--- /dev/null
+/*
+ * arch/s390/lib/spinlock.c
+ * Out of line spinlock code.
+ *
+ * S390 version
+ * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <asm/io.h>
+
+atomic_t spin_retry_counter;
+int spin_retry = 1000;
+
+/**
+ * spin_retry= parameter
+ */
+static int __init spin_retry_setup(char *str)
+{
+ spin_retry = simple_strtoul(str, &str, 0);
+ return 1;
+}
+__setup("spin_retry=", spin_retry_setup);
+
+static inline void
+_diag44(void)
+{
+#ifdef __s390x__
+ if (MACHINE_HAS_DIAG44)
+#endif
+ asm volatile("diag 0,0,0x44");
+}
+
+void
+_raw_spin_lock_wait(spinlock_t *lp, unsigned int pc)
+{
+ int count = spin_retry;
+
+ while (1) {
+ if (count-- <= 0) {
+ _diag44();
+ count = spin_retry;
+ }
+ atomic_inc(&spin_retry_counter);
+ if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0)
+ return;
+ }
+}
+EXPORT_SYMBOL(_raw_spin_lock_wait);
+
+int
+_raw_spin_trylock_retry(spinlock_t *lp, unsigned int pc)
+{
+ int count = spin_retry;
+
+ while (count-- > 0) {
+ atomic_inc(&spin_retry_counter);
+ if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0)
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(_raw_spin_trylock_retry);
+
+void
+_raw_read_lock_wait(rwlock_t *rw)
+{
+ unsigned int old;
+ int count = spin_retry;
+
+ while (1) {
+ if (count-- <= 0) {
+ _diag44();
+ count = spin_retry;
+ }
+ atomic_inc(&spin_retry_counter);
+ old = rw->lock & 0x7fffffffU;
+ if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+ return;
+ }
+}
+EXPORT_SYMBOL(_raw_read_lock_wait);
+
+int
+_raw_read_trylock_retry(rwlock_t *rw)
+{
+ unsigned int old;
+ int count = spin_retry;
+
+ while (count-- > 0) {
+ atomic_inc(&spin_retry_counter);
+ old = rw->lock & 0x7fffffffU;
+ if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(_raw_read_trylock_retry);
+
+void
+_raw_write_lock_wait(rwlock_t *rw)
+{
+ int count = spin_retry;
+
+ while (1) {
+ if (count-- <= 0) {
+ _diag44();
+ count = spin_retry;
+ }
+ atomic_inc(&spin_retry_counter);
+ if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+ return;
+ }
+}
+EXPORT_SYMBOL(_raw_write_lock_wait);
+
+int
+_raw_write_trylock_retry(rwlock_t *rw)
+{
+ int count = spin_retry;
+
+ while (count-- > 0) {
+ atomic_inc(&spin_retry_counter);
+ if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(_raw_write_trylock_retry);
#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H
-#ifdef __s390x__
-/*
- * Grmph, take care of %&#! user space programs that include
- * asm/spinlock.h. The diagnose is only available in kernel
- * context.
- */
-#ifdef __KERNEL__
-#include <asm/lowcore.h>
-#define __DIAG44_INSN "ex"
-#define __DIAG44_OPERAND __LC_DIAG44_OPCODE
-#else
-#define __DIAG44_INSN "#"
-#define __DIAG44_OPERAND 0
-#endif
-#endif /* __s390x__ */
+static inline int
+_raw_compare_and_swap(volatile unsigned int *lock,
+ unsigned int old, unsigned int new)
+{
+ asm volatile ("cs %0,%3,0(%4)"
+ : "=d" (old), "=m" (*lock)
+ : "0" (old), "d" (new), "a" (lock), "m" (*lock)
+ : "cc", "memory" );
+ return old;
+}
/*
* Simple spin lock operations. There are two variants, one clears IRQ's
#endif
} __attribute__ ((aligned (4))) spinlock_t;
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
-#define spin_lock_init(lp) do { (lp)->lock = 0; } while(0)
+#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
+#define spin_lock_init(lp) do { (lp)->lock = 0; } while(0)
#define spin_unlock_wait(lp) do { barrier(); } while(((volatile spinlock_t *)(lp))->lock)
-#define spin_is_locked(x) ((x)->lock != 0)
+#define spin_is_locked(x) ((x)->lock != 0)
#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
-extern inline void _raw_spin_lock(spinlock_t *lp)
+extern void _raw_spin_lock_wait(spinlock_t *lp, unsigned int pc);
+extern int _raw_spin_trylock_retry(spinlock_t *lp, unsigned int pc);
+
+static inline void _raw_spin_lock(spinlock_t *lp)
{
-#ifndef __s390x__
- unsigned int reg1, reg2;
- __asm__ __volatile__(" bras %0,1f\n"
- "0: diag 0,0,68\n"
- "1: slr %1,%1\n"
- " cs %1,%0,0(%3)\n"
- " jl 0b\n"
- : "=&d" (reg1), "=&d" (reg2), "=m" (lp->lock)
- : "a" (&lp->lock), "m" (lp->lock)
- : "cc", "memory" );
-#else /* __s390x__ */
- unsigned long reg1, reg2;
- __asm__ __volatile__(" bras %1,1f\n"
- "0: " __DIAG44_INSN " 0,%4\n"
- "1: slr %0,%0\n"
- " cs %0,%1,0(%3)\n"
- " jl 0b\n"
- : "=&d" (reg1), "=&d" (reg2), "=m" (lp->lock)
- : "a" (&lp->lock), "i" (__DIAG44_OPERAND),
- "m" (lp->lock) : "cc", "memory" );
-#endif /* __s390x__ */
+ unsigned long pc = (unsigned long) __builtin_return_address(0);
+
+ if (unlikely(_raw_compare_and_swap(&lp->lock, 0, pc) != 0))
+ _raw_spin_lock_wait(lp, pc);
}
-extern inline int _raw_spin_trylock(spinlock_t *lp)
+static inline int _raw_spin_trylock(spinlock_t *lp)
{
- unsigned long reg;
- unsigned int result;
-
- __asm__ __volatile__(" basr %1,0\n"
- "0: cs %0,%1,0(%3)"
- : "=d" (result), "=&d" (reg), "=m" (lp->lock)
- : "a" (&lp->lock), "m" (lp->lock), "0" (0)
- : "cc", "memory" );
- return !result;
+ unsigned long pc = (unsigned long) __builtin_return_address(0);
+
+ if (likely(_raw_compare_and_swap(&lp->lock, 0, pc) == 0))
+ return 1;
+ return _raw_spin_trylock_retry(lp, pc);
}
-extern inline void _raw_spin_unlock(spinlock_t *lp)
+static inline void _raw_spin_unlock(spinlock_t *lp)
{
- unsigned int old;
-
- __asm__ __volatile__("cs %0,%3,0(%4)"
- : "=d" (old), "=m" (lp->lock)
- : "0" (lp->lock), "d" (0), "a" (lp)
- : "cc", "memory" );
+ _raw_compare_and_swap(&lp->lock, lp->lock, 0);
}
/*
* read-locks.
*/
typedef struct {
- volatile unsigned long lock;
+ volatile unsigned int lock;
volatile unsigned long owner_pc;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
*/
#define write_can_lock(x) ((x)->lock == 0)
-#ifndef __s390x__
-#define _raw_read_lock(rw) \
- asm volatile(" l 2,0(%1)\n" \
- " j 1f\n" \
- "0: diag 0,0,68\n" \
- "1: la 2,0(2)\n" /* clear high (=write) bit */ \
- " la 3,1(2)\n" /* one more reader */ \
- " cs 2,3,0(%1)\n" /* try to write new value */ \
- " jl 0b" \
- : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#else /* __s390x__ */
-#define _raw_read_lock(rw) \
- asm volatile(" lg 2,0(%1)\n" \
- " j 1f\n" \
- "0: " __DIAG44_INSN " 0,%2\n" \
- "1: nihh 2,0x7fff\n" /* clear high (=write) bit */ \
- " la 3,1(2)\n" /* one more reader */ \
- " csg 2,3,0(%1)\n" /* try to write new value */ \
- " jl 0b" \
- : "=m" ((rw)->lock) \
- : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#endif /* __s390x__ */
-
-#ifndef __s390x__
-#define _raw_read_unlock(rw) \
- asm volatile(" l 2,0(%1)\n" \
- " j 1f\n" \
- "0: diag 0,0,68\n" \
- "1: lr 3,2\n" \
- " ahi 3,-1\n" /* one less reader */ \
- " cs 2,3,0(%1)\n" \
- " jl 0b" \
- : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#else /* __s390x__ */
-#define _raw_read_unlock(rw) \
- asm volatile(" lg 2,0(%1)\n" \
- " j 1f\n" \
- "0: " __DIAG44_INSN " 0,%2\n" \
- "1: lgr 3,2\n" \
