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Subject[PATCH v1 2/2] perf bpf filter: Support pre-5.16 kernels
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The mem_hops bits were added in 5.16 with no prior equivalent.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/bpf_skel/sample_filter.bpf.c | 28 ++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/bpf_skel/sample_filter.bpf.c b/tools/perf/util/bpf_skel/sample_filter.bpf.c
index 57e3c67d6d37..cffe493af1ed 100644
--- a/tools/perf/util/bpf_skel/sample_filter.bpf.c
+++ b/tools/perf/util/bpf_skel/sample_filter.bpf.c
@@ -24,6 +24,24 @@ 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)
@@ -89,8 +107,14 @@ static inline __u64 perf_get_sample(struct bpf_perf_event_data_kern *kctx,
return kctx->data->data_src.mem_dtlb;
if (entry->part == 7)
return kctx->data->data_src.mem_blk;
- if (entry->part == 8)
- return kctx->data->data_src.mem_hops;
+ 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:
--
2.40.0.577.gac1e443424-goog
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