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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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44 lines
874 B
C
44 lines
874 B
C
/*
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* arch/alpha/lib/dec_and_lock.c
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*
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* ll/sc version of atomic_dec_and_lock()
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*
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*/
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#include <linux/spinlock.h>
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#include <linux/atomic.h>
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#include <linux/export.h>
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asm (".text \n\
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.global _atomic_dec_and_lock \n\
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.ent _atomic_dec_and_lock \n\
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.align 4 \n\
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_atomic_dec_and_lock: \n\
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.prologue 0 \n\
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1: ldl_l $1, 0($16) \n\
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subl $1, 1, $1 \n\
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beq $1, 2f \n\
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stl_c $1, 0($16) \n\
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beq $1, 4f \n\
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mb \n\
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clr $0 \n\
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ret \n\
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2: br $29, 3f \n\
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3: ldgp $29, 0($29) \n\
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br $atomic_dec_and_lock_1..ng \n\
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.subsection 2 \n\
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4: br 1b \n\
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.previous \n\
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.end _atomic_dec_and_lock");
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static int __used atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock)
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{
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/* Slow path */
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spin_lock(lock);
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if (atomic_dec_and_test(atomic))
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return 1;
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spin_unlock(lock);
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return 0;
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}
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EXPORT_SYMBOL(_atomic_dec_and_lock);
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