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Commit fb1c8f93 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[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: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarArjan van de Ven <arjanv@infradead.org>
Signed-off-by: default avatarGrant Grundler <grundler@parisc-linux.org>
Cc: Matthew Wilcox <willy@debian.org>
Signed-off-by: default avatarHirokazu Takata <takata@linux-m32r.org>
Signed-off-by: default avatarMikael Pettersson <mikpe@csd.uu.se>
Signed-off-by: default avatarBenoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 4327edf6
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Showing with 28 additions and 1137 deletions
arch/alpha/kernel/alpha_ksyms.c
View file @ fb1c8f93
......@@ -185,15 +185,6 @@ EXPORT_SYMBOL(smp_num_cpus);
EXPORT_SYMBOL(smp_call_function);
EXPORT_SYMBOL(smp_call_function_on_cpu);
EXPORT_SYMBOL(_atomic_dec_and_lock);
#ifdef CONFIG_DEBUG_SPINLOCK
EXPORT_SYMBOL(_raw_spin_unlock);
EXPORT_SYMBOL(debug_spin_lock);
EXPORT_SYMBOL(debug_spin_trylock);
#endif
#ifdef CONFIG_DEBUG_RWLOCK
EXPORT_SYMBOL(_raw_write_lock);
EXPORT_SYMBOL(_raw_read_lock);
#endif
EXPORT_SYMBOL(cpu_present_mask);
#endif /* CONFIG_SMP */
......
arch/alpha/kernel/smp.c
View file @ fb1c8f93
......@@ -989,175 +989,3 @@ flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
preempt_enable();
}
#ifdef CONFIG_DEBUG_SPINLOCK
void
_raw_spin_unlock(spinlock_t * lock)
{
mb();
lock->lock = 0;
lock->on_cpu = -1;
lock->previous = NULL;
lock->task = NULL;
lock->base_file = "none";
lock->line_no = 0;
}
void
debug_spin_lock(spinlock_t * lock, const char *base_file, int line_no)
{
long tmp;
long stuck;
void *inline_pc = __builtin_return_address(0);
unsigned long started = jiffies;
int printed = 0;
int cpu = smp_processor_id();
stuck = 1L << 30;
try_again:
/* Use sub-sections to put the actual loop at the end
of this object file's text section so as to perfect
branch prediction. */
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" subq %2,1,%2\n"
" blbs %0,2f\n"
" or %0,1,%0\n"
" stl_c %0,%1\n"
" beq %0,3f\n"
"4: mb\n"
".subsection 2\n"
"2: ldl %0,%1\n"
" subq %2,1,%2\n"
"3: blt %2,4b\n"
" blbs %0,2b\n"
" br 1b\n"
".previous"
: "=r" (tmp), "=m" (lock->lock), "=r" (stuck)
: "m" (lock->lock), "2" (stuck) : "memory");
if (stuck < 0) {
printk(KERN_WARNING
"%s:%d spinlock stuck in %s at %p(%d)"
" owner %s at %p(%d) %s:%d\n",
base_file, line_no,
current->comm, inline_pc, cpu,
lock->task->comm, lock->previous,
lock->on_cpu, lock->base_file, lock->line_no);
stuck = 1L << 36;
printed = 1;
goto try_again;
}
/* Exiting. Got the lock. */
lock->on_cpu = cpu;
lock->previous = inline_pc;
lock->task = current;
lock->base_file = base_file;
lock->line_no = line_no;
if (printed) {
printk(KERN_WARNING
"%s:%d spinlock grabbed in %s at %p(%d) %ld ticks\n",
base_file, line_no, current->comm, inline_pc,
cpu, jiffies - started);
}
}
int
debug_spin_trylock(spinlock_t * lock, const char *base_file, int line_no)
{
int ret;
if ((ret = !test_and_set_bit(0, lock))) {
lock->on_cpu = smp_processor_id();
lock->previous = __builtin_return_address(0);
lock->task = current;
} else {
lock->base_file = base_file;
lock->line_no = line_no;
}
return ret;
}
#endif /* CONFIG_DEBUG_SPINLOCK */
#ifdef CONFIG_DEBUG_RWLOCK
void _raw_write_lock(rwlock_t * lock)
{
long regx, regy;
int stuck_lock, stuck_reader;
void *inline_pc = __builtin_return_address(0);
try_again:
stuck_lock = 1<<30;
stuck_reader = 1<<30;
__asm__ __volatile__(
"1: ldl_l %1,%0\n"
" blbs %1,6f\n"
" blt %1,8f\n"
" mov 1,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
"4: mb\n"
".subsection 2\n"
"6: blt %3,4b # debug\n"
" subl %3,1,%3 # debug\n"
" ldl %1,%0\n"
" blbs %1,6b\n"
"8: blt %4,4b # debug\n"
" subl %4,1,%4 # debug\n"
" ldl %1,%0\n"
" blt %1,8b\n"
" br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (regy),
"=&r" (stuck_lock), "=&r" (stuck_reader)
: "m" (*(volatile int *)lock), "3" (stuck_lock), "4" (stuck_reader) : "memory");
if (stuck_lock < 0) {
printk(KERN_WARNING "write_lock stuck at %p\n", inline_pc);
goto try_again;
}
if (stuck_reader < 0) {
printk(KERN_WARNING "write_lock stuck on readers at %p\n",
inline_pc);
goto try_again;
}
}
void _raw_read_lock(rwlock_t * lock)
{
long regx;
int stuck_lock;
void *inline_pc = __builtin_return_address(0);
try_again:
stuck_lock = 1<<30;
__asm__ __volatile__(
"1: ldl_l %1,%0;"
" blbs %1,6f;"
" subl %1,2,%1;"
" stl_c %1,%0;"
" beq %1,6f;"
"4: mb\n"
".subsection 2\n"
"6: ldl %1,%0;"
" blt %2,4b # debug\n"
" subl %2,1,%2 # debug\n"
" blbs %1,6b;"
" br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (stuck_lock)
: "m" (*(volatile int *)lock), "2" (stuck_lock) : "memory");
if (stuck_lock < 0) {
printk(KERN_WARNING "read_lock stuck at %p\n", inline_pc);
goto try_again;
}
}
#endif /* CONFIG_DEBUG_RWLOCK */
arch/ia64/kernel/mca.c
View file @ fb1c8f93
......@@ -491,12 +491,7 @@ init_handler_platform (pal_min_state_area_t *ms,
unw_init_from_interruption(&info, current, pt, sw);
ia64_do_show_stack(&info, NULL);
#ifdef CONFIG_SMP
/* read_trylock() would be handy... */
if (!tasklist_lock.write_lock)
read_lock(&tasklist_lock);
#endif
{
if (read_trylock(&tasklist_lock)) {
struct task_struct *g, *t;
do_each_thread (g, t) {
if (t == current)
......@@ -506,10 +501,6 @@ init_handler_platform (pal_min_state_area_t *ms,
show_stack(t, NULL);
} while_each_thread (g, t);
}
#ifdef CONFIG_SMP
if (!tasklist_lock.write_lock)
read_unlock(&tasklist_lock);
#endif
printk("\nINIT dump complete. Please reboot now.\n");
while (1); /* hang city if no debugger */
......
