[PATCH bpf-next 3/3] selftests/bpf: Run stacktrace_ips raw_tp, tp and fentry tests on arm64

[Andrii Nakryiko <andrii@kernel.org>]

The raw_tp, tp and fentry subtests check stacks unwound from
perf_fetch_caller_regs() regs, which arm64 reported with the caller
twice until perf_arch_fetch_caller_regs() was fixed. Run them on arm64
as well, where kernel stacks are always unwound through frame records.

Leave the kprobe and fexit subtests x86-only: on arm64, kprobes at
function entry miss the probed function's caller, and fexit stacks
have an extra entry for the traced function (kretprobe subtests pass,
but don't use these regs).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 .../selftests/bpf/prog_tests/stacktrace_ips.c     | 15 +++++++++++----
 .../testing/selftests/bpf/progs/stacktrace_ips.c  |  5 +++--
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c
index a03d4c10c469..aee46543f390 100644
--- a/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c
+++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c
@@ -2,7 +2,7 @@
 #include <test_progs.h>
 #include "stacktrace_ips.skel.h"
 
-#ifdef __x86_64__
+#if defined(__x86_64__) || defined(__aarch64__)
 static int check_stacktrace_ips(int fd, __u32 key, int cnt, ...)
 {
 	__u64 ips[PERF_MAX_STACK_DEPTH];
@@ -47,6 +47,12 @@ static int check_stacktrace_ips(int fd, __u32 key, int cnt, ...)
 	return err;
 }
 
+/* arm64 always unwinds kernel stacks through frame records */
+static bool unwinder_ok(struct stacktrace_ips *skel)
+{
+	return skel->kconfig->CONFIG_UNWINDER_ORC || skel->kconfig->CONFIG_ARM64;
+}
+
 static void test_stacktrace_ips_kprobe_multi(bool retprobe)
 {
 	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts,
@@ -106,7 +112,7 @@ static void test_stacktrace_ips_raw_tp(void)
 	if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))
 		return;
 
-	if (!skel->kconfig->CONFIG_UNWINDER_ORC) {
+	if (!unwinder_ok(skel)) {
 		test__skip();
 		goto cleanup;
 	}
@@ -149,7 +155,7 @@ static void test_stacktrace_ips_tp(void)
 	if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))
 		return;
 
-	if (!skel->kconfig->CONFIG_UNWINDER_ORC) {
+	if (!unwinder_ok(skel)) {
 		test__skip();
 		goto cleanup;
 	}
@@ -244,7 +250,8 @@ static void test_stacktrace_ips_trampoline(bool retprobe)
 	if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))
 		return;
 
-	if (!skel->kconfig->CONFIG_UNWINDER_ORC) {
+	/* on arm64, fexit stacks also have a frame for the traced function */
+	if ((retprobe && !skel->kconfig->CONFIG_UNWINDER_ORC) || !unwinder_ok(skel)) {
 		test__skip();
 		goto cleanup;
 	}
diff --git a/tools/testing/selftests/bpf/progs/stacktrace_ips.c b/tools/testing/selftests/bpf/progs/stacktrace_ips.c
index df10ef3cb14d..11dfebd4ddb2 100644
--- a/tools/testing/selftests/bpf/progs/stacktrace_ips.c
+++ b/tools/testing/selftests/bpf/progs/stacktrace_ips.c
@@ -19,14 +19,15 @@ struct {
 } stackmap SEC(".maps");
 
 extern bool CONFIG_UNWINDER_ORC __kconfig __weak;
+extern bool CONFIG_ARM64 __kconfig __weak;
 
 /*
- * This function is here to have CONFIG_UNWINDER_ORC
+ * This function is here to have CONFIG_UNWINDER_ORC and CONFIG_ARM64
  * used and added to object BTF.
  */
 int unused(void)
 {
-	return CONFIG_UNWINDER_ORC ? 0 : 1;
+	return CONFIG_UNWINDER_ORC || CONFIG_ARM64 ? 0 : 1;
 }
 
 __u32 stack_key;
-- 
2.53.1-Meta