[PATCH v4 perf,bpf 12/15] perf, bpf: enable annotation of bpf program

From: Song Liu
Date: Mon Feb 25 2019 - 19:21:01 EST

This patch enables the annotation of bpf program.

A new dso type DSO_BINARY_TYPE__BPF_PROG_INFO is introduced to for BPF
programs. In symbol__disassemble(), DSO_BINARY_TYPE__BPF_PROG_INFO dso
calls into a new function symbol__disassemble_bpf(), where annotation
line information is filled based bpf_prog_info and btf saved in given
perf_env.

symbol__disassemble_bpf() uses libbfd to disassemble bpf programs.

Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
tools/build/Makefile.feature | 6 +-
tools/perf/Makefile.config | 4 +
tools/perf/util/annotate.c | 149 ++++++++++++++++++++++++++++++++++-
tools/perf/util/dso.c | 1 +
tools/perf/util/dso.h | 33 +++++---
tools/perf/util/header.c | 7 +-
tools/perf/util/symbol.c | 1 +
tools/perf/util/util.c | 10 +++
tools/perf/util/util.h | 2 +
9 files changed, 193 insertions(+), 20 deletions(-)

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 5467c6bf9ceb..4f35e9ff1e00 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -71,7 +71,8 @@ FEATURE_TESTS_BASIC := \
sdt \
setns \
libopencsd \
- libaio
+ libaio \
+ disassembler-four-args

# FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
# of all feature tests
@@ -118,7 +119,8 @@ FEATURE_DISPLAY ?= \
lzma \
get_cpuid \
bpf \
- libaio
+ libaio \
+ disassembler-four-args

# Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features.
# If in the future we need per-feature checks/flags for features not
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index e0bafbc273af..ab223239f1fb 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -796,6 +796,10 @@ ifdef HAVE_KVM_STAT_SUPPORT
CFLAGS += -DHAVE_KVM_STAT_SUPPORT
endif

+ifeq ($(feature-disassembler-four-args), 1)
+ CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
+endif
+
ifeq (${IS_64_BIT}, 1)
ifndef NO_PERF_READ_VDSO32
$(call feature_check,compile-32)
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 70de8f6b3aee..716fdb07f45e 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -9,6 +9,10 @@

#include <errno.h>
#include <inttypes.h>
+#include <bpf/bpf.h>
+#include <bpf/btf.h>
+#include <bpf/libbpf.h>
+#include <linux/btf.h>
#include "util.h"
#include "ui/ui.h"
#include "sort.h"
@@ -22,6 +26,7 @@
#include "annotate.h"
#include "evsel.h"
#include "evlist.h"
+#include "bpf-event.h"
#include "block-range.h"
#include "string2.h"
#include "arch/common.h"
@@ -29,6 +34,9 @@
#include <pthread.h>
#include <linux/bitops.h>
#include <linux/kernel.h>
+#include <bfd.h>
+#include <dis-asm.h>
+#include <bpf/libbpf.h>

/* FIXME: For the HE_COLORSET */
#include "ui/browser.h"
@@ -1672,6 +1680,143 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
return 0;
}

