patch-2.4.4 linux/arch/ia64/sn/sn1/sv.c

• Lines: 552
• Date: Thu Apr 5 12:51:47 2001
• Orig file: v2.4.3/linux/arch/ia64/sn/sn1/sv.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.3/linux/arch/ia64/sn/sn1/sv.c linux/arch/ia64/sn/sn1/sv.c
@@ -0,0 +1,551 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2000 Silicon Graphics, Inc.  All rights reserved
+ *
+ * This implemenation of synchronization variables is heavily based on
+ * one done by Steve Lord <lord@sgi.com>
+ *
+ * Paul Cassella <pwc@sgi.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+
+#include <asm/semaphore.h>
+#include <asm/hardirq.h>
+#include <asm/softirq.h>
+#include <asm/current.h>
+
+#include <asm/sn/sv.h>
+
+/* Define this to have sv_test() run some simple tests.
+   kernel_thread() must behave as expected when this is called.  */
+#undef RUN_SV_TEST
+
+#define DEBUG
+
+/* Set up some macros so sv_wait(), sv_signal(), and sv_broadcast()
+   can sanity check interrupt state on architectures where we know
+   how. */
+#ifdef DEBUG
+ #define SV_DEBUG_INTERRUPT_STATE
+ #ifdef __mips64
+  #define SV_TEST_INTERRUPTS_ENABLED(flags) ((flags & 0x1) != 0)
+  #define SV_TEST_INTERRUPTS_DISABLED(flags) ((flags & 0x1) == 0)
+  #define SV_INTERRUPT_TEST_WORKERS 31
+ #elif defined(__ia64)
+  #define SV_TEST_INTERRUPTS_ENABLED(flags) ((flags & 0x4000) != 0)
+  #define SV_TEST_INTERRUPTS_DISABLED(flags) ((flags & 0x4000) == 0)
+  #define SV_INTERRUPT_TEST_WORKERS 4 /* simulator's slow */
+ #else
+  #undef  SV_DEBUG_INTERRUPT_STATE
+  #define SV_INTERRUPT_TEST_WORKERS 4 /* reasonable? default. */
+ #endif /* __mips64 */
+#endif /* DEBUG */
+
+
+/* XXX FIXME hack hack hack.  Our mips64 tree is from before the
+   switch to WQ_FLAG_EXCLUSIVE, and our ia64 tree is from after it. */
+#ifdef TASK_EXCLUSIVE
+  #undef EXCLUSIVE_IN_QUEUE
+#else
+  #define EXCLUSIVE_IN_QUEUE
+  #define TASK_EXCLUSIVE 0 /* for the set_current_state() in sv_wait() */
+#endif
+
+
+static inline void sv_lock(sv_t *sv) {
+	spin_lock(&sv->sv_lock);
+}
+
+static inline void sv_unlock(sv_t *sv) {
+	spin_unlock(&sv->sv_lock);
+}
+
+/* up() is "extern inline", so we can't pass its address to sv_wait.
+   Use this function's address instead. */
+static void up_wrapper(struct semaphore *sem) {
+	up(sem);
+}
+
+/* spin_unlock() is sometimes a macro. */
+static void spin_unlock_wrapper(spinlock_t *s) {
+	spin_unlock(s);
+}
+
+/* XXX Perhaps sv_wait() should do the switch() each time and avoid
+   the extra indirection and the need for the _wrapper functions? */
+
+static inline void sv_set_mon_type(sv_t *sv, int type) {
+	switch (type) {
+	case SV_MON_SPIN:
+		sv->sv_mon_unlock_func =
+		  (sv_mon_unlock_func_t)spin_unlock_wrapper;
+		break;
+	case SV_MON_SEMA:
+		sv->sv_mon_unlock_func =
+		  (sv_mon_unlock_func_t)up_wrapper;
+		if(sv->sv_flags & SV_INTS) {
+			printk(KERN_ERR "sv_set_mon_type: The monitor lock "
+			       "cannot be shared with interrupts if it is a "
+			       "semaphore!\n");
+			BUG();
+		}
+		if(sv->sv_flags & SV_BHS) {
+			printk(KERN_ERR "sv_set_mon_type: The monitor lock "
+			       "cannot be shared with bottom-halves if it is "
+			       "a semaphore!\n");
+			BUG();
+		}
+		break;
+#if 0 
+	/*
+	 * If needed, and will need to think about interrupts.  This
+	 * may be needed, for example, if someone wants to use sv's
+	 * with something like dev_base; writers need to hold two
+	 * locks. 
