1/* spinlock.h: 64-bit Sparc spinlock support. 2 * 3 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu) 4 */ 5 6#ifndef __SPARC64_SPINLOCK_H 7#define __SPARC64_SPINLOCK_H 8 9#include <linux/config.h> 10 11#ifndef __ASSEMBLY__ 12 13/* To get debugging spinlocks which detect and catch 14 * deadlock situations, set CONFIG_DEBUG_SPINLOCK 15 * and rebuild your kernel. 16 */ 17 18/* All of these locking primitives are expected to work properly 19 * even in an RMO memory model, which currently is what the kernel 20 * runs in. 21 * 22 * There is another issue. Because we play games to save cycles 23 * in the non-contention case, we need to be extra careful about 24 * branch targets into the "spinning" code. They live in their 25 * own section, but the newer V9 branches have a shorter range 26 * than the traditional 32-bit sparc branch variants. The rule 27 * is that the branches that go into and out of the spinner sections 28 * must be pre-V9 branches. 29 */ 30 31#ifndef CONFIG_DEBUG_SPINLOCK 32 33typedef unsigned char spinlock_t; 34#define SPIN_LOCK_UNLOCKED 0 35 36#define spin_lock_init(lock) (*((unsigned char *)(lock)) = 0) 37#define spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0) 38 39#define spin_unlock_wait(lock) \ 40do { membar("#LoadLoad"); \ 41} while(*((volatile unsigned char *)lock)) 42 43extern __inline__ void spin_lock(spinlock_t *lock) 44{ 45 __asm__ __volatile__( 46"1: ldstub [%0], %%g7\n" 47" brnz,pn %%g7, 2f\n" 48" membar #StoreLoad | #StoreStore\n" 49" .subsection 2\n" 50"2: ldub [%0], %%g7\n" 51" brnz,pt %%g7, 2b\n" 52" membar #LoadLoad\n" 53" b,a,pt %%xcc, 1b\n" 54" .previous\n" 55 : /* no outputs */ 56 : "r" (lock) 57 : "g7", "memory"); 58} 59 60extern __inline__ int spin_trylock(spinlock_t *lock) 61{ 62 unsigned int result; 63 __asm__ __volatile__("ldstub [%1], %0\n\t" 64 "membar #StoreLoad | #StoreStore" 65 : "=r" (result) 66 : "r" (lock) 67 : "memory"); 68 return (result == 0); 69} 70 71extern __inline__ void spin_unlock(spinlock_t *lock) 72{ 73 __asm__ __volatile__("membar #StoreStore | #LoadStore\n\t" 74 "stb %%g0, [%0]" 75 : /* No outputs */ 76 : "r" (lock) 77 : "memory"); 78} 79 80#else /* !(CONFIG_DEBUG_SPINLOCK) */ 81 82typedef struct { 83 unsigned char lock; 84 unsigned int owner_pc, owner_cpu; 85} spinlock_t; 86#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff } 87#define spin_lock_init(__lock) \ 88do { (__lock)->lock = 0; \ 89 (__lock)->owner_pc = 0; \ 90 (__lock)->owner_cpu = 0xff; \ 91} while(0) 92#define spin_is_locked(__lock) (*((volatile unsigned char *)(&((__lock)->lock))) != 0) 93#define spin_unlock_wait(__lock) \ 94do { \ 95 membar("#LoadLoad"); \ 96} while(*((volatile unsigned char *)(&((__lock)->lock)))) 97 98extern void _do_spin_lock (spinlock_t *lock, char *str); 99extern void _do_spin_unlock (spinlock_t *lock); 100extern int _spin_trylock (spinlock_t *lock); 101 102#define spin_trylock(lp) _spin_trylock(lp) 103#define spin_lock(lock) _do_spin_lock(lock, "spin_lock") 104#define spin_unlock(lock) _do_spin_unlock(lock) 105 106#endif /* CONFIG_DEBUG_SPINLOCK */ 107 108/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */ 109 110#ifndef CONFIG_DEBUG_SPINLOCK 111 112typedef unsigned int rwlock_t; 113#define RW_LOCK_UNLOCKED 0 114#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0) 115 116extern void __read_lock(rwlock_t *); 117extern void __read_unlock(rwlock_t *); 118extern void __write_lock(rwlock_t *); 119extern void __write_unlock(rwlock_t *); 120 121#define read_lock(p) __read_lock(p) 122#define read_unlock(p) __read_unlock(p) 123#define write_lock(p) __write_lock(p) 124#define write_unlock(p) __write_unlock(p) 125 126#else /* !(CONFIG_DEBUG_SPINLOCK) */ 127 128typedef struct { 129 unsigned long lock; 130 unsigned int writer_pc, writer_cpu; 131 unsigned int reader_pc[4]; 132} rwlock_t; 133#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, 0xff, { 0, 0, 0, 0 } } 134#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0) 135 136extern void _do_read_lock(rwlock_t *rw, char *str); 137extern void _do_read_unlock(rwlock_t *rw, char *str); 138extern void _do_write_lock(rwlock_t *rw, char *str); 139extern void _do_write_unlock(rwlock_t *rw); 140 141#define read_lock(lock) \ 142do { unsigned long flags; \ 143 __save_and_cli(flags); \ 144 _do_read_lock(lock, "read_lock"); \ 145 __restore_flags(flags); \ 146} while(0) 147 148#define read_unlock(lock) \ 149do { unsigned long flags; \ 150 __save_and_cli(flags); \ 151 _do_read_unlock(lock, "read_unlock"); \ 152 __restore_flags(flags); \ 153} while(0) 154 155#define write_lock(lock) \ 156do { unsigned long flags; \ 157 __save_and_cli(flags); \ 158 _do_write_lock(lock, "write_lock"); \ 159 __restore_flags(flags); \ 160} while(0) 161 162#define write_unlock(lock) \ 163do { unsigned long flags; \ 164 __save_and_cli(flags); \ 165 _do_write_unlock(lock); \ 166 __restore_flags(flags); \ 167} while(0) 168 169#endif /* CONFIG_DEBUG_SPINLOCK */ 170 171#endif /* !(__ASSEMBLY__) */ 172 173#endif /* !(__SPARC64_SPINLOCK_H) */ 174