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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2020 Facebook */
#include <stddef.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#define MAX_STACK 260
static __attribute__ ((noinline))
int f0(int var, struct __sk_buff *skb)
{
asm volatile ("");
return skb->len;
}
__attribute__ ((noinline))
int f1(struct __sk_buff *skb)
{
volatile char buf[MAX_STACK] = {};
__sink(buf[MAX_STACK - 1]);
return f0(0, skb) + skb->len;
}
int f3(int, struct __sk_buff *skb, int);
__attribute__ ((noinline))
int f2(int val, struct __sk_buff *skb)
{
volatile char buf[MAX_STACK] = {};
__sink(buf[MAX_STACK - 1]);
return f1(skb) + f3(val, skb, 1);
}
__attribute__ ((noinline))
int f3(int val, struct __sk_buff *skb, int var)
{
volatile char buf[MAX_STACK] = {};
__sink(buf[MAX_STACK - 1]);
return skb->ifindex * val * var;
}
SEC("tc")
__load_if_no_large_stack()
__failure __msg("combined stack size of 3 calls is")
int global_func1(struct __sk_buff *skb)
{
return f0(1, skb) + f1(skb) + f2(2, skb) + f3(3, skb, 4);
}
/*
* A chain of five frames that stay under 512 bytes each but add up to more
* than the 2 KiB budget of JITs with large stacks; the chain also exceeds
* 512 bytes after two frames, so it is rejected everywhere.
*/
#define MAX_STACK_LARGE 480
__attribute__ ((noinline))
int g0(struct __sk_buff *skb)
{
volatile char buf[MAX_STACK_LARGE] = {};
__sink(buf[MAX_STACK_LARGE - 1]);
return skb->len;
}
__attribute__ ((noinline))
int g1(struct __sk_buff *skb)
{
volatile char buf[MAX_STACK_LARGE] = {};
__sink(buf[MAX_STACK_LARGE - 1]);
return g0(skb) + skb->len;
}
__attribute__ ((noinline))
int g2(struct __sk_buff *skb)
{
volatile char buf[MAX_STACK_LARGE] = {};
__sink(buf[MAX_STACK_LARGE - 1]);
return g1(skb) + skb->len;
}
__attribute__ ((noinline))
int g3(struct __sk_buff *skb)
{
volatile char buf[MAX_STACK_LARGE] = {};
__sink(buf[MAX_STACK_LARGE - 1]);
return g2(skb) + skb->len;
}
__attribute__ ((noinline))
int g4(struct __sk_buff *skb)
{
volatile char buf[MAX_STACK_LARGE] = {};
__sink(buf[MAX_STACK_LARGE - 1]);
return g3(skb) + skb->len;
}
SEC("tc")
__failure __msg("combined stack size of {{[0-9]+}} calls is")
int global_func1_deep(struct __sk_buff *skb)
{
return g4(skb);
}
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