+	 */
+	case SV_MON_CUSTOM: 
+		{
+		struct sv_mon_custom *c = lock;
+		sv->sv_mon_unlock_func = c->sv_mon_unlock_func;
+		sv->sv_mon_lock        = c->sv_mon_lock;
+		break;
+		}
+#endif
+		
+	default:
+		printk(KERN_ERR "sv_set_mon_type: unknown type %d (0x%x)! "
+		       "(flags 0x%x)\n", type, type, sv->sv_flags);
+		BUG();
+		break;
+	}
+	sv->sv_flags |= type;
+}
+
+static inline void sv_set_ord(sv_t *sv, int ord) {
+	if (!ord)
+		ord = SV_ORDER_DEFAULT;
+
+	if (ord != SV_ORDER_FIFO && ord != SV_ORDER_LIFO) {
+		printk(KERN_EMERG "sv_set_ord: unknown order %d (0x%x)! ",
+		       ord, ord);
+		BUG();
+	}
+
+	sv->sv_flags |= ord;
+}
+
+void sv_init(sv_t *sv, sv_mon_lock_t *lock, int flags) 
+{
+	int ord = flags & SV_ORDER_MASK;
+	int type = flags & SV_MON_MASK;
+
+	/* Copy all non-order, non-type flags */
+	sv->sv_flags = (flags & ~(SV_ORDER_MASK | SV_MON_MASK));
+
+	if((sv->sv_flags & (SV_INTS | SV_BHS)) == (SV_INTS | SV_BHS)) {
+	  printk(KERN_ERR "sv_init: do not set both SV_INTS and SV_BHS, only SV_INTS.\n");
+	  BUG();
+	}
+
+	sv_set_ord(sv, ord);
+	sv_set_mon_type(sv, type);
+
+	/* If lock is NULL, we'll get it from sv_wait_compat() (and
+           ignore it in sv_signal() and sv_broadcast()). */
+	sv->sv_mon_lock = lock;
+
+	spin_lock_init(&sv->sv_lock);
+	init_waitqueue_head(&sv->sv_waiters);
+}
+
+/*
+ * The associated lock must be locked on entry.  It is unlocked on return.
+ *
+ * Return values:
+ *
+ * n < 0 : interrupted,  -n jiffies remaining on timeout, or -1 if timeout == 0
+ * n = 0 : timeout expired
+ * n > 0 : sv_signal()'d, n jiffies remaining on timeout, or 1 if timeout == 0
+ */
+signed long sv_wait(sv_t *sv, int sv_wait_flags, unsigned long timeout) 
+{
+	DECLARE_WAITQUEUE( wait, current );
+	unsigned long flags;
+	signed long ret = 0;
+
+#ifdef SV_DEBUG_INTERRUPT_STATE
+	{
+	unsigned long flags;
+	__save_flags(flags);
+
+	if(sv->sv_flags & SV_INTS) {
+		if(SV_TEST_INTERRUPTS_ENABLED(flags)) {
+			printk(KERN_ERR "sv_wait: SV_INTS and interrupts "
+			       "enabled (flags: 0x%lx)\n", flags);
+			BUG();
+		}
+	} else {
+		if (SV_TEST_INTERRUPTS_DISABLED(flags)) {
+			printk(KERN_WARNING "sv_wait: !SV_INTS and interrupts "
+			       "disabled! (flags: 0x%lx)\n", flags);
+		}
+	}
+	}
+#endif  /* SV_DEBUG_INTERRUPT_STATE */
+
+	sv_lock(sv);
+
+	sv->sv_mon_unlock_func(sv->sv_mon_lock);
+
+	/* Add ourselves to the wait queue and set the state before
+	 * releasing the sv_lock so as to avoid racing with the
+	 * wake_up() in sv_signal() and sv_broadcast(). 
