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perf bpf filter: Add uid and gid terms

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Allow the BPF filter to use the uid and gid terms determined by the
bpf_get_current_uid_gid BPF helper. For example, the following will
record the cpu-clock event system wide discarding samples that don't
belong to the current user.

$ perf record -e cpu-clock --filter "uid == $(id -u)" -a sleep 0.1

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240524205227.244375-3-irogers@google.com
This commit is contained in:
Ian Rogers 2024-05-24 13:52:26 -07:00 committed by Namhyung Kim
parent 63b9cbd794
commit d92aa899fe
5 changed files with 15 additions and 1 deletions
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2
tools/perf/Documentation/perf-record.txt
View File

@ -200,7 +200,7 @@ OPTIONS
ip, id, tid, pid, cpu, time, addr, period, txn, weight, phys_addr,
code_pgsz, data_pgsz, weight1, weight2, weight3, ins_lat, retire_lat,
p_stage_cyc, mem_op, mem_lvl, mem_snoop, mem_remote, mem_lock,
mem_dtlb, mem_blk, mem_hops
mem_dtlb, mem_blk, mem_hops, uid, gid
The <operator> can be one of:
==, !=, >, >=, <, <=, &

5
tools/perf/util/bpf-filter.c
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@ -63,6 +63,11 @@ static int check_sample_flags(struct evsel *evsel, struct perf_bpf_filter_expr *
(evsel->core.attr.sample_type & (1 << (expr->term - PBF_TERM_SAMPLE_START))))
return 0;
if (expr->term == PBF_TERM_UID || expr->term == PBF_TERM_GID) {
/* Not dependent on the sample_type as computed from a BPF helper. */
return 0;
}
if (expr->op == PBF_OP_GROUP_BEGIN) {
struct perf_bpf_filter_expr *group;

2
tools/perf/util/bpf-filter.l
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@ -95,6 +95,8 @@ mem_lock { return sample_part(PBF_TERM_DATA_SRC, 5); }
mem_dtlb { return sample_part(PBF_TERM_DATA_SRC, 6); }
mem_blk { return sample_part(PBF_TERM_DATA_SRC, 7); }
mem_hops { return sample_part(PBF_TERM_DATA_SRC, 8); }
uid { return sample(PBF_TERM_UID); }
gid { return sample(PBF_TERM_GID); }
"==" { return operator(PBF_OP_EQ); }
"!=" { return operator(PBF_OP_NEQ); }

3
tools/perf/util/bpf_skel/sample-filter.h
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@ -47,6 +47,9 @@ enum perf_bpf_filter_term {
PBF_TERM_CODE_PAGE_SIZE = PBF_TERM_SAMPLE_START + 23, /* SAMPLE_CODE_PAGE_SIZE = 1U << 23 */
PBF_TERM_WEIGHT_STRUCT = PBF_TERM_SAMPLE_START + 24, /* SAMPLE_WEIGHT_STRUCT = 1U << 24 */
PBF_TERM_SAMPLE_END = PBF_TERM_WEIGHT_STRUCT,
/* Terms computed from BPF helpers. */
PBF_TERM_UID,
PBF_TERM_GID,
};
/* BPF map entry for filtering */

4
tools/perf/util/bpf_skel/sample_filter.bpf.c
View File

@ -140,6 +140,10 @@ static inline __u64 perf_get_sample(struct bpf_perf_event_data_kern *kctx,
}
/* return the whole word */
return kctx->data->data_src.val;
case PBF_TERM_UID:
return bpf_get_current_uid_gid() & 0xFFFFFFFF;
case PBF_TERM_GID:
return bpf_get_current_uid_gid() >> 32;
case PBF_TERM_NONE:
case __PBF_UNUSED_TERM4:
case __PBF_UNUSED_TERM5: