include/asm-s390/spinlock.h

   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
  37 typedef 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
  50 extern 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
  75 extern 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
  88 extern 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  */
 108 typedef 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
 232 extern 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 */