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b791d1193a
On some CPUs, it is more efficient to disable and enable interrupts in the kernel rather than use ll/sc for atomic operations. But if we were to set cpu_has_llsc to false, we would break the userspace futex interface (in asm/futex.h). We separate the two concepts, with a new predicate kernel_uses_llsc, that lets us disable the kernel's use of ll/sc while still allowing the futex code to use it. Also there were a couple of cases in bitops.h where we were using ll/sc unconditionally even if cpu_has_llsc were false. Signed-off-by: David Daney <ddaney@caviumnetworks.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
711 lines
17 KiB
C
711 lines
17 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (c) 1994 - 1997, 99, 2000, 06, 07 Ralf Baechle (ralf@linux-mips.org)
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* Copyright (c) 1999, 2000 Silicon Graphics, Inc.
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*/
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#ifndef _ASM_BITOPS_H
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#define _ASM_BITOPS_H
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#ifndef _LINUX_BITOPS_H
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#error only <linux/bitops.h> can be included directly
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#endif
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#include <linux/compiler.h>
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#include <linux/irqflags.h>
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#include <linux/types.h>
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#include <asm/barrier.h>
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#include <asm/bug.h>
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#include <asm/byteorder.h> /* sigh ... */
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#include <asm/cpu-features.h>
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#include <asm/sgidefs.h>
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#include <asm/war.h>
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#if _MIPS_SZLONG == 32
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#define SZLONG_LOG 5
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#define SZLONG_MASK 31UL
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#define __LL "ll "
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#define __SC "sc "
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#define __INS "ins "
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#define __EXT "ext "
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#elif _MIPS_SZLONG == 64
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#define SZLONG_LOG 6
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#define SZLONG_MASK 63UL
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#define __LL "lld "
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#define __SC "scd "
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#define __INS "dins "
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#define __EXT "dext "
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#endif
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/*
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* clear_bit() doesn't provide any barrier for the compiler.
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*/
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#define smp_mb__before_clear_bit() smp_llsc_mb()
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#define smp_mb__after_clear_bit() smp_llsc_mb()
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/*
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* set_bit - Atomically set a bit in memory
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* @nr: the bit to set
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* @addr: the address to start counting from
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*
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* This function is atomic and may not be reordered. See __set_bit()
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* if you do not require the atomic guarantees.
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* Note that @nr may be almost arbitrarily large; this function is not
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* restricted to acting on a single-word quantity.
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*/
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static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned short bit = nr & SZLONG_MASK;
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unsigned long temp;
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # set_bit \n"
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" or %0, %2 \n"
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" " __SC "%0, %1 \n"
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" beqzl %0, 1b \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (1UL << bit), "m" (*m));
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#ifdef CONFIG_CPU_MIPSR2
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} else if (kernel_uses_llsc && __builtin_constant_p(bit)) {
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__asm__ __volatile__(
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"1: " __LL "%0, %1 # set_bit \n"
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" " __INS "%0, %4, %2, 1 \n"
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" " __SC "%0, %1 \n"
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" beqz %0, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (bit), "m" (*m), "r" (~0));
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#endif /* CONFIG_CPU_MIPSR2 */
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} else if (kernel_uses_llsc) {
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # set_bit \n"
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" or %0, %2 \n"
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" " __SC "%0, %1 \n"
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" beqz %0, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (1UL << bit), "m" (*m));
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} else {
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volatile unsigned long *a = addr;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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*a |= mask;
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raw_local_irq_restore(flags);
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}
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}
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/*
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* clear_bit - Clears a bit in memory
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* @nr: Bit to clear
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* @addr: Address to start counting from
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*
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* clear_bit() is atomic and may not be reordered. However, it does
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* not contain a memory barrier, so if it is used for locking purposes,
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* you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
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* in order to ensure changes are visible on other processors.
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*/
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static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned short bit = nr & SZLONG_MASK;
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unsigned long temp;
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # clear_bit \n"
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" and %0, %2 \n"
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" " __SC "%0, %1 \n"
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" beqzl %0, 1b \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (~(1UL << bit)), "m" (*m));
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#ifdef CONFIG_CPU_MIPSR2
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} else if (kernel_uses_llsc && __builtin_constant_p(bit)) {
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__asm__ __volatile__(
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"1: " __LL "%0, %1 # clear_bit \n"
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" " __INS "%0, $0, %2, 1 \n"
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" " __SC "%0, %1 \n"
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" beqz %0, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (bit), "m" (*m));
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#endif /* CONFIG_CPU_MIPSR2 */
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} else if (kernel_uses_llsc) {
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # clear_bit \n"
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" and %0, %2 \n"
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" " __SC "%0, %1 \n"
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" beqz %0, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (~(1UL << bit)), "m" (*m));
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} else {
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volatile unsigned long *a = addr;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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*a &= ~mask;
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raw_local_irq_restore(flags);
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}
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}
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/*
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* clear_bit_unlock - Clears a bit in memory
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* @nr: Bit to clear
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* @addr: Address to start counting from
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*
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* clear_bit() is atomic and implies release semantics before the memory
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* operation. It can be used for an unlock.
