File: /usr/src/linux/include/asm-s390x/atomic.h
1 #ifndef __ARCH_S390_ATOMIC__
2 #define __ARCH_S390_ATOMIC__
3
4 /*
5 * include/asm-s390x/atomic.h
6 *
7 * S390 version
8 * Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
9 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
10 * Denis Joseph Barrow
11 *
12 * Derived from "include/asm-i386/bitops.h"
13 * Copyright (C) 1992, Linus Torvalds
14 *
15 */
16
17 /*
18 * Atomic operations that C can't guarantee us. Useful for
19 * resource counting etc..
20 * S390 uses 'Compare And Swap' for atomicity in SMP enviroment
21 */
22
23 typedef struct { volatile int counter; } atomic_t __attribute__ ((aligned (4)));
24 #define ATOMIC_INIT(i) { (i) }
25
26 #define atomic_eieio() __asm__ __volatile__ ("BCR 15,0")
27
28 #define __CS_LOOP(old_val, new_val, ptr, op_val, op_string) \
29 __asm__ __volatile__(" l %0,0(%2)\n" \
30 "0: lr %1,%0\n" \
31 op_string " %1,%3\n" \
32 " cs %0,%1,0(%2)\n" \
33 " jl 0b" \
34 : "=&d" (old_val), "=&d" (new_val) \
35 : "a" (ptr), "d" (op_val) : "cc" );
36
37 static __inline__ int atomic_read(atomic_t *v)
38 {
39 int retval;
40 __asm__ __volatile__("bcr 15,0\n\t"
41 "l %0,%1"
42 : "=d" (retval) : "m" (*v) );
43 return retval;
44 }
45
46 static __inline__ void atomic_set(atomic_t *v, int i)
47 {
48 __asm__ __volatile__("st %1,%0\n\t"
49 "bcr 15,0"
50 : "=m" (*v) : "d" (i) );
51 }
52
53 static __inline__ void atomic_add(int i, atomic_t *v)
54 {
55 int old_val, new_val;
56 __CS_LOOP(old_val, new_val, v, i, "ar");
57 }
58
59 static __inline__ int atomic_add_return (int i, atomic_t *v)
60 {
61 int old_val, new_val;
62 __CS_LOOP(old_val, new_val, v, i, "ar");
63 return new_val;
64 }
65
66 static __inline__ int atomic_add_negative(int i, atomic_t *v)
67 {
68 int old_val, new_val;
69 __CS_LOOP(old_val, new_val, v, i, "ar");
70 return new_val < 0;
71 }
72
73 static __inline__ void atomic_sub(int i, atomic_t *v)
74 {
75 int old_val, new_val;
76 __CS_LOOP(old_val, new_val, v, i, "sr");
77 }
78
79 static __inline__ void atomic_inc(volatile atomic_t *v)
80 {
81 int old_val, new_val;
82 __CS_LOOP(old_val, new_val, v, 1, "ar");
83 }
84
85 static __inline__ int atomic_inc_return(volatile atomic_t *v)
86 {
87 int old_val, new_val;
88 __CS_LOOP(old_val, new_val, v, 1, "ar");
89 return new_val;
90 }
91
92 static __inline__ int atomic_inc_and_test(volatile atomic_t *v)
93 {
94 int old_val, new_val;
95 __CS_LOOP(old_val, new_val, v, 1, "ar");
96 return new_val != 0;
97 }
98
99 static __inline__ void atomic_dec(volatile atomic_t *v)
100 {
101 int old_val, new_val;
102 __CS_LOOP(old_val, new_val, v, 1, "sr");
103 }
104
105 static __inline__ int atomic_dec_return(volatile atomic_t *v)
106 {
107 int old_val, new_val;
108 __CS_LOOP(old_val, new_val, v, 1, "sr");
109 return new_val;
110 }
111
112 static __inline__ int atomic_dec_and_test(volatile atomic_t *v)
113 {
114 int old_val, new_val;
115 __CS_LOOP(old_val, new_val, v, 1, "sr");
116 return new_val == 0;
117 }
118
119 static __inline__ void atomic_clear_mask(unsigned long mask, atomic_t *v)
120 {
121 int old_val, new_val;
122 __CS_LOOP(old_val, new_val, v, ~mask, "nr");
123 }
124
125 static __inline__ void atomic_set_mask(unsigned long mask, atomic_t *v)
126 {
127 int old_val, new_val;
128 __CS_LOOP(old_val, new_val, v, mask, "or");
129 }
130
131 /*
132 returns 0 if expected_oldval==value in *v ( swap was successful )
133 returns 1 if unsuccessful.
134 */
135 static __inline__ int
136 atomic_compare_and_swap(int expected_oldval,int new_val,atomic_t *v)
137 {
138 int retval;
139
140 __asm__ __volatile__(
141 " lr 0,%2\n"
142 " cs 0,%3,0(%1)\n"
143 " ipm %0\n"
144 " srl %0,28\n"
145 "0:"
146 : "=&d" (retval)
147 : "a" (v), "d" (expected_oldval) , "d" (new_val)
148 : "0", "cc");
149 return retval;
150 }
151
152 /*
153 Spin till *v = expected_oldval then swap with newval.
154 */
155 static __inline__ void
156 atomic_compare_and_swap_spin(int expected_oldval,int new_val,atomic_t *v)
157 {
158 __asm__ __volatile__(
159 "0: lr 0,%1\n"
160 " cs 0,%2,0(%0)\n"
161 " jl 0b\n"
162 : : "a" (v), "d" (expected_oldval) , "d" (new_val)
163 : "cc", "0" );
164 }
165
166 #define atomic_compare_and_swap_debug(where,from,to) \
167 if (atomic_compare_and_swap ((from), (to), (where))) {\
168 printk (KERN_WARNING"%s/%d atomic counter:%s couldn't be changed from %d(%s) to %d(%s), was %d\n",\
169 __FILE__,__LINE__,#where,(from),#from,(to),#to,atomic_read (where));\
170 atomic_set(where,(to));\
171 }
172
173 #define smp_mb__before_atomic_dec() smp_mb()
174 #define smp_mb__after_atomic_dec() smp_mb()
175 #define smp_mb__before_atomic_inc() smp_mb()
176 #define smp_mb__after_atomic_inc() smp_mb()
177
178 #endif /* __ARCH_S390_ATOMIC __ */
179