176 lines
5.2 KiB
C
176 lines
5.2 KiB
C
/* 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>
|
|
#include <asm/barrier.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)));
|
|
}
|
|
|
|
/**
|
|
* generic_test_bit_acquire - Determine, with acquire semantics, whether a bit is set
|
|
* @nr: bit number to test
|
|
* @addr: Address to start counting from
|
|
*/
|
|
static __always_inline bool
|
|
generic_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr)
|
|
{
|
|
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
|
|
return 1UL & (smp_load_acquire(p) >> (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
|
|
#define const_test_bit_acquire generic_test_bit_acquire
|
|
|
|
/**
|
|
* 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 */
|