+	 */
+
+	/* don't need the _irqsave part, but there is no wq_write_lock() */
+	wq_write_lock_irqsave(&sv->sv_waiters.lock, flags);
+
+#ifdef EXCLUSIVE_IN_QUEUE
+	wait.flags |= WQ_FLAG_EXCLUSIVE;
+#endif
+
+	switch(sv->sv_flags & SV_ORDER_MASK) {
+	case SV_ORDER_FIFO:
+		__add_wait_queue_tail(&sv->sv_waiters, &wait);
+		break;
+	case SV_ORDER_FILO:
+		__add_wait_queue(&sv->sv_waiters, &wait);
+		break;
+	default:
+		printk(KERN_ERR "sv_wait: unknown order!  (sv: 0x%p, flags: 0x%x)\n",
+					sv, sv->sv_flags);
+		BUG();
+	}
+	wq_write_unlock_irqrestore(&sv->sv_waiters.lock, flags);
+
+	if(sv_wait_flags & SV_WAIT_SIG)
+		set_current_state(TASK_EXCLUSIVE | TASK_INTERRUPTIBLE  );
+	else
+		set_current_state(TASK_EXCLUSIVE | TASK_UNINTERRUPTIBLE);
+
+	spin_unlock(&sv->sv_lock);
+
+	if(sv->sv_flags & SV_INTS)
+		local_irq_enable();
+	else if(sv->sv_flags & SV_BHS)
+		local_bh_enable();
+
+	if (timeout)
+		ret = schedule_timeout(timeout);
+	else
+		schedule();
+
+	if(current->state != TASK_RUNNING) /* XXX Is this possible? */ {
+		printk(KERN_ERR "sv_wait: state not TASK_RUNNING after "
+		       "schedule().\n");
+		set_current_state(TASK_RUNNING);
+	}
+
+	remove_wait_queue(&sv->sv_waiters, &wait);
+
+	/* Return cases:
+	   - woken by a sv_signal/sv_broadcast
+	   - woken by a signal
+	   - woken by timeout expiring
+	*/
+
+	/* XXX This isn't really accurate; we may have been woken
+           before the signal anyway.... */
+	if(signal_pending(current))
+		return timeout ? -ret : -1;
+	return timeout ? ret : 1;
+}
+
+
+void sv_signal(sv_t *sv) 
+{
+	/* If interrupts can acquire this lock, they can also acquire the
+	   sv_mon_lock, which we must already have to have called this, so
+	   interrupts must be disabled already.  If interrupts cannot
+	   contend for this lock, we don't have to worry about it. */
+
+#ifdef SV_DEBUG_INTERRUPT_STATE
+	if(sv->sv_flags & SV_INTS) {
+		unsigned long flags;
+		__save_flags(flags);
+		if(SV_TEST_INTERRUPTS_ENABLED(flags))
+			printk(KERN_ERR "sv_signal: SV_INTS and "
+			"interrupts enabled! (flags: 0x%lx)\n", flags);
+	}
+#endif /* SV_DEBUG_INTERRUPT_STATE */
+
+	sv_lock(sv);
+	wake_up(&sv->sv_waiters);
+	sv_unlock(sv);
+}
+
+void sv_broadcast(sv_t *sv) 
+{
+#ifdef SV_DEBUG_INTERRUPT_STATE
+	if(sv->sv_flags & SV_INTS) {
+		unsigned long flags;
+		__save_flags(flags);
+		if(SV_TEST_INTERRUPTS_ENABLED(flags))
+			printk(KERN_ERR "sv_broadcast: SV_INTS and "
+			       "interrupts enabled! (flags: 0x%lx)\n", flags);
+	}
+#endif /* SV_DEBUG_INTERRUPT_STATE */
+
+	sv_lock(sv);
+	wake_up_all(&sv->sv_waiters);
+	sv_unlock(sv);
+}
+
+void sv_destroy(sv_t *sv) 
+{
+	if(!spin_trylock(&sv->sv_lock)) {
+		printk(KERN_ERR "sv_destroy: someone else has sv 0x%p locked!\n", sv);
+		BUG();
+	}
+
+	/* XXX Check that the waitqueue is empty? 
+	       Mark the sv destroyed?
