1 files changed, 19 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c b/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c
index 9a06e5eb1fbef..143c8a4852bfe 100644
--- a/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c
+++ b/tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c
@@ -26,6 +26,23 @@ int kprobe_typedef_ctx(void *ctx)
 	return kprobe_typedef_ctx_subprog(ctx);
 }
 
+/* s390x defines:
+ *
+ * typedef user_pt_regs bpf_user_pt_regs_t;
+ * typedef struct { ... } user_pt_regs;
+ *
+ * And so "canonical" underlying struct type is anonymous.
+ * So on s390x only valid ways to have PTR_TO_CTX argument in global subprogs
+ * are:
+ *   - bpf_user_pt_regs_t *ctx (typedef);
+ *   - struct bpf_user_pt_regs_t *ctx (backwards compatible struct hack);
+ *   - void *ctx __arg_ctx (arg:ctx tag)
+ *
+ * Other architectures also allow using underlying struct types (e.g.,
+ * `struct pt_regs *ctx` for x86-64)
+ */
+#ifndef bpf_target_s390
+
 #define pt_regs_struct_t typeof(*(__PT_REGS_CAST((struct pt_regs *)NULL)))
 
 __weak int kprobe_struct_ctx_subprog(pt_regs_struct_t *ctx)
@@ -40,6 +57,8 @@ int kprobe_resolved_ctx(void *ctx)
 	return kprobe_struct_ctx_subprog(ctx);
 }
 
+#endif
+
 /* this is current hack to make this work on old kernels */
 struct bpf_user_pt_regs_t {};