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 * Sorted alphabetically.
21 */
22
23#include <kunit/test-bug.h>
24#include <linux/bug.h>
25#include <linux/build_bug.h>
26#include <linux/err.h>
27#include <linux/errname.h>
28#include <linux/mutex.h>
29#include <linux/refcount.h>
30#include <linux/sched/signal.h>
31#include <linux/spinlock.h>
32#include <linux/wait.h>
33
34__noreturn void rust_helper_BUG(void)
35{
36 BUG();
37}
38EXPORT_SYMBOL_GPL(rust_helper_BUG);
39
40void rust_helper_mutex_lock(struct mutex *lock)
41{
42 mutex_lock(lock);
43}
44EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
45
46void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
47 struct lock_class_key *key)
48{
49#ifdef CONFIG_DEBUG_SPINLOCK
50 __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
51#else
52 spin_lock_init(lock);
53#endif
54}
55EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
56
57void rust_helper_spin_lock(spinlock_t *lock)
58{
59 spin_lock(lock);
60}
61EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
62
63void rust_helper_spin_unlock(spinlock_t *lock)
64{
65 spin_unlock(lock);
66}
67EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
68
69void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
70{
71 init_wait(wq_entry);
72}
73EXPORT_SYMBOL_GPL(rust_helper_init_wait);
74
75int rust_helper_signal_pending(struct task_struct *t)
76{
77 return signal_pending(t);
78}
79EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
80
81refcount_t rust_helper_REFCOUNT_INIT(int n)
82{
83 return (refcount_t)REFCOUNT_INIT(n);
84}
85EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
86
87void rust_helper_refcount_inc(refcount_t *r)
88{
89 refcount_inc(r);
90}
91EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
92
93bool rust_helper_refcount_dec_and_test(refcount_t *r)
94{
95 return refcount_dec_and_test(r);
96}
97EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
98
99__force void *rust_helper_ERR_PTR(long err)
100{
101 return ERR_PTR(err);
102}
103EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
104
105bool rust_helper_IS_ERR(__force const void *ptr)
106{
107 return IS_ERR(ptr);
108}
109EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
110
111long rust_helper_PTR_ERR(__force const void *ptr)
112{
113 return PTR_ERR(ptr);
114}
115EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
116
117const char *rust_helper_errname(int err)
118{
119 return errname(err);
120}
121EXPORT_SYMBOL_GPL(rust_helper_errname);
122
123struct task_struct *rust_helper_get_current(void)
124{
125 return current;
126}
127EXPORT_SYMBOL_GPL(rust_helper_get_current);
128
129void rust_helper_get_task_struct(struct task_struct *t)
130{
131 get_task_struct(t);
132}
133EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
134
135void rust_helper_put_task_struct(struct task_struct *t)
136{
137 put_task_struct(t);
138}
139EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
140
141struct kunit *rust_helper_kunit_get_current_test(void)
142{
143 return kunit_get_current_test();
144}
145EXPORT_SYMBOL_GPL(rust_helper_kunit_get_current_test);
146
147/*
148 * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
149 * use it in contexts where Rust expects a `usize` like slice (array) indices.
150 * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
151 * pointer) but not necessarily the same as `size_t` (can hold the size of any
152 * single object). Most modern platforms use the same concrete integer type for
153 * both of them, but in case we find ourselves on a platform where
154 * that's not true, fail early instead of risking ABI or
155 * integer-overflow issues.
156 *
157 * If your platform fails this assertion, it means that you are in
158 * danger of integer-overflow bugs (even if you attempt to add
159 * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
160 * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
161 * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
162 */
163static_assert(
164 sizeof(size_t) == sizeof(uintptr_t) &&
165 __alignof__(size_t) == __alignof__(uintptr_t),
166 "Rust code expects C `size_t` to match Rust `usize`"
167);