mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-06 02:50:43 +00:00
![Paul Mundt](/assets/img/avatar_default.png)
This rips out some of the old spinlock and rwlock behaviour that the SH-2 parts were using and reworks them for LL/SC semantics on the SH-4A. This is primarily only useful for SH-X3 multi-cores, but can also be used for building CONFIG_SMP=y testing kernels on SH-4A UP. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
223 lines
4.8 KiB
C
223 lines
4.8 KiB
C
/*
|
|
* include/asm-sh/spinlock.h
|
|
*
|
|
* Copyright (C) 2002, 2003 Paul Mundt
|
|
* Copyright (C) 2006, 2007 Akio Idehara
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*/
|
|
#ifndef __ASM_SH_SPINLOCK_H
|
|
#define __ASM_SH_SPINLOCK_H
|
|
|
|
/*
|
|
* The only locking implemented here uses SH-4A opcodes. For others,
|
|
* split this out as per atomic-*.h.
|
|
*/
|
|
#ifndef CONFIG_CPU_SH4A
|
|
#error "Need movli.l/movco.l for spinlocks"
|
|
#endif
|
|
|
|
/*
|
|
* Your basic SMP spinlocks, allowing only a single CPU anywhere
|
|
*/
|
|
|
|
#define __raw_spin_is_locked(x) ((x)->lock <= 0)
|
|
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
|
|
#define __raw_spin_unlock_wait(x) \
|
|
do { cpu_relax(); } while ((x)->lock)
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
static inline void __raw_spin_lock(raw_spinlock_t *lock)
|
|
{
|
|
unsigned long tmp;
|
|
unsigned long oldval;
|
|
|
|
__asm__ __volatile__ (
|
|
"1: \n\t"
|
|
"movli.l @%2, %0 ! __raw_spin_lock \n\t"
|
|
"mov %0, %1 \n\t"
|
|
"mov #0, %0 \n\t"
|
|
"movco.l %0, @%2 \n\t"
|
|
"bf 1b \n\t"
|
|
"cmp/pl %1 \n\t"
|
|
"bf 1b \n\t"
|
|
: "=&z" (tmp), "=&r" (oldval)
|
|
: "r" (&lock->lock)
|
|
: "t", "memory"
|
|
);
|
|
}
|
|
|
|
static inline void __raw_spin_unlock(raw_spinlock_t *lock)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
__asm__ __volatile__ (
|
|
"mov #1, %0 ! __raw_spin_unlock \n\t"
|
|
"mov.l %0, @%1 \n\t"
|
|
: "=&z" (tmp)
|
|
: "r" (&lock->lock)
|
|
: "t", "memory"
|
|
);
|
|
}
|
|
|
|
static inline int __raw_spin_trylock(raw_spinlock_t *lock)
|
|
{
|
|
unsigned long tmp, oldval;
|
|
|
|
__asm__ __volatile__ (
|
|
"1: \n\t"
|
|
"movli.l @%2, %0 ! __raw_spin_trylock \n\t"
|
|
"mov %0, %1 \n\t"
|
|
"mov #0, %0 \n\t"
|
|
"movco.l %0, @%2 \n\t"
|
|
"bf 1b \n\t"
|
|
"synco \n\t"
|
|
: "=&z" (tmp), "=&r" (oldval)
|
|
: "r" (&lock->lock)
|
|
: "t", "memory"
|
|
);
|
|
|
|
return oldval;
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
/**
|
|
* read_can_lock - would read_trylock() succeed?
|
|
* @lock: the rwlock in question.
|
|
*/
|
|
#define __raw_read_can_lock(x) ((x)->lock > 0)
|
|
|
|
/**
|
|
* write_can_lock - would write_trylock() succeed?
|
|
* @lock: the rwlock in question.
|
|
*/
|
|
#define __raw_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
|
|
|
|
static inline void __raw_read_lock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
__asm__ __volatile__ (
|
|
"1: \n\t"
|
|
"movli.l @%1, %0 ! __raw_read_lock \n\t"
|
|
"cmp/pl %0 \n\t"
|
|
"bf 1b \n\t"
|
|
"add #-1, %0 \n\t"
|
|
"movco.l %0, @%1 \n\t"
|
|
"bf 1b \n\t"
|
|
: "=&z" (tmp)
|
|
: "r" (&rw->lock)
|
|
: "t", "memory"
|
|
);
|
|
}
|
|
|
|
static inline void __raw_read_unlock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
__asm__ __volatile__ (
|
|
"1: \n\t"
|
|
"movli.l @%1, %0 ! __raw_read_unlock \n\t"
|
|
"add #1, %0 \n\t"
|
|
"movco.l %0, @%1 \n\t"
|
|
"bf 1b \n\t"
|
|
: "=&z" (tmp)
|
|
: "r" (&rw->lock)
|
|
: "t", "memory"
|
|
);
|
|
}
|
|
|
|
static inline void __raw_write_lock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
__asm__ __volatile__ (
|
|
"1: \n\t"
|
|
"movli.l @%1, %0 ! __raw_write_lock \n\t"
|
|
"cmp/hs %2, %0 \n\t"
|
|
"bf 1b \n\t"
|
|
"sub %2, %0 \n\t"
|
|
"movco.l %0, @%1 \n\t"
|
|
"bf 1b \n\t"
|
|
: "=&z" (tmp)
|
|
: "r" (&rw->lock), "r" (RW_LOCK_BIAS)
|
|
: "t", "memory"
|
|
);
|
|
}
|
|
|
|
static inline void __raw_write_unlock(raw_rwlock_t *rw)
|
|
{
|
|
__asm__ __volatile__ (
|
|
"mov.l %1, @%0 ! __raw_write_unlock \n\t"
|
|
:
|
|
: "r" (&rw->lock), "r" (RW_LOCK_BIAS)
|
|
: "t", "memory"
|
|
);
|
|
}
|
|
|
|
static inline int __raw_read_trylock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned long tmp, oldval;
|
|
|
|
__asm__ __volatile__ (
|
|
"1: \n\t"
|
|
"movli.l @%2, %0 ! __raw_read_trylock \n\t"
|
|
"mov %0, %1 \n\t"
|
|
"cmp/pl %0 \n\t"
|
|
"bf 2f \n\t"
|
|
"add #-1, %0 \n\t"
|
|
"movco.l %0, @%2 \n\t"
|
|
"bf 1b \n\t"
|
|
"2: \n\t"
|
|
"synco \n\t"
|
|
: "=&z" (tmp), "=&r" (oldval)
|
|
: "r" (&rw->lock)
|
|
: "t", "memory"
|
|
);
|
|
|
|
return (oldval > 0);
|
|
}
|
|
|
|
static inline int __raw_write_trylock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned long tmp, oldval;
|
|
|
|
__asm__ __volatile__ (
|
|
"1: \n\t"
|
|
"movli.l @%2, %0 ! __raw_write_trylock \n\t"
|
|
"mov %0, %1 \n\t"
|
|
"cmp/hs %3, %0 \n\t"
|
|
"bf 2f \n\t"
|
|
"sub %3, %0 \n\t"
|
|
"2: \n\t"
|
|
"movco.l %0, @%2 \n\t"
|
|
"bf 1b \n\t"
|
|
"synco \n\t"
|
|
: "=&z" (tmp), "=&r" (oldval)
|
|
: "r" (&rw->lock), "r" (RW_LOCK_BIAS)
|
|
: "t", "memory"
|
|
);
|
|
|
|
return (oldval > (RW_LOCK_BIAS - 1));
|
|
}
|
|
|
|
#define _raw_spin_relax(lock) cpu_relax()
|
|
#define _raw_read_relax(lock) cpu_relax()
|
|
#define _raw_write_relax(lock) cpu_relax()
|
|
|
|
#endif /* __ASM_SH_SPINLOCK_H */
|