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