diff options
Diffstat (limited to 'tools/perf/util/bpf_skel/sample_filter.bpf.c')
| -rw-r--r-- | tools/perf/util/bpf_skel/sample_filter.bpf.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/tools/perf/util/bpf_skel/sample_filter.bpf.c b/tools/perf/util/bpf_skel/sample_filter.bpf.c new file mode 100644 index 000000000000..fb94f5280626 --- /dev/null +++ b/tools/perf/util/bpf_skel/sample_filter.bpf.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +// Copyright (c) 2023 Google +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_core_read.h> + +#include "sample-filter.h" + +/* BPF map that will be filled by user space */ +struct filters { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct perf_bpf_filter_entry); + __uint(max_entries, MAX_FILTERS); +} filters SEC(".maps"); + +int dropped; + +void *bpf_cast_to_kern_ctx(void *) __ksym; + +/* new kernel perf_sample_data definition */ +struct perf_sample_data___new { + __u64 sample_flags; +} __attribute__((preserve_access_index)); + +/* new kernel perf_mem_data_src definition */ +union perf_mem_data_src___new { + __u64 val; + struct { + __u64 mem_op:5, /* type of opcode */ + mem_lvl:14, /* memory hierarchy level */ + mem_snoop:5, /* snoop mode */ + mem_lock:2, /* lock instr */ + mem_dtlb:7, /* tlb access */ + mem_lvl_num:4, /* memory hierarchy level number */ + mem_remote:1, /* remote */ + mem_snoopx:2, /* snoop mode, ext */ + mem_blk:3, /* access blocked */ + mem_hops:3, /* hop level */ + mem_rsvd:18; + }; +}; + +/* helper function to return the given perf sample data */ +static inline __u64 perf_get_sample(struct bpf_perf_event_data_kern *kctx, + struct perf_bpf_filter_entry *entry) +{ + struct perf_sample_data___new *data = (void *)kctx->data; + + if (!bpf_core_field_exists(data->sample_flags) || + (data->sample_flags & entry->flags) == 0) + return 0; + + switch (entry->flags) { + case PERF_SAMPLE_IP: + return kctx->data->ip; + case PERF_SAMPLE_ID: + return kctx->data->id; + case PERF_SAMPLE_TID: + if (entry->part) + return kctx->data->tid_entry.pid; + else + return kctx->data->tid_entry.tid; + case PERF_SAMPLE_CPU: + return kctx->data->cpu_entry.cpu; + case PERF_SAMPLE_TIME: + return kctx->data->time; + case PERF_SAMPLE_ADDR: + return kctx->data->addr; + case PERF_SAMPLE_PERIOD: + return kctx->data->period; + case PERF_SAMPLE_TRANSACTION: + return kctx->data->txn; + case PERF_SAMPLE_WEIGHT_STRUCT: + if (entry->part == 1) + return kctx->data->weight.var1_dw; + if (entry->part == 2) + return kctx->data->weight.var2_w; + if (entry->part == 3) + return kctx->data->weight.var3_w; + /* fall through */ + case PERF_SAMPLE_WEIGHT: + return kctx->data->weight.full; + case PERF_SAMPLE_PHYS_ADDR: + return kctx->data->phys_addr; + case PERF_SAMPLE_CODE_PAGE_SIZE: + return kctx->data->code_page_size; + case PERF_SAMPLE_DATA_PAGE_SIZE: + return kctx->data->data_page_size; + case PERF_SAMPLE_DATA_SRC: + if (entry->part == 1) + return kctx->data->data_src.mem_op; + if (entry->part == 2) + return kctx->data->data_src.mem_lvl_num; + if (entry->part == 3) { + __u32 snoop = kctx->data->data_src.mem_snoop; + __u32 snoopx = kctx->data->data_src.mem_snoopx; + + return (snoopx << 5) | snoop; + } + if (entry->part == 4) + return kctx->data->data_src.mem_remote; + if (entry->part == 5) + return kctx->data->data_src.mem_lock; + if (entry->part == 6) + return kctx->data->data_src.mem_dtlb; + if (entry->part == 7) + return kctx->data->data_src.mem_blk; + if (entry->part == 8) { + union perf_mem_data_src___new *data = (void *)&kctx->data->data_src; + + if (bpf_core_field_exists(data->mem_hops)) + return data->mem_hops; + + return 0; + } + /* return the whole word */ + return kctx->data->data_src.val; + default: + break; + } + return 0; +} + +#define CHECK_RESULT(data, op, val) \ + if (!(data op val)) { \ + if (!in_group) \ + goto drop; \ + } else if (in_group) { \ + group_result = 1; \ + } + +/* BPF program to be called from perf event overflow handler */ +SEC("perf_event") +int perf_sample_filter(void *ctx) +{ + struct bpf_perf_event_data_kern *kctx; + struct perf_bpf_filter_entry *entry; + __u64 sample_data; + int in_group = 0; + int group_result = 0; + int i; + + kctx = bpf_cast_to_kern_ctx(ctx); + + for (i = 0; i < MAX_FILTERS; i++) { + int key = i; /* needed for verifier :( */ + + entry = bpf_map_lookup_elem(&filters, &key); + if (entry == NULL) + break; + sample_data = perf_get_sample(kctx, entry); + + switch (entry->op) { + case PBF_OP_EQ: + CHECK_RESULT(sample_data, ==, entry->value) + break; + case PBF_OP_NEQ: + CHECK_RESULT(sample_data, !=, entry->value) + break; + case PBF_OP_GT: + CHECK_RESULT(sample_data, >, entry->value) + break; + case PBF_OP_GE: + CHECK_RESULT(sample_data, >=, entry->value) + break; + case PBF_OP_LT: + CHECK_RESULT(sample_data, <, entry->value) + break; + case PBF_OP_LE: + CHECK_RESULT(sample_data, <=, entry->value) + break; + case PBF_OP_AND: + CHECK_RESULT(sample_data, &, entry->value) + break; + case PBF_OP_GROUP_BEGIN: + in_group = 1; + group_result = 0; + break; + case PBF_OP_GROUP_END: + if (group_result == 0) + goto drop; + in_group = 0; + break; + } + } + /* generate sample data */ + return 1; + +drop: + __sync_fetch_and_add(&dropped, 1); + return 0; +} + +char LICENSE[] SEC("license") = "Dual BSD/GPL"; |