perf bpf filter: Support pre-5.16 kernels where 'mem_hops' isn't in 'union perf_mem_d...

The 'mem_hops' bits were added in 5.16 with no prior equivalent.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230408055208.1283832-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/bpf_skel/sample_filter.bpf.c b/tools/perf/util/bpf_skel/sample_filter.bpf.c
index 57e3c67d6d37c40612f2a865d0c07dc8688323f3..cffe493af1ed5f3110ad0481c820f5e90688f267 100644 (file)
--- 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: