Adding new link to allow to attach program to multiple function BTF IDs. The link is represented by struct bpf_tracing_multi_link. To configure the link, new fields are added to bpf_attr::link_create to pass array of BTF IDs; struct { __aligned_u64 ids; __u32 cnt; } tracing_multi; Each BTF ID represents function (BTF_KIND_FUNC) that the link will attach bpf program to. We use previously added bpf_trampoline_multi_attach/detach functions to attach/detach the link. The linkinfo/fdinfo callbacks will be implemented in following changes. Note this is supported only for archs (x86_64) with ftrace direct and have single ops support. CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS && CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS Signed-off-by: Jiri Olsa --- include/linux/bpf_types.h | 1 + include/linux/trace_events.h | 6 +++ include/uapi/linux/bpf.h | 5 ++ kernel/bpf/syscall.c | 2 + kernel/trace/bpf_trace.c | 87 ++++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 6 +++ tools/lib/bpf/libbpf.c | 1 + 7 files changed, 108 insertions(+) diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index b13de31e163f..c1656f026790 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -155,3 +155,4 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_PERF_EVENT, perf) BPF_LINK_TYPE(BPF_LINK_TYPE_KPROBE_MULTI, kprobe_multi) BPF_LINK_TYPE(BPF_LINK_TYPE_STRUCT_OPS, struct_ops) BPF_LINK_TYPE(BPF_LINK_TYPE_UPROBE_MULTI, uprobe_multi) +BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING_MULTI, tracing) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 0a2b8229b999..7a28cc824fca 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -778,6 +778,7 @@ int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, unsigned long *missed); int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); +int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr); #else static inline unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) { @@ -830,6 +831,11 @@ bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { return -EOPNOTSUPP; } +static inline int +bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) +{ + return -EOPNOTSUPP; +} #endif enum { diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 68600972a778..7f5c51f27a36 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1180,6 +1180,7 @@ enum bpf_link_type { BPF_LINK_TYPE_UPROBE_MULTI = 12, BPF_LINK_TYPE_NETKIT = 13, BPF_LINK_TYPE_SOCKMAP = 14, + BPF_LINK_TYPE_TRACING_MULTI = 15, __MAX_BPF_LINK_TYPE, }; @@ -1863,6 +1864,10 @@ union bpf_attr { }; __u64 expected_revision; } cgroup; + struct { + __aligned_u64 ids; + __u32 cnt; + } tracing_multi; }; } link_create; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index ff85a9fa080e..5892dca20b7e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5751,6 +5751,8 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) ret = bpf_iter_link_attach(attr, uattr, prog); else if (prog->expected_attach_type == BPF_LSM_CGROUP) ret = cgroup_bpf_link_attach(attr, prog); + else if (is_tracing_multi(prog->expected_attach_type)) + ret = bpf_tracing_multi_attach(prog, attr); else ret = bpf_tracing_prog_attach(prog, attr->link_create.target_fd, diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index eadaef8592a3..bfae9ec5d1b1 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -42,6 +42,7 @@ #define MAX_UPROBE_MULTI_CNT (1U << 20) #define MAX_KPROBE_MULTI_CNT (1U << 20) +#define MAX_TRACING_MULTI_CNT (1U << 20) #ifdef CONFIG_MODULES struct bpf_trace_module { @@ -3592,3 +3593,89 @@ __bpf_kfunc int bpf_copy_from_user_task_str_dynptr(struct bpf_dynptr *dptr, u64 } __bpf_kfunc_end_defs(); + +#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) && defined(CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS) + +static void bpf_tracing_multi_link_release(struct bpf_link *link) +{ + struct bpf_tracing_multi_link *tr_link = + container_of(link, struct bpf_tracing_multi_link, link); + + WARN_ON_ONCE(bpf_trampoline_multi_detach(link->prog, tr_link)); +} + +static void bpf_tracing_multi_link_dealloc(struct bpf_link *link) +{ + struct bpf_tracing_multi_link *tr_link = + container_of(link, struct bpf_tracing_multi_link, link); + + kfree(tr_link); +} + +static const struct bpf_link_ops bpf_tracing_multi_link_lops = { + .release = bpf_tracing_multi_link_release, + .dealloc = bpf_tracing_multi_link_dealloc, +}; + +int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) +{ + struct bpf_tracing_multi_link *link = NULL; + struct bpf_link_primer link_primer; + u32 cnt, *ids = NULL; + u32 __user *uids; + int err; + + uids = u64_to_user_ptr(attr->link_create.tracing_multi.ids); + cnt = attr->link_create.tracing_multi.cnt; + + if (!cnt || !uids) + return -EINVAL; + if (cnt > MAX_TRACING_MULTI_CNT) + return -E2BIG; + + ids = kvmalloc_array(cnt, sizeof(*ids), GFP_KERNEL); + if (!ids) + return -ENOMEM; + + if (copy_from_user(ids, uids, cnt * sizeof(*ids))) { + err = -EFAULT; + goto error; + } + + link = kzalloc(struct_size(link, nodes, cnt), GFP_KERNEL); + if (!link) { + err = -ENOMEM; + goto error; + } + + bpf_link_init(&link->link, BPF_LINK_TYPE_TRACING_MULTI, + &bpf_tracing_multi_link_lops, prog, prog->expected_attach_type); + + err = bpf_link_prime(&link->link, &link_primer); + if (err) + goto error; + + link->nodes_cnt = cnt; + + err = bpf_trampoline_multi_attach(prog, ids, link); + kvfree(ids); + if (err) { + bpf_link_cleanup(&link_primer); + return err; + } + return bpf_link_settle(&link_primer); + +error: + kvfree(ids); + kfree(link); + return err; +} + +#else + +int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) +{ + return -EOPNOTSUPP; +} + +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) && CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS */ diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 61f0fe5bc0aa..7f5c51f27a36 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1180,6 +1180,7 @@ enum bpf_link_type { BPF_LINK_TYPE_UPROBE_MULTI = 12, BPF_LINK_TYPE_NETKIT = 13, BPF_LINK_TYPE_SOCKMAP = 14, + BPF_LINK_TYPE_TRACING_MULTI = 15, __MAX_BPF_LINK_TYPE, }; @@ -1863,6 +1864,10 @@ union bpf_attr { }; __u64 expected_revision; } cgroup; + struct { + __aligned_u64 ids; + __u32 cnt; + } tracing_multi; }; } link_create; @@ -7236,6 +7241,7 @@ enum { TCP_BPF_SOCK_OPS_CB_FLAGS = 1008, /* Get or Set TCP sock ops flags */ SK_BPF_CB_FLAGS = 1009, /* Get or set sock ops flags in socket */ SK_BPF_BYPASS_PROT_MEM = 1010, /* Get or Set sk->sk_bypass_prot_mem */ + }; enum { diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 1e19c7b861ec..74e579d7f310 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -156,6 +156,7 @@ static const char * const link_type_name[] = { [BPF_LINK_TYPE_UPROBE_MULTI] = "uprobe_multi", [BPF_LINK_TYPE_NETKIT] = "netkit", [BPF_LINK_TYPE_SOCKMAP] = "sockmap", + [BPF_LINK_TYPE_TRACING_MULTI] = "tracing_multi", }; static const char * const map_type_name[] = { -- 2.52.0