kernel-ark/include/asm-ppc64/spinlock.h
Ingo Molnar fb1c8f93d8 [PATCH] spinlock consolidation
This patch (written by me and also containing many suggestions of Arjan van
de Ven) does a major cleanup of the spinlock code.  It does the following
things:

 - consolidates and enhances the spinlock/rwlock debugging code

 - simplifies the asm/spinlock.h files

 - encapsulates the raw spinlock type and moves generic spinlock
   features (such as ->break_lock) into the generic code.

 - cleans up the spinlock code hierarchy to get rid of the spaghetti.

Most notably there's now only a single variant of the debugging code,
located in lib/spinlock_debug.c.  (previously we had one SMP debugging
variant per architecture, plus a separate generic one for UP builds)

Also, i've enhanced the rwlock debugging facility, it will now track
write-owners.  There is new spinlock-owner/CPU-tracking on SMP builds too.
All locks have lockup detection now, which will work for both soft and hard
spin/rwlock lockups.

The arch-level include files now only contain the minimally necessary
subset of the spinlock code - all the rest that can be generalized now
lives in the generic headers:

 include/asm-i386/spinlock_types.h       |   16
 include/asm-x86_64/spinlock_types.h     |   16

I have also split up the various spinlock variants into separate files,
making it easier to see which does what. The new layout is:

   SMP                         |  UP
   ----------------------------|-----------------------------------
   asm/spinlock_types_smp.h    |  linux/spinlock_types_up.h
   linux/spinlock_types.h      |  linux/spinlock_types.h
   asm/spinlock_smp.h          |  linux/spinlock_up.h
   linux/spinlock_api_smp.h    |  linux/spinlock_api_up.h
   linux/spinlock.h            |  linux/spinlock.h

/*
 * here's the role of the various spinlock/rwlock related include files:
 *
 * on SMP builds:
 *
 *  asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
 *                        initializers
 *
 *  linux/spinlock_types.h:
 *                        defines the generic type and initializers
 *
 *  asm/spinlock.h:       contains the __raw_spin_*()/etc. lowlevel
 *                        implementations, mostly inline assembly code
 *
 *   (also included on UP-debug builds:)
 *
 *  linux/spinlock_api_smp.h:
 *                        contains the prototypes for the _spin_*() APIs.
 *
 *  linux/spinlock.h:     builds the final spin_*() APIs.
 *
 * on UP builds:
 *
 *  linux/spinlock_type_up.h:
 *                        contains the generic, simplified UP spinlock type.
 *                        (which is an empty structure on non-debug builds)
 *
 *  linux/spinlock_types.h:
 *                        defines the generic type and initializers
 *
 *  linux/spinlock_up.h:
 *                        contains the __raw_spin_*()/etc. version of UP
 *                        builds. (which are NOPs on non-debug, non-preempt
 *                        builds)
 *
 *   (included on UP-non-debug builds:)
 *
 *  linux/spinlock_api_up.h:
 *                        builds the _spin_*() APIs.
 *
 *  linux/spinlock.h:     builds the final spin_*() APIs.
 */

All SMP and UP architectures are converted by this patch.

arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via
crosscompilers.  m32r, mips, sh, sparc, have not been tested yet, but should
be mostly fine.

From: Grant Grundler <grundler@parisc-linux.org>

  Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU).
  Builds 32-bit SMP kernel (not booted or tested).  I did not try to build
  non-SMP kernels.  That should be trivial to fix up later if necessary.

  I converted bit ops atomic_hash lock to raw_spinlock_t.  Doing so avoids
  some ugly nesting of linux/*.h and asm/*.h files.  Those particular locks
  are well tested and contained entirely inside arch specific code.  I do NOT
  expect any new issues to arise with them.

 If someone does ever need to use debug/metrics with them, then they will
  need to unravel this hairball between spinlocks, atomic ops, and bit ops
  that exist only because parisc has exactly one atomic instruction: LDCW
  (load and clear word).

From: "Luck, Tony" <tony.luck@intel.com>

   ia64 fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjanv@infradead.org>
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Cc: Matthew Wilcox <willy@debian.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se>
Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 10:06:21 -07:00

