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tools/bpf: bpftool: add support for func types

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This patch added support to print function signature
if btf func_info is available. Note that ksym
now uses function name instead of prog_name as
prog_name has a limit of 16 bytes including
ending '\0'.

The following is a sample output for selftests
test_btf with file test_btf_haskv.o for translated insns
and jited insns respectively.

  $ bpftool prog dump xlated id 1
  int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
     0: (85) call pc+2#bpf_prog_2dcecc18072623fc_test_long_fname_1
     1: (b7) r0 = 0
     2: (95) exit
  int test_long_fname_1(struct dummy_tracepoint_args * arg):
     3: (85) call pc+1#bpf_prog_89d64e4abf0f0126_test_long_fname_2
     4: (95) exit
  int test_long_fname_2(struct dummy_tracepoint_args * arg):
     5: (b7) r2 = 0
     6: (63) *(u32 *)(r10 -4) = r2
     7: (79) r1 = *(u64 *)(r1 +8)
     ...
     22: (07) r1 += 1
     23: (63) *(u32 *)(r0 +4) = r1
     24: (95) exit

  $ bpftool prog dump jited id 1
  int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
  bpf_prog_b07ccb89267cf242__dummy_tracepoint:
     0:   push   %rbp
     1:   mov    %rsp,%rbp
    ......
    3c:   add    $0x28,%rbp
    40:   leaveq
    41:   retq

  int test_long_fname_1(struct dummy_tracepoint_args * arg):
  bpf_prog_2dcecc18072623fc_test_long_fname_1:
     0:   push   %rbp
     1:   mov    %rsp,%rbp
    ......
    3a:   add    $0x28,%rbp
    3e:   leaveq
    3f:   retq

  int test_long_fname_2(struct dummy_tracepoint_args * arg):
  bpf_prog_89d64e4abf0f0126_test_long_fname_2:
     0:   push   %rbp
     1:   mov    %rsp,%rbp
    ......
    80:   add    $0x28,%rbp
    84:   leaveq
    85:   retq

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song
2018-11-19 15:29:21 -08:00
committed by Alexei Starovoitov
parent 999d82cbc0
commit 254471e57a
5 changed files with 230 additions and 0 deletions
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56
tools/bpf/bpftool/prog.c
View File

@@ -47,6 +47,7 @@
#include <linux/err.h>
#include <bpf.h>
#include <btf.h>
#include <libbpf.h>
#include "cfg.h"
@@ -451,14 +452,19 @@ static int do_dump(int argc, char **argv)
struct bpf_prog_info info = {};
unsigned int *func_lens = NULL;
const char *disasm_opt = NULL;
unsigned int finfo_rec_size;
unsigned int nr_func_ksyms;
unsigned int nr_func_lens;
struct dump_data dd = {};
__u32 len = sizeof(info);
struct btf *btf = NULL;
void *func_info = NULL;
unsigned int finfo_cnt;
unsigned int buf_size;
char *filepath = NULL;
bool opcodes = false;
bool visual = false;
char func_sig[1024];
unsigned char *buf;
__u32 *member_len;
__u64 *member_ptr;
@@ -551,6 +557,17 @@ static int do_dump(int argc, char **argv)
}
}
finfo_cnt = info.func_info_cnt;
finfo_rec_size = info.func_info_rec_size;
if (finfo_cnt && finfo_rec_size) {
func_info = malloc(finfo_cnt * finfo_rec_size);
if (!func_info) {
p_err("mem alloc failed");
close(fd);
goto err_free;
}
}
memset(&info, 0, sizeof(info));
*member_ptr = ptr_to_u64(buf);
@@ -559,6 +576,9 @@ static int do_dump(int argc, char **argv)
info.nr_jited_ksyms = nr_func_ksyms;
info.jited_func_lens = ptr_to_u64(func_lens);
info.nr_jited_func_lens = nr_func_lens;
info.func_info_cnt = finfo_cnt;
info.func_info_rec_size = finfo_rec_size;
info.func_info = ptr_to_u64(func_info);
err = bpf_obj_get_info_by_fd(fd, &info, &len);
close(fd);
@@ -582,6 +602,18 @@ static int do_dump(int argc, char **argv)
goto err_free;
}
if (info.func_info_cnt != finfo_cnt) {
p_err("incorrect func_info_cnt %d vs. expected %d",
info.func_info_cnt, finfo_cnt);
goto err_free;
}
if (info.func_info_rec_size != finfo_rec_size) {
p_err("incorrect func_info_rec_size %d vs. expected %d",
info.func_info_rec_size, finfo_rec_size);
goto err_free;
}
if ((member_len == &info.jited_prog_len &&
info.jited_prog_insns == 0) ||
(member_len == &info.xlated_prog_len &&
@@ -590,6 +622,11 @@ static int do_dump(int argc, char **argv)
goto err_free;
}
if (info.btf_id && btf_get_from_id(info.btf_id, &btf)) {
p_err("failed to get btf");
goto err_free;
}
if (filepath) {
fd = open(filepath, O_WRONLY | O_CREAT | O_TRUNC, 0600);
if (fd < 0) {
@@ -622,6 +659,7 @@ static int do_dump(int argc, char **argv)
if (info.nr_jited_func_lens && info.jited_func_lens) {
struct kernel_sym *sym = NULL;
struct bpf_func_info *record;
char sym_name[SYM_MAX_NAME];
unsigned char *img = buf;
__u64 *ksyms = NULL;
@@ -648,12 +686,25 @@ static int do_dump(int argc, char **argv)
strcpy(sym_name, "unknown");
}
if (func_info) {
record = func_info + i * finfo_rec_size;
btf_dumper_type_only(btf, record->type_id,
func_sig,
sizeof(func_sig));
}
if (json_output) {
jsonw_start_object(json_wtr);
if (func_info && func_sig[0] != '\0') {
jsonw_name(json_wtr, "proto");
jsonw_string(json_wtr, func_sig);
}
jsonw_name(json_wtr, "name");
jsonw_string(json_wtr, sym_name);
jsonw_name(json_wtr, "insns");
} else {
if (func_info && func_sig[0] != '\0')
printf("%s:\n", func_sig);
printf("%s:\n", sym_name);
}
@@ -682,6 +733,9 @@ static int do_dump(int argc, char **argv)
kernel_syms_load(&dd);
dd.nr_jited_ksyms = info.nr_jited_ksyms;
dd.jited_ksyms = (__u64 *) info.jited_ksyms;
dd.btf = btf;
dd.func_info = func_info;
dd.finfo_rec_size = finfo_rec_size;
if (json_output)
dump_xlated_json(&dd, buf, *member_len, opcodes);
@@ -693,12 +747,14 @@ static int do_dump(int argc, char **argv)
free(buf);
free(func_ksyms);
free(func_lens);
free(func_info);
return 0;
err_free:
free(buf);
free(func_ksyms);
free(func_lens);
free(func_info);
return -1;
}