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/refcount.h> 25 #include <linux/mutex.h> 26 #include <linux/spinlock.h> 27 #include <linux/sched/signal.h> 28 #include <linux/wait.h> 29 30 __noreturn void rust_helper_BUG(void) 31 { 32 BUG(); 33 } 34 EXPORT_SYMBOL_GPL(rust_helper_BUG); 35 36 void rust_helper_mutex_lock(struct mutex *lock) 37 { 38 mutex_lock(lock); 39 } 40 EXPORT_SYMBOL_GPL(rust_helper_mutex_lock); 41 42 void rust_helper___spin_lock_init(spinlock_t *lock, const char *name, 43 struct lock_class_key *key) 44 { 45 #ifdef CONFIG_DEBUG_SPINLOCK 46 __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG); 47 #else 48 spin_lock_init(lock); 49 #endif 50 } 51 EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init); 52 53 void rust_helper_spin_lock(spinlock_t *lock) 54 { 55 spin_lock(lock); 56 } 57 EXPORT_SYMBOL_GPL(rust_helper_spin_lock); 58 59 void rust_helper_spin_unlock(spinlock_t *lock) 60 { 61 spin_unlock(lock); 62 } 63 EXPORT_SYMBOL_GPL(rust_helper_spin_unlock); 64 65 void rust_helper_init_wait(struct wait_queue_entry *wq_entry) 66 { 67 init_wait(wq_entry); 68 } 69 EXPORT_SYMBOL_GPL(rust_helper_init_wait); 70 71 int rust_helper_signal_pending(struct task_struct *t) 72 { 73 return signal_pending(t); 74 } 75 EXPORT_SYMBOL_GPL(rust_helper_signal_pending); 76 77 refcount_t rust_helper_REFCOUNT_INIT(int n) 78 { 79 return (refcount_t)REFCOUNT_INIT(n); 80 } 81 EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT); 82 83 void rust_helper_refcount_inc(refcount_t *r) 84 { 85 refcount_inc(r); 86 } 87 EXPORT_SYMBOL_GPL(rust_helper_refcount_inc); 88 89 bool rust_helper_refcount_dec_and_test(refcount_t *r) 90 { 91 return refcount_dec_and_test(r); 92 } 93 EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test); 94 95 __force void *rust_helper_ERR_PTR(long err) 96 { 97 return ERR_PTR(err); 98 } 99 EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR); 100 101 bool rust_helper_IS_ERR(__force const void *ptr) 102 { 103 return IS_ERR(ptr); 104 } 105 EXPORT_SYMBOL_GPL(rust_helper_IS_ERR); 106 107 long rust_helper_PTR_ERR(__force const void *ptr) 108 { 109 return PTR_ERR(ptr); 110 } 111 EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR); 112 113 struct task_struct *rust_helper_get_current(void) 114 { 115 return current; 116 } 117 EXPORT_SYMBOL_GPL(rust_helper_get_current); 118 119 void rust_helper_get_task_struct(struct task_struct *t) 120 { 121 get_task_struct(t); 122 } 123 EXPORT_SYMBOL_GPL(rust_helper_get_task_struct); 124 125 void rust_helper_put_task_struct(struct task_struct *t) 126 { 127 put_task_struct(t); 128 } 129 EXPORT_SYMBOL_GPL(rust_helper_put_task_struct); 130 131 /* 132 * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type 133 * as the Rust `usize` type, so we can use it in contexts where Rust 134 * expects a `usize` like slice (array) indices. `usize` is defined to be 135 * the same as C's `uintptr_t` type (can hold any pointer) but not 136 * necessarily the same as `size_t` (can hold the size of any single 137 * object). Most modern platforms use the same concrete integer type for 138 * both of them, but in case we find ourselves on a platform where 139 * that's not true, fail early instead of risking ABI or 140 * integer-overflow issues. 141 * 142 * If your platform fails this assertion, it means that you are in 143 * danger of integer-overflow bugs (even if you attempt to remove 144 * `--size_t-is-usize`). It may be easiest to change the kernel ABI on 145 * your platform such that `size_t` matches `uintptr_t` (i.e., to increase 146 * `size_t`, because `uintptr_t` has to be at least as big as `size_t`). 147 */ 148 static_assert( 149 sizeof(size_t) == sizeof(uintptr_t) && 150 __alignof__(size_t) == __alignof__(uintptr_t), 151 "Rust code expects C `size_t` to match Rust `usize`" 152 ); 153