Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 260 insertions, 0 deletions

diff --git a/include/asm-ppc64/spinlock.h b/include/asm-ppc64/spinlock.h
new file mode 100644
index 000000000000..a9b2a1162cf7
--- /dev/null
+++ b/include/asm-ppc64/spinlock.h
@@ -0,0 +1,260 @@
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+/*
+ * Simple spin lock operations.  
+ *
+ * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM
+ * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
+ * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM
+ *      Rework to support virtual processors
+ *
+ * Type of int is used as a full 64b word is not necessary.
+ *
+ * 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.
+ */
+#include <linux/config.h>
+#include <asm/paca.h>
+#include <asm/hvcall.h>
+#include <asm/iSeries/HvCall.h>
+
+typedef struct {
+        volatile unsigned int lock;
+#ifdef CONFIG_PREEMPT
+        unsigned int break_lock;
+#endif
+} spinlock_t;
+
+typedef struct {
+        volatile signed int lock;
+#ifdef CONFIG_PREEMPT
+        unsigned int break_lock;
+#endif
+} rwlock_t;
+
+#ifdef __KERNEL__
+#define SPIN_LOCK_UNLOCKED      (spinlock_t) { 0 }
+
+#define spin_is_locked(x)       ((x)->lock != 0)
+#define spin_lock_init(x)       do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
+
+static __inline__ void _raw_spin_unlock(spinlock_t *lock)
+{
+        __asm__ __volatile__("lwsync    # spin_unlock": : :"memory");
+        lock->lock = 0;
+}
+
+/*
+ * On a system with shared processors (that is, where a physical
+ * processor is multiplexed between several virtual processors),
+ * there is no point spinning on a lock if the holder of the lock
+ * isn't currently scheduled on a physical processor.  Instead
+ * we detect this situation and ask the hypervisor to give the
+ * rest of our timeslice to the lock holder.
+ *
+ * So that we can tell which virtual processor is holding a lock,
+ * we put 0x80000000 | smp_processor_id() in the lock when it is
+ * held.  Conveniently, we have a word in the paca that holds this
+ * value.
+ */
+
+#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
+/* We only yield to the hypervisor if we are in shared processor mode */
+#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc)
+extern void __spin_yield(spinlock_t *lock);
+extern void __rw_yield(rwlock_t *lock);
+#else /* SPLPAR || ISERIES */
+#define __spin_yield(x) barrier()
+#define __rw_yield(x)   barrier()
+#define SHARED_PROCESSOR        0
+#endif
+extern void spin_unlock_wait(spinlock_t *lock);
+
+/*
+ * This returns the old value in the lock, so we succeeded
+ * in getting the lock if the return value is 0.
+ */
+static __inline__ unsigned long __spin_trylock(spinlock_t *lock)
+{
+        unsigned long tmp, tmp2;
+
+        __asm__ __volatile__(
+"       lwz             %1,%3(13)               # __spin_trylock\n\
+1:      lwarx           %0,0,%2\n\
+        cmpwi           0,%0,0\n\
+        bne-            2f\n\
+        stwcx.          %1,0,%2\n\
+        bne-            1b\n\
+        isync\n\
+2:"     : "=&r" (tmp), "=&r" (tmp2)
+        : "r" (&lock->lock), "i" (offsetof(struct paca_struct, lock_token))
+        : "cr0", "memory");
+
+        return tmp;
+}
+
+static int __inline__ _raw_spin_trylock(spinlock_t *lock)
+{
+        return __spin_trylock(lock) == 0;
+}
+
+static void __inline__ _raw_spin_lock(spinlock_t *lock)
+{
+        while (1) {
+                if (likely(__spin_trylock(lock) == 0))
+                        break;
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __spin_yield(lock);
+                } while (likely(lock->lock != 0));
+                HMT_medium();
+        }
+}
+
+static void __inline__ _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags)
+{
+        unsigned long flags_dis;
+
+        while (1) {
+                if (likely(__spin_trylock(lock) == 0))
+                        break;
+                local_save_flags(flags_dis);
+                local_irq_restore(flags);
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __spin_yield(lock);
+                } while (likely(lock->lock != 0));
+                HMT_medium();
+                local_irq_restore(flags_dis);
+        }
+}
+
+/*
+ * 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.
+ */
+#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
+
+#define rwlock_init(x)          do { *(x) = RW_LOCK_UNLOCKED; } while(0)
+
+#define read_can_lock(rw)       ((rw)->lock >= 0)
+#define write_can_lock(rw)      (!(rw)->lock)
+
+static __inline__ void _raw_write_unlock(rwlock_t *rw)
+{
+        __asm__ __volatile__("lwsync            # write_unlock": : :"memory");
+        rw->lock = 0;
+}
+
+/*
+ * This returns the old value in the lock + 1,
+ * so we got a read lock if the return value is > 0.
+ */
+static long __inline__ __read_trylock(rwlock_t *rw)
+{
+        long tmp;
+
+        __asm__ __volatile__(
+"1:     lwarx           %0,0,%1         # read_trylock\n\
+        extsw           %0,%0\n\
+        addic.          %0,%0,1\n\
+        ble-            2f\n\
+        stwcx.          %0,0,%1\n\
+        bne-            1b\n\
+        isync\n\
+2:"     : "=&r" (tmp)
+        : "r" (&rw->lock)
+        : "cr0", "xer", "memory");
+
+        return tmp;
+}
+
+static int __inline__ _raw_read_trylock(rwlock_t *rw)
+{
+        return __read_trylock(rw) > 0;
+}
+
+static void __inline__ _raw_read_lock(rwlock_t *rw)
+{
+        while (1) {
+                if (likely(__read_trylock(rw) > 0))
+                        break;
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __rw_yield(rw);
+                } while (likely(rw->lock < 0));
+                HMT_medium();
+        }
+}
+
+static void __inline__ _raw_read_unlock(rwlock_t *rw)
+{
+        long tmp;
+
+        __asm__ __volatile__(
+        "eieio                          # read_unlock\n\
+1:      lwarx           %0,0,%1\n\
+        addic           %0,%0,-1\n\
+        stwcx.          %0,0,%1\n\
+        bne-            1b"
+        : "=&r"(tmp)
+        : "r"(&rw->lock)
+        : "cr0", "memory");
+}
+
+/*
+ * This returns the old value in the lock,
+ * so we got the write lock if the return value is 0.
+ */
+static __inline__ long __write_trylock(rwlock_t *rw)
+{
+        long tmp, tmp2;
+
+        __asm__ __volatile__(
+"       lwz             %1,%3(13)       # write_trylock\n\
+1:      lwarx           %0,0,%2\n\
+        cmpwi           0,%0,0\n\
+        bne-            2f\n\
+        stwcx.          %1,0,%2\n\
+        bne-            1b\n\
+        isync\n\
+2:"     : "=&r" (tmp), "=&r" (tmp2)
+        : "r" (&rw->lock), "i" (offsetof(struct paca_struct, lock_token))
+        : "cr0", "memory");
+
+        return tmp;
+}
+
+static int __inline__ _raw_write_trylock(rwlock_t *rw)
+{
+        return __write_trylock(rw) == 0;
+}
+
+static void __inline__ _raw_write_lock(rwlock_t *rw)
+{
+        while (1) {
+                if (likely(__write_trylock(rw) == 0))
+                        break;
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __rw_yield(rw);
+                } while (likely(rw->lock != 0));
+                HMT_medium();
+        }
+}
+
+#endif /* __KERNEL__ */
+#endif /* __ASM_SPINLOCK_H */