+static int symbol__disassemble_bpf(struct symbol *sym,
+ struct annotate_args *args)
+{
+ struct annotation *notes = symbol__annotation(sym);
+ struct annotation_options *opts = args->options;
+ struct bpf_prog_info_linear *info_linear;
+ struct bpf_prog_linfo *prog_linfo = NULL;
+ struct bpf_prog_info_node *info_node;
+ int len = sym->end - sym->start;
+ disassembler_ftype disassemble;
+ struct map *map = args->ms.map;
+ struct disassemble_info info;
+ struct dso *dso = map->dso;
+ int pc = 0, count, sub_id;
+ struct btf *btf = NULL;
+ char tpath[PATH_MAX];
+ size_t buf_size;
+ int nr_skip = 0;
+ int ret = -1;
+ char *buf;
+ bfd *bfdf;
+ FILE *s;
+
+ if (dso->binary_type != DSO_BINARY_TYPE__BPF_PROG_INFO)
+ return -1;
+
+ pr_debug("%s: handling sym %s addr %lx len %lx\n", __func__,
+ sym->name, sym->start, sym->end - sym->start);
+
+ memset(tpath, 0, sizeof(tpath));
+ get_exec_path(tpath, sizeof(tpath));
+
+ bfdf = bfd_openr(tpath, NULL);
+ assert(bfdf);
+ assert(bfd_check_format(bfdf, bfd_object));
+
+ s = open_memstream(&buf, &buf_size);
+ if (!s)
+ goto out;
+ init_disassemble_info(&info, s,
+ (fprintf_ftype) fprintf);
+
+ info.arch = bfd_get_arch(bfdf);
+ info.mach = bfd_get_mach(bfdf);
+
+ info_node = perf_env__find_bpf_prog_info(dso->bpf_prog.env,
+ dso->bpf_prog.id);
+ if (!info_node)
+ goto out;
+ info_linear = info_node->info_linear;
+ sub_id = dso->bpf_prog.sub_id;
+
+ info.buffer = (void *)(info_linear->info.jited_prog_insns);
+ info.buffer_length = info_linear->info.jited_prog_len;
+
+ if (info_linear->info.nr_line_info)
+ prog_linfo = bpf_prog_linfo__new(&info_linear->info);
+
+ if (info_linear->info.btf_id) {
+ struct btf_node *node;
+
+ node = perf_env__find_btf(dso->bpf_prog.env,
+ info_linear->info.btf_id);
+ if (node)
+ btf = btf__new((__u8 *)(node->data),
+ node->data_size);
+ }
+
+ disassemble_init_for_target(&info);
+
+#ifdef DISASM_FOUR_ARGS_SIGNATURE
+ disassemble = disassembler(info.arch,
+ bfd_big_endian(bfdf),
+ info.mach,
+ bfdf);
+#else
+ disassemble = disassembler(bfdf);
+#endif
+ assert(disassemble);
+
+ fflush(s);
+ do {
+ const struct bpf_line_info *linfo = NULL;
+ struct disasm_line *dl;
+ size_t prev_buf_size;
+ const char *srcline;
+ u64 addr;
+
+ addr = pc + ((u64 *)(info_linear->info.jited_ksyms))[sub_id];
+ count = disassemble(pc, &info);
+
+ if (prog_linfo)
+ linfo = bpf_prog_linfo__lfind_addr_func(prog_linfo,
+ addr, sub_id,
+ nr_skip);
+
+ if (linfo && btf) {
+ srcline = btf__name_by_offset(btf, linfo->line_off);
+ nr_skip++;
+ } else
+ srcline = NULL;
+
+ fprintf(s, "\n");
+ prev_buf_size = buf_size;
+ fflush(s);
+
+ if (!opts->hide_src_code && srcline) {
+ args->offset = -1;
+ args->line = strdup(srcline);
+ args->line_nr = 0;
+ args->ms.sym = sym;
+ dl = disasm_line__new(args);
+ if (dl)
+ annotation_line__add(&dl->al,
+ &notes->src->source);
+ }
+
+ args->offset = pc;
+ args->line = buf + prev_buf_size;
+ args->line_nr = 0;
+ args->ms.sym = sym;
+ dl = disasm_line__new(args);
+ if (dl)
+ annotation_line__add(&dl->al, &notes->src->source);
+
+ pc += count;
+ } while (count > 0 && pc < len);
+
+ ret = 0;
+out:
+ free(prog_linfo);
+ free(btf);
+ fclose(s);
+ bfd_close(bfdf);
+ return ret;
+}
+
static int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
{
struct annotation_options *opts = args->options;
@@ -1699,7 +1844,9 @@ static int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
pr_debug("annotating [%p] %30s : [%p] %30s\n",
dso, dso->long_name, sym, sym->name);

