[freenos] r413 committed - Simplified the implementation of the (x86/pc) spinlock.
- From: freenos@xxxxxxxxxxxxxx
- To: freenos@xxxxxxxxxxxxx
- Date: Thu, 21 Oct 2010 21:34:26 +0000
Revision: 413
Author: nieklinnenbank
Date: Thu Oct 21 14:33:28 2010
Log: Simplified the implementation of the (x86/pc) spinlock.
http://code.google.com/p/freenos/source/detail?r=413
Modified:
/branches/scratch/include/kernel/spinlock.h
/branches/scratch/system/x86/pc/spinlock.c
=======================================
--- /branches/scratch/include/kernel/spinlock.h Sun Oct 10 16:06:55 2010
+++ /branches/scratch/include/kernel/spinlock.h Thu Oct 21 14:33:28 2010
@@ -21,10 +21,12 @@
#include "types.h"
#include "macro.h"
+#define SPINLOCK_LOCKED 1
+#define SPINLOCK_UNLOCKED 0
+
typedef struct spinlock
{
- u32 cpu_id;
- u32 context;
+ u32 state;
}
PACKED spinlock_t;
@@ -33,4 +35,3 @@
extern void spinlock_leave(spinlock_t *spinlock);
#endif /* __SPINLOCK_H */
-
=======================================
--- /branches/scratch/system/x86/pc/spinlock.c Sun Oct 10 16:06:55 2010
+++ /branches/scratch/system/x86/pc/spinlock.c Thu Oct 21 14:33:28 2010
@@ -22,34 +22,21 @@
void spinlock_init(spinlock_t *spinlock)
{
- spinlock->cpu_id = -1;
- spinlock->context = 0;
+ spinlock->state = SPINLOCK_UNLOCKED;
}
void spinlock_enter(spinlock_t *spinlock)
{
- /* Obtain current EFLAGS. */
- u32 eflags = get_eflags();
- u32 my_id = smp_id();
-
- /* Disable IRQ's. */
- irq_disable();
-
- /* Try to obtain the lock. Wait for other CPU if needed. */
- __asm__ volatile("1: movl $-1,%%eax; lock; cmpxchgl %0,(%1); jne 1b"
- : : "r" (my_id), "r" (&spinlock->cpu_id) : "eax");
-
- /* Save EFLAGS register in spinlock. */
- spinlock->context = eflags;
+ __asm__ volatile ("1: movl %0, %%eax;"
+ " lock;"
+ " cmpxchgl %1,(%2);"
+ " jne 1b"
+ :: "r" (SPINLOCK_UNLOCKED),
+ "r" (SPINLOCK_LOCKED),
+ "r" (&spinlock->state) : "eax");
}
void spinlock_leave(spinlock_t *spinlock)
{
- /* Unlock the global spin lock. */
- __asm__ volatile("movl %0,(%1)"
- : : "r" (-1), "r" (&spinlock->cpu_id));
-
- /* Restore IRQ state. */
- set_eflags(spinlock->context);
-}
-
+ spinlock->state = SPINLOCK_UNLOCKED;
+}
Other related posts:
- » [freenos] r413 committed - Simplified the implementation of the (x86/pc) spinlock. - freenos
