[PATCH bpf-next] selftest/bpf: make pyperf600 a success again

pyperf600 has been running into 8K BPF_COMPLEXITY_LIMIT_JMP_SEQ limitations
for a long while now, after some internal compiler changes.

Until BPF verifier is bestowed with scalar evolution logic, make that test
actually work by doing what would anyone should do in such situations: by
moving repeatable per-iteration work into independently verified global
functions.

`void *` argument is a problem for global funcs, but a static function wrapper
doing necessary casts and a bit of __arg_nonnull magic dust is all it takes.

Signed-off-by: Andrii Nakryiko <[email protected]>
---
 tools/testing/selftests/bpf/progs/pyperf.h | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/pyperf.h b/tools/testing/selftests/bpf/progs/pyperf.h
index 86484f07e1d1..fd93a96e5901 100644
--- a/tools/testing/selftests/bpf/progs/pyperf.h
+++ b/tools/testing/selftests/bpf/progs/pyperf.h
@@ -85,9 +85,11 @@ static void *get_thread_state(void *tls_base, PidData *pidData)
 	return thread_state;
 }
 
-static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
-					   FrameData *frame, Symbol *symbol)
+__weak bool __get_frame_data(long frame_ptr_, PidData *pidData __arg_nonnull,
+			     FrameData *frame __arg_nonnull, Symbol *symbol __arg_nonnull)
 {
+	void *frame_ptr = (void *)frame_ptr_;
+
 	// read data from PyFrameObject
 	bpf_probe_read_user(&frame->f_back,
 			    sizeof(frame->f_back),
@@ -119,6 +121,12 @@ static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
 	return true;
 }
 
+static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
+					   FrameData *frame, Symbol *symbol)
+{
+	return __get_frame_data((long)frame_ptr, pidData, frame, symbol);
+}
+
 struct {
 	__uint(type, BPF_MAP_TYPE_HASH);
 	__uint(max_entries, 1);
-- 
2.53.0-Meta