arch/m32r/kernel/smp.c
View file @ fb1c8f93
......@@ -892,7 +892,6 @@ unsigned long send_IPI_mask_phys(cpumask_t physid_mask, int ipi_num,
int try)
{
spinlock_t *ipilock;
unsigned long flags = 0;
volatile unsigned long *ipicr_addr;
unsigned long ipicr_val;
unsigned long my_physid_mask;
......@@ -916,50 +915,27 @@ unsigned long send_IPI_mask_phys(cpumask_t physid_mask, int ipi_num,
* write IPICRi (send IPIi)
* unlock ipi_lock[i]
*/
spin_lock(ipilock);
__asm__ __volatile__ (
";; LOCK ipi_lock[i] \n\t"
";; CHECK IPICRi == 0 \n\t"
".fillinsn \n"
"1: \n\t"
"mvfc %1, psw \n\t"
"clrpsw #0x40 -> nop \n\t"
DCACHE_CLEAR("r4", "r5", "%2")
"lock r4, @%2 \n\t"
"addi r4, #-1 \n\t"
"unlock r4, @%2 \n\t"
"mvtc %1, psw \n\t"
"bnez r4, 2f \n\t"
LOCK_SECTION_START(".balign 4 \n\t")
".fillinsn \n"
"2: \n\t"
"ld r4, @%2 \n\t"
"blez r4, 2b \n\t"
"ld %0, @%1 \n\t"
"and %0, %4 \n\t"
"beqz %0, 2f \n\t"
"bnez %3, 3f \n\t"
"bra 1b \n\t"
LOCK_SECTION_END
";; CHECK IPICRi == 0 \n\t"
".fillinsn \n"
"3: \n\t"
"ld %0, @%3 \n\t"
"and %0, %6 \n\t"
"beqz %0, 4f \n\t"
"bnez %5, 5f \n\t"
"bra 3b \n\t"
";; WRITE IPICRi (send IPIi) \n\t"
".fillinsn \n"
"4: \n\t"
"st %4, @%3 \n\t"
";; UNLOCK ipi_lock[i] \n\t"
"2: \n\t"
"st %2, @%1 \n\t"
".fillinsn \n"
"5: \n\t"
"ldi r4, #1 \n\t"
"st r4, @%2 \n\t"
"3: \n\t"
: "=&r"(ipicr_val)
: "r"(flags), "r"(&ipilock->slock), "r"(ipicr_addr),
"r"(mask), "r"(try), "r"(my_physid_mask)
: "memory", "r4"
#ifdef CONFIG_CHIP_M32700_TS1
, "r5"
#endif /* CONFIG_CHIP_M32700_TS1 */
: "r"(ipicr_addr), "r"(mask), "r"(try), "r"(my_physid_mask)
: "memory"
);
spin_unlock(ipilock);
return ipicr_val;
}
arch/mips/lib/dec_and_lock.c
View file @ fb1c8f93
......@@ -20,14 +20,7 @@
* has a cmpxchg, and where atomic->value is an int holding
* the value of the atomic (i.e. the high bits aren't used
* for a lock or anything like that).
*
* N.B. ATOMIC_DEC_AND_LOCK gets defined in include/linux/spinlock.h
* if spinlocks are empty and thus atomic_dec_and_lock is defined
* to be atomic_dec_and_test - in that case we don't need it
* defined here as well.
*/
#ifndef ATOMIC_DEC_AND_LOCK
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
int counter;
......@@ -52,4 +45,3 @@ int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
}
EXPORT_SYMBOL(_atomic_dec_and_lock);
#endif /* ATOMIC_DEC_AND_LOCK */
arch/parisc/lib/Makefile
View file @ fb1c8f93
......@@ -5,5 +5,3 @@
lib-y := lusercopy.o bitops.o checksum.o io.o memset.o fixup.o memcpy.o
obj-y := iomap.o
lib-$(CONFIG_SMP) += debuglocks.o
arch/parisc/lib/bitops.c
View file @ fb1c8f93
......@@ -13,8 +13,8 @@
#include <asm/atomic.h>
#ifdef CONFIG_SMP
spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
[0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED
raw_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
[0 ... (ATOMIC_HASH_SIZE-1)] = __RAW_SPIN_LOCK_UNLOCKED
};
#endif
......
arch/parisc/lib/debuglocks.c deleted 100644 → 0
View file @ 4327edf6
/*
* Debugging versions of SMP locking primitives.
*
* Copyright (C) 2004 Thibaut VARENE <varenet@parisc-linux.org>
*
* Some code stollen from alpha & sparc64 ;)
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* We use pdc_printf() throughout the file for all output messages, to avoid
* losing messages because of disabled interrupts. Since we're using these
* messages for debugging purposes, it makes sense not to send them to the
* linux console.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/hardirq.h> /* in_interrupt() */
#include <asm/system.h>
#include <asm/hardirq.h> /* in_interrupt() */
#include <asm/pdc.h>
#undef INIT_STUCK
#define INIT_STUCK 1L << 30
#ifdef CONFIG_DEBUG_SPINLOCK
void _dbg_spin_lock(spinlock_t * lock, const char *base_file, int line_no)
{
volatile unsigned int *a;
long stuck = INIT_STUCK;
void *inline_pc = __builtin_return_address(0);
unsigned long started = jiffies;
int printed = 0;
int cpu = smp_processor_id();
try_again:
/* Do the actual locking */
/* <T-Bone> ggg: we can't get stuck on the outter loop?
* <ggg> T-Bone: We can hit the outer loop
* alot if multiple CPUs are constantly racing for a lock
* and the backplane is NOT fair about which CPU sees
* the update first. But it won't hang since every failed
* attempt will drop us back into the inner loop and
* decrement `stuck'.
* <ggg> K-class and some of the others are NOT fair in the HW
* implementation so we could see false positives.
* But fixing the lock contention is easier than
* fixing the HW to be fair.
* <tausq> __ldcw() returns 1 if we get the lock; otherwise we
* spin until the value of the lock changes, or we time out.
*/
mb();
a = __ldcw_align(lock);
while (stuck && (__ldcw(a) == 0))
while ((*a == 0) && --stuck);
mb();
if (unlikely(stuck <= 0)) {
pdc_printf(
"%s:%d: spin_lock(%s/%p) stuck in %s at %p(%d)"
" owned by %s:%d in %s at %p(%d)\n",
base_file, line_no, lock->module, lock,
current->comm, inline_pc, cpu,
lock->bfile, lock->bline, lock->task->comm,
lock->previous, lock->oncpu);
stuck = INIT_STUCK;
printed = 1;
goto try_again;
}
/* Exiting. Got the lock. */
lock->oncpu = cpu;
lock->previous = inline_pc;
lock->task = current;
lock->bfile = (char *)base_file;
lock->bline = line_no;
if (unlikely(printed)) {
pdc_printf(
"%s:%d: spin_lock grabbed in %s at %p(%d) %ld ticks\n",
base_file, line_no, current->comm, inline_pc,
cpu, jiffies - started);
}
}
void _dbg_spin_unlock(spinlock_t * lock, const char *base_file, int line_no)
{
CHECK_LOCK(lock);
volatile unsigned int *a;
mb();
a = __ldcw_align(lock);
if (unlikely((*a != 0) && lock->babble)) {
lock->babble--;
pdc_printf(
"%s:%d: spin_unlock(%s:%p) not locked\n",
base_file, line_no, lock->module, lock);
}
*a = 1;
mb();
}
int _dbg_spin_trylock(spinlock_t * lock, const char *base_file, int line_no)
{
int ret;
volatile unsigned int *a;
mb();
a = __ldcw_align(lock);
ret = (__ldcw(a) != 0);
mb();
if (ret) {
lock->oncpu = smp_processor_id();
lock->previous = __builtin_return_address(0);
lock->task = current;
} else {
lock->bfile = (char *)base_file;
lock->bline = line_no;
}
return ret;
}
#endif /* CONFIG_DEBUG_SPINLOCK */
#ifdef CONFIG_DEBUG_RWLOCK
/* Interrupts trouble detailed explanation, thx Grant:
*
* o writer (wants to modify data) attempts to acquire the rwlock
* o He gets the write lock.
* o Interupts are still enabled, we take an interrupt with the
* write still holding the lock.
* o interrupt handler tries to acquire the rwlock for read.
* o deadlock since the writer can't release it at this point.
*
* In general, any use of spinlocks that competes between "base"
* level and interrupt level code will risk deadlock. Interrupts
* need to be disabled in the base level routines to avoid it.
* Or more precisely, only the IRQ the base level routine
* is competing with for the lock. But it's more efficient/faster
* to just disable all interrupts on that CPU to guarantee
* once it gets the lock it can release it quickly too.