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*/
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static inline void clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
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{
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smp_mb__before_clear_bit();
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clear_bit(nr, addr);
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}
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/*
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* change_bit - Toggle a bit in memory
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* @nr: Bit to change
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* @addr: Address to start counting from
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*
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* change_bit() is atomic and may not be reordered.
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* Note that @nr may be almost arbitrarily large; this function is not
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* restricted to acting on a single-word quantity.
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*/
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static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned short bit = nr & SZLONG_MASK;
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # change_bit \n"
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" xor %0, %2 \n"
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" " __SC "%0, %1 \n"
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" beqzl %0, 1b \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (1UL << bit), "m" (*m));
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} else if (kernel_uses_llsc) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # change_bit \n"
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" xor %0, %2 \n"
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" " __SC "%0, %1 \n"
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" beqz %0, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m)
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: "ir" (1UL << bit), "m" (*m));
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} else {
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volatile unsigned long *a = addr;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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*a ^= mask;
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raw_local_irq_restore(flags);
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}
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}
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/*
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* test_and_set_bit - Set a bit and return its old value
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* @nr: Bit to set
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* @addr: Address to count from
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*
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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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static inline int test_and_set_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned short bit = nr & SZLONG_MASK;
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unsigned long res;
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smp_llsc_mb();
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # test_and_set_bit \n"
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" or %2, %0, %3 \n"
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" " __SC "%2, %1 \n"
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" beqzl %2, 1b \n"
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" and %2, %0, %3 \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m), "=&r" (res)
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: "r" (1UL << bit), "m" (*m)
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: "memory");
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} else if (kernel_uses_llsc) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set push \n"
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" .set noreorder \n"
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" .set mips3 \n"
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"1: " __LL "%0, %1 # test_and_set_bit \n"
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" or %2, %0, %3 \n"
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" " __SC "%2, %1 \n"
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" beqz %2, 2f \n"
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" and %2, %0, %3 \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" nop \n"
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" .previous \n"
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" .set pop \n"
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: "=&r" (temp), "=m" (*m), "=&r" (res)
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: "r" (1UL << bit), "m" (*m)
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: "memory");
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} else {
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volatile unsigned long *a = addr;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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res = (mask & *a);
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*a |= mask;
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raw_local_irq_restore(flags);
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}
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smp_llsc_mb();
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return res != 0;
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}
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/*
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* test_and_set_bit_lock - Set a bit and return its old value
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* @nr: Bit to set
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* @addr: Address to count from
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*
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* This operation is atomic and implies acquire ordering semantics
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* after the memory operation.
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*/
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static inline int test_and_set_bit_lock(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned short bit = nr & SZLONG_MASK;
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unsigned long res;
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # test_and_set_bit \n"
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" or %2, %0, %3 \n"
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" " __SC "%2, %1 \n"
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" beqzl %2, 1b \n"
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" and %2, %0, %3 \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m), "=&r" (res)
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: "r" (1UL << bit), "m" (*m)
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: "memory");
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} else if (kernel_uses_llsc) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set push \n"
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" .set noreorder \n"
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" .set mips3 \n"
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"1: " __LL "%0, %1 # test_and_set_bit \n"
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" or %2, %0, %3 \n"
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" " __SC "%2, %1 \n"
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" beqz %2, 2f \n"
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" and %2, %0, %3 \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" nop \n"
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" .previous \n"
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" .set pop \n"
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: "=&r" (temp), "=m" (*m), "=&r" (res)
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: "r" (1UL << bit), "m" (*m)
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: "memory");
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} else {
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volatile unsigned long *a = addr;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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res = (mask & *a);
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*a |= mask;
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raw_local_irq_restore(flags);
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}
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smp_llsc_mb();
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return res != 0;
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}
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/*
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* test_and_clear_bit - Clear a bit and return its old value
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* @nr: Bit to clear
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* @addr: Address to count from
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*
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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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static inline int test_and_clear_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned short bit = nr & SZLONG_MASK;
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unsigned long res;
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smp_llsc_mb();
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set mips3 \n"
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"1: " __LL "%0, %1 # test_and_clear_bit \n"
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" or %2, %0, %3 \n"
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" xor %2, %3 \n"
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" " __SC "%2, %1 \n"
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" beqzl %2, 1b \n"
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" and %2, %0, %3 \n"
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" .set mips0 \n"
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: "=&r" (temp), "=m" (*m), "=&r" (res)
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: "r" (1UL << bit), "m" (*m)
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: "memory");
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#ifdef CONFIG_CPU_MIPSR2
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} else if (kernel_uses_llsc && __builtin_constant_p(nr)) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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"1: " __LL "%0, %1 # test_and_clear_bit \n"
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" " __EXT "%2, %0, %3, 1 \n"
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" " __INS "%0, $0, %3, 1 \n"
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" " __SC "%0, %1 \n"
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" beqz %0, 2f \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" .previous \n"
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: "=&r" (temp), "=m" (*m), "=&r" (res)
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: "ir" (bit), "m" (*m)
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: "memory");
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#endif
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} else if (kernel_uses_llsc) {
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unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
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unsigned long temp;
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__asm__ __volatile__(
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" .set push \n"
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" .set noreorder \n"
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" .set mips3 \n"
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"1: " __LL "%0, %1 # test_and_clear_bit \n"
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" or %2, %0, %3 \n"
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" xor %2, %3 \n"
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" " __SC "%2, %1 \n"
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" beqz %2, 2f \n"
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" and %2, %0, %3 \n"
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" .subsection 2 \n"
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"2: b 1b \n"
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" nop \n"
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" .previous \n"
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" .set pop \n"
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: "=&r" (temp), "=m" (*m), "=&r" (res)
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: "r" (1UL << bit), "m" (*m)
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: "memory");
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} else {
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volatile unsigned long *a = addr;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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res = (mask & *a);
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*a &= ~mask;
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raw_local_irq_restore(flags);
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}
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smp_llsc_mb();
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|
return res != 0;
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
unsigned short bit = nr & SZLONG_MASK;
|
|
unsigned long res;
|
|
|
|
smp_llsc_mb();
|
|
|
|
if (kernel_uses_llsc && R10000_LLSC_WAR) {
|
|
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
|
|
unsigned long temp;
|
|
|
|
__asm__ __volatile__(
|
|
" .set mips3 \n"
|
|
"1: " __LL "%0, %1 # test_and_change_bit \n"
|
|
" xor %2, %0, %3 \n"
|
|
" " __SC "%2, %1 \n"
|
|
" beqzl %2, 1b \n"
|
|
" and %2, %0, %3 \n"
|
|
" .set mips0 \n"
|
|
: "=&r" (temp), "=m" (*m), "=&r" (res)
|
|
: "r" (1UL << bit), "m" (*m)
|
|
: "memory");
|
|
} else if (kernel_uses_llsc) {
|
|
unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
|
|
unsigned long temp;
|
|
|
|
__asm__ __volatile__(
|
|
" .set push \n"
|
|
" .set noreorder \n"
|
|
" .set mips3 \n"
|
|
"1: " __LL "%0, %1 # test_and_change_bit \n"
|
|
" xor %2, %0, %3 \n"
|
|
" " __SC "\t%2, %1 \n"
|
|
" beqz %2, 2f \n"
|
|
" and %2, %0, %3 \n"
|
|
" .subsection 2 \n"
|
|
"2: b 1b \n"
|
|
" nop \n"
|
|
" .previous \n"
|
|
" .set pop \n"
|
|
: "=&r" (temp), "=m" (*m), "=&r" (res)
|
|
: "r" (1UL << bit), "m" (*m)
|
|
: "memory");
|
|
} else {
|
|
volatile unsigned long *a = addr;
|
|
unsigned long mask;
|
|
unsigned long flags;
|
|
|
|
a += nr >> SZLONG_LOG;
|
|
mask = 1UL << bit;
|
|
raw_local_irq_save(flags);
|
|
res = (mask & *a);
|
|
*a ^= mask;
|
|
raw_local_irq_restore(flags);
|
|
}
|
|
|
|
smp_llsc_mb();
|
|
|
|
return res != 0;
|
|
}
|
|
|
|
#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();
|
|
__clear_bit(nr, addr);
|
|
}
|
|
|
|
/*
|
|
* Return the bit position (0..63) of the most significant 1 bit in a word
|
|
* Returns -1 if no 1 bit exists
|
|
*/
|
|
static inline unsigned long __fls(unsigned long word)
|
|
{
|
|
int num;
|
|
|
|
if (BITS_PER_LONG == 32 &&
|
|
__builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
|
|
__asm__(
|
|
" .set push \n"
|
|
" .set mips32 \n"
|
|
" clz %0, %1 \n"
|
|
" .set pop \n"
|
|
: "=r" (num)
|
|
: "r" (word));
|
|
|
|
return 31 - num;
|
|
}
|
|
|
|
if (BITS_PER_LONG == 64 &&
|
|
__builtin_constant_p(cpu_has_mips64) && cpu_has_mips64) {
|
|
__asm__(
|
|
" .set push \n"
|
|
" .set mips64 \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 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(int x)
|
|
{
|
|
int r;
|
|
|
|
if (__builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
|
|
__asm__("clz %0, %1" : "=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 above ffz (man ffs).
|
|
*/
|
|
static inline int ffs(int word)
|
|
{
|
|
if (!word)
|
|
return 0;
|
|
|
|
return fls(word & -word);
|
|
}
|
|
|
|
#include <asm-generic/bitops/ffz.h>
|
|
#include <asm-generic/bitops/find.h>
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <asm-generic/bitops/sched.h>
|
|
#include <asm-generic/bitops/hweight.h>
|
|
#include <asm-generic/bitops/ext2-non-atomic.h>
|
|
#include <asm-generic/bitops/ext2-atomic.h>
|
|
#include <asm-generic/bitops/minix.h>
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif /* _ASM_BITOPS_H */
|