Date:   Tue, 19 Mar 2019 06:05:30 +0000
From:   Song Liu <songliubraving@...com>
To:     Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
CC:     "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        Networking <netdev@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "Alexei Starovoitov" <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        "Kernel Team" <Kernel-team@...com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Arnaldo Carvalho de Melo" <acme@...hat.com>,
        Jiri Olsa <jolsa@...nel.org>,
        "Namhyung Kim" <namhyung@...nel.org>,
        Stanislav Fomichev <sdf@...ichev.me>
Subject: Re: [PATCH v9 perf,bpf 12/15] perf, bpf: enable annotation of bpf
 program

Sorry for the late response. 

> On Mar 18, 2019, at 9:38 AM, Arnaldo Carvalho de Melo <arnaldo.melo@...il.com> wrote:
> 
> 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 <songliubraving@...com>
>> ---
>> 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?

test-disassembler-four-args.c is an existing test used by bpftool.
It was added in fb982666e380c1632a74495b68b3c33a66e76430 .  

> 
> 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.

I used different versions of gcc to verify that current version of the 
patch works for both test-succeed and test-fail cases. I guess something 
like the following is needed? But the test does work without it. 

Thanks,
Song


diff --git i/tools/build/feature/test-all.c w/tools/build/feature/test-all.c
index e903b86b742f..7853e6d91090 100644
--- i/tools/build/feature/test-all.c
+++ w/tools/build/feature/test-all.c
@@ -178,6 +178,10 @@
 # include "test-reallocarray.c"
 #undef main

+#define main main_test_disassembler_four_args
+# include "test-disassembler-four-args.c"
+#undef main
+
 int main(int argc, char *argv[])
 {
        main_test_libpython();
@@ -219,6 +223,7 @@ int main(int argc, char *argv[])
        main_test_setns();
        main_test_libaio();
        main_test_reallocarray();
+       main_test_disassembler_four_args();

        return 0;
 }


> 
> 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.
> 
> Thanks,
> 
> - Arnaldo
> 
>> tools/perf/util/annotate.c   | 150 ++++++++++++++++++++++++++++++++++-
>> tools/perf/util/dso.c        |   1 +
>> tools/perf/util/dso.h        |  32 +++++---
>> tools/perf/util/symbol.c     |   1 +
>> 6 files changed, 180 insertions(+), 14 deletions(-)
>> 
>> diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
>> index 61e46d54a67c..8d3864b061f3 100644
>> --- a/tools/build/Makefile.feature
>> +++ b/tools/build/Makefile.feature
>> @@ -66,7 +66,8 @@ FEATURE_TESTS_BASIC :=                  \
>>         sched_getcpu			\
>>         sdt				\
>>         setns				\
>> -        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 df4ad45599ca..c51b59e43dcc 100644
>> --- a/tools/perf/Makefile.config
>> +++ b/tools/perf/Makefile.config
>> @@ -808,6 +808,10 @@ 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 5f6dbbf5d749..e492b19a157c 100644
>> --- a/tools/perf/util/annotate.c
>> +++ b/tools/perf/util/annotate.c
>> @@ -10,6 +10,10 @@
>> #include <errno.h>
>> #include <inttypes.h>
>> #include <libgen.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"
>> @@ -24,6 +28,7 @@
>> #include "annotate.h"
>> #include "evsel.h"
>> #include "evlist.h"
>> +#include "bpf-event.h"
>> #include "block-range.h"
>> #include "string2.h"
>> #include "arch/common.h"
>> @@ -31,6 +36,9 @@
>> #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"
>> @@ -1674,6 +1682,144 @@ 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;
>> @@ -1701,7 +1847,9 @@ 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 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 758bf5f74e6e..4e2e304d4037 100644
>> --- a/tools/perf/util/symbol.c
>> +++ b/tools/perf/util/symbol.c
>> @@ -1451,6 +1451,7 @@ 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
> 
> -- 
> 
> - Arnaldo

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