Linux kernel mirror (for testing)
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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>
23#include <linux/err.h>
24#include <linux/refcount.h>
25#include <linux/mutex.h>
26#include <linux/spinlock.h>
27#include <linux/sched/signal.h>
28#include <linux/wait.h>
29
30__noreturn void rust_helper_BUG(void)
31{
32 BUG();
33}
34EXPORT_SYMBOL_GPL(rust_helper_BUG);
35
36void rust_helper_mutex_lock(struct mutex *lock)
37{
38 mutex_lock(lock);
39}
40EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
41
42void 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}
51EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
52
53void rust_helper_spin_lock(spinlock_t *lock)
54{
55 spin_lock(lock);
56}
57EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
58
59void rust_helper_spin_unlock(spinlock_t *lock)
60{
61 spin_unlock(lock);
62}
63EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
64
65void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
66{
67 init_wait(wq_entry);
68}
69EXPORT_SYMBOL_GPL(rust_helper_init_wait);
70
71int rust_helper_signal_pending(struct task_struct *t)
72{
73 return signal_pending(t);
74}
75EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
76
77refcount_t rust_helper_REFCOUNT_INIT(int n)
78{
79 return (refcount_t)REFCOUNT_INIT(n);
80}
81EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
82
83void rust_helper_refcount_inc(refcount_t *r)
84{
85 refcount_inc(r);
86}
87EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
88
89bool rust_helper_refcount_dec_and_test(refcount_t *r)
90{
91 return refcount_dec_and_test(r);
92}
93EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
94
95__force void *rust_helper_ERR_PTR(long err)
96{
97 return ERR_PTR(err);
98}
99EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
100
101bool rust_helper_IS_ERR(__force const void *ptr)
102{
103 return IS_ERR(ptr);
104}
105EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
106
107long rust_helper_PTR_ERR(__force const void *ptr)
108{
109 return PTR_ERR(ptr);
110}
111EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
112
113struct task_struct *rust_helper_get_current(void)
114{
115 return current;
116}
117EXPORT_SYMBOL_GPL(rust_helper_get_current);
118
119void rust_helper_get_task_struct(struct task_struct *t)
120{
121 get_task_struct(t);
122}
123EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
124
125void rust_helper_put_task_struct(struct task_struct *t)
126{
127 put_task_struct(t);
128}
129EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
130
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 */
148static_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);