tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy3.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy3.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy3.c
Extension
.c
Size
1276 bytes
Lines
73
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "bpf_test_utils.h"

int classifier_0(struct __sk_buff *skb);

struct {
	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
	__uint(max_entries, 1);
	__uint(key_size, sizeof(__u32));
	__array(values, void (void));
} jmp_table0 SEC(".maps") = {
	.values = {
		[0] = (void *) &classifier_0,
	},
};

struct {
	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
	__uint(max_entries, 1);
	__uint(key_size, sizeof(__u32));
	__array(values, void (void));
} jmp_table1 SEC(".maps") = {
	.values = {
		[0] = (void *) &classifier_0,
	},
};

int count = 0;

static __noinline
int subprog_tail(struct __sk_buff *skb, void *jmp_table)
{
	int ret = 0;

	bpf_tail_call_static(skb, jmp_table, 0);
	barrier_var(ret);
	return ret;
}

__auxiliary
SEC("tc")
int classifier_0(struct __sk_buff *skb)
{
	int ret1, ret2;

	count++;
	ret1 = subprog_tail(skb, &jmp_table0);
	ret2 = subprog_tail(skb, &jmp_table1);
	__sink(ret1);
	__sink(ret2);
	return count;
}

__success
__retval(33)
SEC("tc")
int tailcall_bpf2bpf_hierarchy_3(struct __sk_buff *skb)
{
	int ret = 0;

	clobber_regs_stack();

	bpf_tail_call_static(skb, &jmp_table0, 0);

	__sink(ret);
	return ret;
}

char __license[] SEC("license") = "GPL";

Annotation

Implementation Notes