Subject: Re: [PATCH v9 perf,bpf 12/15] perf, bpf: enable annotation of bpf program

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Mon, 18 Mar 2019 13:43:58 -0300

Em Mon, Mar 18, 2019 at 01:38:48PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Mar 11, 2019 at 10:30:48PM -0700, Song Liu escreveu:
> > 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 <[email-masked]>
> > ---
> >  tools/build/Makefile.feature |   6 +-
> >  tools/perf/Makefile.config   |   4 +
> 
> I see the changes to these two files, but I can't see the feature test
> that it triggers, forgot to do a git-add? Or is it in an upcoming patch
> in this series?
> 
> After applying this test it "works":
> 
>   make: Entering directory '/home/acme/git/perf/tools/perf'
>     BUILD:   Doing 'make -j8' parallel build
> 
>   Auto-detecting system features:
>   ...                         dwarf: [ on  ]
>   ...            dwarf_getlocations: [ on  ]
>   <SNIP>
>   ...                           bpf: [ on  ]
>   ...                        libaio: [ on  ]
>   ...        disassembler-four-args: [ on  ]
> 
> Because you added it to FEATURE_TESTS_BASIC, and this means that if
> tools/build/feature/test-all.c builds, then what is in
> FEATURE_TESTS_BASIC is set to 'on', but you didn't add anything to
> tools/build/feature/test-all.c, so it works because all the other
> features are present.
> 
> Take a look at:
> 
>   2a07d814747b ("tools build feature: Check if libaio is available")
> 
> To see what needs to be done.
> 
> Either way, its interesting to break this patch in two, one adding the
> feature test and another to use it, i.e. the second patch out of this
> should have the commit log message in this patch.
> 
> I've applied the patches up to before this one and will continue
> processing other patches while you address this.

Ok, to continue processing the other patches I chunked out the part
below into a 3rd patch from the above one and have it applied already.

commit f326de312abc3657b0397817c66cd7e1540655f7
Author: Song Liu <[email-masked]>
Date:   Mon Mar 11 22:30:48 2019 -0700

    perf symbols: Introduce DSO_BINARY_TYPE__BPF_PROG_INFO
    
    Introduce a new dso type DSO_BINARY_TYPE__BPF_PROG_INFO for BPF programs. In
    symbol__disassemble(), DSO_BINARY_TYPE__BPF_PROG_INFO dso will call into a new
    function symbol__disassemble_bpf() in an upcoming patch, where annotation line
    information is filled based bpf_prog_info and btf saved in given perf_env.
    
    Signed-off-by: Song Liu <[email-masked]>
    Reviewed-by: Jiri Olsa <[email-masked]>
    Cc: Alexei Starovoitov <[email-masked]>
    Cc: Daniel Borkmann <[email-masked]>
    Cc: Namhyung Kim <[email-masked]>
    Cc: Peter Zijlstra <[email-masked]>
    Cc: Stanislav Fomichev <[email-masked]>
    Cc: [email-masked]
    Link: http://lkml.kernel.org/r/[email-masked]
    [ split from a larger patch ]
    Signed-off-by: Arnaldo Carvalho de Melo <[email-masked]>

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index ba58ba603b69..58547c468c65 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -184,6 +184,7 @@ 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 bb417c54c25a..c274b5aa839d 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -14,6 +14,7 @@
 
 struct machine;
 struct map;
+struct perf_env;
 
 enum dso_binary_type {
 	DSO_BINARY_TYPE__KALLSYMS = 0,
@@ -35,6 +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,
 };
 
@@ -178,17 +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 58442ca5e3c4..5cbad55cd99d 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1455,6 +1455,7 @@ 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;