rust/helpers.c

   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 the bindings directly, 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/device.h>
  27 #include <linux/err.h>
  28 #include <linux/errname.h>
  29 #include <linux/gfp.h>
  30 #include <linux/highmem.h>
  31 #include <linux/mutex.h>
  32 #include <linux/refcount.h>
  33 #include <linux/sched/signal.h>
  34 #include <linux/slab.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/wait.h>
  37 #include <linux/workqueue.h>
  38
  39 __noreturn void rust_helper_BUG(void)
  40 {
  41         BUG();
  42 }
  43 EXPORT_SYMBOL_GPL(rust_helper_BUG);
  44
  45 unsigned long rust_helper_copy_from_user(void *to, const void __user *from,
  46                                          unsigned long n)
  47 {
  48         return copy_from_user(to, from, n);
  49 }
  50 EXPORT_SYMBOL_GPL(rust_helper_copy_from_user);
  51
  52 unsigned long rust_helper_copy_to_user(void __user *to, const void *from,
  53                                        unsigned long n)
  54 {
  55         return copy_to_user(to, from, n);
  56 }
  57 EXPORT_SYMBOL_GPL(rust_helper_copy_to_user);
  58
  59 void rust_helper_mutex_lock(struct mutex *lock)
  60 {
  61         mutex_lock(lock);
  62 }
  63 EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
  64
  65 void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
  66                                   struct lock_class_key *key)
  67 {
  68 #ifdef CONFIG_DEBUG_SPINLOCK
  69         __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
  70 #else
  71         spin_lock_init(lock);
  72 #endif
  73 }
  74 EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
  75
  76 void rust_helper_spin_lock(spinlock_t *lock)
  77 {
  78         spin_lock(lock);
  79 }
  80 EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
  81
  82 void rust_helper_spin_unlock(spinlock_t *lock)
  83 {
  84         spin_unlock(lock);
  85 }
  86 EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
  87
  88 void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
  89 {
  90         init_wait(wq_entry);
  91 }
  92 EXPORT_SYMBOL_GPL(rust_helper_init_wait);
  93
  94 int rust_helper_signal_pending(struct task_struct *t)
  95 {
  96         return signal_pending(t);
  97 }
  98 EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
  99
 100 struct page *rust_helper_alloc_pages(gfp_t gfp_mask, unsigned int order)
 101 {
 102         return alloc_pages(gfp_mask, order);
 103 }
 104 EXPORT_SYMBOL_GPL(rust_helper_alloc_pages);
 105
 106 void *rust_helper_kmap_local_page(struct page *page)
 107 {
 108         return kmap_local_page(page);
 109 }
 110 EXPORT_SYMBOL_GPL(rust_helper_kmap_local_page);
 111
 112 void rust_helper_kunmap_local(const void *addr)
 113 {
 114         kunmap_local(addr);
 115 }
 116 EXPORT_SYMBOL_GPL(rust_helper_kunmap_local);
 117
 118 refcount_t rust_helper_REFCOUNT_INIT(int n)
 119 {
 120         return (refcount_t)REFCOUNT_INIT(n);
 121 }
 122 EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
 123
 124 void rust_helper_refcount_inc(refcount_t *r)
 125 {
 126         refcount_inc(r);
 127 }
 128 EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
 129
 130 bool rust_helper_refcount_dec_and_test(refcount_t *r)
 131 {
 132         return refcount_dec_and_test(r);
 133 }
 134 EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
 135
 136 __force void *rust_helper_ERR_PTR(long err)
 137 {
 138         return ERR_PTR(err);
 139 }
 140 EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR);
 141
 142 bool rust_helper_IS_ERR(__force const void *ptr)
 143 {
 144         return IS_ERR(ptr);
 145 }
 146 EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
 147
 148 long rust_helper_PTR_ERR(__force const void *ptr)
 149 {
 150         return PTR_ERR(ptr);
 151 }
 152 EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
 153
 154 const char *rust_helper_errname(int err)
 155 {
 156         return errname(err);
 157 }
 158 EXPORT_SYMBOL_GPL(rust_helper_errname);
 159
 160 struct task_struct *rust_helper_get_current(void)
 161 {
 162         return current;
 163 }
 164 EXPORT_SYMBOL_GPL(rust_helper_get_current);
 165
 166 void rust_helper_get_task_struct(struct task_struct *t)
 167 {
 168         get_task_struct(t);
 169 }
 170 EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
 171
 172 void rust_helper_put_task_struct(struct task_struct *t)
 173 {
 174         put_task_struct(t);
 175 }
 176 EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
 177
 178 struct kunit *rust_helper_kunit_get_current_test(void)
 179 {
 180         return kunit_get_current_test();
 181 }
 182 EXPORT_SYMBOL_GPL(rust_helper_kunit_get_current_test);
 183
 184 void rust_helper_init_work_with_key(struct work_struct *work, work_func_t func,
 185                                     bool onstack, const char *name,
 186                                     struct lock_class_key *key)
 187 {
 188         __init_work(work, onstack);
 189         work->data = (atomic_long_t)WORK_DATA_INIT();
 190         lockdep_init_map(&work->lockdep_map, name, key, 0);
 191         INIT_LIST_HEAD(&work->entry);
 192         work->func = func;
 193 }
 194 EXPORT_SYMBOL_GPL(rust_helper_init_work_with_key);
 195
 196 void * __must_check __realloc_size(2)
 197 rust_helper_krealloc(const void *objp, size_t new_size, gfp_t flags)
 198 {
 199         return krealloc(objp, new_size, flags);
 200 }
 201 EXPORT_SYMBOL_GPL(rust_helper_krealloc);
 202
 203 /*
 204  * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
 205  * use it in contexts where Rust expects a `usize` like slice (array) indices.
 206  * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
 207  * pointer) but not necessarily the same as `size_t` (can hold the size of any
 208  * single object). Most modern platforms use the same concrete integer type for
 209  * both of them, but in case we find ourselves on a platform where
 210  * that's not true, fail early instead of risking ABI or
 211  * integer-overflow issues.
 212  *
 213  * If your platform fails this assertion, it means that you are in
 214  * danger of integer-overflow bugs (even if you attempt to add
 215  * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
 216  * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
 217  * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
 218  */
 219 static_assert(
 220         sizeof(size_t) == sizeof(uintptr_t) &&
 221         __alignof__(size_t) == __alignof__(uintptr_t),
 222         "Rust code expects C `size_t` to match Rust `usize`"
 223 );
 224
 225 // This will soon be moved to a separate file, so no need to merge with above.
 226 #include <linux/blk-mq.h>
 227 #include <linux/blkdev.h>
 228
 229 void *rust_helper_blk_mq_rq_to_pdu(struct request *rq)
 230 {
 231         return blk_mq_rq_to_pdu(rq);
 232 }
 233 EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_to_pdu);
 234
 235 struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu)
 236 {
 237         return blk_mq_rq_from_pdu(pdu);
 238 }
 239 EXPORT_SYMBOL_GPL(rust_helper_blk_mq_rq_from_pdu);