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, 251 insertions, 0 deletions

diff --git a/arch/sparc64/kernel/semaphore.c b/arch/sparc64/kernel/semaphore.c
new file mode 100644
index 000000000000..63496c43fe17
--- /dev/null
+++ b/arch/sparc64/kernel/semaphore.c
@@ -0,0 +1,251 @@
+/* $Id: semaphore.c,v 1.9 2001/11/18 00:12:56 davem Exp $
+ * semaphore.c: Sparc64 semaphore implementation.
+ *
+ * This is basically the PPC semaphore scheme ported to use
+ * the sparc64 atomic instructions, so see the PPC code for
+ * credits.
+ */
+
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+
+/*
+ * Atomically update sem->count.
+ * This does the equivalent of the following:
+ *
+ *      old_count = sem->count;
+ *      tmp = MAX(old_count, 0) + incr;
+ *      sem->count = tmp;
+ *      return old_count;
+ */
+static __inline__ int __sem_update_count(struct semaphore *sem, int incr)
+{
+        int old_count, tmp;
+
+        __asm__ __volatile__("\n"
+"       ! __sem_update_count old_count(%0) tmp(%1) incr(%4) &sem->count(%3)\n"
+"1:     ldsw    [%3], %0\n"
+"       mov     %0, %1\n"
+"       cmp     %0, 0\n"
+"       movl    %%icc, 0, %1\n"
+"       add     %1, %4, %1\n"
+"       cas     [%3], %0, %1\n"
+"       cmp     %0, %1\n"
+"       bne,pn  %%icc, 1b\n"
+"        membar #StoreLoad | #StoreStore\n"
+        : "=&r" (old_count), "=&r" (tmp), "=m" (sem->count)
+        : "r" (&sem->count), "r" (incr), "m" (sem->count)
+        : "cc");
+
+        return old_count;
+}
+
+static void __up(struct semaphore *sem)
+{
+        __sem_update_count(sem, 1);
+        wake_up(&sem->wait);
+}
+
+void up(struct semaphore *sem)
+{
+        /* This atomically does:
+         *      old_val = sem->count;
+         *      new_val = sem->count + 1;
+         *      sem->count = new_val;
+         *      if (old_val < 0)
+         *              __up(sem);
+         *
+         * The (old_val < 0) test is equivalent to
+         * the more straightforward (new_val <= 0),
+         * but it is easier to test the former because
+         * of how the CAS instruction works.
+         */
+
+        __asm__ __volatile__("\n"
+"       ! up sem(%0)\n"
+"       membar  #StoreLoad | #LoadLoad\n"
+"1:     lduw    [%0], %%g1\n"
+"       add     %%g1, 1, %%g7\n"
+"       cas     [%0], %%g1, %%g7\n"
+"       cmp     %%g1, %%g7\n"
+"       bne,pn  %%icc, 1b\n"
+"        addcc  %%g7, 1, %%g0\n"
+"       ble,pn  %%icc, 3f\n"
+"        membar #StoreLoad | #StoreStore\n"
+"2:\n"
+"       .subsection 2\n"
+"3:     mov     %0, %%g1\n"
+"       save    %%sp, -160, %%sp\n"
+"       call    %1\n"
+"        mov    %%g1, %%o0\n"
+"       ba,pt   %%xcc, 2b\n"
+"        restore\n"
+"       .previous\n"
+        : : "r" (sem), "i" (__up)
+        : "g1", "g2", "g3", "g7", "memory", "cc");
+}
+
+static void __sched __down(struct semaphore * sem)
+{
+        struct task_struct *tsk = current;
+        DECLARE_WAITQUEUE(wait, tsk);
+
+        tsk->state = TASK_UNINTERRUPTIBLE;
+        add_wait_queue_exclusive(&sem->wait, &wait);
+
+        while (__sem_update_count(sem, -1) <= 0) {
+                schedule();
+                tsk->state = TASK_UNINTERRUPTIBLE;
+        }
+        remove_wait_queue(&sem->wait, &wait);
+        tsk->state = TASK_RUNNING;
+
+        wake_up(&sem->wait);
+}
+
+void __sched down(struct semaphore *sem)
+{
+        might_sleep();
+        /* This atomically does:
+         *      old_val = sem->count;
+         *      new_val = sem->count - 1;
+         *      sem->count = new_val;
+         *      if (old_val < 1)
+         *              __down(sem);
+         *
+         * The (old_val < 1) test is equivalent to
+         * the more straightforward (new_val < 0),
+         * but it is easier to test the former because
+         * of how the CAS instruction works.
