diff options
Diffstat (limited to 'kernel/trace/bpf_trace.c')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 7f9691c86b6e..463e72d18c4c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -735,6 +735,86 @@ static const struct bpf_func_proto *pe_prog_func_proto(enum bpf_func_id func_id) } } +/* + * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp + * to avoid potential recursive reuse issue when/if tracepoints are added + * inside bpf_*_event_output and/or bpf_get_stack_id + */ +static DEFINE_PER_CPU(struct pt_regs, bpf_raw_tp_regs); +BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, + struct bpf_map *, map, u64, flags, void *, data, u64, size) +{ + struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + + perf_fetch_caller_regs(regs); + return ____bpf_perf_event_output(regs, map, flags, data, size); +} + +static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { + .func = bpf_perf_event_output_raw_tp, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_MEM, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + +BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, + struct bpf_map *, map, u64, flags) +{ + struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + + perf_fetch_caller_regs(regs); + /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ + return bpf_get_stackid((unsigned long) regs, (unsigned long) map, + flags, 0, 0); +} + +static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { + .func = bpf_get_stackid_raw_tp, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, +}; + +static const struct bpf_func_proto *raw_tp_prog_func_proto(enum bpf_func_id func_id) +{ + switch (func_id) { + case BPF_FUNC_perf_event_output: + return &bpf_perf_event_output_proto_raw_tp; + case BPF_FUNC_get_stackid: + return &bpf_get_stackid_proto_raw_tp; + default: + return tracing_func_proto(func_id); + } +} + +static bool raw_tp_prog_is_valid_access(int off, int size, + enum bpf_access_type type, + struct bpf_insn_access_aux *info) +{ + /* largest tracepoint in the kernel has 12 args */ + if (off < 0 || off >= sizeof(__u64) * 12) + return false; + if (type != BPF_READ) + return false; + if (off % size != 0) + return false; + return true; +} + +const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { + .get_func_proto = raw_tp_prog_func_proto, + .is_valid_access = raw_tp_prog_is_valid_access, +}; + +const struct bpf_prog_ops raw_tracepoint_prog_ops = { +}; + static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, struct bpf_insn_access_aux *info) { @@ -908,3 +988,106 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) return ret; } + +extern struct bpf_raw_event_map __start__bpf_raw_tp[]; +extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; + +struct bpf_raw_event_map *bpf_find_raw_tracepoint(const char *name) +{ + struct bpf_raw_event_map *btp = __start__bpf_raw_tp; + + for (; btp < __stop__bpf_raw_tp; btp++) { + if (!strcmp(btp->tp->name, name)) + return btp; + } + return NULL; +} + +static __always_inline +void __bpf_trace_run(struct bpf_prog *prog, u64 *args) +{ + rcu_read_lock(); + preempt_disable(); + (void) BPF_PROG_RUN(prog, args); + preempt_enable(); + rcu_read_unlock(); +} + +#define UNPACK(...) __VA_ARGS__ +#define REPEAT_1(FN, DL, X, ...) FN(X) +#define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) +#define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) +#define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) +#define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) +#define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) +#define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) +#define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) +#define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) +#define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) +#define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) +#define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) +#define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) + +#define SARG(X) u64 arg##X +#define COPY(X) args[X] = arg##X + +#define __DL_COM (,) +#define __DL_SEM (;) + +#define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 + +#define BPF_TRACE_DEFN_x(x) \ + void bpf_trace_run##x(struct bpf_prog *prog, \ + REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ + { \ + u64 args[x]; \ + REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ + __bpf_trace_run(prog, args); \ + } \ + EXPORT_SYMBOL_GPL(bpf_trace_run##x) +BPF_TRACE_DEFN_x(1); +BPF_TRACE_DEFN_x(2); +BPF_TRACE_DEFN_x(3); +BPF_TRACE_DEFN_x(4); +BPF_TRACE_DEFN_x(5); +BPF_TRACE_DEFN_x(6); +BPF_TRACE_DEFN_x(7); +BPF_TRACE_DEFN_x(8); +BPF_TRACE_DEFN_x(9); +BPF_TRACE_DEFN_x(10); +BPF_TRACE_DEFN_x(11); +BPF_TRACE_DEFN_x(12); + +static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +{ + struct tracepoint *tp = btp->tp; + + /* + * check that program doesn't access arguments beyond what's + * available in this tracepoint + */ + if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) + return -EINVAL; + + return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); +} + +int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +{ + int err; + + mutex_lock(&bpf_event_mutex); + err = __bpf_probe_register(btp, prog); + mutex_unlock(&bpf_event_mutex); + return err; +} + +int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +{ + int err; + + mutex_lock(&bpf_event_mutex); + err = tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); + mutex_unlock(&bpf_event_mutex); + return err; +} |