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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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9026737703
Use smp_mb__before_atomic() rather than smp_mb__before_llsc() in test_and_set_bit(), test_and_clear_bit() & test_and_change_bit(). The _atomic() versions make semantic sense in these cases, and will allow a later patch to omit redundant barriers for Loongson3 systems that already include a barrier within __test_bit_op(). Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
464 lines
11 KiB
C
464 lines
11 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/bits.h>
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/barrier.h>
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#include <asm/byteorder.h> /* sigh ... */
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#include <asm/compiler.h>
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#include <asm/cpu-features.h>
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#include <asm/isa-rev.h>
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#include <asm/llsc.h>
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#include <asm/sgidefs.h>
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#include <asm/war.h>
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#define __bit_op(mem, insn, inputs...) do { \
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unsigned long temp; \
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\
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asm volatile( \
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" .set push \n" \
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" .set " MIPS_ISA_LEVEL " \n" \
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" " __SYNC(full, loongson3_war) " \n" \
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"1: " __LL "%0, %1 \n" \
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" " insn " \n" \
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" " __SC "%0, %1 \n" \
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" " __SC_BEQZ "%0, 1b \n" \
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" .set pop \n" \
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: "=&r"(temp), "+" GCC_OFF_SMALL_ASM()(mem) \
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: inputs \
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: __LLSC_CLOBBER); \
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} while (0)
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#define __test_bit_op(mem, ll_dst, insn, inputs...) ({ \
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unsigned long orig, temp; \
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\
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asm volatile( \
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" .set push \n" \
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" .set " MIPS_ISA_LEVEL " \n" \
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" " __SYNC(full, loongson3_war) " \n" \
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"1: " __LL ll_dst ", %2 \n" \
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" " insn " \n" \
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" " __SC "%1, %2 \n" \
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" " __SC_BEQZ "%1, 1b \n" \
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" .set pop \n" \
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: "=&r"(orig), "=&r"(temp), \
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"+" GCC_OFF_SMALL_ASM()(mem) \
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: inputs \
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: __LLSC_CLOBBER); \
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\
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orig; \
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})
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/*
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* These are the "slower" versions of the functions and are in bitops.c.
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* These functions call raw_local_irq_{save,restore}().
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*/
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void __mips_set_bit(unsigned long nr, volatile unsigned long *addr);
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void __mips_clear_bit(unsigned long nr, volatile unsigned long *addr);
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void __mips_change_bit(unsigned long nr, volatile unsigned long *addr);
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int __mips_test_and_set_bit_lock(unsigned long nr,
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volatile unsigned long *addr);
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int __mips_test_and_clear_bit(unsigned long nr,
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volatile unsigned long *addr);
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int __mips_test_and_change_bit(unsigned long nr,
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volatile unsigned long *addr);
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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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volatile unsigned long *m = &addr[BIT_WORD(nr)];
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int bit = nr % BITS_PER_LONG;
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if (!kernel_uses_llsc) {
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__mips_set_bit(nr, addr);
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return;
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}
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if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(bit) && (bit >= 16)) {
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__bit_op(*m, __INS "%0, %3, %2, 1", "i"(bit), "r"(~0));
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return;
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}
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__bit_op(*m, "or\t%0, %2", "ir"(BIT(bit)));
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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_atomic() and/or smp_mb__after_atomic()
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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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volatile unsigned long *m = &addr[BIT_WORD(nr)];
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int bit = nr % BITS_PER_LONG;
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if (!kernel_uses_llsc) {
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__mips_clear_bit(nr, addr);
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return;
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}
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if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(bit)) {
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__bit_op(*m, __INS "%0, $0, %2, 1", "i"(bit));
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return;
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}
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__bit_op(*m, "and\t%0, %2", "ir"(~BIT(bit)));
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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_atomic();
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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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volatile unsigned long *m = &addr[BIT_WORD(nr)];
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int bit = nr % BITS_PER_LONG;
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if (!kernel_uses_llsc) {
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__mips_change_bit(nr, addr);
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return;
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}
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__bit_op(*m, "xor\t%0, %2", "ir"(BIT(bit)));
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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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volatile unsigned long *m = &addr[BIT_WORD(nr)];
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int bit = nr % BITS_PER_LONG;
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unsigned long res, orig;
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if (!kernel_uses_llsc) {
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res = __mips_test_and_set_bit_lock(nr, addr);
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} else {
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orig = __test_bit_op(*m, "%0",
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"or\t%1, %0, %3",
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"ir"(BIT(bit)));
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res = (orig & BIT(bit)) != 0;
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}
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smp_llsc_mb();
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return res;
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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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smp_mb__before_atomic();
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return test_and_set_bit_lock(nr, addr);
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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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volatile unsigned long *m = &addr[BIT_WORD(nr)];
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int bit = nr % BITS_PER_LONG;
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unsigned long res, orig;
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smp_mb__before_atomic();
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if (!kernel_uses_llsc) {
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res = __mips_test_and_clear_bit(nr, addr);
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} else if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(nr)) {
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res = __test_bit_op(*m, "%1",
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__EXT "%0, %1, %3, 1;"
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__INS "%1, $0, %3, 1",
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"i"(bit));
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} else {
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orig = __test_bit_op(*m, "%0",
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"or\t%1, %0, %3;"
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"xor\t%1, %1, %3",
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"ir"(BIT(bit)));
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res = (orig & BIT(bit)) != 0;
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}
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smp_llsc_mb();
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return res;
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}
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/*
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* test_and_change_bit - Change a bit and return its old value
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* @nr: Bit to change
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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_change_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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volatile unsigned long *m = &addr[BIT_WORD(nr)];
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int bit = nr % BITS_PER_LONG;
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unsigned long res, orig;
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smp_mb__before_atomic();
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if (!kernel_uses_llsc) {
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res = __mips_test_and_change_bit(nr, addr);
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} else {
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orig = __test_bit_op(*m, "%0",
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"xor\t%1, %0, %3",
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"ir"(BIT(bit)));
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res = (orig & BIT(bit)) != 0;
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}
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smp_llsc_mb();
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return res;
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}
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#undef __bit_op
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#undef __test_bit_op
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#include <asm-generic/bitops/non-atomic.h>
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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 non-atomic and implies release semantics before the memory
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* operation. It can be used for an unlock if no other CPUs can concurrently
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* modify other bits in the word.
