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authorGlauber de Oliveira Costa <gcosta@redhat.com>2008-01-30 13:30:33 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:30:33 +0100
commit2fed0c507cf0101d511366f36e8573f403dbfea5 (patch)
treed73332fca3b4a515755ad10b313780ca54f84fc1 /include/asm-x86/spinlock_64.h
parentx86: irqflags consolidation (diff)
downloadlinux-dev-2fed0c507cf0101d511366f36e8573f403dbfea5.tar.xz
linux-dev-2fed0c507cf0101d511366f36e8573f403dbfea5.zip
x86: consolidate spinlock.h
The cli and sti instructions need to be replaced by paravirt hooks. For the i386 architecture, this is already done. The code requirements aren't much different from x86_64 POV, so this part is consolidated in the common header Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to '')
-rw-r--r--include/asm-x86/spinlock_64.h37
1 files changed, 24 insertions, 13 deletions
diff --git a/include/asm-x86/spinlock_64.h b/include/asm-x86/spinlock_64.h
index 88bf981e73cf..3b5adf92ad08 100644
--- a/include/asm-x86/spinlock_64.h
+++ b/include/asm-x86/spinlock_64.h
@@ -33,14 +33,21 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
"cmpl $0,%0\n\t"
"jle 3b\n\t"
"jmp 1b\n"
- "2:\t" : "=m" (lock->slock) : : "memory");
+ "2:\t"
+ : "=m" (lock->slock) : : "memory");
}
/*
- * Same as __raw_spin_lock, but reenable interrupts during spinning.
+ * It is easier for the lock validator if interrupts are not re-enabled
+ * in the middle of a lock-acquire. This is a performance feature anyway
+ * so we turn it off:
+ *
+ * NOTE: there's an irqs-on section here, which normally would have to be
+ * irq-traced, but on CONFIG_TRACE_IRQFLAGS we never use this variant.
*/
#ifndef CONFIG_PROVE_LOCKING
-static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
+static inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
+ unsigned long flags)
{
asm volatile(
"\n1:\t"
@@ -48,12 +55,12 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla
"jns 5f\n"
"testl $0x200, %1\n\t" /* interrupts were disabled? */
"jz 4f\n\t"
- "sti\n"
+ STI_STRING "\n"
"3:\t"
"rep;nop\n\t"
"cmpl $0, %0\n\t"
"jle 3b\n\t"
- "cli\n\t"
+ CLI_STRING "\n\t"
"jmp 1b\n"
"4:\t"
"rep;nop\n\t"
@@ -61,7 +68,9 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla
"jg 1b\n\t"
"jmp 4b\n"
"5:\n\t"
- : "+m" (lock->slock) : "r" ((unsigned)flags) : "memory");
+ : "+m" (lock->slock)
+ : "r" ((unsigned)flags) CLI_STI_INPUT_ARGS
+ : "memory" CLI_STI_CLOBBERS);
}
#endif
@@ -79,7 +88,7 @@ static inline int __raw_spin_trylock(raw_spinlock_t *lock)
static inline void __raw_spin_unlock(raw_spinlock_t *lock)
{
- asm volatile("movl $1,%0" :"=m" (lock->slock) :: "memory");
+ asm volatile("movl $1,%0" : "=m" (lock->slock) :: "memory");
}
static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
@@ -114,18 +123,18 @@ static inline int __raw_write_can_lock(raw_rwlock_t *lock)
static inline void __raw_read_lock(raw_rwlock_t *rw)
{
- asm volatile(LOCK_PREFIX "subl $1,(%0)\n\t"
+ asm volatile(LOCK_PREFIX " subl $1,(%0)\n\t"
"jns 1f\n"
- "call __read_lock_failed\n"
+ "call __read_lock_failed\n\t"
"1:\n"
::"D" (rw), "i" (RW_LOCK_BIAS) : "memory");
}
static inline void __raw_write_lock(raw_rwlock_t *rw)
{
- asm volatile(LOCK_PREFIX "subl %1,(%0)\n\t"
+ asm volatile(LOCK_PREFIX " subl %1,(%0)\n\t"
"jz 1f\n"
- "\tcall __write_lock_failed\n\t"
+ "call __write_lock_failed\n\t"
"1:\n"
::"D" (rw), "i" (RW_LOCK_BIAS) : "memory");
}
@@ -133,6 +142,7 @@ static inline void __raw_write_lock(raw_rwlock_t *rw)
static inline int __raw_read_trylock(raw_rwlock_t *lock)
{
atomic_t *count = (atomic_t *)lock;
+
atomic_dec(count);
if (atomic_read(count) >= 0)
return 1;
@@ -143,6 +153,7 @@ static inline int __raw_read_trylock(raw_rwlock_t *lock)
static inline int __raw_write_trylock(raw_rwlock_t *lock)
{
atomic_t *count = (atomic_t *)lock;
+
if (atomic_sub_and_test(RW_LOCK_BIAS, count))
return 1;
atomic_add(RW_LOCK_BIAS, count);
@@ -151,12 +162,12 @@ static inline int __raw_write_trylock(raw_rwlock_t *lock)
static inline void __raw_read_unlock(raw_rwlock_t *rw)
{
- asm volatile(LOCK_PREFIX " ; incl %0" :"=m" (rw->lock) : : "memory");
+ asm volatile(LOCK_PREFIX "incl %0" :"=m" (rw->lock) : : "memory");
}
static inline void __raw_write_unlock(raw_rwlock_t *rw)
{
- asm volatile(LOCK_PREFIX " ; addl $" RW_LOCK_BIAS_STR ",%0"
+ asm volatile(LOCK_PREFIX "addl $" RW_LOCK_BIAS_STR ",%0"
: "=m" (rw->lock) : : "memory");
}