1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * bitops.c: atomic operations which got too long to be inlined all over 4 * the place. 5 * 6 * Copyright 1999 Philipp Rumpf (prumpf@tux.org) 7 * Copyright 2000 Grant Grundler (grundler@cup.hp.com) 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/spinlock.h> 12 #include <linux/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 notrace __xchg64(unsigned long x, volatile 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 notrace __xchg32(int x, volatile 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 notrace __xchg8(char x, volatile 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 #define CMPXCHG(T) \ 60 T notrace __cmpxchg_##T(volatile T *ptr, T old, T new) \ 61 { \ 62 unsigned long flags; \ 63 T 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 72 CMPXCHG(u64) 73 CMPXCHG(u32) 74 CMPXCHG(u16) 75 CMPXCHG(u8) 76