Branch data     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/kasan-checks.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                 :      33871 : static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
      24                 :            : {
      25                 :      33871 :         kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
      26                 :      33871 :         arch_clear_bit_unlock(nr, addr);
      27                 :      33871 : }
      28                 :            : 
      29                 :            : /**
      30                 :            :  * __clear_bit_unlock - Clears a bit in memory
      31                 :            :  * @nr: Bit to clear
      32                 :            :  * @addr: Address to start counting from
      33                 :            :  *
      34                 :            :  * This is a non-atomic operation but implies a release barrier before the
      35                 :            :  * memory operation. It can be used for an unlock if no other CPUs can
      36                 :            :  * concurrently modify other bits in the word.
      37                 :            :  */
      38                 :     996031 : static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
      39                 :            : {
      40                 :     996031 :         kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
      41                 :     996031 :         arch___clear_bit_unlock(nr, addr);
      42                 :            : }
      43                 :            : 
      44                 :            : /**
      45                 :            :  * test_and_set_bit_lock - Set a bit and return its old value, for lock
      46                 :            :  * @nr: Bit to set
      47                 :            :  * @addr: Address to count from
      48                 :            :  *
      49                 :            :  * This operation is atomic and provides acquire barrier semantics if
      50                 :            :  * the returned value is 0.
      51                 :            :  * It can be used to implement bit locks.
      52                 :            :  */
      53                 :    7532977 : static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
      54                 :            : {
      55                 :    7532977 :         kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
      56                 :    7532977 :         return arch_test_and_set_bit_lock(nr, addr);
      57                 :            : }
      58                 :            : 
      59                 :            : #if defined(arch_clear_bit_unlock_is_negative_byte)
      60                 :            : /**
      61                 :            :  * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom
      62                 :            :  *                                     byte is negative, for unlock.
      63                 :            :  * @nr: the bit to clear
      64                 :            :  * @addr: the address to start counting from
      65                 :            :  *
      66                 :            :  * This operation is atomic and provides release barrier semantics.
      67                 :            :  *
      68                 :            :  * This is a bit of a one-trick-pony for the filemap code, which clears
      69                 :            :  * PG_locked and tests PG_waiters,
      70                 :            :  */
      71                 :            : static inline bool
      72                 :    6596096 : clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
      73                 :            : {
      74                 :    6596096 :         kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
      75                 :    6596096 :         return arch_clear_bit_unlock_is_negative_byte(nr, addr);
      76                 :            : }
      77                 :            : /* Let everybody know we have it. */
      78                 :            : #define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte
      79                 :            : #endif
      80                 :            : 
      81                 :            : #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */