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, 216 deletions

diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
deleted file mode 100644
index 5d1c725cea29..000000000000
--- a/tools/perf/util/bpf-loader.h
+++ /dev/null
@@ -1,216 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
- * Copyright (C) 2015, Huawei Inc.
- */
-#ifndef __BPF_LOADER_H
-#define __BPF_LOADER_H
-
-#include <linux/compiler.h>
-#include <linux/err.h>
-
-#ifdef HAVE_LIBBPF_SUPPORT
-#include <bpf/libbpf.h>
-
-enum bpf_loader_errno {
-	__BPF_LOADER_ERRNO__START = __LIBBPF_ERRNO__START - 100,
-	/* Invalid config string */
-	BPF_LOADER_ERRNO__CONFIG = __BPF_LOADER_ERRNO__START,
-	BPF_LOADER_ERRNO__GROUP,	/* Invalid group name */
-	BPF_LOADER_ERRNO__EVENTNAME,	/* Event name is missing */
-	BPF_LOADER_ERRNO__INTERNAL,	/* BPF loader internal error */
-	BPF_LOADER_ERRNO__COMPILE,	/* Error when compiling BPF scriptlet */
-	BPF_LOADER_ERRNO__PROGCONF_TERM,/* Invalid program config term in config string */
-	BPF_LOADER_ERRNO__PROLOGUE,	/* Failed to generate prologue */
-	BPF_LOADER_ERRNO__PROLOGUE2BIG,	/* Prologue too big for program */
-	BPF_LOADER_ERRNO__PROLOGUEOOB,	/* Offset out of bound for prologue */
-	BPF_LOADER_ERRNO__OBJCONF_OPT,	/* Invalid object config option */
-	BPF_LOADER_ERRNO__OBJCONF_CONF,	/* Config value not set (lost '=')) */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_OPT,	/* Invalid object map config option */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_NOTEXIST,	/* Target map not exist */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_VALUE,	/* Incorrect value type for map */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_TYPE,	/* Incorrect map type */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_KEYSIZE,	/* Incorrect map key size */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_VALUESIZE,/* Incorrect map value size */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_NOEVT,	/* Event not found for map setting */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_MAPSIZE,	/* Invalid map size for event setting */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_EVTDIM,	/* Event dimension too large */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_EVTINH,	/* Doesn't support inherit event */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_EVTTYPE,	/* Wrong event type for map */
-	BPF_LOADER_ERRNO__OBJCONF_MAP_IDX2BIG,	/* Index too large */
-	__BPF_LOADER_ERRNO__END,
-};
-#endif // HAVE_LIBBPF_SUPPORT
-
-struct evsel;
-struct evlist;
-struct bpf_object;
-struct parse_events_term;
-#define PERF_BPF_PROBE_GROUP "perf_bpf_probe"
-
-typedef int (*bpf_prog_iter_callback_t)(const char *group, const char *event,
-					int fd, struct bpf_object *obj, void *arg);
-
-#ifdef HAVE_LIBBPF_SUPPORT
-struct bpf_object *bpf__prepare_load(const char *filename, bool source);
-int bpf__strerror_prepare_load(const char *filename, bool source,
-			       int err, char *buf, size_t size);
-
-struct bpf_object *bpf__prepare_load_buffer(void *obj_buf, size_t obj_buf_sz,
-					    const char *name);
-
-void bpf__clear(void);
-
-int bpf__probe(struct bpf_object *obj);
-int bpf__unprobe(struct bpf_object *obj);
-int bpf__strerror_probe(struct bpf_object *obj, int err,
-			char *buf, size_t size);
-
-int bpf__load(struct bpf_object *obj);
-int bpf__strerror_load(struct bpf_object *obj, int err,
-		       char *buf, size_t size);
-int bpf__foreach_event(struct bpf_object *obj,
-		       bpf_prog_iter_callback_t func, void *arg);
-
-int bpf__config_obj(struct bpf_object *obj, struct parse_events_term *term,
-		    struct evlist *evlist, int *error_pos);
