linux/kernel/spinlock.c

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/*
* Copyright (2004) Linus Torvalds
*
* Author: Zwane Mwaikambo <zwane@fsmlabs.com>
*
[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 07:25:56 +00:00
* Copyright (2004, 2005) Ingo Molnar
*
* This file contains the spinlock/rwlock implementations for the
* SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
*
* Note that some architectures have special knowledge about the
* stack frames of these functions in their profile_pc. If you
* change anything significant here that could change the stack
* frame contact the architecture maintainers.
*/
#include <linux/linkage.h>
#include <linux/preempt.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include <linux/export.h>
/*
* If lockdep is enabled then we use the non-preemption spin-ops
* even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
* not re-enabled during lock-acquire (which the preempt-spin-ops do):
*/
#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
/*
* The __lock_function inlines are taken from
* include/linux/spinlock_api_smp.h
*/
#else
#define raw_read_can_lock(l) read_can_lock(l)
#define raw_write_can_lock(l) write_can_lock(l)
/*
* We build the __lock_function inlines here. They are too large for
* inlining all over the place, but here is only one user per function
* which embedds them into the calling _lock_function below.
*
* This could be a long-held lock. We both prepare to spin for a long
* time (making _this_ CPU preemptable if possible), and we also signal
* towards that other CPU that it should break the lock ASAP.
*/
#define BUILD_LOCK_OPS(op, locktype) \
void __lockfunc __raw_##op##_lock(locktype##_t *lock) \
{ \
for (;;) { \
preempt_disable(); \
if (likely(do_raw_##op##_trylock(lock))) \
break; \
preempt_enable(); \
\
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
arch_##op##_relax(&lock->raw_lock); \
} \
(lock)->break_lock = 0; \
} \
\
unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \
{ \
unsigned long flags; \
\
for (;;) { \
preempt_disable(); \
local_irq_save(flags); \
if (likely(do_raw_##op##_trylock(lock))) \
break; \
local_irq_restore(flags); \
preempt_enable(); \
\
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
arch_##op##_relax(&lock->raw_lock); \
} \
(lock)->break_lock = 0; \
return flags; \
} \
\
void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock) \
{ \
_raw_##op##_lock_irqsave(lock); \
} \
\
void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock) \
{ \
unsigned long flags; \
\
/* */ \
/* Careful: we must exclude softirqs too, hence the */ \
/* irq-disabling. We use the generic preemption-aware */ \
/* function: */ \
/**/ \
flags = _raw_##op##_lock_irqsave(lock); \
local_bh_disable(); \
local_irq_restore(flags); \
} \
/*
* Build preemption-friendly versions of the following
* lock-spinning functions:
*
* __[spin|read|write]_lock()
* __[spin|read|write]_lock_irq()
* __[spin|read|write]_lock_irqsave()
* __[spin|read|write]_lock_bh()
*/
BUILD_LOCK_OPS(spin, raw_spinlock);
BUILD_LOCK_OPS(read, rwlock);
BUILD_LOCK_OPS(write, rwlock);
#endif
#ifndef CONFIG_INLINE_SPIN_TRYLOCK
int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
{
return __raw_spin_trylock(lock);
}
EXPORT_SYMBOL(_raw_spin_trylock);
#endif
#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
{
return __raw_spin_trylock_bh(lock);
}
EXPORT_SYMBOL(_raw_spin_trylock_bh);
#endif
#ifndef CONFIG_INLINE_SPIN_LOCK
void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
{
__raw_spin_lock(lock);
}
EXPORT_SYMBOL(_raw_spin_lock);
#endif
#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
{
return __raw_spin_lock_irqsave(lock);
}
EXPORT_SYMBOL(_raw_spin_lock_irqsave);
#endif
#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
{
__raw_spin_lock_irq(lock);
}
EXPORT_SYMBOL(_raw_spin_lock_irq);
#endif
#ifndef CONFIG_INLINE_SPIN_LOCK_BH
void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
{
__raw_spin_lock_bh(lock);
}
EXPORT_SYMBOL(_raw_spin_lock_bh);
#endif
#ifndef CONFIG_INLINE_SPIN_UNLOCK
void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
{
__raw_spin_unlock(lock);
}
EXPORT_SYMBOL(_raw_spin_unlock);
#endif
#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
{
__raw_spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
#endif
#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
{
__raw_spin_unlock_irq(lock);
}
EXPORT_SYMBOL(_raw_spin_unlock_irq);
#endif
#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
{
__raw_spin_unlock_bh(lock);
}
EXPORT_SYMBOL(_raw_spin_unlock_bh);
#endif
#ifndef CONFIG_INLINE_READ_TRYLOCK
int __lockfunc _raw_read_trylock(rwlock_t *lock)
{
return __raw_read_trylock(lock);
}
EXPORT_SYMBOL(_raw_read_trylock);
#endif
#ifndef CONFIG_INLINE_READ_LOCK
void __lockfunc _raw_read_lock(rwlock_t *lock)
{
__raw_read_lock(lock);
}
EXPORT_SYMBOL(_raw_read_lock);
#endif
#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
{
return __raw_read_lock_irqsave(lock);
}
EXPORT_SYMBOL(_raw_read_lock_irqsave);
#endif
#ifndef CONFIG_INLINE_READ_LOCK_IRQ
void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
{
__raw_read_lock_irq(lock);
}
EXPORT_SYMBOL(_raw_read_lock_irq);
#endif
#ifndef CONFIG_INLINE_READ_LOCK_BH
void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
{
__raw_read_lock_bh(lock);
}
EXPORT_SYMBOL(_raw_read_lock_bh);
#endif
#ifndef CONFIG_INLINE_READ_UNLOCK
void __lockfunc _raw_read_unlock(rwlock_t *lock)
{
__raw_read_unlock(lock);
}
EXPORT_SYMBOL(_raw_read_unlock);
#endif
#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
__raw_read_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
#endif
#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
{
__raw_read_unlock_irq(lock);
}
EXPORT_SYMBOL(_raw_read_unlock_irq);
#endif
#ifndef CONFIG_INLINE_READ_UNLOCK_BH
void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
{
__raw_read_unlock_bh(lock);
}
EXPORT_SYMBOL(_raw_read_unlock_bh);
#endif
#ifndef CONFIG_INLINE_WRITE_TRYLOCK
int __lockfunc _raw_write_trylock(rwlock_t *lock)
{
return __raw_write_trylock(lock);
}
EXPORT_SYMBOL(_raw_write_trylock);
#endif
#ifndef CONFIG_INLINE_WRITE_LOCK
void __lockfunc _raw_write_lock(rwlock_t *lock)
{
__raw_write_lock(lock);
}
EXPORT_SYMBOL(_raw_write_lock);
#endif
#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
{
return __raw_write_lock_irqsave(lock);
}
EXPORT_SYMBOL(_raw_write_lock_irqsave);
#endif
#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
{
__raw_write_lock_irq(lock);
}
EXPORT_SYMBOL(_raw_write_lock_irq);
#endif
#ifndef CONFIG_INLINE_WRITE_LOCK_BH
void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
{
__raw_write_lock_bh(lock);
}
EXPORT_SYMBOL(_raw_write_lock_bh);
#endif
#ifndef CONFIG_INLINE_WRITE_UNLOCK
void __lockfunc _raw_write_unlock(rwlock_t *lock)
{
__raw_write_unlock(lock);
}
EXPORT_SYMBOL(_raw_write_unlock);
#endif
#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
__raw_write_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
#endif
#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
{
__raw_write_unlock_irq(lock);
}
EXPORT_SYMBOL(_raw_write_unlock_irq);
#endif
#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
{
__raw_write_unlock_bh(lock);
}
EXPORT_SYMBOL(_raw_write_unlock_bh);
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
{
preempt_disable();
spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
}
EXPORT_SYMBOL(_raw_spin_lock_nested);
unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
int subclass)
{
unsigned long flags;
local_irq_save(flags);
preempt_disable();
spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,
do_raw_spin_lock_flags, &flags);
return flags;
}
EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
struct lockdep_map *nest_lock)
{
preempt_disable();
spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
}
EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
#endif
notrace int in_lock_functions(unsigned long addr)
{
/* Linker adds these: start and end of __lockfunc functions */
extern char __lock_text_start[], __lock_text_end[];
return addr >= (unsigned long)__lock_text_start
&& addr < (unsigned long)__lock_text_end;
}
EXPORT_SYMBOL(in_lock_functions);