Merge branch 'non-jit-btf-func_info'

Yonghong Song says:

====================
Commit 838e96904ff3 ("bpf: Introduce bpf_func_info")
added bpf func info support. The userspace is able
to get better ksym's for bpf programs with jit, and
is able to print out func prototypes.

For a program containing func-to-func calls, the existing
implementation returns user specified number of function
calls and BTF types if jit is enabled. If the jit is not
enabled, it only returns the type for the main function.

This is undesirable. Interpreter may still be used
and we should keep feature identical regardless of
whether jit is enabled or not.
This patch fixed this discrepancy.

The following example shows bpftool output for
the bpf program in selftests test_btf_haskv.o when jit
is disabled:
  $ bpftool prog dump xlated id 1490
  int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
     0: (85) call pc+2#__bpf_prog_run_args32
     1: (b7) r0 = 0
     2: (95) exit
  int test_long_fname_1(struct dummy_tracepoint_args * arg):
     3: (85) call pc+1#__bpf_prog_run_args32
     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)
     8: (15) if r1 == 0x0 goto pc+9
     9: (bf) r2 = r10
    10: (07) r2 += -4
    11: (18) r1 = map[id:1173]
    13: (85) call bpf_map_lookup_elem#77088
    14: (15) if r0 == 0x0 goto pc+3
    15: (61) r1 = *(u32 *)(r0 +4)
    16: (07) r1 += 1
    17: (63) *(u32 *)(r0 +4) = r1
    18: (95) exit
  $ bpftool prog dump jited id 1490
    no instructions returned
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 3 insertions, 30 deletions

diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index bcbda7037840..b4c8725b3004 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -29,7 +29,6 @@
 static uint32_t pass_cnt;
 static uint32_t error_cnt;
 static uint32_t skip_cnt;
-static bool jit_enabled;
 
 #define CHECK(condition, format...) ({					\
 	int __ret = !!(condition);					\
@@ -65,24 +64,6 @@ static int __base_pr(const char *format, ...)
 	return err;
 }
 
-static bool is_jit_enabled(void)
-{
-	const char *jit_sysctl = "/proc/sys/net/core/bpf_jit_enable";
-	bool enabled = false;
-	int sysctl_fd;
-
-	sysctl_fd = open(jit_sysctl, 0, O_RDONLY);
-	if (sysctl_fd != -1) {
-		char tmpc;
-
-		if (read(sysctl_fd, &tmpc, sizeof(tmpc)) == 1)
-			enabled = (tmpc != '0');
-		close(sysctl_fd);
-	}
-
-	return enabled;
-}
-
 #define BTF_INFO_ENC(kind, root, vlen)			\
 	((!!(root) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
 
@@ -2547,8 +2528,8 @@ static int do_test_file(unsigned int test_num)
 		  test->btf_kv_notfound))
 		goto done;
 
-	if (!jit_enabled || !has_btf_ext)
-		goto skip_jit;
+	if (!has_btf_ext)
+		goto skip;
 
 	/* get necessary program info */
 	info_len = sizeof(struct bpf_prog_info);
@@ -2636,7 +2617,7 @@ static int do_test_file(unsigned int test_num)
 		finfo = (void *)finfo + rec_size;
 	}
 
-skip_jit:
+skip:
 	fprintf(stderr, "OK");
 
 done:
@@ -3270,12 +3251,6 @@ static int do_test_func_type(int test_num)
 		err = -1;
 		goto done;
 	}
-	if (!jit_enabled) {
-		skip_cnt++;
-		fprintf(stderr, "SKIPPED, please enable sysctl bpf_jit_enable\n");
-		err = 0;
-		goto done;
-	}
 
 	/* get necessary lens */
 	info_len = sizeof(struct bpf_prog_info);
@@ -3452,8 +3427,6 @@ int main(int argc, char **argv)
 	if (args.always_log)
 		libbpf_set_print(__base_pr, __base_pr, __base_pr);
 
-	jit_enabled = is_jit_enabled();
-
 	if (args.raw_test)
 		err |= test_raw();