-int bpf__strerror_config_obj(struct bpf_object *obj,
-			     struct parse_events_term *term,
-			     struct evlist *evlist,
-			     int *error_pos, int err, char *buf,
-			     size_t size);
-int bpf__apply_obj_config(void);
-int bpf__strerror_apply_obj_config(int err, char *buf, size_t size);
-
-int bpf__setup_stdout(struct evlist *evlist);
-struct evsel *bpf__setup_output_event(struct evlist *evlist, const char *name);
-int bpf__strerror_setup_output_event(struct evlist *evlist, int err, char *buf, size_t size);
-#else
-#include <errno.h>
-#include <string.h>
-#include "debug.h"
-
-static inline struct bpf_object *
-bpf__prepare_load(const char *filename __maybe_unused,
-		  bool source __maybe_unused)
-{
-	pr_debug("ERROR: eBPF object loading is disabled during compiling.\n");
-	return ERR_PTR(-ENOTSUP);
-}
-
-static inline struct bpf_object *
-bpf__prepare_load_buffer(void *obj_buf __maybe_unused,
-					   size_t obj_buf_sz __maybe_unused)
-{
-	return ERR_PTR(-ENOTSUP);
-}
-
-static inline void bpf__clear(void) { }
-
-static inline int bpf__probe(struct bpf_object *obj __maybe_unused) { return 0;}
-static inline int bpf__unprobe(struct bpf_object *obj __maybe_unused) { return 0;}
-static inline int bpf__load(struct bpf_object *obj __maybe_unused) { return 0; }
-
-static inline int
-bpf__foreach_event(struct bpf_object *obj __maybe_unused,
-		   bpf_prog_iter_callback_t func __maybe_unused,
-		   void *arg __maybe_unused)
-{
-	return 0;
-}
-
-static inline int
-bpf__config_obj(struct bpf_object *obj __maybe_unused,
-		struct parse_events_term *term __maybe_unused,
-		struct evlist *evlist __maybe_unused,
-		int *error_pos __maybe_unused)
-{
-	return 0;
-}
-
-static inline int
-bpf__apply_obj_config(void)
-{
-	return 0;
-}
-
-static inline int
-bpf__setup_stdout(struct evlist *evlist __maybe_unused)
-{
-	return 0;
-}
-
-static inline struct evsel *
-bpf__setup_output_event(struct evlist *evlist __maybe_unused, const char *name __maybe_unused)
-{
-	return NULL;
-}
-
-static inline int
-__bpf_strerror(char *buf, size_t size)
-{
-	if (!size)
-		return 0;
-	strncpy(buf,
-		"ERROR: eBPF object loading is disabled during compiling.\n",
-		size);
-	buf[size - 1] = '\0';
-	return 0;
-}
-
-static inline
-int bpf__strerror_prepare_load(const char *filename __maybe_unused,
-			       bool source __maybe_unused,
-			       int err __maybe_unused,
-			       char *buf, size_t size)
-{
-	return __bpf_strerror(buf, size);
-}
-
-static inline int
-bpf__strerror_probe(struct bpf_object *obj __maybe_unused,
-		    int err __maybe_unused,
-		    char *buf, size_t size)
-{
-	return __bpf_strerror(buf, size);
-}
-
-static inline int bpf__strerror_load(struct bpf_object *obj __maybe_unused,
-				     int err __maybe_unused,
-				     char *buf, size_t size)
-{
-	return __bpf_strerror(buf, size);
-}
-
-static inline int
-bpf__strerror_config_obj(struct bpf_object *obj __maybe_unused,
-			 struct parse_events_term *term __maybe_unused,
-			 struct evlist *evlist __maybe_unused,
-			 int *error_pos __maybe_unused,
-			 int err __maybe_unused,
-			 char *buf, size_t size)
-{
-	return __bpf_strerror(buf, size);
-}
-
-static inline int
-bpf__strerror_apply_obj_config(int err __maybe_unused,
-			       char *buf, size_t size)
-{
-	return __bpf_strerror(buf, size);
-}
-
-static inline int
-bpf__strerror_setup_output_event(struct evlist *evlist __maybe_unused,
-				 int err __maybe_unused, char *buf, size_t size)
-{
-	return __bpf_strerror(buf, size);
-}
-
-#endif
-
-static inline int bpf__strerror_setup_stdout(struct evlist *evlist, int err, char *buf, size_t size)
-{
-	return bpf__strerror_setup_output_event(evlist, err, buf, size);
-}
-#endif