perf parse-events: Remove BPF event support

New features like the BPF --filter support in perf record have made the
BPF event functionality somewhat redundant. As shown by commit
fcb027c1a4f6 ("perf tools: Revert enable indices setting syntax for BPF
map") and commit 14e4b9f4289a ("perf trace: Raw augmented syscalls fix
libbpf 1.0+ compatibility") the BPF event support hasn't been well
maintained and it adds considerable complexity in areas like event
parsing, not least as '/' is a separator for event modifiers as well as
in paths.

This patch removes support in the event parser for BPF events and then
the associated functions are removed. This leads to the removal of whole
source files like bpf-loader.c.  Removing support means that augmented
syscalls in perf trace is broken, this will be fixed in a later commit
adding support using BPF skeletons.

The removal of BPF events causes an unused label warning from flex
generated code, so update build to ignore it:

  ```
  util/parse-events-flex.c:2704:1: error: label ‘find_rule’ defined but not used [-Werror=unused-label]
  2704 | find_rule: /* we branch to this label when backing up */
  ```

Committer notes:

Extracted from a larger patch that was also removing the support for
linking with libllvm and libclang, that were an alternative to using an
external clang execution to compile the .c event source code into BPF
bytecode.

Testing it:

  # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Bad event or PMU

  Unabled to find PMU or event on a PMU of 'home'

  Initial error:
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Cannot find PMU `home'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf trace [<options>] [<command>]
      or: perf trace [<options>] -- <command> [<options>]
      or: perf trace record [<options>] [<command>]
      or: perf trace record [<options>] -- <command> [<options>]

      -e, --event <event>   event/syscall selector. use 'perf list' to list available events
  #

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Carsten Haitzler <carsten.haitzler@arm.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Fangrui Song <maskray@google.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Tom Rix <trix@redhat.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: bpf@vger.kernel.org
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20230810184853.2860737-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 0 insertions, 268 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 0b5075ef00c8..00a8ec94f5b2 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -14,7 +14,6 @@
 #include "parse-events.h"
 #include "string2.h"
 #include "strlist.h"
-#include "bpf-loader.h"
 #include "debug.h"
 #include <api/fs/tracing_path.h>
 #include <perf/cpumap.h>
@@ -648,272 +647,6 @@ static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
 }
 #endif /* HAVE_LIBTRACEEVENT */
 
-#ifdef HAVE_LIBBPF_SUPPORT
-struct __add_bpf_event_param {
-	struct parse_events_state *parse_state;
-	struct list_head *list;
-	struct list_head *head_config;
-	YYLTYPE *loc;
-};
-
-static int add_bpf_event(const char *group, const char *event, int fd, struct bpf_object *obj,
-			 void *_param)
-{
-	LIST_HEAD(new_evsels);
-	struct __add_bpf_event_param *param = _param;
-	struct parse_events_state *parse_state = param->parse_state;
-	struct list_head *list = param->list;
-	struct evsel *pos;
-	int err;
-	/*
-	 * Check if we should add the event, i.e. if it is a TP but starts with a '!',
-	 * then don't add the tracepoint, this will be used for something else, like
-	 * adding to a BPF_MAP_TYPE_PROG_ARRAY.
-	 *
-	 * See tools/perf/examples/bpf/augmented_raw_syscalls.c
-	 */
-	if (group[0] == '!')
-		return 0;
-
-	pr_debug("add bpf event %s:%s and attach bpf program %d\n",
-		 group, event, fd);
-
-	err = parse_events_add_tracepoint(&new_evsels, &parse_state->idx, group,
-					  event, parse_state->error,
-					  param->head_config, param->loc);
-	if (err) {
-		struct evsel *evsel, *tmp;
-
-		pr_debug("Failed to add BPF event %s:%s\n",
-			 group, event);
-		list_for_each_entry_safe(evsel, tmp, &new_evsels, core.node) {
-			list_del_init(&evsel->core.node);
-			evsel__delete(evsel);
-		}
-		return err;
-	}
-	pr_debug("adding %s:%s\n", group, event);
-
-	list_for_each_entry(pos, &new_evsels, core.node) {
-		pr_debug("adding %s:%s to %p\n",
-			 group, event, pos);
-		pos->bpf_fd = fd;
-		pos->bpf_obj = obj;
-	}
-	list_splice(&new_evsels, list);
-	return 0;
-}
-
-int parse_events_load_bpf_obj(struct parse_events_state *parse_state,
-			      struct list_head *list,
-			      struct bpf_object *obj,
-			      struct list_head *head_config,
-			      void *loc)
-{
-	int err;
-	char errbuf[BUFSIZ];
-	struct __add_bpf_event_param param = {parse_state, list, head_config, loc};
-	static bool registered_unprobe_atexit = false;
-	YYLTYPE test_loc = {.first_column = -1};
-
-	if (IS_ERR(obj) || !obj) {
-		snprintf(errbuf, sizeof(errbuf),
-			 "Internal error: load bpf obj with NULL");
-		err = -EINVAL;
-		goto errout;
-	}
-
-	/*
-	 * Register atexit handler before calling bpf__probe() so
-	 * bpf__probe() don't need to unprobe probe points its already
-	 * created when failure.
-	 */
-	if (!registered_unprobe_atexit) {
-		atexit(bpf__clear);
-		registered_unprobe_atexit = true;
-	}
-
-	err = bpf__probe(obj);
-	if (err) {
-		bpf__strerror_probe(obj, err, errbuf, sizeof(errbuf));
-		goto errout;
-	}
-
-	err = bpf__load(obj);
-	if (err) {
-		bpf__strerror_load(obj, err, errbuf, sizeof(errbuf));
-		goto errout;
-	}
-
-	if (!param.loc)
-		param.loc = &test_loc;
-
-	err = bpf__foreach_event(obj, add_bpf_event, &param);
-	if (err) {
-		snprintf(errbuf, sizeof(errbuf),
-			 "Attach events in BPF object failed");
-		goto errout;
-	}
-
-	return 0;
-errout:
-	parse_events_error__handle(parse_state->error, param.loc ? param.loc->first_column : 0,
-				strdup(errbuf), strdup("(add -v to see detail)"));
-	return err;
-}
-
-static int
-parse_events_config_bpf(struct parse_events_state *parse_state,
-			struct bpf_object *obj,
-			struct list_head *head_config)
-{
-	struct parse_events_term *term;
-	int error_pos = 0;
-
-	if (!head_config || list_empty(head_config))
-		return 0;
-
-	list_for_each_entry(term, head_config, list) {
-		int err;
-
-		if (term->type_term != PARSE_EVENTS__TERM_TYPE_USER) {
-			parse_events_error__handle(parse_state->error, term->err_term,
-						strdup("Invalid config term for BPF object"),
-						NULL);
-			return -EINVAL;
-		}
-
-		err = bpf__config_obj(obj, term, parse_state->evlist, &error_pos);
-		if (err) {
-			char errbuf[BUFSIZ];
-			int idx;
-
-			bpf__strerror_config_obj(obj, term, parse_state->evlist,
-						 &error_pos, err, errbuf,
-						 sizeof(errbuf));
-
-			if (err == -BPF_LOADER_ERRNO__OBJCONF_MAP_VALUE)
-				idx = term->err_val;
-			else
-				idx = term->err_term + error_pos;
-
-			parse_events_error__handle(parse_state->error, idx,
-						strdup(errbuf),
-						NULL);
-			return err;
-		}
-	}
-	return 0;
-}
-
-/*
- * Split config terms:
- * perf record -e bpf.c/call-graph=fp,map:array.value[0]=1/ ...
- *  'call-graph=fp' is 'evt config', should be applied to each
- *  events in bpf.c.
- * 'map:array.value[0]=1' is 'obj config', should be processed
- * with parse_events_config_bpf.
- *
- * Move object config terms from the first list to obj_head_config.
- */
-static void
-split_bpf_config_terms(struct list_head *evt_head_config,
-		       struct list_head *obj_head_config)
-{
-	struct parse_events_term *term, *temp;
-
-	/*
-	 * Currently, all possible user config term
-	 * belong to bpf object. parse_events__is_hardcoded_term()
-	 * happens to be a good flag.
-	 *
-	 * See parse_events_config_bpf() and
-	 * config_term_tracepoint().
-	 */
-	list_for_each_entry_safe(term, temp, evt_head_config, list)
-		if (!parse_events__is_hardcoded_term(term))
-			list_move_tail(&term->list, obj_head_config);
-}
-
-int parse_events_load_bpf(struct parse_events_state *parse_state,
-			  struct list_head *list,
-			  char *bpf_file_name,
-			  bool source,
-			  struct list_head *head_config,
-			  void *loc_)
-{
-	int err;
-	struct bpf_object *obj;
-	LIST_HEAD(obj_head_config);
-	YYLTYPE *loc = loc_;
-
-	if (head_config)
-		split_bpf_config_terms(head_config, &obj_head_config);
-
-	obj = bpf__prepare_load(bpf_file_name, source);
-	if (IS_ERR(obj)) {
-		char errbuf[BUFSIZ];
-
-		err = PTR_ERR(obj);
-
-		if (err == -ENOTSUP)
-			snprintf(errbuf, sizeof(errbuf),
-				 "BPF support is not compiled");
-		else
-			bpf__strerror_prepare_load(bpf_file_name,
-						   source,
-						   -err, errbuf,
-						   sizeof(errbuf));
-
-		parse_events_error__handle(parse_state->error, loc->first_column,
-					strdup(errbuf), strdup("(add -v to see detail)"));
-		return err;
-	}
-
-	err = parse_events_load_bpf_obj(parse_state, list, obj, head_config, loc);
-	if (err)
-		return err;
-	err = parse_events_config_bpf(parse_state, obj, &obj_head_config);
-
-	/*
-	 * Caller doesn't know anything about obj_head_config,
-	 * so combine them together again before returning.
-	 */
-	if (head_config)
-		list_splice_tail(&obj_head_config, head_config);
-	return err;
-}
-#else // HAVE_LIBBPF_SUPPORT
-int parse_events_load_bpf_obj(struct parse_events_state *parse_state,
-			      struct list_head *list __maybe_unused,
-			      struct bpf_object *obj __maybe_unused,
-			      struct list_head *head_config __maybe_unused,
-			      void *loc_)
-{
-	YYLTYPE *loc = loc_;
-
-	parse_events_error__handle(parse_state->error, loc->first_column,
-				   strdup("BPF support is not compiled"),
-				   strdup("Make sure libbpf-devel is available at build time."));
-	return -ENOTSUP;
-}
-
-int parse_events_load_bpf(struct parse_events_state *parse_state,
-			  struct list_head *list __maybe_unused,
-			  char *bpf_file_name __maybe_unused,
-			  bool source __maybe_unused,
-			  struct list_head *head_config __maybe_unused,
-			  void *loc_)
-{
-	YYLTYPE *loc = loc_;
-
-	parse_events_error__handle(parse_state->error, loc->first_column,
-				   strdup("BPF support is not compiled"),
-				   strdup("Make sure libbpf-devel is available at build time."));
-	return -ENOTSUP;
-}
-#endif // HAVE_LIBBPF_SUPPORT
-
 static int
 parse_breakpoint_type(const char *type, struct perf_event_attr *attr)
 {
@@ -2274,7 +2007,6 @@ int __parse_events(struct evlist *evlist, const char *str, const char *pmu_filte
 		.list	  = LIST_HEAD_INIT(parse_state.list),
 		.idx	  = evlist->core.nr_entries,
 		.error	  = err,
-		.evlist	  = evlist,
 		.stoken	  = PE_START_EVENTS,
 		.fake_pmu = fake_pmu,
 		.pmu_filter = pmu_filter,