Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : 
       3             : /*
       4             :  * This file provides wrappers with sanitizer instrumentation for bit
       5             :  * locking operations.
       6             :  *
       7             :  * To use this functionality, an arch's bitops.h file needs to define each of
       8             :  * the below bit operations with an arch_ prefix (e.g. arch_set_bit(),
       9             :  * arch___set_bit(), etc.).
      10             :  */
      11             : #ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H
      12             : #define _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H
      13             : 
      14             : #include <linux/instrumented.h>
      15             : 
      16             : /**
      17             :  * clear_bit_unlock - Clear a bit in memory, for unlock
      18             :  * @nr: the bit to set
      19             :  * @addr: the address to start counting from
      20             :  *
      21             :  * This operation is atomic and provides release barrier semantics.
      22             :  */
      23             : static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
      24             : {
      25             :         kcsan_release();
      26           0 :         instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long));
      27           0 :         arch_clear_bit_unlock(nr, addr);
      28             : }
      29             : 
      30             : /**
      31             :  * __clear_bit_unlock - Clears a bit in memory
      32             :  * @nr: Bit to clear
      33             :  * @addr: Address to start counting from
      34             :  *
      35             :  * This is a non-atomic operation but implies a release barrier before the
      36             :  * memory operation. It can be used for an unlock if no other CPUs can
      37             :  * concurrently modify other bits in the word.
      38             :  */
      39             : static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
      40             : {
      41             :         kcsan_release();
      42             :         instrument_write(addr + BIT_WORD(nr), sizeof(long));
      43             :         arch___clear_bit_unlock(nr, addr);
      44             : }
      45             : 
      46             : /**
      47             :  * test_and_set_bit_lock - Set a bit and return its old value, for lock
      48             :  * @nr: Bit to set
      49             :  * @addr: Address to count from
      50             :  *
      51             :  * This operation is atomic and provides acquire barrier semantics if
      52             :  * the returned value is 0.
      53             :  * It can be used to implement bit locks.
      54             :  */
      55             : static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
      56             : {
      57           0 :         instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long));
      58           0 :         return arch_test_and_set_bit_lock(nr, addr);
      59             : }
      60             : 
      61             : #if defined(arch_clear_bit_unlock_is_negative_byte)
      62             : /**
      63             :  * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom
      64             :  *                                     byte is negative, for unlock.
      65             :  * @nr: the bit to clear
      66             :  * @addr: the address to start counting from
      67             :  *
      68             :  * This operation is atomic and provides release barrier semantics.
      69             :  *
      70             :  * This is a bit of a one-trick-pony for the filemap code, which clears
      71             :  * PG_locked and tests PG_waiters,
      72             :  */
      73             : static inline bool
      74             : clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
      75             : {
      76             :         kcsan_release();
      77           0 :         instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long));
      78           0 :         return arch_clear_bit_unlock_is_negative_byte(nr, addr);
      79             : }
      80             : /* Let everybody know we have it. */
      81             : #define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte
      82             : #endif
      83             : 
      84             : #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */