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-rw-r--r--include/asm-s390/spinlock.h251
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diff --git a/include/asm-s390/spinlock.h b/include/asm-s390/spinlock.h
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1/*
2 * include/asm-s390/spinlock.h
3 *
4 * S390 version
5 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
7 *
8 * Derived from "include/asm-i386/spinlock.h"
9 */
10
11#ifndef __ASM_SPINLOCK_H
12#define __ASM_SPINLOCK_H
13
14#ifdef __s390x__
15/*
16 * Grmph, take care of %&#! user space programs that include
17 * asm/spinlock.h. The diagnose is only available in kernel
18 * context.
19 */
20#ifdef __KERNEL__
21#include <asm/lowcore.h>
22#define __DIAG44_INSN "ex"
23#define __DIAG44_OPERAND __LC_DIAG44_OPCODE
24#else
25#define __DIAG44_INSN "#"
26#define __DIAG44_OPERAND 0
27#endif
28#endif /* __s390x__ */
29
30/*
31 * Simple spin lock operations. There are two variants, one clears IRQ's
32 * on the local processor, one does not.
33 *
34 * We make no fairness assumptions. They have a cost.
35 */
36
37typedef struct {
38 volatile unsigned int lock;
39#ifdef CONFIG_PREEMPT
40 unsigned int break_lock;
41#endif
42} __attribute__ ((aligned (4))) spinlock_t;
43
44#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
45#define spin_lock_init(lp) do { (lp)->lock = 0; } while(0)
46#define spin_unlock_wait(lp) do { barrier(); } while(((volatile spinlock_t *)(lp))->lock)
47#define spin_is_locked(x) ((x)->lock != 0)
48#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
49
50extern inline void _raw_spin_lock(spinlock_t *lp)
51{
52#ifndef __s390x__
53 unsigned int reg1, reg2;
54 __asm__ __volatile__(" bras %0,1f\n"
55 "0: diag 0,0,68\n"
56 "1: slr %1,%1\n"
57 " cs %1,%0,0(%3)\n"
58 " jl 0b\n"
59 : "=&d" (reg1), "=&d" (reg2), "=m" (lp->lock)
60 : "a" (&lp->lock), "m" (lp->lock)
61 : "cc", "memory" );
62#else /* __s390x__ */
63 unsigned long reg1, reg2;
64 __asm__ __volatile__(" bras %1,1f\n"
65 "0: " __DIAG44_INSN " 0,%4\n"
66 "1: slr %0,%0\n"
67 " cs %0,%1,0(%3)\n"
68 " jl 0b\n"
69 : "=&d" (reg1), "=&d" (reg2), "=m" (lp->lock)
70 : "a" (&lp->lock), "i" (__DIAG44_OPERAND),
71 "m" (lp->lock) : "cc", "memory" );
72#endif /* __s390x__ */
73}
74
75extern inline int _raw_spin_trylock(spinlock_t *lp)
76{
77 unsigned long reg;
78 unsigned int result;
79
80 __asm__ __volatile__(" basr %1,0\n"
81 "0: cs %0,%1,0(%3)"
82 : "=d" (result), "=&d" (reg), "=m" (lp->lock)
83 : "a" (&lp->lock), "m" (lp->lock), "0" (0)
84 : "cc", "memory" );
85 return !result;
86}
87
88extern inline void _raw_spin_unlock(spinlock_t *lp)
89{
90 unsigned int old;
91
92 __asm__ __volatile__("cs %0,%3,0(%4)"
93 : "=d" (old), "=m" (lp->lock)
94 : "0" (lp->lock), "d" (0), "a" (lp)
95 : "cc", "memory" );
96}
97
98/*
99 * Read-write spinlocks, allowing multiple readers
100 * but only one writer.
101 *
102 * NOTE! it is quite common to have readers in interrupts
103 * but no interrupt writers. For those circumstances we
104 * can "mix" irq-safe locks - any writer needs to get a
105 * irq-safe write-lock, but readers can get non-irqsafe
106 * read-locks.
107 */
108typedef struct {
109 volatile unsigned long lock;
110 volatile unsigned long owner_pc;
111#ifdef CONFIG_PREEMPT
112 unsigned int break_lock;
113#endif
114} rwlock_t;
115
116#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
117
118#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
119
120/**
121 * read_can_lock - would read_trylock() succeed?
122 * @lock: the rwlock in question.
123 */
124#define read_can_lock(x) ((int)(x)->lock >= 0)
125
126/**
127 * write_can_lock - would write_trylock() succeed?
128 * @lock: the rwlock in question.
