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
6 struct arena_list_node;
7
8 typedef struct arena_list_node __arena arena_list_node_t;
9
10 struct arena_list_node {
11 arena_list_node_t *next;
12 arena_list_node_t * __arena *pprev;
13 };
14
15 struct arena_list_head {
16 struct arena_list_node __arena *first;
17 };
18 typedef 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__
28 static inline void *bpf_iter_num_new(struct bpf_iter_num *it, int i, int j) { return NULL; }
29 static inline void bpf_iter_num_destroy(struct bpf_iter_num *it) {}
30 static 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
43 static 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
65 static 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
87 static 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 }
93
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