) 1020271de525SMartin KaFai Lau return sleepable ? __bpf_prog_enter_sleepable_recur : 1021271de525SMartin KaFai Lau __bpf_prog_enter_recur; 1022271de525SMartin KaFai Lau 1023271de525SMartin KaFai Lau if (resolve_prog_type(prog) == BPF_PROG_TYPE_LSM && 1024271de525SMartin KaFai Lau prog->expected_attach_type == BPF_LSM_CGROUP) 1025271de525SMartin KaFai Lau return __bpf_prog_enter_lsm_cgroup; 1026271de525SMartin KaFai Lau 1027271de525SMartin KaFai Lau return sleepable ? __bpf_prog_enter_sleepable : __bpf_prog_enter; 1028271de525SMartin KaFai Lau } 1029271de525SMartin KaFai Lau 1030271de525SMartin KaFai Lau bpf_trampoline_exit_t bpf_trampoline_exit(const struct bpf_prog *prog) 1031271de525SMartin KaFai Lau { 1032*66c84731SAndrii Nakryiko bool sleepable = prog->sleepable; 1033271de525SMartin KaFai Lau 1034271de525SMartin KaFai Lau if (bpf_prog_check_recur(prog)) 1035271de525SMartin KaFai Lau return sleepable ? __bpf_prog_exit_sleepable_recur : 1036271de525SMartin KaFai Lau __bpf_prog_exit_recur; 1037271de525SMartin KaFai Lau 1038271de525SMartin KaFai Lau if (resolve_prog_type(prog) == BPF_PROG_TYPE_LSM && 1039271de525SMartin KaFai Lau prog->expected_attach_type == BPF_LSM_CGROUP) 1040271de525SMartin KaFai Lau return __bpf_prog_exit_lsm_cgroup; 1041271de525SMartin KaFai Lau 1042271de525SMartin KaFai Lau return sleepable ? __bpf_prog_exit_sleepable : __bpf_prog_exit; 1043271de525SMartin KaFai Lau } 1044271de525SMartin KaFai Lau 1045fec56f58SAlexei Starovoitov int __weak 10467a3d9a15SSong Liu arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end, 104785d33df3SMartin KaFai Lau const struct btf_func_model *m, u32 flags, 1048f7e0beafSKui-Feng Lee struct bpf_tramp_links *tlinks, 10497a3d9a15SSong Liu void *func_addr) 1050fec56f58SAlexei Starovoitov { 1051fec56f58SAlexei Starovoitov return -ENOTSUPP; 1052fec56f58SAlexei Starovoitov } 1053fec56f58SAlexei Starovoitov 105482583daaSSong Liu void * __weak arch_alloc_bpf_trampoline(unsigned int size) 105582583daaSSong Liu { 105682583daaSSong Liu void *image; 105782583daaSSong Liu 105882583daaSSong Liu if (WARN_ON_ONCE(size > PAGE_SIZE)) 105982583daaSSong Liu return NULL; 106082583daaSSong Liu image = bpf_jit_alloc_exec(PAGE_SIZE); 106182583daaSSong Liu if (image) 106282583daaSSong Liu set_vm_flush_reset_perms(image); 106382583daaSSong Liu return image; 106482583daaSSong Liu } 106582583daaSSong Liu 106682583daaSSong Liu void __weak arch_free_bpf_trampoline(void *image, unsigned int size) 106782583daaSSong Liu { 106882583daaSSong Liu WARN_ON_ONCE(size > PAGE_SIZE); 106982583daaSSong Liu /* bpf_jit_free_exec doesn't need "size", but 107082583daaSSong Liu * bpf_prog_pack_free() needs it. 107182583daaSSong Liu */ 107282583daaSSong Liu bpf_jit_free_exec(image); 107382583daaSSong Liu } 107482583daaSSong Liu 107582583daaSSong Liu void __weak arch_protect_bpf_trampoline(void *image, unsigned int size) 107682583daaSSong Liu { 107782583daaSSong Liu WARN_ON_ONCE(size > PAGE_SIZE); 107882583daaSSong Liu set_memory_rox((long)image, 1); 107982583daaSSong Liu } 108082583daaSSong Liu 108182583daaSSong Liu void __weak arch_unprotect_bpf_trampoline(void *image, unsigned int size) 108282583daaSSong Liu { 108382583daaSSong Liu WARN_ON_ONCE(size > PAGE_SIZE); 108482583daaSSong Liu set_memory_nx((long)image, 1); 108582583daaSSong Liu set_memory_rw((long)image, 1); 108682583daaSSong Liu } 108782583daaSSong Liu 108896d1b7c0SSong Liu int __weak arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags, 108996d1b7c0SSong Liu struct bpf_tramp_links *tlinks, void *func_addr) 109096d1b7c0SSong Liu { 109196d1b7c0SSong Liu return -ENOTSUPP; 109296d1b7c0SSong Liu } 109396d1b7c0SSong Liu 1094fec56f58SAlexei Starovoitov static int __init init_trampolines(void) 1095fec56f58SAlexei Starovoitov { 1096fec56f58SAlexei Starovoitov int i; 1097fec56f58SAlexei Starovoitov 1098fec56f58SAlexei Starovoitov for (i = 0; i < TRAMPOLINE_TABLE_SIZE; i++) 1099fec56f58SAlexei Starovoitov INIT_HLIST_HEAD(&trampoline_table[i]); 1100fec56f58SAlexei Starovoitov return 0; 1101fec56f58SAlexei Starovoitov } 1102fec56f58SAlexei Starovoitov late_initcall(init_trampolines); 1103