*/
void _dbg_write_lock(rwlock_t *rw, const char *bfile, int bline)
{
void *inline_pc = __builtin_return_address(0);
unsigned long started = jiffies;
long stuck = INIT_STUCK;
int printed = 0;
int cpu = smp_processor_id();
if(unlikely(in_interrupt())) { /* acquiring write lock in interrupt context, bad idea */
pdc_printf("write_lock caller: %s:%d, IRQs enabled,\n", bfile, bline);
BUG();
}
/* Note: if interrupts are disabled (which is most likely), the printk
will never show on the console. We might need a polling method to flush
the dmesg buffer anyhow. */
retry:
_raw_spin_lock(&rw->lock);
if(rw->counter != 0) {
/* this basically never happens */
_raw_spin_unlock(&rw->lock);
stuck--;
if ((unlikely(stuck <= 0)) && (rw->counter < 0)) {
pdc_printf(
"%s:%d: write_lock stuck on writer"
" in %s at %p(%d) %ld ticks\n",
bfile, bline, current->comm, inline_pc,
cpu, jiffies - started);
stuck = INIT_STUCK;
printed = 1;
}
else if (unlikely(stuck <= 0)) {
pdc_printf(
"%s:%d: write_lock stuck on reader"
" in %s at %p(%d) %ld ticks\n",
bfile, bline, current->comm, inline_pc,
cpu, jiffies - started);
stuck = INIT_STUCK;
printed = 1;
}
while(rw->counter != 0);
goto retry;
}
/* got it. now leave without unlocking */
rw->counter = -1; /* remember we are locked */
if (unlikely(printed)) {
pdc_printf(
"%s:%d: write_lock grabbed in %s at %p(%d) %ld ticks\n",
bfile, bline, current->comm, inline_pc,
cpu, jiffies - started);
}
}
int _dbg_write_trylock(rwlock_t *rw, const char *bfile, int bline)
{
#if 0
void *inline_pc = __builtin_return_address(0);
int cpu = smp_processor_id();
#endif
if(unlikely(in_interrupt())) { /* acquiring write lock in interrupt context, bad idea */
pdc_printf("write_lock caller: %s:%d, IRQs enabled,\n", bfile, bline);
BUG();
}
/* Note: if interrupts are disabled (which is most likely), the printk
will never show on the console. We might need a polling method to flush
the dmesg buffer anyhow. */
_raw_spin_lock(&rw->lock);
if(rw->counter != 0) {
/* this basically never happens */
_raw_spin_unlock(&rw->lock);
return 0;
}
/* got it. now leave without unlocking */
rw->counter = -1; /* remember we are locked */
#if 0
pdc_printf("%s:%d: try write_lock grabbed in %s at %p(%d)\n",
bfile, bline, current->comm, inline_pc, cpu);
#endif
return 1;
}
void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline)
{
#if 0
void *inline_pc = __builtin_return_address(0);
unsigned long started = jiffies;
int cpu = smp_processor_id();
#endif
unsigned long flags;
local_irq_save(flags);
_raw_spin_lock(&rw->lock);
rw->counter++;
#if 0
pdc_printf(
"%s:%d: read_lock grabbed in %s at %p(%d) %ld ticks\n",
bfile, bline, current->comm, inline_pc,
cpu, jiffies - started);
#endif
_raw_spin_unlock(&rw->lock);
local_irq_restore(flags);
}
#endif /* CONFIG_DEBUG_RWLOCK */
arch/ppc/lib/Makefile
View file @ fb1c8f93
......@@ -4,6 +4,5 @@
obj-y := checksum.o string.o strcase.o dec_and_lock.o div64.o
obj-$(CONFIG_SMP) += locks.o
obj-$(CONFIG_8xx) += rheap.o
obj-$(CONFIG_CPM2) += rheap.o
arch/ppc/lib/dec_and_lock.c
View file @ fb1c8f93
......@@ -11,14 +11,7 @@
* has a cmpxchg, and where atomic->value is an int holding
* the value of the atomic (i.e. the high bits aren't used
* for a lock or anything like that).
*
* N.B. ATOMIC_DEC_AND_LOCK gets defined in include/linux/spinlock.h
* if spinlocks are empty and thus atomic_dec_and_lock is defined
* to be atomic_dec_and_test - in that case we don't need it
* defined here as well.
*/
#ifndef ATOMIC_DEC_AND_LOCK
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
int counter;
......@@ -43,4 +36,3 @@ int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
}
EXPORT_SYMBOL(_atomic_dec_and_lock);
#endif /* ATOMIC_DEC_AND_LOCK */
arch/ppc64/lib/dec_and_lock.c
View file @ fb1c8f93
......@@ -20,14 +20,7 @@
* has a cmpxchg, and where atomic->value is an int holding
* the value of the atomic (i.e. the high bits aren't used
* for a lock or anything like that).
*
* N.B. ATOMIC_DEC_AND_LOCK gets defined in include/linux/spinlock.h
* if spinlocks are empty and thus atomic_dec_and_lock is defined
* to be atomic_dec_and_test - in that case we don't need it
* defined here as well.
*/
#ifndef ATOMIC_DEC_AND_LOCK
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
int counter;
......@@ -52,4 +45,3 @@ int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
}
EXPORT_SYMBOL(_atomic_dec_and_lock);
#endif /* ATOMIC_DEC_AND_LOCK */
arch/ppc64/lib/locks.c
View file @ fb1c8f93
......@@ -23,12 +23,12 @@
/* waiting for a spinlock... */
#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
void __spin_yield(spinlock_t *lock)
void __spin_yield(raw_spinlock_t *lock)
{
unsigned int lock_value, holder_cpu, yield_count;
struct paca_struct *holder_paca;
lock_value = lock->lock;
lock_value = lock->slock;
if (lock_value == 0)
return;
holder_cpu = lock_value & 0xffff;
......@@ -38,7 +38,7 @@ void __spin_yield(spinlock_t *lock)
if ((yield_count & 1) == 0)
return; /* virtual cpu is currently running */
rmb();
if (lock->lock != lock_value)
if (lock->slock != lock_value)
return; /* something has changed */
#ifdef CONFIG_PPC_ISERIES
HvCall2(HvCallBaseYieldProcessor, HvCall_YieldToProc,
......@@ -54,7 +54,7 @@ void __spin_yield(spinlock_t *lock)
* This turns out to be the same for read and write locks, since
* we only know the holder if it is write-locked.
*/
void __rw_yield(rwlock_t *rw)
void __rw_yield(raw_rwlock_t *rw)
{
int lock_value;
unsigned int holder_cpu, yield_count;
......@@ -82,9 +82,9 @@ void __rw_yield(rwlock_t *rw)
}
#endif
void spin_unlock_wait(spinlock_t *lock)
void __raw_spin_unlock_wait(raw_spinlock_t *lock)
{
while (lock->lock) {
while (lock->slock) {
HMT_low();
if (SHARED_PROCESSOR)
__spin_yield(lock);
......@@ -92,4 +92,4 @@ void spin_unlock_wait(spinlock_t *lock)
HMT_medium();
}
EXPORT_SYMBOL(spin_unlock_wait);
EXPORT_SYMBOL(__raw_spin_unlock_wait);
arch/s390/lib/spinlock.c
View file @ fb1c8f93
......@@ -36,7 +36,7 @@ _diag44(void)
}
void
_raw_spin_lock_wait(spinlock_t *lp, unsigned int pc)
_raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc)
{
int count = spin_retry;
......@@ -53,7 +53,7 @@ _raw_spin_lock_wait(spinlock_t *lp, unsigned int pc)
EXPORT_SYMBOL(_raw_spin_lock_wait);
int
_raw_spin_trylock_retry(spinlock_t *lp, unsigned int pc)
_raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc)
{
int count = spin_retry;
......@@ -67,7 +67,7 @@ _raw_spin_trylock_retry(spinlock_t *lp, unsigned int pc)
EXPORT_SYMBOL(_raw_spin_trylock_retry);
void
_raw_read_lock_wait(rwlock_t *rw)
_raw_read_lock_wait(raw_rwlock_t *rw)
{
unsigned int old;
int count = spin_retry;
......@@ -86,7 +86,7 @@ _raw_read_lock_wait(rwlock_t *rw)
EXPORT_SYMBOL(_raw_read_lock_wait);
int
_raw_read_trylock_retry(rwlock_t *rw)
_raw_read_trylock_retry(raw_rwlock_t *rw)
{
unsigned int old;
int count = spin_retry;
......@@ -102,7 +102,7 @@ _raw_read_trylock_retry(rwlock_t *rw)
EXPORT_SYMBOL(_raw_read_trylock_retry);
void
_raw_write_lock_wait(rwlock_t *rw)
_raw_write_lock_wait(raw_rwlock_t *rw)
{
int count = spin_retry;
......@@ -119,7 +119,7 @@ _raw_write_lock_wait(rwlock_t *rw)
EXPORT_SYMBOL(_raw_write_lock_wait);
int
_raw_write_trylock_retry(rwlock_t *rw)
_raw_write_trylock_retry(raw_rwlock_t *rw)
{
int count = spin_retry;
......
arch/sparc/kernel/sparc_ksyms.c
View file @ fb1c8f93
......@@ -114,17 +114,7 @@ DOT_ALIAS2(unsigned, urem, unsigned, unsigned)
/* used by various drivers */
EXPORT_SYMBOL(sparc_cpu_model);
EXPORT_SYMBOL(kernel_thread);
#ifdef CONFIG_DEBUG_SPINLOCK
#ifdef CONFIG_SMP
EXPORT_SYMBOL(_do_spin_lock);
EXPORT_SYMBOL(_do_spin_unlock);
EXPORT_SYMBOL(_spin_trylock);
EXPORT_SYMBOL(_do_read_lock);
EXPORT_SYMBOL(_do_read_unlock);
EXPORT_SYMBOL(_do_write_lock);
EXPORT_SYMBOL(_do_write_unlock);
#endif
#else
// XXX find what uses (or used) these.
EXPORT_SYMBOL(___rw_read_enter);
EXPORT_SYMBOL(___rw_read_exit);
......
arch/sparc/lib/Makefile
View file @ fb1c8f93
......@@ -9,5 +9,3 @@ lib-y := mul.o rem.o sdiv.o udiv.o umul.o urem.o ashrdi3.o memcpy.o memset.o \
strncpy_from_user.o divdi3.o udivdi3.o strlen_user.o \
copy_user.o locks.o atomic.o atomic32.o bitops.o \
lshrdi3.o ashldi3.o rwsem.o muldi3.o bitext.o
lib-$(CONFIG_DEBUG_SPINLOCK) += debuglocks.o
arch/sparc/lib/debuglocks.c deleted 100644 → 0
View file @ 4327edf6
/* $Id: debuglocks.c,v 1.11 2001/09/20 00:35:31 davem Exp $
* debuglocks.c: Debugging versions of SMP locking primitives.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1998-99 Anton Blanchard (anton@progsoc.uts.edu.au)
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/threads.h> /* For NR_CPUS */
#include <linux/spinlock.h>
#include <asm/psr.h>
#include <asm/system.h>
#ifdef CONFIG_SMP
/* Some notes on how these debugging routines work. When a lock is acquired
* an extra debugging member lock->owner_pc is set to the caller of the lock
* acquisition routine. Right before releasing a lock, the debugging program
* counter is cleared to zero.
*
* Furthermore, since PC's are 4 byte aligned on Sparc, we stuff the CPU
* number of the owner in the lowest two bits.
