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/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef __ASM_GENERIC_BITOPS_GENERIC_NON_ATOMIC_H
#define __ASM_GENERIC_BITOPS_GENERIC_NON_ATOMIC_H
#include <linux/bits.h>
#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif
/*
* Generic definitions for bit operations, should not be used in regular code
* directly.
*/
/**
* generic___set_bit - Set a bit in memory
* @nr: the bit to set
* @addr: the address to start counting from
*
* Unlike set_bit(), this function is non-atomic and may be reordered.
* If it's called on the same region of memory simultaneously, the effect
* may be that only one operation succeeds.
*/
static __always_inline void
generic___set_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p |= mask;
}
static __always_inline void
generic___clear_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p &= ~mask;
}
/**
* generic___change_bit - Toggle a bit in memory
* @nr: the bit to change
* @addr: the address to start counting from
*
* Unlike change_bit(), this function is non-atomic and may be reordered.
* If it's called on the same region of memory simultaneously, the effect
* may be that only one operation succeeds.
*/
static __always_inline void
generic___change_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p ^= mask;
}
/**
* generic___test_and_set_bit - Set a bit and return its old value
* @nr: Bit to set
* @addr: Address to count from
*
* This operation is non-atomic and can be reordered.
* If two examples of this operation race, one can appear to succeed
* but actually fail. You must protect multiple accesses with a lock.
*/
static __always_inline bool
generic___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old | mask;
return (old & mask) != 0;
}
/**
* generic___test_and_clear_bit - Clear a bit and return its old value
* @nr: Bit to clear
* @addr: Address to count from
*
* This operation is non-atomic and can be reordered.
* If two examples of this operation race, one can appear to succeed
* but actually fail. You must protect multiple accesses with a lock.
*/
static __always_inline bool
generic___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old & ~mask;
return (old & mask) != 0;
}
/* WARNING: non atomic and it can be reordered! */
static __always_inline bool
generic___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old ^ mask;
return (old & mask) != 0;
}
/**
* generic_test_bit - Determine whether a bit is set
* @nr: bit number to test
* @addr: Address to start counting from
*/
static __always_inline bool
generic_test_bit(unsigned long nr, const volatile unsigned long *addr)
{
/*
* Unlike the bitops with the '__' prefix above, this one *is* atomic,
* so `volatile` must always stay here with no cast-aways. See
* `Documentation/atomic_bitops.txt` for the details.
*/
return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
}
/*
* const_*() definitions provide good compile-time optimizations when
* the passed arguments can be resolved at compile time.
*/
#define const___set_bit generic___set_bit
#define const___clear_bit generic___clear_bit
#define const___change_bit generic___change_bit
#define const___test_and_set_bit generic___test_and_set_bit
#define const___test_and_clear_bit generic___test_and_clear_bit
#define const___test_and_change_bit generic___test_and_change_bit
/**
* const_test_bit - Determine whether a bit is set
* @nr: bit number to test
* @addr: Address to start counting from
*
* A version of generic_test_bit() which discards the `volatile` qualifier to
* allow a compiler to optimize code harder. Non-atomic and to be called only
* for testing compile-time constants, e.g. by the corresponding macros, not
* directly from "regular" code.
*/
static __always_inline bool
const_test_bit(unsigned long nr, const volatile unsigned long *addr)
{
const unsigned long *p = (const unsigned long *)addr + BIT_WORD(nr);
unsigned long mask = BIT_MASK(nr);
unsigned long val = *p;
return !!(val & mask);
}
#endif /* __ASM_GENERIC_BITOPS_GENERIC_NON_ATOMIC_H */
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