xref: /kernel/linux/linux-6.6/arch/mips/include/asm/bitops.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 1994 - 1997, 99, 2000, 06, 07  Ralf Baechle (ralf@linux-mips.org)
 * Copyright (c) 1999, 2000  Silicon Graphics, Inc.
 */
#ifndef _ASM_BITOPS_H
#define _ASM_BITOPS_H

#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif

#include <linux/bits.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <asm/asm.h>
#include <asm/barrier.h>
#include <asm/byteorder.h>		/* sigh ... */
#include <asm/compiler.h>
#include <asm/cpu-features.h>
#include <asm/sgidefs.h>

#define __bit_op(mem, insn, inputs...) do {			\
	unsigned long __temp;					\
								\
	asm volatile(						\
	"	.set		push			\n"	\
	"	.set		" MIPS_ISA_LEVEL "	\n"	\
	"	" __SYNC(full, loongson3_war) "		\n"	\
	"1:	" __stringify(LONG_LL)	"	%0, %1	\n"	\
	"	" insn		"			\n"	\
	"	" __stringify(LONG_SC)	"	%0, %1	\n"	\
	"	" __stringify(SC_BEQZ)	"	%0, 1b	\n"	\
	"	.set		pop			\n"	\
	: "=&r"(__temp), "+" GCC_OFF_SMALL_ASM()(mem)		\
	: inputs						\
	: __LLSC_CLOBBER);					\
} while (0)

#define __test_bit_op(mem, ll_dst, insn, inputs...) ({		\
	unsigned long __orig, __temp;				\
								\
	asm volatile(						\
	"	.set		push			\n"	\
	"	.set		" MIPS_ISA_LEVEL "	\n"	\
	"	" __SYNC(full, loongson3_war) "		\n"	\
	"1:	" __stringify(LONG_LL) " "	ll_dst ", %2\n"	\
	"	" insn		"			\n"	\
	"	" __stringify(LONG_SC)	"	%1, %2	\n"	\
	"	" __stringify(SC_BEQZ)	"	%1, 1b	\n"	\
	"	.set		pop			\n"	\
	: "=&r"(__orig), "=&r"(__temp),				\
	  "+" GCC_OFF_SMALL_ASM()(mem)				\
	: inputs						\
	: __LLSC_CLOBBER);					\
								\
	__orig;							\
})

/*
 * These are the "slower" versions of the functions and are in bitops.c.
 * These functions call raw_local_irq_{save,restore}().
 */
void __mips_set_bit(unsigned long nr, volatile unsigned long *addr);
void __mips_clear_bit(unsigned long nr, volatile unsigned long *addr);
void __mips_change_bit(unsigned long nr, volatile unsigned long *addr);
int __mips_test_and_set_bit_lock(unsigned long nr,
				 volatile unsigned long *addr);
int __mips_test_and_clear_bit(unsigned long nr,
			      volatile unsigned long *addr);
int __mips_test_and_change_bit(unsigned long nr,
			       volatile unsigned long *addr);


/*
 * set_bit - Atomically set a bit in memory
 * @nr: the bit to set
 * @addr: the address to start counting from
 *
 * This function is atomic and may not be reordered.  See __set_bit()
 * if you do not require the atomic guarantees.
 * Note that @nr may be almost arbitrarily large; this function is not
 * restricted to acting on a single-word quantity.
 */
static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
{
	volatile unsigned long *m = &addr[BIT_WORD(nr)];
	int bit = nr % BITS_PER_LONG;

	if (!kernel_uses_llsc) {
		__mips_set_bit(nr, addr);
		return;
	}

	if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(bit) && (bit >= 16)) {
		__bit_op(*m, __stringify(LONG_INS) " %0, %3, %2, 1", "i"(bit), "r"(~0));
		return;
	}

