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Groups > linux.kernel > #1270093
| From | Wang Nan <wangnan0@huawei.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 11/13] perf tools: Generate prologue for BPF programs |
| Date | 2015-11-16 14:00 +0100 |
| Message-ID | <qvry3-7qr-29@gated-at.bofh.it> (permalink) |
| References | <qvrom-7n2-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
This patch generates prologue for each 'struct probe_trace_event' for
fetching arguments for BPF programs.
After bpf__probe(), iterate over each programs to check whether
prologue is required. If none of 'struct perf_probe_event' a program
will attach to has at least one argument, simply skip preprocessor
hooking. For those who prologue is required, calls bpf__gen_prologue()
and paste original instruction after prologue.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
tools/perf/util/bpf-loader.c | 120 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 119 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index e0045c3..cad0d0f 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -5,12 +5,15 @@
* Copyright (C) 2015 Huawei Inc.
*/
+#include <linux/bpf.h>
#include <bpf/libbpf.h>
#include <linux/err.h>
#include <linux/string.h>
#include "perf.h"
#include "debug.h"
#include "bpf-loader.h"
+#include "bpf-prologue.h"
+#include "llvm-utils.h"
#include "probe-event.h"
#include "probe-finder.h" // for MAX_PROBES
#include "llvm-utils.h"
@@ -33,6 +36,8 @@ DEFINE_PRINT_FN(debug, 1)
struct bpf_prog_priv {
struct perf_probe_event pev;
+ bool need_prologue;
+ struct bpf_insn *insns_buf;
};
static bool libbpf_initialized;
@@ -107,6 +112,7 @@ bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused,
struct bpf_prog_priv *priv = _priv;
cleanup_perf_probe_events(&priv->pev, 1);
+ zfree(&priv->insns_buf);
free(priv);
}
@@ -365,6 +371,102 @@ static int bpf__prepare_probe(void)
return err;
}
+static int
+preproc_gen_prologue(struct bpf_program *prog, int n,
+ struct bpf_insn *orig_insns, int orig_insns_cnt,
+ struct bpf_prog_prep_result *res)
+{
+ struct probe_trace_event *tev;
+ struct perf_probe_event *pev;
+ struct bpf_prog_priv *priv;
+ struct bpf_insn *buf;
+ size_t prologue_cnt = 0;
+ int err;
+
+ err = bpf_program__get_private(prog, (void **)&priv);
+ if (err || !priv)
+ goto errout;
+
+ pev = &priv->pev;
+
+ if (n < 0 || n >= pev->ntevs)
+ goto errout;
+
+ tev = &pev->tevs[n];
+
+ buf = priv->insns_buf;
+ err = bpf__gen_prologue(tev->args, tev->nargs,
+ buf, &prologue_cnt,
+ BPF_MAXINSNS - orig_insns_cnt);
+ if (err) {
+ const char *title;
+
+ title = bpf_program__title(prog, false);
+ if (!title)
+ title = "[unknown]";
+
+ pr_debug("Failed to generate prologue for program %s\n",
+ title);
+ return err;
+ }
+
+ memcpy(&buf[prologue_cnt], orig_insns,
+ sizeof(struct bpf_insn) * orig_insns_cnt);
+
+ res->new_insn_ptr = buf;
+ res->new_insn_cnt = prologue_cnt + orig_insns_cnt;
+ res->pfd = NULL;
+ return 0;
+
+errout:
+ pr_debug("Internal error in preproc_gen_prologue\n");
+ return -BPF_LOADER_ERRNO__PROLOGUE;
+}
+
+static int hook_load_preprocessor(struct bpf_program *prog)
+{
+ struct perf_probe_event *pev;
+ struct bpf_prog_priv *priv;
+ bool need_prologue = false;
+ int err, i;
+
+ err = bpf_program__get_private(prog, (void **)&priv);
+ if (err || !priv) {
+ pr_debug("Internal error when hook preprocessor\n");
+ return -BPF_LOADER_ERRNO__INTERNAL;
+ }
+
+ pev = &priv->pev;
+ for (i = 0; i < pev->ntevs; i++) {
+ struct probe_trace_event *tev = &pev->tevs[i];
+
+ if (tev->nargs > 0) {
+ need_prologue = true;
+ break;
+ }
+ }
+
+ /*
+ * Since all tevs don't have argument, we don't need generate
+ * prologue.
+ */
+ if (!need_prologue) {
+ priv->need_prologue = false;
+ return 0;
+ }
+
+ priv->need_prologue = true;
+ priv->insns_buf = malloc(sizeof(struct bpf_insn) * BPF_MAXINSNS);
+ if (!priv->insns_buf) {
+ pr_debug("No enough memory: alloc insns_buf failed\n");
+ return -ENOMEM;
+ }
+
+ err = bpf_program__set_prep(prog, pev->ntevs,
+ preproc_gen_prologue);
+ return err;
+}
+
int bpf__probe(struct bpf_object *obj)
{
int err = 0;
@@ -399,6 +501,18 @@ int bpf__probe(struct bpf_object *obj)
pr_debug("bpf_probe: failed to apply perf probe events");
goto out;
}
+
+ /*
+ * After probing, let's consider prologue, which
+ * adds program fetcher to BPF programs.
+ *
+ * hook_load_preprocessorr() hooks pre-processor
+ * to bpf_program, let it generate prologue
+ * dynamically during loading.
+ */
+ err = hook_load_preprocessor(prog);
+ if (err)
+ goto out;
}
out:
return err < 0 ? err : 0;
@@ -482,7 +596,11 @@ int bpf__foreach_tev(struct bpf_object *obj,
for (i = 0; i < pev->ntevs; i++) {
tev = &pev->tevs[i];
- fd = bpf_program__fd(prog);
+ if (priv->need_prologue)
+ fd = bpf_program__nth_fd(prog, i);
+ else
+ fd = bpf_program__fd(prog);
+
if (fd < 0) {
pr_debug("bpf: failed to get file descriptor\n");
return fd;
--
1.8.3.4
--
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[PATCH 00/13] perf tools: bpf: Improve BPF program ability Wang Nan <wangnan0@huawei.com> - 2015-11-16 13:50 +0100
[PATCH 03/13] perf tools: Allow BPF program attach to uprobe events Wang Nan <wangnan0@huawei.com> - 2015-11-16 13:50 +0100
Re: [PATCH 03/13] perf tools: Allow BPF program attach to uprobe events Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-16 15:20 +0100
[tip:perf/core] perf bpf: Allow BPF program attach to uprobe events tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 10/13] perf tools: Add prologue for BPF programs for fetching arguments Wang Nan <wangnan0@huawei.com> - 2015-11-16 13:50 +0100
[tip:perf/core] perf bpf: Add prologue for BPF programs for fetching arguments tip-bot for He Kuang <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 04/13] perf tools: Allow BPF program attach to modules Wang Nan <wangnan0@huawei.com> - 2015-11-16 13:50 +0100
[tip:perf/core] perf bpf: Allow attaching BPF programs to modules symbols tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 07/13] bpf tools: Load a program with different instances using preprocessor Wang Nan <wangnan0@huawei.com> - 2015-11-16 13:50 +0100
Re: [PATCH 07/13] bpf tools: Load a program with different instances using preprocessor Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-16 20:10 +0100
Re: [PATCH 07/13] bpf tools: Load a program with different instances using preprocessor "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-17 05:00 +0100
[tip:perf/core] bpf tools: Load a program with different instances using preprocessor tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 13/13] perf tools: Use same BPF program if arguments are identical Wang Nan <wangnan0@huawei.com> - 2015-11-16 14:00 +0100
Re: [PATCH 13/13] perf tools: Use same BPF program if arguments are identical "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-17 04:10 +0100
Re: [PATCH 13/13] perf tools: Use same BPF program if arguments are identical Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 14:20 +0100
[PATCH 12/13] perf test: Test BPF prologue Wang Nan <wangnan0@huawei.com> - 2015-11-16 14:00 +0100
Re: [PATCH 12/13] perf test: Test BPF prologue Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 02:30 +0100
Re: [PATCH 12/13] perf test: Test BPF prologue "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-17 02:40 +0100
Re: [PATCH 12/13] perf test: Test BPF prologue "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-17 05:40 +0100
Re: [PATCH 12/13] perf test: Test BPF prologue Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 13:30 +0100
[PATCH 0/5] perf tools: Improve BPF support Wang Nan <wangnan0@huawei.com> - 2015-11-17 09:40 +0100
[PATCH 5/5] perf test: Mute test cases if verbose == 0 Wang Nan <wangnan0@huawei.com> - 2015-11-17 09:40 +0100
Re: [PATCH 5/5] perf test: Mute test cases if verbose == 0 Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 14:20 +0100
