1/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
 2/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
 3#pragma once
 4#include "bpf_arena_common.h"
 5
 6struct arena_list_node;
 7
 8typedef struct arena_list_node __arena arena_list_node_t;
 9
10struct arena_list_node {
11	arena_list_node_t *next;
12	arena_list_node_t * __arena *pprev;
13};
14
15struct arena_list_head {
16	struct arena_list_node __arena *first;
17};
18typedef struct arena_list_head __arena arena_list_head_t;
19
20#define list_entry(ptr, type, member) arena_container_of(ptr, type, member)
21
22#define list_entry_safe(ptr, type, member) \
23	({ typeof(*ptr) * ___ptr = (ptr); \
24	 ___ptr ? ({ cast_kern(___ptr); list_entry(___ptr, type, member); }) : NULL; \
25	 })
26
27#ifndef __BPF__
28static inline void *bpf_iter_num_new(struct bpf_iter_num *it, int i, int j) { return NULL; }
29static inline void bpf_iter_num_destroy(struct bpf_iter_num *it) {}
30static inline bool bpf_iter_num_next(struct bpf_iter_num *it) { return true; }
31#define cond_break ({})
32#define can_loop true
33#endif
34
35/* Safely walk link list elements. Deletion of elements is allowed. */
36#define list_for_each_entry(pos, head, member)					\
37	for (void * ___tmp = (pos = list_entry_safe((head)->first,		\
38						    typeof(*(pos)), member),	\
39			      (void *)0);					\
40	     pos && ({ ___tmp = (void *)pos->member.next; 1; }) && can_loop;    \
41	     pos = list_entry_safe((void __arena *)___tmp, typeof(*(pos)), member))
42
43static inline void list_add_head(arena_list_node_t *n, arena_list_head_t *h)
44{
45	arena_list_node_t *first = h->first, * __arena *tmp;
46
47	cast_user(first);
48	cast_kern(n);
49	WRITE_ONCE(n->next, first);
50	cast_kern(first);
51	if (first) {
52		tmp = &n->next;
53		cast_user(tmp);
54		WRITE_ONCE(first->pprev, tmp);
55	}
56	cast_user(n);
57	WRITE_ONCE(h->first, n);
58
59	tmp = &h->first;
60	cast_user(tmp);
61	cast_kern(n);
62	WRITE_ONCE(n->pprev, tmp);
63}
64
65static inline void __list_del(arena_list_node_t *n)
66{
67	arena_list_node_t *next = n->next, *tmp;
68	arena_list_node_t * __arena *pprev = n->pprev;
69
70	cast_user(next);
71	cast_kern(pprev);
72	tmp = *pprev;
73	cast_kern(tmp);
74	WRITE_ONCE(tmp, next);
75	if (next) {
76		cast_user(pprev);
77		cast_kern(next);
78		WRITE_ONCE(next->pprev, pprev);
79	}
80}
81
82#define POISON_POINTER_DELTA 0
83
84#define LIST_POISON1  ((void __arena *) 0x100 + POISON_POINTER_DELTA)
85#define LIST_POISON2  ((void __arena *) 0x122 + POISON_POINTER_DELTA)
86
87static inline void list_del(arena_list_node_t *n)
88{
89	__list_del(n);
90	n->next = LIST_POISON1;
91	n->pprev = LIST_POISON2;
92}