1 /* 2 * bitops.c: atomic operations which got too long to be inlined all over 3 * the place. 4 * 5 * Copyright 1999 Philipp Rumpf (prumpf@tux.org) 6 * Copyright 2000 Grant Grundler (grundler@cup.hp.com) 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/spinlock.h> 11 #include <asm/system.h> 12 #include <asm/atomic.h> 13 14 #ifdef CONFIG_SMP 15 arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = { 16 [0 ... (ATOMIC_HASH_SIZE-1)] = __ARCH_SPIN_LOCK_UNLOCKED 17 }; 18 #endif 19 20 #ifdef CONFIG_64BIT 21 unsigned long __xchg64(unsigned long x, unsigned long *ptr) 22 { 23 unsigned long temp, flags; 24 25 _atomic_spin_lock_irqsave(ptr, flags); 26 temp = *ptr; 27 *ptr = x; 28 _atomic_spin_unlock_irqrestore(ptr, flags); 29 return temp; 30 } 31 #endif 32 33 unsigned long __xchg32(int x, int *ptr) 34 { 35 unsigned long flags; 36 long temp; 37 38 _atomic_spin_lock_irqsave(ptr, flags); 39 temp = (long) *ptr; /* XXX - sign extension wanted? */ 40 *ptr = x; 41 _atomic_spin_unlock_irqrestore(ptr, flags); 42 return (unsigned long)temp; 43 } 44 45 46 unsigned long __xchg8(char x, char *ptr) 47 { 48 unsigned long flags; 49 long temp; 50 51 _atomic_spin_lock_irqsave(ptr, flags); 52 temp = (long) *ptr; /* XXX - sign extension wanted? */ 53 *ptr = x; 54 _atomic_spin_unlock_irqrestore(ptr, flags); 55 return (unsigned long)temp; 56 } 57 58 59 #ifdef CONFIG_64BIT 60 unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long new) 61 { 62 unsigned long flags; 63 unsigned long prev; 64 65 _atomic_spin_lock_irqsave(ptr, flags); 66 if ((prev = *ptr) == old) 67 *ptr = new; 68 _atomic_spin_unlock_irqrestore(ptr, flags); 69 return prev; 70 } 71 #endif 72 73 unsigned long __cmpxchg_u32(volatile unsigned int *ptr, unsigned int old, unsigned int new) 74 { 75 unsigned long flags; 76 unsigned int prev; 77 78 _atomic_spin_lock_irqsave(ptr, flags); 79 if ((prev = *ptr) == old) 80 *ptr = new; 81 _atomic_spin_unlock_irqrestore(ptr, flags); 82 return (unsigned long)prev; 83 } 84