mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-29 13:00:35 +00:00
aac72277fd
All architecture specific rwsem headers carry the same function prototypes. Just x86 adds asmregparm, which is an empty define on all other architectures. S390 has a stale rwsem_downgrade_write() prototype. Remove the duplicates and add the prototypes to linux/rwsem.h Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Acked-by: Tony Luck <tony.luck@intel.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: David Miller <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> LKML-Reference: <20110126195833.970840140@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
324 lines
7.0 KiB
C
324 lines
7.0 KiB
C
#ifndef _S390_RWSEM_H
|
|
#define _S390_RWSEM_H
|
|
|
|
/*
|
|
* include/asm-s390/rwsem.h
|
|
*
|
|
* S390 version
|
|
* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
|
|
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
|
|
*
|
|
* Based on asm-alpha/semaphore.h and asm-i386/rwsem.h
|
|
*/
|
|
|
|
/*
|
|
*
|
|
* The MSW of the count is the negated number of active writers and waiting
|
|
* lockers, and the LSW is the total number of active locks
|
|
*
|
|
* The lock count is initialized to 0 (no active and no waiting lockers).
|
|
*
|
|
* When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an
|
|
* uncontended lock. This can be determined because XADD returns the old value.
|
|
* Readers increment by 1 and see a positive value when uncontended, negative
|
|
* if there are writers (and maybe) readers waiting (in which case it goes to
|
|
* sleep).
|
|
*
|
|
* The value of WAITING_BIAS supports up to 32766 waiting processes. This can
|
|
* be extended to 65534 by manually checking the whole MSW rather than relying
|
|
* on the S flag.
|
|
*
|
|
* The value of ACTIVE_BIAS supports up to 65535 active processes.
|
|
*
|
|
* This should be totally fair - if anything is waiting, a process that wants a
|
|
* lock will go to the back of the queue. When the currently active lock is
|
|
* released, if there's a writer at the front of the queue, then that and only
|
|
* that will be woken up; if there's a bunch of consequtive readers at the
|
|
* front, then they'll all be woken up, but no other readers will be.
|
|
*/
|
|
|
|
#ifndef _LINUX_RWSEM_H
|
|
#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
|
|
#endif
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#ifndef __s390x__
|
|
#define RWSEM_UNLOCKED_VALUE 0x00000000
|
|
#define RWSEM_ACTIVE_BIAS 0x00000001
|
|
#define RWSEM_ACTIVE_MASK 0x0000ffff
|
|
#define RWSEM_WAITING_BIAS (-0x00010000)
|
|
#else /* __s390x__ */
|
|
#define RWSEM_UNLOCKED_VALUE 0x0000000000000000L
|
|
#define RWSEM_ACTIVE_BIAS 0x0000000000000001L
|
|
#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL
|
|
#define RWSEM_WAITING_BIAS (-0x0000000100000000L)
|
|
#endif /* __s390x__ */
|
|
#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
|
|
#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
|
|
|
|
/*
|
|
* lock for reading
|
|
*/
|
|
static inline void __down_read(struct rw_semaphore *sem)
|
|
{
|
|
signed long old, new;
|
|
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: lr %1,%0\n"
|
|
" ahi %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: lgr %1,%0\n"
|
|
" aghi %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "i" (RWSEM_ACTIVE_READ_BIAS)
|
|
: "cc", "memory");
|
|
if (old < 0)
|
|
rwsem_down_read_failed(sem);
|
|
}
|
|
|
|
/*
|
|
* trylock for reading -- returns 1 if successful, 0 if contention
|
|
*/
|
|
static inline int __down_read_trylock(struct rw_semaphore *sem)
|
|
{
|
|
signed long old, new;
|
|
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: ltr %1,%0\n"
|
|
" jm 1f\n"
|
|
" ahi %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b\n"
|
|
"1:"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: ltgr %1,%0\n"
|
|
" jm 1f\n"
|
|
" aghi %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b\n"
|
|
"1:"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "i" (RWSEM_ACTIVE_READ_BIAS)
|
|
: "cc", "memory");
|
|
return old >= 0 ? 1 : 0;
|
|
}
|
|
|
|
/*
|
|
* lock for writing
|
|
*/
|
|
static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
|
|
{
|
|
signed long old, new, tmp;
|
|
|
|
tmp = RWSEM_ACTIVE_WRITE_BIAS;
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: lr %1,%0\n"
|
|
" a %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: lgr %1,%0\n"
|
|
" ag %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "m" (tmp)
|
|
: "cc", "memory");
|
|
if (old != 0)
|
|
rwsem_down_write_failed(sem);
|
|
}
|
|
|
|
static inline void __down_write(struct rw_semaphore *sem)
|
|
{
|
|
__down_write_nested(sem, 0);
|
|
}
|
|
|
|
/*
|
|
* trylock for writing -- returns 1 if successful, 0 if contention
|
|
*/
|
|
static inline int __down_write_trylock(struct rw_semaphore *sem)
|
|
{
|
|
signed long old;
|
|
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%1\n"
|
|
"0: ltr %0,%0\n"
|
|
" jnz 1f\n"
|
|
" cs %0,%3,%1\n"
|
|
" jl 0b\n"
|
|
#else /* __s390x__ */
|
|
" lg %0,%1\n"
|
|
"0: ltgr %0,%0\n"
|
|
" jnz 1f\n"
|
|
" csg %0,%3,%1\n"
|
|
" jl 0b\n"
|
|
#endif /* __s390x__ */
|
|
"1:"
|
|
: "=&d" (old), "=Q" (sem->count)
|
|
: "Q" (sem->count), "d" (RWSEM_ACTIVE_WRITE_BIAS)
|
|
: "cc", "memory");
|
|
return (old == RWSEM_UNLOCKED_VALUE) ? 1 : 0;
|
|
}
|
|
|
|
/*
|
|
* unlock after reading
|
|
*/
|
|
static inline void __up_read(struct rw_semaphore *sem)
|
|
{
|
|
signed long old, new;
|
|
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: lr %1,%0\n"
|
|
" ahi %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: lgr %1,%0\n"
|
|
" aghi %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "i" (-RWSEM_ACTIVE_READ_BIAS)
|
|
: "cc", "memory");
|
|
if (new < 0)
|
|
if ((new & RWSEM_ACTIVE_MASK) == 0)
|
|
rwsem_wake(sem);
|
|
}
|
|
|
|
/*
|
|
* unlock after writing
|
|
*/
|
|
static inline void __up_write(struct rw_semaphore *sem)
|
|
{
|
|
signed long old, new, tmp;
|
|
|
|
tmp = -RWSEM_ACTIVE_WRITE_BIAS;
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: lr %1,%0\n"
|
|
" a %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: lgr %1,%0\n"
|
|
" ag %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "m" (tmp)
|
|
: "cc", "memory");
|
|
if (new < 0)
|
|
if ((new & RWSEM_ACTIVE_MASK) == 0)
|
|
rwsem_wake(sem);
|
|
}
|
|
|
|
/*
|
|
* downgrade write lock to read lock
|
|
*/
|
|
static inline void __downgrade_write(struct rw_semaphore *sem)
|
|
{
|
|
signed long old, new, tmp;
|
|
|
|
tmp = -RWSEM_WAITING_BIAS;
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: lr %1,%0\n"
|
|
" a %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: lgr %1,%0\n"
|
|
" ag %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "m" (tmp)
|
|
: "cc", "memory");
|
|
if (new > 1)
|
|
rwsem_downgrade_wake(sem);
|
|
}
|
|
|
|
/*
|
|
* implement atomic add functionality
|
|
*/
|
|
static inline void rwsem_atomic_add(long delta, struct rw_semaphore *sem)
|
|
{
|
|
signed long old, new;
|
|
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: lr %1,%0\n"
|
|
" ar %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: lgr %1,%0\n"
|
|
" agr %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "d" (delta)
|
|
: "cc", "memory");
|
|
}
|
|
|
|
/*
|
|
* implement exchange and add functionality
|
|
*/
|
|
static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem)
|
|
{
|
|
signed long old, new;
|
|
|
|
asm volatile(
|
|
#ifndef __s390x__
|
|
" l %0,%2\n"
|
|
"0: lr %1,%0\n"
|
|
" ar %1,%4\n"
|
|
" cs %0,%1,%2\n"
|
|
" jl 0b"
|
|
#else /* __s390x__ */
|
|
" lg %0,%2\n"
|
|
"0: lgr %1,%0\n"
|
|
" agr %1,%4\n"
|
|
" csg %0,%1,%2\n"
|
|
" jl 0b"
|
|
#endif /* __s390x__ */
|
|
: "=&d" (old), "=&d" (new), "=Q" (sem->count)
|
|
: "Q" (sem->count), "d" (delta)
|
|
: "cc", "memory");
|
|
return new;
|
|
}
|
|
|
|
#endif /* __KERNEL__ */
|
|
#endif /* _S390_RWSEM_H */
|