*/
#define STORE_CALLER(A) __asm__ __volatile__("mov %%i7, %0" : "=r" (A));
static inline void show(char *str, spinlock_t *lock, unsigned long caller)
{
int cpu = smp_processor_id();
printk("%s(%p) CPU#%d stuck at %08lx, owner PC(%08lx):CPU(%lx)\n",str,
lock, cpu, caller, lock->owner_pc & ~3, lock->owner_pc & 3);
}
static inline void show_read(char *str, rwlock_t *lock, unsigned long caller)
{
int cpu = smp_processor_id();
printk("%s(%p) CPU#%d stuck at %08lx, owner PC(%08lx):CPU(%lx)\n", str,
lock, cpu, caller, lock->owner_pc & ~3, lock->owner_pc & 3);
}
static inline void show_write(char *str, rwlock_t *lock, unsigned long caller)
{
int cpu = smp_processor_id();
int i;
printk("%s(%p) CPU#%d stuck at %08lx, owner PC(%08lx):CPU(%lx)", str,
lock, cpu, caller, lock->owner_pc & ~3, lock->owner_pc & 3);
for(i = 0; i < NR_CPUS; i++)
printk(" reader[%d]=%08lx", i, lock->reader_pc[i]);
printk("\n");
}
#undef INIT_STUCK
#define INIT_STUCK 100000000
void _do_spin_lock(spinlock_t *lock, char *str)
{
unsigned long caller;
unsigned long val;
int cpu = smp_processor_id();
int stuck = INIT_STUCK;
STORE_CALLER(caller);
again:
__asm__ __volatile__("ldstub [%1], %0" : "=r" (val) : "r" (&(lock->lock)));
if(val) {
while(lock->lock) {
if (!--stuck) {
show(str, lock, caller);
stuck = INIT_STUCK;
}
barrier();
}
goto again;
}
lock->owner_pc = (cpu & 3) | (caller & ~3);
}
int _spin_trylock(spinlock_t *lock)
{
unsigned long val;
unsigned long caller;
int cpu = smp_processor_id();
STORE_CALLER(caller);
__asm__ __volatile__("ldstub [%1], %0" : "=r" (val) : "r" (&(lock->lock)));
if(!val) {
/* We got it, record our identity for debugging. */
lock->owner_pc = (cpu & 3) | (caller & ~3);
}
return val == 0;
}
void _do_spin_unlock(spinlock_t *lock)
{
lock->owner_pc = 0;
barrier();
lock->lock = 0;
}
void _do_read_lock(rwlock_t *rw, char *str)
{
unsigned long caller;
unsigned long val;
int cpu = smp_processor_id();
int stuck = INIT_STUCK;
STORE_CALLER(caller);
wlock_again:
__asm__ __volatile__("ldstub [%1 + 3], %0" : "=r" (val) : "r" (&(rw->lock)));
if(val) {
while(rw->lock & 0xff) {
if (!--stuck) {
show_read(str, rw, caller);
stuck = INIT_STUCK;
}
barrier();
}
goto wlock_again;
}
rw->reader_pc[cpu] = caller;
barrier();
rw->lock++;
}
void _do_read_unlock(rwlock_t *rw, char *str)
{
unsigned long caller;
unsigned long val;
int cpu = smp_processor_id();
int stuck = INIT_STUCK;
STORE_CALLER(caller);
wlock_again:
__asm__ __volatile__("ldstub [%1 + 3], %0" : "=r" (val) : "r" (&(rw->lock)));
if(val) {
while(rw->lock & 0xff) {
if (!--stuck) {
show_read(str, rw, caller);
stuck = INIT_STUCK;
}
barrier();
}
goto wlock_again;
}
rw->reader_pc[cpu] = 0;
barrier();
rw->lock -= 0x1ff;
}
void _do_write_lock(rwlock_t *rw, char *str)
{
unsigned long caller;
unsigned long val;
int cpu = smp_processor_id();
int stuck = INIT_STUCK;
STORE_CALLER(caller);
wlock_again:
__asm__ __volatile__("ldstub [%1 + 3], %0" : "=r" (val) : "r" (&(rw->lock)));
if(val) {
wlock_wait:
while(rw->lock) {
if (!--stuck) {
show_write(str, rw, caller);
stuck = INIT_STUCK;
}
barrier();
}
goto wlock_again;
}
if (rw->lock & ~0xff) {
*(((unsigned char *)&rw->lock)+3) = 0;
barrier();
goto wlock_wait;
}
barrier();
rw->owner_pc = (cpu & 3) | (caller & ~3);
}
void _do_write_unlock(rwlock_t *rw)
{
rw->owner_pc = 0;
barrier();
rw->lock = 0;
}
#endif /* SMP */
arch/sparc64/kernel/process.c
View file @ fb1c8f93
......@@ -607,11 +607,6 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
struct thread_info *t = p->thread_info;
char *child_trap_frame;
#ifdef CONFIG_DEBUG_SPINLOCK
p->thread.smp_lock_count = 0;
p->thread.smp_lock_pc = 0;
#endif
/* Calculate offset to stack_frame & pt_regs */
child_trap_frame = ((char *)t) + (THREAD_SIZE - (TRACEREG_SZ+STACKFRAME_SZ));
memcpy(child_trap_frame, (((struct sparc_stackf *)regs)-1), (TRACEREG_SZ+STACKFRAME_SZ));
......
arch/sparc64/kernel/sparc64_ksyms.c
View file @ fb1c8f93
......@@ -115,17 +115,12 @@ EXPORT_PER_CPU_SYMBOL(__cpu_data);
/* used by various drivers */
#ifdef CONFIG_SMP
#ifndef CONFIG_DEBUG_SPINLOCK
/* Out of line rw-locking implementation. */
EXPORT_SYMBOL(__read_lock);
EXPORT_SYMBOL(__read_unlock);
EXPORT_SYMBOL(__write_lock);
EXPORT_SYMBOL(__write_unlock);
EXPORT_SYMBOL(__write_trylock);
/* Out of line spin-locking implementation. */
EXPORT_SYMBOL(_raw_spin_lock);
EXPORT_SYMBOL(_raw_spin_lock_flags);
#endif
/* Hard IRQ locking */
EXPORT_SYMBOL(synchronize_irq);
......
arch/sparc64/lib/Makefile
View file @ fb1c8f93
......@@ -14,7 +14,6 @@ lib-y := PeeCeeI.o copy_page.o clear_page.o strlen.o strncmp.o \
copy_in_user.o user_fixup.o memmove.o \
mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o
lib-$(CONFIG_DEBUG_SPINLOCK) += debuglocks.o
lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
obj-y += iomap.o
arch/sparc64/lib/debuglocks.c deleted 100644 → 0
View file @ 4327edf6
/* $Id: debuglocks.c,v 1.9 2001/11/17 00:10:48 davem Exp $
* debuglocks.c: Debugging versions of SMP locking primitives.
*
* Copyright (C) 1998 David S. Miller (davem@redhat.com)
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <asm/system.h>
#ifdef CONFIG_SMP
static inline void show (char *str, spinlock_t *lock, unsigned long caller)
{
int cpu = smp_processor_id();
printk("%s(%p) CPU#%d stuck at %08x, owner PC(%08x):CPU(%x)\n",
str, lock, cpu, (unsigned int) caller,
lock->owner_pc, lock->owner_cpu);
}
static inline void show_read (char *str, rwlock_t *lock, unsigned long caller)
{
int cpu = smp_processor_id();
printk("%s(%p) CPU#%d stuck at %08x, writer PC(%08x):CPU(%x)\n",
str, lock, cpu, (unsigned int) caller,
lock->writer_pc, lock->writer_cpu);
}
static inline void show_write (char *str, rwlock_t *lock, unsigned long caller)
{
int cpu = smp_processor_id();
int i;
printk("%s(%p) CPU#%d stuck at %08x\n",
str, lock, cpu, (unsigned int) caller);
printk("Writer: PC(%08x):CPU(%x)\n",
lock->writer_pc, lock->writer_cpu);
printk("Readers:");
for (i = 0; i < NR_CPUS; i++)
if (lock->reader_pc[i])
printk(" %d[%08x]", i, lock->reader_pc[i]);
printk("\n");
}
#undef INIT_STUCK
#define INIT_STUCK 100000000
void _do_spin_lock(spinlock_t *lock, char *str, unsigned long caller)
{
unsigned long val;
int stuck = INIT_STUCK;
int cpu = get_cpu();
int shown = 0;
again:
__asm__ __volatile__("ldstub [%1], %0"
: "=r" (val)
: "r" (&(lock->lock))
: "memory");
membar_storeload_storestore();
if (val) {
while (lock->lock) {
if (!--stuck) {
if (shown++ <= 2)
show(str, lock, caller);
stuck = INIT_STUCK;
}
rmb();
}
goto again;
}
lock->owner_pc = ((unsigned int)caller);
lock->owner_cpu = cpu;
current->thread.smp_lock_count++;
current->thread.smp_lock_pc = ((unsigned int)caller);
put_cpu();
}
int _do_spin_trylock(spinlock_t *lock, unsigned long caller)
{
unsigned long val;
int cpu = get_cpu();
__asm__ __volatile__("ldstub [%1], %0"
: "=r" (val)
: "r" (&(lock->lock))
: "memory");
membar_storeload_storestore();
if (!val) {
lock->owner_pc = ((unsigned int)caller);
lock->owner_cpu = cpu;
current->thread.smp_lock_count++;
current->thread.smp_lock_pc = ((unsigned int)caller);
}
put_cpu();
return val == 0;
}
void _do_spin_unlock(spinlock_t *lock)
{
lock->owner_pc = 0;
lock->owner_cpu = NO_PROC_ID;
membar_storestore_loadstore();
lock->lock = 0;
current->thread.smp_lock_count--;
}
/* Keep INIT_STUCK the same... */
void _do_read_lock(rwlock_t *rw, char *str, unsigned long caller)
{
unsigned long val;
int stuck = INIT_STUCK;
int cpu = get_cpu();
int shown = 0;
wlock_again:
/* Wait for any writer to go away. */
while (((long)(rw->lock)) < 0) {
if (!--stuck) {
if (shown++ <= 2)
show_read(str, rw, caller);
stuck = INIT_STUCK;
}
rmb();
}
/* Try once to increment the counter. */
__asm__ __volatile__(
" ldx [%0], %%g1\n"
" brlz,a,pn %%g1, 2f\n"
" mov 1, %0\n"
" add %%g1, 1, %%g7\n"
" casx [%0], %%g1, %%g7\n"
" sub %%g1, %%g7, %0\n"
"2:" : "=r" (val)
: "0" (&(rw->lock))
: "g1", "g7", "memory");
membar_storeload_storestore();
if (val)
goto wlock_again;
rw->reader_pc[cpu] = ((unsigned int)caller);
current->thread.smp_lock_count++;
current->thread.smp_lock_pc = ((unsigned int)caller);
put_cpu();
}
void _do_read_unlock(rwlock_t *rw, char *str, unsigned long caller)
{
unsigned long val;
int stuck = INIT_STUCK;
int cpu = get_cpu();
int shown = 0;
/* Drop our identity _first_. */
rw->reader_pc[cpu] = 0;
current->thread.smp_lock_count--;
runlock_again:
/* Spin trying to decrement the counter using casx. */
