arch/mips/lib/bitops.c

Source file repositories/reference/linux-study-clean/arch/mips/lib/bitops.c

File Facts

System
Linux kernel
Corpus path
arch/mips/lib/bitops.c
Extension
.c
Size
4106 bytes
Lines
163
Domain
Architecture Layer
Bucket
arch/mips
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/bitops.h>
#include <linux/bits.h>
#include <linux/irqflags.h>
#include <linux/export.h>


/**
 * __mips_set_bit - Atomically set a bit in memory.  This is called by
 * set_bit() if it cannot find a faster solution.
 * @nr: the bit to set
 * @addr: the address to start counting from
 */
void __mips_set_bit(unsigned long nr, volatile unsigned long *addr)
{
	volatile unsigned long *a = &addr[BIT_WORD(nr)];
	unsigned int bit = nr % BITS_PER_LONG;
	unsigned long mask;
	unsigned long flags;

	mask = 1UL << bit;
	raw_local_irq_save(flags);
	*a |= mask;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL(__mips_set_bit);


/**
 * __mips_clear_bit - Clears a bit in memory.  This is called by clear_bit() if
 * it cannot find a faster solution.
 * @nr: Bit to clear
 * @addr: Address to start counting from
 */
void __mips_clear_bit(unsigned long nr, volatile unsigned long *addr)
{
	volatile unsigned long *a = &addr[BIT_WORD(nr)];
	unsigned int bit = nr % BITS_PER_LONG;
	unsigned long mask;
	unsigned long flags;

	mask = 1UL << bit;
	raw_local_irq_save(flags);
	*a &= ~mask;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL(__mips_clear_bit);


/**
 * __mips_change_bit - Toggle a bit in memory.	This is called by change_bit()
 * if it cannot find a faster solution.
 * @nr: Bit to change
 * @addr: Address to start counting from
 */
void __mips_change_bit(unsigned long nr, volatile unsigned long *addr)
{
	volatile unsigned long *a = &addr[BIT_WORD(nr)];
	unsigned int bit = nr % BITS_PER_LONG;
	unsigned long mask;
	unsigned long flags;

	mask = 1UL << bit;
	raw_local_irq_save(flags);
	*a ^= mask;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL(__mips_change_bit);


/**
 * __mips_test_and_set_bit_lock - Set a bit and return its old value.  This is
 * called by test_and_set_bit_lock() if it cannot find a faster solution.
 * @nr: Bit to set
 * @addr: Address to count from
 */
int __mips_test_and_set_bit_lock(unsigned long nr,
				 volatile unsigned long *addr)
{
	volatile unsigned long *a = &addr[BIT_WORD(nr)];
	unsigned int bit = nr % BITS_PER_LONG;
	unsigned long mask;
	unsigned long flags;
	int res;

	mask = 1UL << bit;
	raw_local_irq_save(flags);
	res = (mask & *a) != 0;
	*a |= mask;
	raw_local_irq_restore(flags);
	return res;

Annotation

Implementation Notes