242 lines
5.6 KiB
C

#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H
/*
* Simple spin lock operations.
*
* Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM
* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
* Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM
* Rework to support virtual processors
*
* Type of int is used as a full 64b word is not necessary.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* (the type definitions are in asm/spinlock_types.h)
*/
#include <linux/config.h>
#include <asm/paca.h>
#include <asm/hvcall.h>
#include <asm/iSeries/HvCall.h>
#define __raw_spin_is_locked(x) ((x)->slock != 0)
/*
* This returns the old value in the lock, so we succeeded
* in getting the lock if the return value is 0.
*/
static __inline__ unsigned long __spin_trylock(raw_spinlock_t *lock)
{
unsigned long tmp, tmp2;
__asm__ __volatile__(
" lwz %1,%3(13) # __spin_trylock\n\
1: lwarx %0,0,%2\n\
cmpwi 0,%0,0\n\
bne- 2f\n\
stwcx. %1,0,%2\n\
bne- 1b\n\
isync\n\
2:" : "=&r" (tmp), "=&r" (tmp2)
: "r" (&lock->slock), "i" (offsetof(struct paca_struct, lock_token))
: "cr0", "memory");
return tmp;
}
static int __inline__ __raw_spin_trylock(raw_spinlock_t *lock)
{
return __spin_trylock(lock) == 0;
}
/*
* On a system with shared processors (that is, where a physical
* processor is multiplexed between several virtual processors),
* there is no point spinning on a lock if the holder of the lock
* isn't currently scheduled on a physical processor. Instead
* we detect this situation and ask the hypervisor to give the
* rest of our timeslice to the lock holder.
*
* So that we can tell which virtual processor is holding a lock,
* we put 0x80000000 | smp_processor_id() in the lock when it is
* held. Conveniently, we have a word in the paca that holds this
* value.
*/
#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
/* We only yield to the hypervisor if we are in shared processor mode */
#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc)
extern void __spin_yield(raw_spinlock_t *lock);
extern void __rw_yield(raw_rwlock_t *lock);
#else /* SPLPAR || ISERIES */
#define __spin_yield(x) barrier()
#define __rw_yield(x) barrier()
#define SHARED_PROCESSOR 0
#endif
static void __inline__ __raw_spin_lock(raw_spinlock_t *lock)
{
while (1) {
if (likely(__spin_trylock(lock) == 0))
break;
do {
HMT_low();
if (SHARED_PROCESSOR)
__spin_yield(lock);
} while (unlikely(lock->slock != 0));
HMT_medium();
}
}
static void __inline__ __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
{
unsigned long flags_dis;
while (1) {
if (likely(__spin_trylock(lock) == 0))
break;
local_save_flags(flags_dis);
local_irq_restore(flags);
do {
HMT_low();
if (SHARED_PROCESSOR)
__spin_yield(lock);
} while (unlikely(lock->slock != 0));
HMT_medium();
local_irq_restore(flags_dis);
}
}
static __inline__ void __raw_spin_unlock(raw_spinlock_t *lock)
{
__asm__ __volatile__("lwsync # __raw_spin_unlock": : :"memory");
lock->slock = 0;
}
extern void __raw_spin_unlock_wait(raw_spinlock_t *lock);
/*
* 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.
*/
#define __raw_read_can_lock(rw) ((rw)->lock >= 0)
#define __raw_write_can_lock(rw) (!(rw)->lock)
/*
* This returns the old value in the lock + 1,
* so we got a read lock if the return value is > 0.
*/
static long __inline__ __read_trylock(raw_rwlock_t *rw)
{
long tmp;
__asm__ __volatile__(
"1: lwarx %0,0,%1 # read_trylock\n\
extsw %0,%0\n\
addic. %0,%0,1\n\
ble- 2f\n\
stwcx. %0,0,%1\n\
bne- 1b\n\
isync\n\
2:" : "=&r" (tmp)
: "r" (&rw->lock)
: "cr0", "xer", "memory");
return tmp;
}
/*
* This returns the old value in the lock,
* so we got the write lock if the return value is 0.
*/
static __inline__ long __write_trylock(raw_rwlock_t *rw)
{
long tmp, tmp2;
__asm__ __volatile__(
" lwz %1,%3(13) # write_trylock\n\
1: lwarx %0,0,%2\n\
cmpwi 0,%0,0\n\
bne- 2f\n\
stwcx. %1,0,%2\n\
bne- 1b\n\
isync\n\
2:" : "=&r" (tmp), "=&r" (tmp2)
: "r" (&rw->lock), "i" (offsetof(struct paca_struct, lock_token))
: "cr0", "memory");
return tmp;
}
static void __inline__ __raw_read_lock(raw_rwlock_t *rw)
{
while (1) {
if (likely(__read_trylock(rw) > 0))
break;
do {
HMT_low();
if (SHARED_PROCESSOR)
__rw_yield(rw);
} while (unlikely(rw->lock < 0));
HMT_medium();
}
}
static void __inline__ __raw_write_lock(raw_rwlock_t *rw)
{
while (1) {
if (likely(__write_trylock(rw) == 0))
break;
do {
HMT_low();
if (SHARED_PROCESSOR)
__rw_yield(rw);
} while (unlikely(rw->lock != 0));
HMT_medium();
}
}
static int __inline__ __raw_read_trylock(raw_rwlock_t *rw)
{
return __read_trylock(rw) > 0;
}
static int __inline__ __raw_write_trylock(raw_rwlock_t *rw)
{
return __write_trylock(rw) == 0;
}
static void __inline__ __raw_read_unlock(raw_rwlock_t *rw)
{
long tmp;
__asm__ __volatile__(
"eieio # read_unlock\n\
1: lwarx %0,0,%1\n\
addic %0,%0,-1\n\
stwcx. %0,0,%1\n\
bne- 1b"
: "=&r"(tmp)
: "r"(&rw->lock)
: "cr0", "memory");
}
static __inline__ void __raw_write_unlock(raw_rwlock_t *rw)
{
__asm__ __volatile__("lwsync # write_unlock": : :"memory");
rw->lock = 0;
}
#endif /* __ASM_SPINLOCK_H */