__asm__ __volatile__(
" membar #StoreLoad | #LoadLoad\n"
" ldx [%0], %%g1\n"
" sub %%g1, 1, %%g7\n"
" casx [%0], %%g1, %%g7\n"
" membar #StoreLoad | #StoreStore\n"
" sub %%g1, %%g7, %0\n"
: "=r" (val)
: "0" (&(rw->lock))
: "g1", "g7", "memory");
if (val) {
if (!--stuck) {
if (shown++ <= 2)
show_read(str, rw, caller);
stuck = INIT_STUCK;
}
goto runlock_again;
}
put_cpu();
}
void _do_write_lock(rwlock_t *rw, char *str, unsigned long caller)
{
unsigned long val;
int stuck = INIT_STUCK;
int cpu = get_cpu();
int shown = 0;
wlock_again:
/* Spin while there is another writer. */
while (((long)rw->lock) < 0) {
if (!--stuck) {
if (shown++ <= 2)
show_write(str, rw, caller);
stuck = INIT_STUCK;
}
rmb();
}
/* Try to acuire the write bit. */
__asm__ __volatile__(
" mov 1, %%g3\n"
" sllx %%g3, 63, %%g3\n"
" ldx [%0], %%g1\n"
" brlz,pn %%g1, 1f\n"
" or %%g1, %%g3, %%g7\n"
" casx [%0], %%g1, %%g7\n"
" membar #StoreLoad | #StoreStore\n"
" ba,pt %%xcc, 2f\n"
" sub %%g1, %%g7, %0\n"
"1: mov 1, %0\n"
"2:" : "=r" (val)
: "0" (&(rw->lock))
: "g3", "g1", "g7", "memory");
if (val) {
/* We couldn't get the write bit. */
if (!--stuck) {
if (shown++ <= 2)
show_write(str, rw, caller);
stuck = INIT_STUCK;
}
goto wlock_again;
}
if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) {
/* Readers still around, drop the write
* lock, spin, and try again.
*/
if (!--stuck) {
if (shown++ <= 2)
show_write(str, rw, caller);
stuck = INIT_STUCK;
}
__asm__ __volatile__(
" mov 1, %%g3\n"
" sllx %%g3, 63, %%g3\n"
"1: ldx [%0], %%g1\n"
" andn %%g1, %%g3, %%g7\n"
" casx [%0], %%g1, %%g7\n"
" cmp %%g1, %%g7\n"
" membar #StoreLoad | #StoreStore\n"
" bne,pn %%xcc, 1b\n"
" nop"
: /* no outputs */
: "r" (&(rw->lock))
: "g3", "g1", "g7", "cc", "memory");
while(rw->lock != 0) {
if (!--stuck) {
if (shown++ <= 2)
show_write(str, rw, caller);
stuck = INIT_STUCK;
}
rmb();
}
goto wlock_again;
}
/* We have it, say who we are. */
rw->writer_pc = ((unsigned int)caller);
rw->writer_cpu = cpu;
current->thread.smp_lock_count++;
current->thread.smp_lock_pc = ((unsigned int)caller);
put_cpu();
}
void _do_write_unlock(rwlock_t *rw, unsigned long caller)
{
unsigned long val;
int stuck = INIT_STUCK;
int shown = 0;
/* Drop our identity _first_ */
rw->writer_pc = 0;
rw->writer_cpu = NO_PROC_ID;
current->thread.smp_lock_count--;
wlock_again:
__asm__ __volatile__(
" membar #StoreLoad | #LoadLoad\n"
" mov 1, %%g3\n"
" sllx %%g3, 63, %%g3\n"
" ldx [%0], %%g1\n"
" andn %%g1, %%g3, %%g7\n"
" casx [%0], %%g1, %%g7\n"
" membar #StoreLoad | #StoreStore\n"
" sub %%g1, %%g7, %0\n"
: "=r" (val)
: "0" (&(rw->lock))
: "g3", "g1", "g7", "memory");
if (val) {
if (!--stuck) {
if (shown++ <= 2)
show_write("write_unlock", rw, caller);
stuck = INIT_STUCK;
}
goto wlock_again;
}
}
int _do_write_trylock(rwlock_t *rw, char *str, unsigned long caller)
{
unsigned long val;
int cpu = get_cpu();
/* Try to acuire the write bit. */
__asm__ __volatile__(
" mov 1, %%g3\n"
" sllx %%g3, 63, %%g3\n"
" ldx [%0], %%g1\n"
" brlz,pn %%g1, 1f\n"
" or %%g1, %%g3, %%g7\n"
" casx [%0], %%g1, %%g7\n"
" membar #StoreLoad | #StoreStore\n"
" ba,pt %%xcc, 2f\n"
" sub %%g1, %%g7, %0\n"
"1: mov 1, %0\n"
"2:" : "=r" (val)
: "0" (&(rw->lock))
: "g3", "g1", "g7", "memory");
if (val) {
put_cpu();
return 0;
}
if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) {
/* Readers still around, drop the write
* lock, return failure.
*/
__asm__ __volatile__(
" mov 1, %%g3\n"
" sllx %%g3, 63, %%g3\n"
"1: ldx [%0], %%g1\n"
" andn %%g1, %%g3, %%g7\n"
" casx [%0], %%g1, %%g7\n"
" cmp %%g1, %%g7\n"
" membar #StoreLoad | #StoreStore\n"
" bne,pn %%xcc, 1b\n"
" nop"
: /* no outputs */
: "r" (&(rw->lock))
: "g3", "g1", "g7", "cc", "memory");
put_cpu();
return 0;
}
/* We have it, say who we are. */
rw->writer_pc = ((unsigned int)caller);
rw->writer_cpu = cpu;
current->thread.smp_lock_count++;
current->thread.smp_lock_pc = ((unsigned int)caller);
put_cpu();
return 1;
}
#endif /* CONFIG_SMP */
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