Tests for multiple analyses performed by the verifier need the
verifier log to contain analysis results alongside the program
disassembly. This patch moves log level 2 program dump from
bpf_compute_live_registers() to a standalone function called from
bpf_check(), in order to provide a common logging function for such
analyses (and thus avoid printing program disassembly multiple times).

This is a preparatory refactoring, subsequent commit extends this log
with loop hierarchy.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 kernel/bpf/liveness.c                              | 22 +--------------
 kernel/bpf/verifier.c                              | 31 ++++++++++++++++++++++
 .../selftests/bpf/progs/verifier_live_stack.c      |  2 +-
 3 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/kernel/bpf/liveness.c b/kernel/bpf/liveness.c
index 0aadfbae0acc..16d030fdd83a 100644
--- a/kernel/bpf/liveness.c
+++ b/kernel/bpf/liveness.c
@@ -2209,7 +2209,7 @@ int bpf_compute_live_registers(struct bpf_verifier_env *env)
 	struct bpf_insn *insns = env->prog->insnsi;
 	struct insn_live_regs *state;
 	int insn_cnt = env->prog->len;
-	int err = 0, i, j;
+	int err = 0, i;
 	bool changed;
 
 	/* Use the following algorithm:
@@ -2270,26 +2270,6 @@ int bpf_compute_live_registers(struct bpf_verifier_env *env)
 	for (i = 0; i < insn_cnt; ++i)
 		insn_aux[i].live_regs_before = state[i].in;
 
-	if (env->log.level & BPF_LOG_LEVEL2) {
-		verbose(env, "Live regs before insn:\n");
-		for (i = 0; i < insn_cnt; ++i) {
-			if (env->insn_aux_data[i].scc)
-				verbose(env, "%3d ", env->insn_aux_data[i].scc);
-			else
-				verbose(env, "    ");
-			verbose(env, "%3d: ", i);
-			for (j = BPF_REG_0; j < BPF_REG_10; ++j)
-				if (insn_aux[i].live_regs_before & BIT(j))
-					verbose(env, "%d", j);
-				else
-					verbose(env, ".");
-			verbose(env, " ");
-			bpf_verbose_insn(env, &insns[i]);
-			if (bpf_is_ldimm64(&insns[i]))
-				i++;
-		}
-	}
-
 out:
 	kvfree(state);
 	return err;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c8d980fdd709..3d569e36128c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -19619,6 +19619,34 @@ int bpf_fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 	return 0;
 }
 
+/* Various log level 2 information about the program */
+static void log_program(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *insn_aux = env->insn_aux_data;
+	struct bpf_insn *insns = env->prog->insnsi;
+	u32 insn_cnt = env->prog->len;
+	u32 i, j;
+
+	verbose(env, "Program dump (scc? insn#: live_regs_before):\n");
+	for (i = 0; i < insn_cnt; ++i) {
+		verbose_linfo(env, i, "    ; ");
+		if (env->insn_aux_data[i].scc)
+			verbose(env, "%3d ", env->insn_aux_data[i].scc);
+		else
+			verbose(env, "    ");
+		verbose(env, "%3d: ", i);
+		for (j = BPF_REG_0; j < BPF_REG_10; ++j)
+			if (insn_aux[i].live_regs_before & BIT(j))
+				verbose(env, "%d", j);
+			else
+				verbose(env, ".");
+		verbose(env, " ");
+		bpf_verbose_insn(env, &insns[i]);
+		if (bpf_is_ldimm64(&insns[i]))
+			i++;
+	}
+}
+
 int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr,
 	      struct bpf_log_attr *attr_log)
 {
@@ -19771,6 +19799,9 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr,
 	if (ret < 0)
 		goto skip_full_check;
 
+	if (env->log.level & BPF_LOG_LEVEL2)
+		log_program(env);
+
 	ret = mark_fastcall_patterns(env);
 	if (ret < 0)
 		goto skip_full_check;
diff --git a/tools/testing/selftests/bpf/progs/verifier_live_stack.c b/tools/testing/selftests/bpf/progs/verifier_live_stack.c
index 401152b2b64f..923572df4bbf 100644
--- a/tools/testing/selftests/bpf/progs/verifier_live_stack.c
+++ b/tools/testing/selftests/bpf/progs/verifier_live_stack.c
@@ -64,7 +64,7 @@ SEC("socket")
 __log_level(2)
 __msg("stack use/def subprog#0 must_write_not_same_slot (d0,cs0):")
 __msg("6: (7b) *(u64 *)(r2 +0) = r0{{$}}")
-__msg("Live regs before insn:")
+__msg("Program dump")
 __naked void must_write_not_same_slot(void)
 {
 	asm volatile (

-- 
2.54.0