	__bit_op(*m, "or\t%0, %2", "ir"(BIT(bit)));
}

/*
 * clear_bit - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 *
 * clear_bit() is atomic and may not be reordered.  However, it does
 * not contain a memory barrier, so if it is used for locking purposes,
 * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic()
 * in order to ensure changes are visible on other processors.
 */
static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
{
	volatile unsigned long *m = &addr[BIT_WORD(nr)];
	int bit = nr % BITS_PER_LONG;

	if (!kernel_uses_llsc) {
		__mips_clear_bit(nr, addr);
		return;
	}

	if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(bit)) {
		__bit_op(*m, __stringify(LONG_INS) " %0, $0, %2, 1", "i"(bit));
		return;
	}

	__bit_op(*m, "and\t%0, %2", "ir"(~BIT(bit)));
}

/*
 * clear_bit_unlock - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 *
 * clear_bit() is atomic and implies release semantics before the memory
 * operation. It can be used for an unlock.
 */
static inline void clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
{
	smp_mb__before_atomic();
	clear_bit(nr, addr);
}

/*
 * change_bit - Toggle a bit in memory
 * @nr: Bit to change
 * @addr: Address to start counting from
 *
 * change_bit() is atomic and may not be reordered.
 * Note that @nr may be almost arbitrarily large; this function is not
 * restricted to acting on a single-word quantity.
 */
static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
{
	volatile unsigned long *m = &addr[BIT_WORD(nr)];
	int bit = nr % BITS_PER_LONG;

	if (!kernel_uses_llsc) {
		__mips_change_bit(nr, addr);
		return;
	}

	__bit_op(*m, "xor\t%0, %2", "ir"(BIT(bit)));
}

/*
 * test_and_set_bit_lock - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 *
 * This operation is atomic and implies acquire ordering semantics
 * after the memory operation.
 */
static inline int test_and_set_bit_lock(unsigned long nr,
	volatile unsigned long *addr)
{
	volatile unsigned long *m = &addr[BIT_WORD(nr)];
	int bit = nr % BITS_PER_LONG;
	unsigned long res, orig;

	if (!kernel_uses_llsc) {
		res = __mips_test_and_set_bit_lock(nr, addr);
	} else {
		orig = __test_bit_op(*m, "%0",
				     "or\t%1, %0, %3",
				     "ir"(BIT(bit)));
		res = (orig & BIT(bit)) != 0;
	}

	smp_llsc_mb();

	return res;
}

/*
 * test_and_set_bit - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_set_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	smp_mb__before_atomic();
	return test_and_set_bit_lock(nr, addr);
}

/*
 * test_and_clear_bit - Clear a bit and return its old value
 * @nr: Bit to clear
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_clear_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	volatile unsigned long *m = &addr[BIT_WORD(nr)];
	int bit = nr % BITS_PER_LONG;
	unsigned long res, orig;

	smp_mb__before_atomic();

	if (!kernel_uses_llsc) {
		res = __mips_test_and_clear_bit(nr, addr);
	} else if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(nr)) {
		res = __test_bit_op(*m, "%1",
				    __stringify(LONG_EXT) " %0, %1, %3, 1;"
				    __stringify(LONG_INS) " %1, $0, %3, 1",
				    "i"(bit));
	} else {
		orig = __test_bit_op(*m, "%0",
				     "or\t%1, %0, %3;"
				     "xor\t%1, %1, %3",
				     "ir"(BIT(bit)));
		res = (orig & BIT(bit)) != 0;
	}

	smp_llsc_mb();

	return res;
}

/*
 * test_and_change_bit - Change a bit and return its old value
 * @nr: Bit to change
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_change_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	volatile unsigned long *m = &addr[BIT_WORD(nr)];
	int bit = nr % BITS_PER_LONG;
	unsigned long res, orig;

	smp_mb__before_atomic();

	if (!kernel_uses_llsc) {
		res = __mips_test_and_change_bit(nr, addr);
	} else {
		orig = __test_bit_op(*m, "%0",
				     "xor\t%1, %0, %3",
				     "ir"(BIT(bit)));
		res = (orig & BIT(bit)) != 0;
	}

	smp_llsc_mb();

	return res;
}

#undef __bit_op
#undef __test_bit_op

#include <asm-generic/bitops/non-atomic.h>

/*
 * __clear_bit_unlock - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 *
 * __clear_bit() is non-atomic and implies release semantics before the memory
 * operation. It can be used for an unlock if no other CPUs can concurrently
 * modify other bits in the word.
 */
static inline void __clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
{
	smp_mb__before_llsc();
	__clear_bit(nr, addr);
	nudge_writes();
}