+         */
+
+        __asm__ __volatile__("\n"
+"       ! down sem(%0)\n"
+"1:     lduw    [%0], %%g1\n"
+"       sub     %%g1, 1, %%g7\n"
+"       cas     [%0], %%g1, %%g7\n"
+"       cmp     %%g1, %%g7\n"
+"       bne,pn  %%icc, 1b\n"
+"        cmp    %%g7, 1\n"
+"       bl,pn   %%icc, 3f\n"
+"        membar #StoreLoad | #StoreStore\n"
+"2:\n"
+"       .subsection 2\n"
+"3:     mov     %0, %%g1\n"
+"       save    %%sp, -160, %%sp\n"
+"       call    %1\n"
+"        mov    %%g1, %%o0\n"
+"       ba,pt   %%xcc, 2b\n"
+"        restore\n"
+"       .previous\n"
+        : : "r" (sem), "i" (__down)
+        : "g1", "g2", "g3", "g7", "memory", "cc");
+}
+
+int down_trylock(struct semaphore *sem)
+{
+        int ret;
+
+        /* This atomically does:
+         *      old_val = sem->count;
+         *      new_val = sem->count - 1;
+         *      if (old_val < 1) {
+         *              ret = 1;
+         *      } else {
+         *              sem->count = new_val;
+         *              ret = 0;
+         *      }
+         *
+         * The (old_val < 1) test is equivalent to
+         * the more straightforward (new_val < 0),
+         * but it is easier to test the former because
+         * of how the CAS instruction works.
+         */
+
+        __asm__ __volatile__("\n"
+"       ! down_trylock sem(%1) ret(%0)\n"
+"1:     lduw    [%1], %%g1\n"
+"       sub     %%g1, 1, %%g7\n"
+"       cmp     %%g1, 1\n"
+"       bl,pn   %%icc, 2f\n"
+"        mov    1, %0\n"
+"       cas     [%1], %%g1, %%g7\n"
+"       cmp     %%g1, %%g7\n"
+"       bne,pn  %%icc, 1b\n"
+"        mov    0, %0\n"
+"       membar  #StoreLoad | #StoreStore\n"
+"2:\n"
+        : "=&r" (ret)
+        : "r" (sem)
+        : "g1", "g7", "memory", "cc");
+
+        return ret;
+}
+
+static int __sched __down_interruptible(struct semaphore * sem)
+{
+        int retval = 0;
+        struct task_struct *tsk = current;
+        DECLARE_WAITQUEUE(wait, tsk);
+
+        tsk->state = TASK_INTERRUPTIBLE;
+        add_wait_queue_exclusive(&sem->wait, &wait);
+
+        while (__sem_update_count(sem, -1) <= 0) {
+                if (signal_pending(current)) {
+                        __sem_update_count(sem, 0);
+                        retval = -EINTR;
+                        break;
+                }
+                schedule();
+                tsk->state = TASK_INTERRUPTIBLE;
+        }
+        tsk->state = TASK_RUNNING;
+        remove_wait_queue(&sem->wait, &wait);
+        wake_up(&sem->wait);
+        return retval;
+}
+
+int __sched down_interruptible(struct semaphore *sem)
+{
+        int ret = 0;
+        
+        might_sleep();
+        /* This atomically does:
+         *      old_val = sem->count;
+         *      new_val = sem->count - 1;
+         *      sem->count = new_val;
+         *      if (old_val < 1)
+         *              ret = __down_interruptible(sem);
+         *
+         * The (old_val < 1) test is equivalent to
+         * the more straightforward (new_val < 0),
+         * but it is easier to test the former because
+         * of how the CAS instruction works.
+         */
+
+        __asm__ __volatile__("\n"
+"       ! down_interruptible sem(%2) ret(%0)\n"
+"1:     lduw    [%2], %%g1\n"
+"       sub     %%g1, 1, %%g7\n"
+"       cas     [%2], %%g1, %%g7\n"
+"       cmp     %%g1, %%g7\n"
+"       bne,pn  %%icc, 1b\n"
+"        cmp    %%g7, 1\n"
+"       bl,pn   %%icc, 3f\n"
+"        membar #StoreLoad | #StoreStore\n"
+"2:\n"
+"       .subsection 2\n"
+"3:     mov     %2, %%g1\n"
+"       save    %%sp, -160, %%sp\n"
+"       call    %3\n"
+"        mov    %%g1, %%o0\n"
+"       ba,pt   %%xcc, 2b\n"
+"        restore\n"
+"       .previous\n"
+        : "=r" (ret)
+        : "0" (ret), "r" (sem), "i" (__down_interruptible)
+        : "g1", "g2", "g3", "g7", "memory", "cc");
+        return ret;
+}