LXR linux/include/asm-generic/bitops/instrumented-lock.h

   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 */
  23static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
  24{
  25        kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
  26        arch_clear_bit_unlock(nr, addr);
  27}
  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 */
  38static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
  39{
  40        kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
  41        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 */
  53static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
  54{
  55        kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
  56        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 */
  71static inline bool
  72clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
  73{
  74        kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
  75        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 */
  82