android_kernel_xiaomi_sm8350/include/asm-sparc/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

141 lines
3.4 KiB
C

/* spinlock.h: 32-bit Sparc spinlock support.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
*/
#ifndef __SPARC_SPINLOCK_H
#define __SPARC_SPINLOCK_H
#include <linux/threads.h> /* For NR_CPUS */
#ifndef __ASSEMBLY__
#include <asm/psr.h>
#define __raw_spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
#define __raw_spin_unlock_wait(lock) \
do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
extern __inline__ void __raw_spin_lock(raw_spinlock_t *lock)
{
__asm__ __volatile__(
"\n1:\n\t"
"ldstub [%0], %%g2\n\t"
"orcc %%g2, 0x0, %%g0\n\t"
"bne,a 2f\n\t"
" ldub [%0], %%g2\n\t"
".subsection 2\n"
"2:\n\t"
"orcc %%g2, 0x0, %%g0\n\t"
"bne,a 2b\n\t"
" ldub [%0], %%g2\n\t"
"b,a 1b\n\t"
".previous\n"
: /* no outputs */
: "r" (lock)
: "g2", "memory", "cc");
}
extern __inline__ int __raw_spin_trylock(raw_spinlock_t *lock)
{
unsigned int result;
__asm__ __volatile__("ldstub [%1], %0"
: "=r" (result)
: "r" (lock)
: "memory");
return (result == 0);
}
extern __inline__ void __raw_spin_unlock(raw_spinlock_t *lock)
{
__asm__ __volatile__("stb %%g0, [%0]" : : "r" (lock) : "memory");
}
/* 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.
*
* XXX This might create some problems with my dual spinlock
* XXX scheme, deadlocks etc. -DaveM
*
* Sort of like atomic_t's on Sparc, but even more clever.
*
* ------------------------------------
* | 24-bit counter | wlock | raw_rwlock_t
* ------------------------------------
* 31 8 7 0
*
* wlock signifies the one writer is in or somebody is updating
* counter. For a writer, if he successfully acquires the wlock,
* but counter is non-zero, he has to release the lock and wait,
* till both counter and wlock are zero.
*
* Unfortunately this scheme limits us to ~16,000,000 cpus.
*/
extern __inline__ void __read_lock(raw_rwlock_t *rw)
{
register raw_rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___rw_read_enter\n\t"
" ldstub [%%g1 + 3], %%g2\n"
: /* no outputs */
: "r" (lp)
: "g2", "g4", "memory", "cc");
}
#define __raw_read_lock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
__raw_read_lock(lock); \
local_irq_restore(flags); \
} while(0)
extern __inline__ void __read_unlock(raw_rwlock_t *rw)
{
register raw_rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___rw_read_exit\n\t"
" ldstub [%%g1 + 3], %%g2\n"
: /* no outputs */
: "r" (lp)
: "g2", "g4", "memory", "cc");
}
#define __raw_read_unlock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
__raw_read_unlock(lock); \
local_irq_restore(flags); \
} while(0)
extern __inline__ void __raw_write_lock(raw_rwlock_t *rw)
{
register raw_rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___rw_write_enter\n\t"
" ldstub [%%g1 + 3], %%g2\n"
: /* no outputs */
: "r" (lp)
: "g2", "g4", "memory", "cc");
}
#define __raw_write_unlock(rw) do { (rw)->lock = 0; } while(0)
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#endif /* !(__ASSEMBLY__) */
#endif /* __SPARC_SPINLOCK_H */