perf bpf filter: Introduce basic BPF filter expression

This implements a tiny parser for the filter expressions used for BPF.
Each expression will be converted to struct perf_bpf_filter_expr and
be passed to a BPF map.

For now, I'd like to start with the very basic comparisons like EQ or
GT.  The LHS should be a term for sample data and the RHS is a number.
The expressions are connected by a comma.  For example,

    period > 10000
    ip < 0x1000000000000, cpu == 3

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230314234237.3008956-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/tools/perf/util/bpf-filter.y b/tools/perf/util/bpf-filter.y
new file mode 100644
index 000000000000..13eca612ecca
--- /dev/null
+++ b/tools/perf/util/bpf-filter.y
@@ -0,0 +1,54 @@
+%parse-param {struct list_head *expr_head}
+%define parse.error verbose
+
+%{
+
+#include <stdio.h>
+#include <string.h>
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include "bpf-filter.h"
+
+static void perf_bpf_filter_error(struct list_head *expr __maybe_unused,
+				  char const *msg)
+{
+	printf("perf_bpf_filter: %s\n", msg);
+}
+
+%}
+
+%union
+{
+	unsigned long num;
+	unsigned long sample;
+	enum perf_bpf_filter_op op;
+	struct perf_bpf_filter_expr *expr;
+}
+
+%token BFT_SAMPLE BFT_OP BFT_ERROR BFT_NUM
+%type <expr> filter_term
+%destructor { free ($$); } <expr>
+%type <sample> BFT_SAMPLE
+%type <op> BFT_OP
+%type <num> BFT_NUM
+
+%%
+
+filter:
+filter ',' filter_term
+{
+	list_add_tail(&$3->list, expr_head);
+}
+|
+filter_term
+{
+	list_add_tail(&$1->list, expr_head);
+}
+
+filter_term:
+BFT_SAMPLE BFT_OP BFT_NUM
+{
+	$$ = perf_bpf_filter_expr__new($1, $2, $3);
+}
+
+%%