/*
 * Return the bit position (0..63) of the most significant 1 bit in a word
 * Returns -1 if no 1 bit exists
 */
static __always_inline unsigned long __fls(unsigned long word)
{
	int num;

	if (BITS_PER_LONG == 32 && !__builtin_constant_p(word) &&
	    __builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
		__asm__(
		"	.set	push					\n"
		"	.set	"MIPS_ISA_LEVEL"			\n"
		"	clz	%0, %1					\n"
		"	.set	pop					\n"
		: "=r" (num)
		: "r" (word));

		return 31 - num;
	}

	if (BITS_PER_LONG == 64 && !__builtin_constant_p(word) &&
	    __builtin_constant_p(cpu_has_mips64) && cpu_has_mips64) {
		__asm__(
		"	.set	push					\n"
		"	.set	"MIPS_ISA_LEVEL"			\n"
		"	dclz	%0, %1					\n"
		"	.set	pop					\n"
		: "=r" (num)
		: "r" (word));

		return 63 - num;
	}

	num = BITS_PER_LONG - 1;

#if BITS_PER_LONG == 64
	if (!(word & (~0ul << 32))) {
		num -= 32;
		word <<= 32;
	}
#endif
	if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
		num -= 16;
		word <<= 16;
	}
	if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
		num -= 8;
		word <<= 8;
	}
	if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
		num -= 4;
		word <<= 4;
	}
	if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
		num -= 2;
		word <<= 2;
	}
	if (!(word & (~0ul << (BITS_PER_LONG-1))))
		num -= 1;
	return num;
}

/*
 * __ffs - find first bit in word.
 * @word: The word to search
 *
 * Returns 0..SZLONG-1
 * Undefined if no bit exists, so code should check against 0 first.
 */
static __always_inline unsigned long __ffs(unsigned long word)
{
	return __fls(word & -word);
}

/*
 * fls - find last bit set.
 * @word: The word to search
 *
 * This is defined the same way as ffs.
 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
 */
static inline int fls(unsigned int x)
{
	int r;

	if (!__builtin_constant_p(x) &&
	    __builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
		__asm__(
		"	.set	push					\n"
		"	.set	"MIPS_ISA_LEVEL"			\n"
		"	clz	%0, %1					\n"
		"	.set	pop					\n"
		: "=r" (x)
		: "r" (x));

		return 32 - x;
	}

	r = 32;
	if (!x)
		return 0;
	if (!(x & 0xffff0000u)) {
		x <<= 16;
		r -= 16;
	}
	if (!(x & 0xff000000u)) {
		x <<= 8;
		r -= 8;
	}
	if (!(x & 0xf0000000u)) {
		x <<= 4;
		r -= 4;
	}
	if (!(x & 0xc0000000u)) {
		x <<= 2;
		r -= 2;
	}
	if (!(x & 0x80000000u)) {
		x <<= 1;
		r -= 1;
	}
	return r;
}

#include <asm-generic/bitops/fls64.h>

/*
 * ffs - find first bit set.
 * @word: The word to search
 *
 * This is defined the same way as
 * the libc and compiler builtin ffs routines, therefore
 * differs in spirit from the below ffz (man ffs).
 */
static inline int ffs(int word)
{
	if (!word)
		return 0;

	return fls(word & -word);
}

#include <asm-generic/bitops/ffz.h>

#ifdef __KERNEL__

#include <asm-generic/bitops/sched.h>

#include <asm/arch_hweight.h>
#include <asm-generic/bitops/const_hweight.h>

#include <asm-generic/bitops/le.h>
#include <asm-generic/bitops/ext2-atomic.h>

#endif /* __KERNEL__ */

#endif /* _ASM_BITOPS_H */