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/*
* include/asm-s390/spinlock.h
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* Derived from "include/asm-i386/spinlock.h"
*/
#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__ */
/*
* Simple spin lock operations. There are two variants, one clears IRQ's
* on the local processor, one does not.
*
* We make no fairness assumptions. They have a cost.
*/
typedef struct {
volatile unsigned int lock;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#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_unlock_wait(lp) do { barrier(); } while(((volatile spinlock_t *)(lp))->lock)
#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)
{
#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__ */
}
extern 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;
}
extern 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" );
}
/*
* Read-write spinlocks, allowing multiple readers
* but only one writer.
*
* NOTE! it is quite common to have readers in interrupts
* but no interrupt writers. For those circumstances we
* can "mix" irq-safe locks - any writer needs to get a
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*/
typedef struct {
volatile unsigned long lock;
volatile unsigned long owner_pc;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
/**
* read_can_lock - would read_trylock() succeed?
* @lock: the rwlock in question.
*/
#define read_can_lock(x) ((int)(x)->lock >= 0)
/**
* write_can_lock - would write_trylock() succeed?
* @lock: the rwlock in question.
*/
#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)
{
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;
}
#endif /* __ASM_SPINLOCK_H */
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