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 } 35 EXPORT_SYMBOL_GPL(rust_helper_BUG); 36 37 void rust_helper_mutex_lock(struct mutex *lock) 38 { 39 mutex_lock(lock); 40 } 41 EXPORT_SYMBOL_GPL(rust_helper_mutex_lock); 42 43 void 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 } 52 EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init); 53 54 void rust_helper_spin_lock(spinlock_t *lock) 55 { 56 spin_lock(lock); 57 } 58 EXPORT_SYMBOL_GPL(rust_helper_spin_lock); 59 60 void rust_helper_spin_unlock(spinlock_t *lock) 61 { 62 spin_unlock(lock); 63 } 64 EXPORT_SYMBOL_GPL(rust_helper_spin_unlock); 65 66 void rust_helper_init_wait(struct wait_queue_entry *wq_entry) 67 { 68 init_wait(wq_entry); 69 } 70 EXPORT_SYMBOL_GPL(rust_helper_init_wait); 71 72 int rust_helper_signal_pending(struct task_struct *t) 73 { 74 return signal_pending(t); 75 } 76 EXPORT_SYMBOL_GPL(rust_helper_signal_pending); 77 78 refcount_t rust_helper_REFCOUNT_INIT(int n) 79 { 80 return (refcount_t)REFCOUNT_INIT(n); 81 } 82 EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT); 83 84 void rust_helper_refcount_inc(refcount_t *r) 85 { 86 refcount_inc(r); 87 } 88 EXPORT_SYMBOL_GPL(rust_helper_refcount_inc); 89 90 bool rust_helper_refcount_dec_and_test(refcount_t *r) 91 { 92 return refcount_dec_and_test(r); 93 } 94 EXPORT_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 } 100 EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR); 101 102 bool rust_helper_IS_ERR(__force const void *ptr) 103 { 104 return IS_ERR(ptr); 105 } 106 EXPORT_SYMBOL_GPL(rust_helper_IS_ERR); 107 108 long rust_helper_PTR_ERR(__force const void *ptr) 109 { 110 return PTR_ERR(ptr); 111 } 112 EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR); 113 114 const char *rust_helper_errname(int err) 115 { 116 return errname(err); 117 } 118 EXPORT_SYMBOL_GPL(rust_helper_errname); 119 120 struct task_struct *rust_helper_get_current(void) 121 { 122 return current; 123 } 124 EXPORT_SYMBOL_GPL(rust_helper_get_current); 125 126 void rust_helper_get_task_struct(struct task_struct *t) 127 { 128 get_task_struct(t); 129 } 130 EXPORT_SYMBOL_GPL(rust_helper_get_task_struct); 131 132 void rust_helper_put_task_struct(struct task_struct *t) 133 { 134 put_task_struct(t); 135 } 136 EXPORT_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 */ 155 static_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 ); 160