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 <songliubrav...@fb.com>
---
 tools/build/Makefile.feature |   6 +-
 tools/perf/Makefile.config   |   4 +
 tools/perf/util/annotate.c   | 150 ++++++++++++++++++++++++++++++++++-
 tools/perf/util/dso.c        |   1 +
 tools/perf/util/dso.h        |  33 +++++---
 tools/perf/util/symbol.c     |   1 +
 6 files changed, 181 insertions(+), 14 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..e467aa0ef0c2 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 +1680,144 @@ 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));
+       perf_exe(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 +1845,9 @@ 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/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;
-- 
2.17.1

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