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#include <linux/workqueue.h>
 34
 35__noreturn void rust_helper_BUG(void)
 36{
 37	BUG();
 38}
 39EXPORT_SYMBOL_GPL(rust_helper_BUG);
 40
 41void rust_helper_mutex_lock(struct mutex *lock)
 42{
 43	mutex_lock(lock);
 44}
 45EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
 46
 47void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
 48				  struct lock_class_key *key)
 49{
 50#ifdef CONFIG_DEBUG_SPINLOCK
 51	__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
 52#else
 53	spin_lock_init(lock);
 54#endif
 55}
 56EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
 57
 58void rust_helper_spin_lock(spinlock_t *lock)
 59{
 60	spin_lock(lock);
 61}
 62EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
 63
 64void rust_helper_spin_unlock(spinlock_t *lock)
 65{
 66	spin_unlock(lock);
 67}
 68EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
 69
 70void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
 71{
 72	init_wait(wq_entry);
 73}
 74EXPORT_SYMBOL_GPL(rust_helper_init_wait);
 75
 76int rust_helper_signal_pending(struct task_struct *t)
 77{
 78	return signal_pending(t);
 79}
 80EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
 81
 82refcount_t rust_helper_REFCOUNT_INIT(int n)
 83{
 84	return (refcount_t)REFCOUNT_INIT(n);
 85}
 86EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
 87
 88void rust_helper_refcount_inc(refcount_t *r)
 89{
 90	refcount_inc(r);
 91}
 92EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
 93
 94bool rust_helper_refcount_dec_and_test(refcount_t *r)
 95{
 96	return refcount_dec_and_test(r);
 97}
 98EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
 99
100__force void *rust_helper_ERR_PTR(long err)
101{
102	return ERR_PTR(err);
103}
104EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
105
106bool rust_helper_IS_ERR(__force const void *ptr)
107{
108	return IS_ERR(ptr);
109}
110EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
111
112long rust_helper_PTR_ERR(__force const void *ptr)
113{
114	return PTR_ERR(ptr);
115}
116EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
117
118const char *rust_helper_errname(int err)
119{
120	return errname(err);
121}
122EXPORT_SYMBOL_GPL(rust_helper_errname);
123
124struct task_struct *rust_helper_get_current(void)
125{
126	return current;
127}
128EXPORT_SYMBOL_GPL(rust_helper_get_current);
129
130void rust_helper_get_task_struct(struct task_struct *t)
131{
132	get_task_struct(t);
133}
134EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
135
136void rust_helper_put_task_struct(struct task_struct *t)
137{
138	put_task_struct(t);
139}
140EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
141
142struct kunit *rust_helper_kunit_get_current_test(void)
143{
144	return kunit_get_current_test();
145}
146EXPORT_SYMBOL_GPL(rust_helper_kunit_get_current_test);
147
148void rust_helper_init_work_with_key(struct work_struct *work, work_func_t func,
149				    bool onstack, const char *name,
150				    struct lock_class_key *key)
151{
152	__init_work(work, onstack);
153	work->data = (atomic_long_t)WORK_DATA_INIT();
154	lockdep_init_map(&work->lockdep_map, name, key, 0);
155	INIT_LIST_HEAD(&work->entry);
156	work->func = func;
157}
158EXPORT_SYMBOL_GPL(rust_helper_init_work_with_key);
159
160/*
161 * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
162 * use it in contexts where Rust expects a `usize` like slice (array) indices.
163 * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
164 * pointer) but not necessarily the same as `size_t` (can hold the size of any
165 * single object). Most modern platforms use the same concrete integer type for
166 * both of them, but in case we find ourselves on a platform where
167 * that's not true, fail early instead of risking ABI or
168 * integer-overflow issues.
169 *
170 * If your platform fails this assertion, it means that you are in
171 * danger of integer-overflow bugs (even if you attempt to add
172 * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
173 * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
174 * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
175 */
176static_assert(
177	sizeof(size_t) == sizeof(uintptr_t) &&
178	__alignof__(size_t) == __alignof__(uintptr_t),
179	"Rust code expects C `size_t` to match Rust `usize`"
180);