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 <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Carsten Haitzler <[email protected]>
Cc: Eduard Zingerman <[email protected]>
Cc: Fangrui Song <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Tiezhu Yang <[email protected]>
Cc: Tom Rix <[email protected]>
Cc: Wang Nan <[email protected]>
Cc: Wang ShaoBo <[email protected]>
Cc: Yang Jihong <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: YueHaibing <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 0 insertions, 60 deletions

diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
deleted file mode 100644
index b638cc99d5ae..000000000000
--- a/tools/perf/tests/bpf-script-example.c
+++ /dev/null
@@ -1,60 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * bpf-script-example.c
- * Test basic LLVM building
- */
-#ifndef LINUX_VERSION_CODE
-# error Need LINUX_VERSION_CODE
-# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
-#endif
-#define BPF_ANY 0
-#define BPF_MAP_TYPE_ARRAY 2
-#define BPF_FUNC_map_lookup_elem 1
-#define BPF_FUNC_map_update_elem 2
-
-static void *(*bpf_map_lookup_elem)(void *map, void *key) =
-	(void *) BPF_FUNC_map_lookup_elem;
-static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
-	(void *) BPF_FUNC_map_update_elem;
-
-/*
- * Following macros are taken from tools/lib/bpf/bpf_helpers.h,
- * and are used to create BTF defined maps. It is easier to take
- * 2 simple macros, than being able to include above header in
- * runtime.
- *
- * __uint - defines integer attribute of BTF map definition,
- * Such attributes are represented using a pointer to an array,
- * in which dimensionality of array encodes specified integer
- * value.
- *
- * __type - defines pointer variable with typeof(val) type for
- * attributes like key or value, which will be defined by the
- * size of the type.
- */
-#define __uint(name, val) int (*name)[val]
-#define __type(name, val) typeof(val) *name
-
-#define SEC(NAME) __attribute__((section(NAME), used))
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
-	__uint(max_entries, 1);
-	__type(key, int);
-	__type(value, int);
-} flip_table SEC(".maps");
-
-SEC("syscalls:sys_enter_epoll_pwait")
-int bpf_func__SyS_epoll_pwait(void *ctx)
-{
-	int ind =0;
-	int *flag = bpf_map_lookup_elem(&flip_table, &ind);
-	int new_flag;
-	if (!flag)
-		return 0;
-	/* flip flag and store back */
-	new_flag = !*flag;
-	bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY);
-	return new_flag;
-}
-char _license[] SEC("license") = "GPL";
-int _version SEC("version") = LINUX_VERSION_CODE;