1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2020 Facebook */ 3 #include <stddef.h> 4 #include <linux/bpf.h> 5 #include <bpf/bpf_helpers.h> 6 #include "bpf_misc.h" 7 8 #define MAX_STACK (512 - 3 * 32) 9 10 static __attribute__ ((noinline)) 11 int f0(int var, struct __sk_buff *skb) 12 { 13 return skb->len; 14 } 15 16 __attribute__ ((noinline)) 17 int f1(struct __sk_buff *skb) 18 { 19 volatile char buf[MAX_STACK] = {}; 20 21 __sink(buf[MAX_STACK - 1]); 22 23 return f0(0, skb) + skb->len; 24 } 25 26 int f3(int, struct __sk_buff *skb, int); 27 28 __attribute__ ((noinline)) 29 int f2(int val, struct __sk_buff *skb) 30 { 31 return f1(skb) + f3(val, skb, 1); 32 } 33 34 __attribute__ ((noinline)) 35 int f3(int val, struct __sk_buff *skb, int var) 36 { 37 volatile char buf[MAX_STACK] = {}; 38 39 __sink(buf[MAX_STACK - 1]); 40 41 return skb->ifindex * val * var; 42 } 43 44 SEC("tc") 45 __success 46 int global_func2(struct __sk_buff *skb) 47 { 48 return f0(1, skb) + f1(skb) + f2(2, skb) + f3(3, skb, 4); 49 } 50