- " bctgr 3,0\n" /* one less reader */ \
- " csg 2,3,0(%1)\n" \
- " jl 0b" \
- : "=m" ((rw)->lock) \
- : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#endif /* __s390x__ */
-
-#ifndef __s390x__
-#define _raw_write_lock(rw) \
- asm volatile(" lhi 3,1\n" \
- " sll 3,31\n" /* new lock value = 0x80000000 */ \
- " j 1f\n" \
- "0: diag 0,0,68\n" \
- "1: slr 2,2\n" /* old lock value must be 0 */ \
- " cs 2,3,0(%1)\n" \
- " jl 0b" \
- : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#else /* __s390x__ */
-#define _raw_write_lock(rw) \
- asm volatile(" llihh 3,0x8000\n" /* new lock value = 0x80...0 */ \
- " j 1f\n" \
- "0: " __DIAG44_INSN " 0,%2\n" \
- "1: slgr 2,2\n" /* old lock value must be 0 */ \
- " csg 2,3,0(%1)\n" \
- " jl 0b" \
- : "=m" ((rw)->lock) \
- : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#endif /* __s390x__ */
-
-#ifndef __s390x__
-#define _raw_write_unlock(rw) \
- asm volatile(" slr 3,3\n" /* new lock value = 0 */ \
- " j 1f\n" \
- "0: diag 0,0,68\n" \
- "1: lhi 2,1\n" \
- " sll 2,31\n" /* old lock value must be 0x80000000 */ \
- " cs 2,3,0(%1)\n" \
- " jl 0b" \
- : "=m" ((rw)->lock) : "a" (&(rw)->lock), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#else /* __s390x__ */
-#define _raw_write_unlock(rw) \
- asm volatile(" slgr 3,3\n" /* new lock value = 0 */ \
- " j 1f\n" \
- "0: " __DIAG44_INSN " 0,%2\n" \
- "1: llihh 2,0x8000\n" /* old lock value must be 0x8..0 */\
- " csg 2,3,0(%1)\n" \
- " jl 0b" \
- : "=m" ((rw)->lock) \
- : "a" (&(rw)->lock), "i" (__DIAG44_OPERAND), \
- "m" ((rw)->lock) : "2", "3", "cc", "memory" )
-#endif /* __s390x__ */
-
-#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
-
-extern inline int _raw_write_trylock(rwlock_t *rw)
+extern void _raw_read_lock_wait(rwlock_t *lp);
+extern int _raw_read_trylock_retry(rwlock_t *lp);
+extern void _raw_write_lock_wait(rwlock_t *lp);
+extern int _raw_write_trylock_retry(rwlock_t *lp);
+
+static inline void _raw_read_lock(rwlock_t *rw)
+{
+ unsigned int old;
+ old = rw->lock & 0x7fffffffU;
+ if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old)
+ _raw_read_lock_wait(rw);
+}
+
+static inline void _raw_read_unlock(rwlock_t *rw)
+{
+ unsigned int old, cmp;
+
+ old = rw->lock;
+ do {
+ cmp = old;
+ old = _raw_compare_and_swap(&rw->lock, old, old - 1);
+ } while (cmp != old);
+}
+
+static inline void _raw_write_lock(rwlock_t *rw)
+{
+ if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
+ _raw_write_lock_wait(rw);
+}
+
+static inline void _raw_write_unlock(rwlock_t *rw)
+{
+ _raw_compare_and_swap(&rw->lock, 0x80000000, 0);
+}
+
+static inline int _raw_read_trylock(rwlock_t *rw)
+{
+ unsigned int old;
+ old = rw->lock & 0x7fffffffU;
+ if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1) == old))
+ return 1;
+ return _raw_read_trylock_retry(rw);
+}
+
+static inline int _raw_write_trylock(rwlock_t *rw)
{
- unsigned long result, reg;
-
- __asm__ __volatile__(
-#ifndef __s390x__
- " lhi %1,1\n"
- " sll %1,31\n"
- " cs %0,%1,0(%3)"
-#else /* __s390x__ */
- " llihh %1,0x8000\n"
- "0: csg %0,%1,0(%3)\n"
-#endif /* __s390x__ */
- : "=d" (result), "=&d" (reg), "=m" (rw->lock)
- : "a" (&rw->lock), "m" (rw->lock), "0" (0UL)
- : "cc", "memory" );
- return result == 0;
+ if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))
+ return 1;
+ return _raw_write_trylock_retry(rw);
}
#endif /* __ASM_SPINLOCK_H */
projects / linux-flexiantxendom0-natty.git / commitdiff