diff options
Diffstat (limited to 'kernel/trace/bpf_trace.c')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 100 |
1 files changed, 84 insertions, 16 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f92d6ad5e080..1c9a4745e596 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -410,8 +410,6 @@ static const struct bpf_func_proto bpf_perf_event_read_value_proto = { .arg4_type = ARG_CONST_SIZE, }; -static DEFINE_PER_CPU(struct perf_sample_data, bpf_trace_sd); - static __always_inline u64 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, u64 flags, struct perf_sample_data *sd) @@ -442,24 +440,50 @@ __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, return perf_event_output(event, sd, regs); } +/* + * Support executing tracepoints in normal, irq, and nmi context that each call + * bpf_perf_event_output + */ +struct bpf_trace_sample_data { + struct perf_sample_data sds[3]; +}; + +static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); +static DEFINE_PER_CPU(int, bpf_trace_nest_level); BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, u64, flags, void *, data, u64, size) { - struct perf_sample_data *sd = this_cpu_ptr(&bpf_trace_sd); + struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds); + int nest_level = this_cpu_inc_return(bpf_trace_nest_level); struct perf_raw_record raw = { .frag = { .size = size, .data = data, }, }; + struct perf_sample_data *sd; + int err; - if (unlikely(flags & ~(BPF_F_INDEX_MASK))) - return -EINVAL; + if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { + err = -EBUSY; + goto out; + } + + sd = &sds->sds[nest_level - 1]; + + if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { + err = -EINVAL; + goto out; + } perf_sample_data_init(sd, 0, 0); sd->raw = &raw; - return __bpf_perf_event_output(regs, map, flags, sd); + err = __bpf_perf_event_output(regs, map, flags, sd); + +out: + this_cpu_dec(bpf_trace_nest_level); + return err; } static const struct bpf_func_proto bpf_perf_event_output_proto = { @@ -822,16 +846,48 @@ pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) /* * 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, bpf_get_stackid and/or bpf_get_stack + * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. + * + * Since raw tracepoints run despite bpf_prog_active, support concurrent usage + * in normal, irq, and nmi context. */ -static DEFINE_PER_CPU(struct pt_regs, bpf_raw_tp_regs); +struct bpf_raw_tp_regs { + struct pt_regs regs[3]; +}; +static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); +static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); +static struct pt_regs *get_bpf_raw_tp_regs(void) +{ + struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); + int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); + + if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { + this_cpu_dec(bpf_raw_tp_nest_level); + return ERR_PTR(-EBUSY); + } + + return &tp_regs->regs[nest_level - 1]; +} + +static void put_bpf_raw_tp_regs(void) +{ + this_cpu_dec(bpf_raw_tp_nest_level); +} + 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); + struct pt_regs *regs = get_bpf_raw_tp_regs(); + int ret; + + if (IS_ERR(regs)) + return PTR_ERR(regs); perf_fetch_caller_regs(regs); - return ____bpf_perf_event_output(regs, map, flags, data, size); + ret = ____bpf_perf_event_output(regs, map, flags, data, size); + + put_bpf_raw_tp_regs(); + return ret; } static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { @@ -848,12 +904,18 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { 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); + struct pt_regs *regs = get_bpf_raw_tp_regs(); + int ret; + + if (IS_ERR(regs)) + return PTR_ERR(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); + ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, + flags, 0, 0); + put_bpf_raw_tp_regs(); + return ret; } static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { @@ -868,11 +930,17 @@ static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, void *, buf, u32, size, u64, flags) { - struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + struct pt_regs *regs = get_bpf_raw_tp_regs(); + int ret; + + if (IS_ERR(regs)) + return PTR_ERR(regs); perf_fetch_caller_regs(regs); - return bpf_get_stack((unsigned long) regs, (unsigned long) buf, - (unsigned long) size, flags, 0); + ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, + (unsigned long) size, flags, 0); + put_bpf_raw_tp_regs(); + return ret; } static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { |