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12f57721 MO |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions | |
4 | * cannot be called either. This file explicitly creates functions ("helpers") | |
5 | * that wrap those so that they can be called from Rust. | |
6 | * | |
7 | * Even though Rust kernel modules should never use directly the bindings, some | |
8 | * of these helpers need to be exported because Rust generics and inlined | |
9 | * functions may not get their code generated in the crate where they are | |
10 | * defined. Other helpers, called from non-inline functions, may not be | |
11 | * exported, in principle. However, in general, the Rust compiler does not | |
12 | * guarantee codegen will be performed for a non-inline function either. | |
13 | * Therefore, this file exports all the helpers. In the future, this may be | |
14 | * revisited to reduce the number of exports after the compiler is informed | |
15 | * about the places codegen is required. | |
16 | * | |
17 | * All symbols are exported as GPL-only to guarantee no GPL-only feature is | |
18 | * accidentally exposed. | |
19 | */ | |
20 | ||
21 | #include <linux/bug.h> | |
22 | #include <linux/build_bug.h> | |
c7e20faa | 23 | #include <linux/err.h> |
9dc04365 | 24 | #include <linux/refcount.h> |
6d20d629 | 25 | #include <linux/mutex.h> |
c6d917a4 | 26 | #include <linux/spinlock.h> |
313c4281 | 27 | #include <linux/sched/signal.h> |
19096bce | 28 | #include <linux/wait.h> |
12f57721 MO |
29 | |
30 | __noreturn void rust_helper_BUG(void) | |
31 | { | |
32 | BUG(); | |
33 | } | |
34 | EXPORT_SYMBOL_GPL(rust_helper_BUG); | |
35 | ||
6d20d629 WAF |
36 | void rust_helper_mutex_lock(struct mutex *lock) |
37 | { | |
38 | mutex_lock(lock); | |
39 | } | |
40 | EXPORT_SYMBOL_GPL(rust_helper_mutex_lock); | |
41 | ||
c6d917a4 WAF |
42 | void rust_helper___spin_lock_init(spinlock_t *lock, const char *name, |
43 | struct lock_class_key *key) | |
44 | { | |
45 | #ifdef CONFIG_DEBUG_SPINLOCK | |
46 | __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG); | |
47 | #else | |
48 | spin_lock_init(lock); | |
49 | #endif | |
50 | } | |
51 | EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init); | |
52 | ||
53 | void rust_helper_spin_lock(spinlock_t *lock) | |
54 | { | |
55 | spin_lock(lock); | |
56 | } | |
57 | EXPORT_SYMBOL_GPL(rust_helper_spin_lock); | |
58 | ||
59 | void rust_helper_spin_unlock(spinlock_t *lock) | |
60 | { | |
61 | spin_unlock(lock); | |
62 | } | |
63 | EXPORT_SYMBOL_GPL(rust_helper_spin_unlock); | |
64 | ||
19096bce WAF |
65 | void rust_helper_init_wait(struct wait_queue_entry *wq_entry) |
66 | { | |
67 | init_wait(wq_entry); | |
68 | } | |
69 | EXPORT_SYMBOL_GPL(rust_helper_init_wait); | |
70 | ||
313c4281 WAF |
71 | int rust_helper_signal_pending(struct task_struct *t) |
72 | { | |
73 | return signal_pending(t); | |
74 | } | |
75 | EXPORT_SYMBOL_GPL(rust_helper_signal_pending); | |
76 | ||
9dc04365 WAF |
77 | refcount_t rust_helper_REFCOUNT_INIT(int n) |
78 | { | |
79 | return (refcount_t)REFCOUNT_INIT(n); | |
80 | } | |
81 | EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT); | |
82 | ||
83 | void rust_helper_refcount_inc(refcount_t *r) | |
84 | { | |
85 | refcount_inc(r); | |
86 | } | |
87 | EXPORT_SYMBOL_GPL(rust_helper_refcount_inc); | |
88 | ||
89 | bool rust_helper_refcount_dec_and_test(refcount_t *r) | |
90 | { | |
91 | return refcount_dec_and_test(r); | |
92 | } | |
93 | EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test); | |
94 | ||
c7e20faa AL |
95 | __force void *rust_helper_ERR_PTR(long err) |
96 | { | |
97 | return ERR_PTR(err); | |
98 | } | |
99 | EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR); | |
100 | ||
752417b3 SVA |
101 | bool rust_helper_IS_ERR(__force const void *ptr) |
102 | { | |
103 | return IS_ERR(ptr); | |
104 | } | |
105 | EXPORT_SYMBOL_GPL(rust_helper_IS_ERR); | |
106 | ||
107 | long rust_helper_PTR_ERR(__force const void *ptr) | |
108 | { | |
109 | return PTR_ERR(ptr); | |
110 | } | |
111 | EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR); | |
112 | ||
8da7a2b7 WAF |
113 | struct task_struct *rust_helper_get_current(void) |
114 | { | |
115 | return current; | |
116 | } | |
117 | EXPORT_SYMBOL_GPL(rust_helper_get_current); | |
118 | ||
313c4281 WAF |
119 | void rust_helper_get_task_struct(struct task_struct *t) |
120 | { | |
121 | get_task_struct(t); | |
122 | } | |
123 | EXPORT_SYMBOL_GPL(rust_helper_get_task_struct); | |
124 | ||
125 | void rust_helper_put_task_struct(struct task_struct *t) | |
126 | { | |
127 | put_task_struct(t); | |
128 | } | |
129 | EXPORT_SYMBOL_GPL(rust_helper_put_task_struct); | |
130 | ||
12f57721 MO |
131 | /* |
132 | * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type | |
133 | * as the Rust `usize` type, so we can use it in contexts where Rust | |
134 | * expects a `usize` like slice (array) indices. `usize` is defined to be | |
135 | * the same as C's `uintptr_t` type (can hold any pointer) but not | |
136 | * necessarily the same as `size_t` (can hold the size of any single | |
137 | * object). Most modern platforms use the same concrete integer type for | |
138 | * both of them, but in case we find ourselves on a platform where | |
139 | * that's not true, fail early instead of risking ABI or | |
140 | * integer-overflow issues. | |
141 | * | |
142 | * If your platform fails this assertion, it means that you are in | |
143 | * danger of integer-overflow bugs (even if you attempt to remove | |
144 | * `--size_t-is-usize`). It may be easiest to change the kernel ABI on | |
145 | * your platform such that `size_t` matches `uintptr_t` (i.e., to increase | |
146 | * `size_t`, because `uintptr_t` has to be at least as big as `size_t`). | |
147 | */ | |
148 | static_assert( | |
149 | sizeof(size_t) == sizeof(uintptr_t) && | |
150 | __alignof__(size_t) == __alignof__(uintptr_t), | |
151 | "Rust code expects C `size_t` to match Rust `usize`" | |
152 | ); |