[PATCH bpf-next v6 6/6] selftests/bpf: Test subprogram instruction statistics

Add small verifier programs with deterministic instruction streams to
exercise per-subprogram own and inclusive instruction accounting. Use
assembly for normal call chains and straight-line callback bodies
containing only moves, calls, and returns or exits, so control-flow
pruning does not make the expected counts unstable.

Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]>
---
 .../selftests/bpf/prog_tests/verifier.c       |   2 +
 .../bpf/progs/verifier_subprog_insn_stats.c   | 225 ++++++++++++++++++
 2 files changed, 227 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_subprog_insn_stats.c

diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
index b79bafca68f7..19d03f6d6525 100644
--- a/tools/testing/selftests/bpf/prog_tests/verifier.c
+++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
@@ -100,6 +100,7 @@
 #include "verifier_stack_arg_order.skel.h"
 #include "verifier_stack_ptr.skel.h"
 #include "verifier_store_release.skel.h"
+#include "verifier_subprog_insn_stats.skel.h"
 #include "verifier_subprog_precision.skel.h"
 #include "verifier_subprog_topo.skel.h"
 #include "verifier_subreg.skel.h"
@@ -255,6 +256,7 @@ void test_verifier_stack_arg(void)            { RUN(verifier_stack_arg); }
 void test_verifier_stack_arg_order(void)      { RUN(verifier_stack_arg_order); }
 void test_verifier_stack_ptr(void)            { RUN(verifier_stack_ptr); }
 void test_verifier_store_release(void)        { RUN(verifier_store_release); }
+void test_verifier_subprog_insn_stats(void)   { RUN(verifier_subprog_insn_stats); }
 void test_verifier_subprog_precision(void)    { RUN(verifier_subprog_precision); }
 void test_verifier_subprog_topo(void)        { RUN(verifier_subprog_topo); }
 void test_verifier_subreg(void)               { RUN(verifier_subreg); }
diff --git a/tools/testing/selftests/bpf/progs/verifier_subprog_insn_stats.c b/tools/testing/selftests/bpf/progs/verifier_subprog_insn_stats.c
new file mode 100644
index 000000000000..b7ac55f4f136
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/verifier_subprog_insn_stats.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+struct timer_value {
+	struct bpf_timer timer;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, struct timer_value);
+} timer_map SEC(".maps");
+
+SEC("?raw_tp")
+__success __log_level(4)
+__msg("subprog 0 (stats_main_only) main insns_own 2 insns_total 2 stack 0")
+__msg("processed 2 insns")
+__naked int stats_main_only(void)
+{
+	asm volatile (
+		"r0 = 0;"
+		"exit;"
+	);
+}
+
+__naked __noinline __used
+static int stats_chain_leaf(void)
+{
+	asm volatile (
+		"r0 = 0;"
+		"exit;"
+	);
+}
+
+__naked __noinline __used
+static int stats_chain_parent(void)
+{
+	asm volatile (
+		"call stats_chain_leaf;"
+		"exit;"
+	);
+}
+
+SEC("?raw_tp")
+__success __log_level(4)
+/*
+ * own: 2 + 2 + 2 = 6
+ * totals: leaf 2, parent 2 + 2 = 4, main 2 + 4 = 6
+ */
+__msg("subprog 0 (stats_static_chain) main insns_own 2 insns_total 6 stack 0")
+__msg("subprog {{[0-9]+}} (stats_chain_parent) static insns_own 2 insns_total 4 stack 0")
+__msg("subprog {{[0-9]+}} (stats_chain_leaf) static insns_own 2 insns_total 2 stack 0")
+__msg("processed 6 insns")
+__naked int stats_static_chain(void)
+{
+	asm volatile (
+		"call stats_chain_parent;"
+		"exit;"
+	);
+}
+
+__naked __noinline __used
+static int stats_shared_leaf(void)
+{
+	asm volatile (
+		"r0 = 0;"
+		"exit;"
+	);
+}
+
+__naked __noinline __used
+int stats_global_root(void)
+{
+	asm volatile (
+		"call stats_shared_leaf;"
+		"exit;"
+	);
+}
+
+SEC("?raw_tp")
