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/errname.h>
25#include <linux/refcount.h>
26#include <linux/mutex.h>
27#include <linux/spinlock.h>
28#include <linux/sched/signal.h>
29#include <linux/wait.h>
30
31__noreturn void rust_helper_BUG(void)
32{
33 BUG();
34}
35EXPORT_SYMBOL_GPL(rust_helper_BUG);
36
37void rust_helper_mutex_lock(struct mutex *lock)
38{
39 mutex_lock(lock);
40}
41EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
42
43void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
44 struct lock_class_key *key)
45{
46#ifdef CONFIG_DEBUG_SPINLOCK
47 __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
48#else
49 spin_lock_init(lock);
50#endif
51}
52EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
53
54void rust_helper_spin_lock(spinlock_t *lock)
55{
56 spin_lock(lock);
57}
58EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
59
60void rust_helper_spin_unlock(spinlock_t *lock)
61{
62 spin_unlock(lock);
63}
64EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
65
66void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
67{
68 init_wait(wq_entry);
69}
70EXPORT_SYMBOL_GPL(rust_helper_init_wait);
71
72int rust_helper_signal_pending(struct task_struct *t)
73{
74 return signal_pending(t);
75}
76EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
77
78refcount_t rust_helper_REFCOUNT_INIT(int n)
79{
80 return (refcount_t)REFCOUNT_INIT(n);
81}
82EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
83
84void rust_helper_refcount_inc(refcount_t *r)
85{
86 refcount_inc(r);
87}
88EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
89
90bool rust_helper_refcount_dec_and_test(refcount_t *r)
91{
92 return refcount_dec_and_test(r);
93}
94EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
95
96__force void *rust_helper_ERR_PTR(long err)
97{
98 return ERR_PTR(err);
99}
100EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
101
102bool rust_helper_IS_ERR(__force const void *ptr)
103{
104 return IS_ERR(ptr);
105}
106EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
107
108long rust_helper_PTR_ERR(__force const void *ptr)
109{
110 return PTR_ERR(ptr);
111}
112EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
113
114const char *rust_helper_errname(int err)
115{
116 return errname(err);
117}
118EXPORT_SYMBOL_GPL(rust_helper_errname);
119
120struct task_struct *rust_helper_get_current(void)
121{
122 return current;
123}
124EXPORT_SYMBOL_GPL(rust_helper_get_current);
125
126void rust_helper_get_task_struct(struct task_struct *t)
127{
128 get_task_struct(t);
129}
130EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
131
132void rust_helper_put_task_struct(struct task_struct *t)
133{
134 put_task_struct(t);
135}
136EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
137
138/*
139 * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
140 * as the Rust `usize` type, so we can use it in contexts where Rust
141 * expects a `usize` like slice (array) indices. `usize` is defined to be
142 * the same as C's `uintptr_t` type (can hold any pointer) but not
143 * necessarily the same as `size_t` (can hold the size of any single
144 * object). Most modern platforms use the same concrete integer type for
145 * both of them, but in case we find ourselves on a platform where
146 * that's not true, fail early instead of risking ABI or
147 * integer-overflow issues.
148 *
149 * If your platform fails this assertion, it means that you are in
150 * danger of integer-overflow bugs (even if you attempt to remove
151 * `--size_t-is-usize`). It may be easiest to change the kernel ABI on
152 * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
153 * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
154 */
155static_assert(
156 sizeof(size_t) == sizeof(uintptr_t) &&
157 __alignof__(size_t) == __alignof__(uintptr_t),
158 "Rust code expects C `size_t` to match Rust `usize`"
159);