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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_llsc();
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__clear_bit(nr, addr);
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nudge_writes();
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}
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/*
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* Return the bit position (0..63) of the most significant 1 bit in a word
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* Returns -1 if no 1 bit exists
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*/
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static __always_inline unsigned long __fls(unsigned long word)
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{
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int num;
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if (BITS_PER_LONG == 32 && !__builtin_constant_p(word) &&
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__builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
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__asm__(
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" .set push \n"
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" .set "MIPS_ISA_LEVEL" \n"
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" clz %0, %1 \n"
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" .set pop \n"
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: "=r" (num)
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: "r" (word));
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return 31 - num;
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}
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if (BITS_PER_LONG == 64 && !__builtin_constant_p(word) &&
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__builtin_constant_p(cpu_has_mips64) && cpu_has_mips64) {
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__asm__(
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" .set push \n"
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" .set "MIPS_ISA_LEVEL" \n"
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" dclz %0, %1 \n"
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" .set pop \n"
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: "=r" (num)
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: "r" (word));
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return 63 - num;
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}
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num = BITS_PER_LONG - 1;
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#if BITS_PER_LONG == 64
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if (!(word & (~0ul << 32))) {
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num -= 32;
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word <<= 32;
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}
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#endif
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if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
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num -= 16;
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word <<= 16;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
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num -= 8;
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word <<= 8;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
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num -= 4;
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word <<= 4;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
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num -= 2;
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word <<= 2;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-1))))
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num -= 1;
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return num;
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}
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/*
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* __ffs - find first bit in word.
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* @word: The word to search
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*
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* Returns 0..SZLONG-1
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* Undefined if no bit exists, so code should check against 0 first.
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*/
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static __always_inline unsigned long __ffs(unsigned long word)
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{
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return __fls(word & -word);
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}
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/*
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* fls - find last bit set.
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* @word: The word to search
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*
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* This is defined the same way as ffs.
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static inline int fls(unsigned int x)
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{
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int r;
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if (!__builtin_constant_p(x) &&
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__builtin_constant_p(cpu_has_clo_clz) && cpu_has_clo_clz) {
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__asm__(
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" .set push \n"
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" .set "MIPS_ISA_LEVEL" \n"
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" clz %0, %1 \n"
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" .set pop \n"
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: "=r" (x)
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: "r" (x));
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return 32 - x;
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}
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r = 32;
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if (!x)
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return 0;
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if (!(x & 0xffff0000u)) {
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x <<= 16;
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r -= 16;
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}
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if (!(x & 0xff000000u)) {
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x <<= 8;
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r -= 8;
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}
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if (!(x & 0xf0000000u)) {
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x <<= 4;
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r -= 4;
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}
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if (!(x & 0xc0000000u)) {
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x <<= 2;
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r -= 2;
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}
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if (!(x & 0x80000000u)) {
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x <<= 1;
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r -= 1;
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}
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return r;
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}
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#include <asm-generic/bitops/fls64.h>
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/*
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* ffs - find first bit set.
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* @word: The word to search
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*
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* This is defined the same way as
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* the libc and compiler builtin ffs routines, therefore
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* differs in spirit from the above ffz (man ffs).
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*/
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static inline int ffs(int word)
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{
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if (!word)
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return 0;
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return fls(word & -word);
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}
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#include <asm-generic/bitops/ffz.h>
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#include <asm-generic/bitops/find.h>
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#ifdef __KERNEL__
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#include <asm-generic/bitops/sched.h>
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#include <asm/arch_hweight.h>
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#include <asm-generic/bitops/const_hweight.h>
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#include <asm-generic/bitops/le.h>
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#include <asm-generic/bitops/ext2-atomic.h>
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#endif /* __KERNEL__ */
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#endif /* _ASM_BITOPS_H */
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