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