[RFC PATCH bpf-next 2/7] bpf: Add struct argument info in btf_func_model

[Yonghong Song <yhs@fb.com>]

Add struct argument information in btf_func_model and such information
will be used in arch specific function arch_prepare_bpf_trampoline()
to prepare argument access properly in trampoline.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 20c26aed7896..173b42cf3940 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -726,10 +726,19 @@ enum bpf_cgroup_storage_type {
  */
 #define MAX_BPF_FUNC_REG_ARGS 5
 
+/* The maximum number of struct arguments a single function may have. */
+#define MAX_BPF_FUNC_STRUCT_ARGS 2
+
 struct btf_func_model {
 	u8 ret_size;
 	u8 nr_args;
 	u8 arg_size[MAX_BPF_FUNC_ARGS];
+	/* The struct_arg_idx should be in increasing order like (0, 2, ...).
+	 * The struct_arg_bsize encodes the struct field byte size
+	 * for the corresponding struct argument index.
+	 */
+	u8 struct_arg_idx[MAX_BPF_FUNC_STRUCT_ARGS];
+	u8 struct_arg_bsize[MAX_BPF_FUNC_STRUCT_ARGS];
 };
 
 /* Restore arguments before returning from trampoline to let original function
-- 
2.30.2