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Subjectalpha spinlock.h update
On Tue, Mar 22, 2005 at 01:01:45PM -0800, Andrew Morton wrote:
> I had the impression Richard planned on something more sophisticated
> than this??

Indeed. I suppose I can pass it along to avoid repeated "it doesn't build"
messages, but an smp kernel doesn't run. *All* processes spawned by init(1)
die with SIGILL very very shortly. I can only guess that there's been some
change to flushing (icache or tlb) that went wrong.



r~



===== include/asm-alpha/spinlock.h 1.14 vs edited =====
--- 1.14/include/asm-alpha/spinlock.h 2005-01-20 08:21:23 -08:00
+++ edited/include/asm-alpha/spinlock.h 2005-03-20 13:53:46 -08:00
@@ -15,7 +15,7 @@
*/

typedef struct {
- volatile unsigned int lock /*__attribute__((aligned(32))) */;
+ volatile unsigned int lock;
#ifdef CONFIG_DEBUG_SPINLOCK
int on_cpu;
int line_no;
@@ -23,40 +23,26 @@
struct task_struct * task;
const char *base_file;
#endif
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
} spinlock_t;

#ifdef CONFIG_DEBUG_SPINLOCK
-#define SPIN_LOCK_UNLOCKED (spinlock_t) {0, -1, 0, NULL, NULL, NULL}
-#define spin_lock_init(x) \
- ((x)->lock = 0, (x)->on_cpu = -1, (x)->previous = NULL, (x)->task = NULL)
+#define SPIN_LOCK_UNLOCKED (spinlock_t){ 0, -1, 0, NULL, NULL, NULL }
#else
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
-#define spin_lock_init(x) ((x)->lock = 0)
+#define SPIN_LOCK_UNLOCKED (spinlock_t){ 0 }
#endif

+#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
#define spin_is_locked(x) ((x)->lock != 0)
-#define spin_unlock_wait(x) ({ do { barrier(); } while ((x)->lock); })
-#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+#define spin_unlock_wait(x) do { barrier(); } while ((x)->lock)

#ifdef CONFIG_DEBUG_SPINLOCK
extern void _raw_spin_unlock(spinlock_t * lock);
extern void debug_spin_lock(spinlock_t * lock, const char *, int);
extern int debug_spin_trylock(spinlock_t * lock, const char *, int);
-
-#define _raw_spin_lock(LOCK) debug_spin_lock(LOCK, __BASE_FILE__, __LINE__)
-#define _raw_spin_trylock(LOCK) debug_spin_trylock(LOCK, __BASE_FILE__, __LINE__)
-
-#define spin_lock_own(LOCK, LOCATION) \
-do { \
- if (!((LOCK)->lock && (LOCK)->on_cpu == smp_processor_id())) \
- printk("%s: called on %d from %p but lock %s on %d\n", \
- LOCATION, smp_processor_id(), \
- __builtin_return_address(0), \
- (LOCK)->lock ? "taken" : "freed", (LOCK)->on_cpu); \
-} while (0)
+#define _raw_spin_lock(LOCK) \
+ debug_spin_lock(LOCK, __BASE_FILE__, __LINE__)
+#define _raw_spin_trylock(LOCK) \
+ debug_spin_trylock(LOCK, __BASE_FILE__, __LINE__)
#else
static inline void _raw_spin_unlock(spinlock_t * lock)
{
@@ -68,19 +54,16 @@
{
long tmp;

- /* 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"
- " blbs %0,2f\n"
- " or %0,1,%0\n"
+ " bne %0,2f\n"
+ " lda %0,1\n"
" stl_c %0,%1\n"
" beq %0,2f\n"
" mb\n"
".subsection 2\n"
"2: ldl %0,%1\n"
- " blbs %0,2b\n"
+ " bne %0,2b\n"
" br 1b\n"
".previous"
: "=&r" (tmp), "=m" (lock->lock)
@@ -91,22 +74,29 @@
{
return !test_and_set_bit(0, &lock->lock);
}
-
-#define spin_lock_own(LOCK, LOCATION) ((void)0)
#endif /* CONFIG_DEBUG_SPINLOCK */

+#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+
/***********************************************************/

typedef struct {
- volatile unsigned int write_lock:1, read_counter:31;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} /*__attribute__((aligned(32)))*/ rwlock_t;
+ volatile unsigned int lock;
+} rwlock_t;
+
+#define RW_LOCK_UNLOCKED (rwlock_t){ 0 }

-#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
+#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)

-#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
+static inline int read_can_lock(rwlock_t *lock)
+{
+ return (lock->lock & 1) == 0;
+}
+
+static inline int write_can_lock(rwlock_t *lock)
+{
+ return lock->lock == 0;
+}

#ifdef CONFIG_DEBUG_RWLOCK
extern void _raw_write_lock(rwlock_t * lock);
@@ -119,7 +109,7 @@
__asm__ __volatile__(
"1: ldl_l %1,%0\n"
" bne %1,6f\n"
- " or $31,1,%1\n"
+ " lda %1,1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
" mb\n"
@@ -142,7 +132,7 @@
" subl %1,2,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
- "4: mb\n"
+ " mb\n"
".subsection 2\n"
"6: ldl %1,%0\n"
" blbs %1,6b\n"
@@ -153,6 +143,28 @@
}
#endif /* CONFIG_DEBUG_RWLOCK */

+static inline int _raw_read_trylock(rwlock_t * lock)
+{
+ long regx;
+ int success;
+
+ __asm__ __volatile__(
+ "1: ldl_l %1,%0\n"
+ " lda %2,0\n"
+ " blbs %1,2f\n"
+ " subl %1,2,%2\n"
+ " stl_c %2,%0\n"
+ " beq %2,6f\n"
+ "2: mb\n"
+ ".subsection 2\n"
+ "6: br 1b\n"
+ ".previous"
+ : "=m" (*lock), "=&r" (regx), "=&r" (success)
+ : "m" (*lock) : "memory");
+
+ return success;
+}
+
static inline int _raw_write_trylock(rwlock_t * lock)
{
long regx;
@@ -162,10 +174,9 @@
"1: ldl_l %1,%0\n"
" lda %2,0\n"
" bne %1,2f\n"
- " or $31,1,%1\n"
- " stl_c %1,%0\n"
- " beq %1,6f\n"
" lda %2,1\n"
+ " stl_c %2,%0\n"
+ " beq %2,6f\n"
"2: mb\n"
".subsection 2\n"
"6: br 1b\n"
@@ -179,7 +190,7 @@
static inline void _raw_write_unlock(rwlock_t * lock)
{
mb();
- *(volatile int *)lock = 0;
+ lock->lock = 0;
}

static inline void _raw_read_unlock(rwlock_t * lock)
-
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