[tip:perf/core] perf test: Mute test cases error messages if verbose == 0 tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:20 +0100
[PATCH 2/5] perf tools: Use same BPF program if arguments are identical Wang Nan <wangnan0@huawei.com> - 2015-11-17 09:40 +0100
[tip:perf/core] perf bpf: Use same BPF program if arguments are identical tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 4/5] perf test: Print result for each subtest for BPF Wang Nan <wangnan0@huawei.com> - 2015-11-17 09:40 +0100
[tip:perf/core] perf test: Print result for each BPF subtest tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:20 +0100
[PATCH 1/5] perf test: Fix 2 bugs in 'perf test BPF' Wang Nan <wangnan0@huawei.com> - 2015-11-17 09:40 +0100
Re: [PATCH 1/5] perf test: Fix 2 bugs in 'perf test BPF' Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 14:00 +0100
Re: [PATCH 1/5] perf test: Fix 2 bugs in 'perf test BPF' pi3orama <pi3orama@163.com> - 2015-11-17 14:10 +0100
Re: [PATCH 1/5] perf test: Fix 2 bugs in 'perf test BPF' Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 14:40 +0100
[tip:perf/core] perf test: Fix 'perf test BPF' when it fails to find a suitable vmlinux tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 3/5] perf test: Print result for each subtest for llvm Wang Nan <wangnan0@huawei.com> - 2015-11-17 09:40 +0100
Re: [PATCH 3/5] perf test: Print result for each subtest for llvm Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 14:10 +0100
[tip:perf/core] perf test: Print result for each LLVM subtest tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:20 +0100
Re: [PATCH 12/13] perf test: Test BPF prologue "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-17 09:50 +0100
[PATCH] perf record: Support custom vmlinux path Wang Nan <wangnan0@huawei.com> - 2015-11-17 11:00 +0100
Re: [PATCH] perf record: Support custom vmlinux path Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 13:40 +0100
Re: [PATCH] perf record: Support custom vmlinux path Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-17 13:50 +0100
Re: [PATCH] perf record: Support custom vmlinux path pi3orama <pi3orama@163.com> - 2015-11-17 13:50 +0100
[PATCH 0/2] perf tools: Builtin options related improvements Wang Nan <wangnan0@huawei.com> - 2015-11-19 15:10 +0100
[PATCH 2/2] perf record: Support custom vmlinux path Wang Nan <wangnan0@huawei.com> - 2015-11-19 15:10 +0100
[PATCH 1/2] perf tools: Always give options even it not compiled Wang Nan <wangnan0@huawei.com> - 2015-11-19 15:10 +0100
RE: [PATCH 1/2] perf tools: Always give options even it not compiled 平松雅巳 / HIRAMATU，MASAMI <masami.hiramatsu.pt@hitachi.com> - 2015-11-20 12:00 +0100
Re: [PATCH 1/2] perf tools: Always give options even it not compiled "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-26 09:10 +0100
Re: [PATCH 1/2] perf tools: Always give options even it not compiled "Wangnan (F)" <wangnan0@huawei.com> - 2015-11-26 10:10 +0100
[tip:perf/core] perf test: Test the BPF prologue adding infrastructure tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 06/13] perf tools: Allow BPF program config probing options Wang Nan <wangnan0@huawei.com> - 2015-11-16 14:00 +0100
[tip:perf/core] perf bpf: Allow BPF program config probing options tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 08/13] perf tools: Add BPF_PROLOGUE config options for further patches Wang Nan <wangnan0@huawei.com> - 2015-11-16 14:00 +0100
[tip:perf/core] perf bpf: Add BPF_PROLOGUE config options for further patches tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 11/13] perf tools: Generate prologue for BPF programs Wang Nan <wangnan0@huawei.com> - 2015-11-16 14:00 +0100
[tip:perf/core] perf bpf: Generate prologue for BPF programs tip-bot for Wang Nan <tipbot@zytor.com> - 2015-11-23 17:10 +0100
[PATCH 02/13] perf probe: Clear probe_trace_event when add_probe_trace_event() fails Wang Nan <wangnan0@huawei.com> - 2015-11-16 14:00 +0100
Re: [PATCH 00/13] perf tools: bpf: Improve BPF program ability Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-11-16 15:20 +0100
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