129 */
130#define write_can_lock(x) ((x)->lock == 0)
131
132#ifndef __s390x__
133#define _raw_read_lock(rw) \
134 asm volatile(" l 2,0(%1)\n" \
135 " j 1f\n" \
136 "0: diag 0,0,68\n" \
137 "1: la 2,0(2)\n" /* clear high (=write) bit */ \
138 " la 3,1(2)\n" /* one more reader */ \
139 " cs 2,3,0(%1)\n" /* try to write new value */ \
140 " jl 0b" \
141 : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
142 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
143#else /* __s390x__ */
144#define _raw_read_lock(rw) \
145 asm volatile(" lg 2,0(%1)\n" \
146 " j 1f\n" \
147 "0: " __DIAG44_INSN " 0,%2\n" \
148 "1: nihh 2,0x7fff\n" /* clear high (=write) bit */ \
149 " la 3,1(2)\n" /* one more reader */ \
150 " csg 2,3,0(%1)\n" /* try to write new value */ \
151 " jl 0b" \
152 : "=m" ((rw)->lock) \
153 : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
154 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
155#endif /* __s390x__ */
156
157#ifndef __s390x__
158#define _raw_read_unlock(rw) \
159 asm volatile(" l 2,0(%1)\n" \
160 " j 1f\n" \
161 "0: diag 0,0,68\n" \
162 "1: lr 3,2\n" \
163 " ahi 3,-1\n" /* one less reader */ \
164 " cs 2,3,0(%1)\n" \
165 " jl 0b" \
166 : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
167 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
168#else /* __s390x__ */
169#define _raw_read_unlock(rw) \
170 asm volatile(" lg 2,0(%1)\n" \
171 " j 1f\n" \
172 "0: " __DIAG44_INSN " 0,%2\n" \
173 "1: lgr 3,2\n" \
174 " bctgr 3,0\n" /* one less reader */ \
175 " csg 2,3,0(%1)\n" \
176 " jl 0b" \
177 : "=m" ((rw)->lock) \
178 : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
179 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
180#endif /* __s390x__ */
181
182#ifndef __s390x__
183#define _raw_write_lock(rw) \
184 asm volatile(" lhi 3,1\n" \
185 " sll 3,31\n" /* new lock value = 0x80000000 */ \
186 " j 1f\n" \
187 "0: diag 0,0,68\n" \
188 "1: slr 2,2\n" /* old lock value must be 0 */ \
189 " cs 2,3,0(%1)\n" \
190 " jl 0b" \
191 : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
192 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
193#else /* __s390x__ */
194#define _raw_write_lock(rw) \
195 asm volatile(" llihh 3,0x8000\n" /* new lock value = 0x80...0 */ \
196 " j 1f\n" \
197 "0: " __DIAG44_INSN " 0,%2\n" \
198 "1: slgr 2,2\n" /* old lock value must be 0 */ \
199 " csg 2,3,0(%1)\n" \
200 " jl 0b" \
201 : "=m" ((rw)->lock) \
202 : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
203 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
204#endif /* __s390x__ */
205
206#ifndef __s390x__
207#define _raw_write_unlock(rw) \
208 asm volatile(" slr 3,3\n" /* new lock value = 0 */ \
209 " j 1f\n" \
210 "0: diag 0,0,68\n" \
211 "1: lhi 2,1\n" \
212 " sll 2,31\n" /* old lock value must be 0x80000000 */ \
213 " cs 2,3,0(%1)\n" \
214 " jl 0b" \
215 : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
216 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
217#else /* __s390x__ */
218#define _raw_write_unlock(rw) \
219 asm volatile(" slgr 3,3\n" /* new lock value = 0 */ \
220 " j 1f\n" \
221 "0: " __DIAG44_INSN " 0,%2\n" \
222 "1: llihh 2,0x8000\n" /* old lock value must be 0x8..0 */\
223 " csg 2,3,0(%1)\n" \
224 " jl 0b" \
225 : "=m" ((rw)->lock) \
226 : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
227 "m" ((rw)->lock) : "2", "3", "cc", "memory" )
228#endif /* __s390x__ */
229
230#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
231
232extern inline int _raw_write_trylock(rwlock_t *rw)
233{
234 unsigned long result, reg;
235
236 __asm__ __volatile__(
237#ifndef __s390x__
238 " lhi %1,1\n"
239 " sll %1,31\n"
240 " cs %0,%1,0(%3)"
241#else /* __s390x__ */
242 " llihh %1,0x8000\n"
243 "0: csg %0,%1,0(%3)\n"
244#endif /* __s390x__ */
245 : "=d" (result), "=&d" (reg), "=m" (rw->lock)
246 : "a" (&rw->lock), "m" (rw->lock), "0" (0UL)
247 : "cc", "memory" );
248 return result == 0;
249}
250
251#endif /* __ASM_SPINLOCK_H */
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