- if (dso__is_kcore(dso)) {
+ if (dso->binary_type == DSO_BINARY_TYPE__BPF_PROG_INFO) {
+ return symbol__disassemble_bpf(sym, args);
+ } else if (dso__is_kcore(dso)) {
kce.kcore_filename = symfs_filename;
kce.addr = map__rip_2objdump(map, sym->start);
kce.offs = sym->start;
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 62c8cf622607..1798192bf0f9 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -181,6 +181,7 @@ int dso__read_binary_type_filename(const struct dso *dso,
case DSO_BINARY_TYPE__KALLSYMS:
case DSO_BINARY_TYPE__GUEST_KALLSYMS:
case DSO_BINARY_TYPE__JAVA_JIT:
+ case DSO_BINARY_TYPE__BPF_PROG_INFO:
case DSO_BINARY_TYPE__NOT_FOUND:
ret = -1;
break;
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 8c8a7abe809d..f20d319463f1 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -14,6 +14,8 @@
#include "namespaces.h"
#include "build-id.h"

+struct perf_env;
+
enum dso_binary_type {
DSO_BINARY_TYPE__KALLSYMS = 0,
DSO_BINARY_TYPE__GUEST_KALLSYMS,
@@ -34,6 +36,7 @@ enum dso_binary_type {
DSO_BINARY_TYPE__KCORE,
DSO_BINARY_TYPE__GUEST_KCORE,
DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
+ DSO_BINARY_TYPE__BPF_PROG_INFO,
DSO_BINARY_TYPE__NOT_FOUND,
};

@@ -177,17 +180,25 @@ struct dso {
struct auxtrace_cache *auxtrace_cache;
int comp;

- /* dso data file */
- struct {
- struct rb_root cache;
- int fd;
- int status;
- u32 status_seen;
- size_t file_size;
- struct list_head open_entry;
- u64 debug_frame_offset;
- u64 eh_frame_hdr_offset;
- } data;
+ union {
+ /* dso data file */
+ struct {
+ struct rb_root cache;
+ int fd;
+ int status;
+ u32 status_seen;
+ size_t file_size;
+ struct list_head open_entry;
+ u64 debug_frame_offset;
+ u64 eh_frame_hdr_offset;
+ } data;
+ /* bpf prog information */
+ struct {
+ u32 id;
+ u32 sub_id;
+ struct perf_env *env;
+ } bpf_prog;
+ };

union { /* Tool specific area */
void *priv;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index ce5402101468..c39e107ac5b8 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -533,12 +533,7 @@ static int write_cmdline(struct feat_fd *ff,
int i, ret;

/* actual path to perf binary */
- ret = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
- if (ret <= 0)
- return -1;
-
- /* readlink() does not add null termination */
- buf[ret] = '\0';
+ get_exec_path(buf, sizeof(buf));

/* account for binary path */
n = perf_env.nr_cmdline + 1;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 48efad6d0f90..33ae59e89da2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1441,6 +1441,7 @@ static bool dso__is_compatible_symtab_type(struct dso *dso, bool kmod,
case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
return true;

+ case DSO_BINARY_TYPE__BPF_PROG_INFO:
case DSO_BINARY_TYPE__NOT_FOUND:
default:
return false;
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 093352e93d50..0bc9ec69f38a 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -506,3 +506,13 @@ const char *perf_tip(const char *dirpath)

return tip;
}
+
+void get_exec_path(char *tpath, size_t size)
+{
+ const char *path = "/proc/self/exe";
+ ssize_t len;
+
+ len = readlink(path, tpath, size - 1);
+ assert(len > 0);
+ tpath[len] = 0;
+}
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index ece040b799f6..8d0a88eb8685 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -76,6 +76,8 @@ extern bool perf_singlethreaded;
void perf_set_singlethreaded(void);
void perf_set_multithreaded(void);

+void get_exec_path(char *tpath, size_t size);
+
#ifndef O_CLOEXEC
#ifdef __sparc__
#define O_CLOEXEC 0x400000
--
2.17.1