bpf, x64: Add union argument support in trampoline

As verifier allows functions with 'union' argument can be traced, add
'union' arguments support in trampoline if the argument's size is in
range '(8, 16]'.

Signed-off-by: Leon Hwang <[email protected]>

Author: Asphaltt

arch/x86/net/bpf_jit_comp.c

@@ -3164,7 +3164,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
 
 	/* extra registers for struct arguments */
 	for (i = 0; i < m->nr_args; i++) {
-		if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+		if (m->arg_flags[i] & (BTF_FMODEL_STRUCT_ARG | BTF_FMODEL_UNION_ARG))
 			nr_regs += (m->arg_size[i] + 7) / 8 - 1;
 	}