linux-hardened/kernel/spinlock.c
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

374 lines
7.9 KiB
C

/*
* Copyright (2004) Linus Torvalds
*
* Author: Zwane Mwaikambo <zwane@fsmlabs.com>
*
* Copyright (2004, 2005) Ingo Molnar
*
* This file contains the spinlock/rwlock implementations for the
* SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
*/
#include <linux/config.h>
#include <linux/linkage.h>
#include <linux/preempt.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/module.h>
/*
* Generic declaration of the raw read_trylock() function,
* architectures are supposed to optimize this:
*/
int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock)
{
__raw_read_lock(lock);
return 1;
}
EXPORT_SYMBOL(generic__raw_read_trylock);
int __lockfunc _spin_trylock(spinlock_t *lock)
{
preempt_disable();
if (_raw_spin_trylock(lock))
return 1;
preempt_enable();
return 0;
}
EXPORT_SYMBOL(_spin_trylock);
int __lockfunc _read_trylock(rwlock_t *lock)
{
preempt_disable();
if (_raw_read_trylock(lock))
return 1;
preempt_enable();
return 0;
}
EXPORT_SYMBOL(_read_trylock);
int __lockfunc _write_trylock(rwlock_t *lock)
{
preempt_disable();
if (_raw_write_trylock(lock))
return 1;
preempt_enable();
return 0;
}
EXPORT_SYMBOL(_write_trylock);
#if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
void __lockfunc _read_lock(rwlock_t *lock)
{
preempt_disable();
_raw_read_lock(lock);
}
EXPORT_SYMBOL(_read_lock);
unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
{
unsigned long flags;
local_irq_save(flags);
preempt_disable();
_raw_spin_lock_flags(lock, &flags);
return flags;
}
EXPORT_SYMBOL(_spin_lock_irqsave);
void __lockfunc _spin_lock_irq(spinlock_t *lock)
{
local_irq_disable();
preempt_disable();
_raw_spin_lock(lock);
}
EXPORT_SYMBOL(_spin_lock_irq);
void __lockfunc _spin_lock_bh(spinlock_t *lock)
{
local_bh_disable();
preempt_disable();
_raw_spin_lock(lock);
}
EXPORT_SYMBOL(_spin_lock_bh);
unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
{
unsigned long flags;
local_irq_save(flags);
preempt_disable();
_raw_read_lock(lock);
return flags;
}
EXPORT_SYMBOL(_read_lock_irqsave);
void __lockfunc _read_lock_irq(rwlock_t *lock)
{
local_irq_disable();
preempt_disable();
_raw_read_lock(lock);
}
EXPORT_SYMBOL(_read_lock_irq);
void __lockfunc _read_lock_bh(rwlock_t *lock)
{
local_bh_disable();
preempt_disable();
_raw_read_lock(lock);
}
EXPORT_SYMBOL(_read_lock_bh);
unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
{
unsigned long flags;
local_irq_save(flags);
preempt_disable();
_raw_write_lock(lock);
return flags;
}
EXPORT_SYMBOL(_write_lock_irqsave);
void __lockfunc _write_lock_irq(rwlock_t *lock)
{
local_irq_disable();
preempt_disable();
_raw_write_lock(lock);
}
EXPORT_SYMBOL(_write_lock_irq);
void __lockfunc _write_lock_bh(rwlock_t *lock)
{
local_bh_disable();
preempt_disable();
_raw_write_lock(lock);
}
EXPORT_SYMBOL(_write_lock_bh);
void __lockfunc _spin_lock(spinlock_t *lock)
{
preempt_disable();
_raw_spin_lock(lock);
}
EXPORT_SYMBOL(_spin_lock);
void __lockfunc _write_lock(rwlock_t *lock)
{
preempt_disable();
_raw_write_lock(lock);
}
EXPORT_SYMBOL(_write_lock);
#else /* CONFIG_PREEMPT: */
/*
* 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.
*
* (We do this in a function because inlining it would be excessive.)
*/
#define BUILD_LOCK_OPS(op, locktype) \
void __lockfunc _##op##_lock(locktype##_t *lock) \
{ \
preempt_disable(); \
for (;;) { \
if (likely(_raw_##op##_trylock(lock))) \
break; \
preempt_enable(); \
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!op##_can_lock(lock) && (lock)->break_lock) \
cpu_relax(); \
preempt_disable(); \
} \
(lock)->break_lock = 0; \
} \
\
EXPORT_SYMBOL(_##op##_lock); \
\
unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \
{ \
unsigned long flags; \
\
preempt_disable(); \
for (;;) { \
local_irq_save(flags); \
if (likely(_raw_##op##_trylock(lock))) \
break; \
local_irq_restore(flags); \
\
preempt_enable(); \
if (!(lock)->break_lock) \
(lock)->break_lock = 1; \
while (!op##_can_lock(lock) && (lock)->break_lock) \
cpu_relax(); \
preempt_disable(); \
} \
(lock)->break_lock = 0; \
return flags; \
} \
\
EXPORT_SYMBOL(_##op##_lock_irqsave); \
\
void __lockfunc _##op##_lock_irq(locktype##_t *lock) \
{ \
_##op##_lock_irqsave(lock); \
} \
\
EXPORT_SYMBOL(_##op##_lock_irq); \
\
void __lockfunc _##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 = _##op##_lock_irqsave(lock); \
local_bh_disable(); \
local_irq_restore(flags); \
} \
\
EXPORT_SYMBOL(_##op##_lock_bh)
/*
* 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, spinlock);
BUILD_LOCK_OPS(read, rwlock);
BUILD_LOCK_OPS(write, rwlock);
#endif /* CONFIG_PREEMPT */
void __lockfunc _spin_unlock(spinlock_t *lock)
{
_raw_spin_unlock(lock);
preempt_enable();
}
EXPORT_SYMBOL(_spin_unlock);
void __lockfunc _write_unlock(rwlock_t *lock)
{
_raw_write_unlock(lock);
preempt_enable();
}
EXPORT_SYMBOL(_write_unlock);
void __lockfunc _read_unlock(rwlock_t *lock)
{
_raw_read_unlock(lock);
preempt_enable();
}
EXPORT_SYMBOL(_read_unlock);
void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
{
_raw_spin_unlock(lock);
local_irq_restore(flags);
preempt_enable();
}
EXPORT_SYMBOL(_spin_unlock_irqrestore);
void __lockfunc _spin_unlock_irq(spinlock_t *lock)
{
_raw_spin_unlock(lock);
local_irq_enable();
preempt_enable();
}
EXPORT_SYMBOL(_spin_unlock_irq);
void __lockfunc _spin_unlock_bh(spinlock_t *lock)
{
_raw_spin_unlock(lock);
preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_spin_unlock_bh);
void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
_raw_read_unlock(lock);
local_irq_restore(flags);
preempt_enable();
}
EXPORT_SYMBOL(_read_unlock_irqrestore);
void __lockfunc _read_unlock_irq(rwlock_t *lock)
{
_raw_read_unlock(lock);
local_irq_enable();
preempt_enable();
}
EXPORT_SYMBOL(_read_unlock_irq);
void __lockfunc _read_unlock_bh(rwlock_t *lock)
{
_raw_read_unlock(lock);
preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_read_unlock_bh);
void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{
_raw_write_unlock(lock);
local_irq_restore(flags);
preempt_enable();
}
EXPORT_SYMBOL(_write_unlock_irqrestore);
void __lockfunc _write_unlock_irq(rwlock_t *lock)
{
_raw_write_unlock(lock);
local_irq_enable();
preempt_enable();
}
EXPORT_SYMBOL(_write_unlock_irq);
void __lockfunc _write_unlock_bh(rwlock_t *lock)
{
_raw_write_unlock(lock);
preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_write_unlock_bh);
int __lockfunc _spin_trylock_bh(spinlock_t *lock)
{
local_bh_disable();
preempt_disable();
if (_raw_spin_trylock(lock))
return 1;
preempt_enable_no_resched();
local_bh_enable();
return 0;
}
EXPORT_SYMBOL(_spin_trylock_bh);
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);