+__success __log_level(4)
+/*
+ * stats_shared_leaf is explored once under each independent root.
+ * own: main 3 + leaf 4 + global 2 = 9
+ * root totals: main 5 + global 4 = 9
+ */
+__msg("subprog 0 (stats_shared_roots) main insns_own 3 insns_total 5 stack 0")
+__msg("subprog {{[0-9]+}} (stats_shared_leaf) static insns_own 4 insns_total 4 stack 0")
+__msg("subprog {{[0-9]+}} (stats_global_root) global insns_own 2 insns_total 4 stack 0")
+__msg("processed 9 insns")
+__naked int stats_shared_roots(void)
+{
+	asm volatile (
+		"call stats_shared_leaf;"
+		"call stats_global_root;"
+		"exit;"
+	);
+}
+
+__noinline __used
+static int stats_async_leaf(void *map, __u32 *key, struct bpf_timer *timer)
+{
+	return 0;
+}
+
+__noinline __used
+static __u64 stats_async_schedule(struct bpf_map *map, __u32 *key,
+				  struct timer_value *value, void *ctx)
+{
+	asm volatile (
+		"r1 = r3;"
+		"r2 = %[stats_async_leaf];"
+		"call %[bpf_timer_set_callback];"
+		:
+		: __imm_ptr(stats_async_leaf),
+		  __imm(bpf_timer_set_callback)
+		: __clobber_common
+	);
+	return 0;
+}
+
+SEC("?raw_tp")
+__success __log_level(4)
+/*
+ * own: 9 + 6 + 2 = 17
+ * totals: leaf 2, scheduler 6 + 2 = 8, main 17
+ */
+__msg("subprog 0 (stats_async_direct) main insns_own 9 insns_total 17 stack 0")
+__msg("subprog {{[0-9]+}} (stats_async_schedule) static insns_own 6 "
+      "insns_total 8 stack 0")
+__msg("subprog {{[0-9]+}} (stats_async_leaf) static insns_own 2 "
+      "insns_total 2 stack 0")
+__msg("processed 17 insns")
+__naked int stats_async_direct(void)
+{
+	asm volatile (
+		"r1 = %[timer_map] ll;"
+		"r2 = %[stats_async_schedule];"
+		"r3 = 0;"
+		"r4 = 0;"
+		"call %[bpf_for_each_map_elem];"
+		"r0 = 0;"
+		"exit;"
+		:
+		: __imm_addr(timer_map),
+		  __imm_ptr(stats_async_schedule),
+		  __imm(bpf_for_each_map_elem)
+		: __clobber_common
+	);
+}
+
+__noinline __used
+static int stats_async_nested_leaf(void *map, __u32 *key, struct bpf_timer *timer)
+{
+	return 0;
+}
+
+__noinline __used
+static int stats_async_outer(void *map, __u32 *key, struct bpf_timer *timer)
+{
+	asm volatile (
+		"r1 = r3;"
+		"r2 = %[stats_async_nested_leaf];"
+		"call %[bpf_timer_set_callback];"
+		:
+		: __imm_ptr(stats_async_nested_leaf),
+		  __imm(bpf_timer_set_callback)
+		: __clobber_common
+	);
+	return 0;
+}
+
+__noinline __used
+static __u64 stats_async_nested_schedule(struct bpf_map *map, __u32 *key,
+					 struct timer_value *value, void *ctx)
+{
+	asm volatile (
+		"r1 = r3;"
+		"r2 = %[stats_async_outer];"
+		"call %[bpf_timer_set_callback];"
+		:
+		: __imm_ptr(stats_async_outer),
+		  __imm(bpf_timer_set_callback)
+		: __clobber_common
+	);
+	return 0;
+}
+
+SEC("?raw_tp")
+__success __log_level(4)
+/*
+ * own: 9 + 6 + 6 + 2 = 23
+ * totals: leaf 2, outer 8, scheduler 14, main 23
+ */
+__msg("subprog 0 (stats_async_nested) main insns_own 9 insns_total 23 stack 0")
+__msg("subprog {{[0-9]+}} (stats_async_nested_schedule) static insns_own 6 "
+      "insns_total 14 stack 0")
+__msg("subprog {{[0-9]+}} (stats_async_outer) static insns_own 6 "
+      "insns_total 8 stack 0")
+__msg("subprog {{[0-9]+}} (stats_async_nested_leaf) static insns_own 2 "
+      "insns_total 2 stack 0")
+__msg("processed 23 insns")
+__naked int stats_async_nested(void)
+{
+	asm volatile (
+		"r1 = %[timer_map] ll;"
+		"r2 = %[stats_async_nested_schedule];"
+		"r3 = 0;"
+		"r4 = 0;"
+		"call %[bpf_for_each_map_elem];"
+		"r0 = 0;"
+		"exit;"
+		:
+		: __imm_addr(timer_map),
+		  __imm_ptr(stats_async_nested_schedule),
+		  __imm(bpf_for_each_map_elem)
+		: __clobber_common
+	);
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.53.0