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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
#define BPF_NO_KFUNC_PROTOTYPES
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include "bpf_experimental.h"
#include <bpf_arena_common.h>
char _license[] SEC("license") = "GPL";
/*
* The module types as a vmlinux.h generated by a libbpf that does not render
* the arena tag with its address space shows them: an attribute on a pointer
* in the kernel address space, so the program has to cast the member to the
* arena address space before using it.
*/
#define __arena_tag __attribute__((btf_type_tag("arena")))
#define __nullable_tag __attribute__((btf_type_tag("nullable")))
struct bpf_testmod_arena_member_args {
__u64 __arena_tag *ptr;
__u64 __arena_tag __nullable_tag *null_ptr;
struct {
__u64 __arena_tag *ptr;
} nested;
} __attribute__((preserve_access_index));
struct bpf_testmod_ops3 {
int (*test_arena_member)(struct bpf_testmod_arena_member_args *args);
};
int bpf_testmod_ops3_call_test_arena_member(__u64 *ptr__arena) __ksym;
struct {
__uint(type, BPF_MAP_TYPE_ARENA);
__uint(map_flags, BPF_F_MMAPABLE);
__uint(max_entries, 2);
} arena SEC(".maps");
/* also associates the callback with the arena */
u64 __arena arena_touch;
SEC("struct_ops/test_arena_member")
int BPF_PROG(test_arena_member_render_cb, struct bpf_testmod_arena_member_args *args)
{
u64 __arena *ptr = (u64 __arena *)args->ptr;
arena_touch++;
*ptr += 1;
if (args->null_ptr)
return 0xbad;
*(u64 __arena *)args->nested.ptr += 1;
return 0;
}
SEC(".struct_ops.link")
struct bpf_testmod_ops3 testmod_arena_member_render = {
.test_arena_member = (void *)test_arena_member_render_cb,
};
SEC("syscall")
int trigger(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
u64 __arena *val;
int ret;
val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (!val)
return 1;
*val = 41;
ret = bpf_testmod_ops3_call_test_arena_member((u64 *)val);
if (ret)
return 2;
/* ptr and nested.ptr each added one */
if (*val != 43)
return 3;
bpf_arena_free_pages(&arena, (void __arena *)val, 1);
#endif
return 0;
}
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