+	*/
+}
+
+
+#ifdef RUN_SV_TEST
+
+static DECLARE_MUTEX_LOCKED(talkback);
+static DECLARE_MUTEX_LOCKED(sem);
+sv_t sv;
+sv_t sv_filo;
+
+static int sv_test_1_w(void *arg) 
+{
+	printk("sv_test_1_w: acquiring spinlock 0x%p...\n", arg);
+
+	spin_lock((spinlock_t*)arg);
+	printk("sv_test_1_w: spinlock acquired, waking sv_test_1_s.\n");
+
+	up(&sem);
+
+	printk("sv_test_1_w: sv_spin_wait()'ing.\n");
+
+	sv_spin_wait(&sv, arg);
+
+	printk("sv_test_1_w: talkback.\n");
+	up(&talkback);
+
+	printk("sv_test_1_w: exiting.\n");
+	return 0;
+}
+
+static int sv_test_1_s(void *arg) 
+{
+	printk("sv_test_1_s: waiting for semaphore.\n");
+	down(&sem);
+	printk("sv_test_1_s: semaphore acquired.  Acquiring spinlock.\n");
+	spin_lock((spinlock_t*)arg);
+	printk("sv_test_1_s: spinlock acquired.  sv_signaling.\n");
+	sv_signal(&sv);
+	printk("sv_test_1_s: talkback.\n");
+	up(&talkback);
+	printk("sv_test_1_s: exiting.\n");
+	return 0;
+
+}
+
+static int count;
+static DECLARE_MUTEX(monitor);
+
+static int sv_test_2_w(void *arg) 
+{
+	int dummy = count++;
+	sv_t *sv = (sv_t *)arg;
+
+	down(&monitor);
+	up(&talkback);
+	printk("sv_test_2_w: thread %d started, sv_waiting.\n", dummy);
+	sv_sema_wait(sv, &monitor);
+	printk("sv_test_2_w: thread %d woken, exiting.\n", dummy);
+	up(&sem);
+	return 0;
+}
+
+static int sv_test_2_s_1(void *arg) 
+{
+	int i;
+	sv_t *sv = (sv_t *)arg;
+
+	down(&monitor);
+	for(i = 0; i < 3; i++) {
+		printk("sv_test_2_s_1: waking one thread.\n");
+		sv_signal(sv);
+		down(&sem);
+	}
+
+	printk("sv_test_2_s_1: signaling and broadcasting again.  Nothing should happen.\n");
+	sv_signal(sv);
+	sv_broadcast(sv);
+	sv_signal(sv);
+	sv_broadcast(sv);
+
+	printk("sv_test_2_s_1: talkbacking.\n");
+	up(&talkback);
+	up(&monitor);
+	return 0;
+}
+
+static int sv_test_2_s(void *arg) 
+{
+	int i;
+	sv_t *sv = (sv_t *)arg;
+
+	down(&monitor);
+	for(i = 0; i < 3; i++) {
+		printk("sv_test_2_s: waking one thread (should be %d.)\n", i);
+		sv_signal(sv);
+		down(&sem);
+	}
+
+	printk("sv_test_3_s: waking remaining threads with broadcast.\n");
+	sv_broadcast(sv);
+	for(; i < 10; i++)
+		down(&sem);
+
+	printk("sv_test_3_s: sending talkback.\n");
+	up(&talkback);
+
+	printk("sv_test_3_s: exiting.\n");
+	up(&monitor);
+	return 0;
+}
+
+
+static void big_test(sv_t *sv) 
+{
+	int i;
+
+	count = 0;
+
+	for(i = 0; i < 3; i++) {
+		printk("big_test: spawning thread %d.\n", i);
+		kernel_thread(sv_test_2_w, sv, 0);
+		down(&talkback);
+	}
+
+	printk("big_test: spawning first wake-up thread.\n");
+	kernel_thread(sv_test_2_s_1, sv, 0);
+
+	down(&talkback);
+	printk("big_test: talkback happened.\n");
+
+
+	for(i = 3; i < 13; i++) {
+		printk("big_test: spawning thread %d.\n", i);
+		kernel_thread(sv_test_2_w, sv, 0);
+		down(&talkback);
+	}
+
+	printk("big_test: spawning wake-up thread.\n");
+	kernel_thread(sv_test_2_s, sv, 0);
+
+	down(&talkback);
+}
+
+sv_t int_test_sv;
+spinlock_t int_test_spin = SPIN_LOCK_UNLOCKED;
+int int_test_ready;
+static int irqtestcount;
+
+static int interrupt_test_worker(void *unused) 
+{
+	int id = ++irqtestcount;
+	int it = 0;
+			unsigned long flags, flags2;
+
+	printk("ITW: thread %d started.\n", id);
+
+	while(1) {
+		__save_flags(flags2);
+		if(jiffies % 3) {
+			printk("ITW %2d %5d: irqsaving          (%lx)\n", id, it, flags2);
+			spin_lock_irqsave(&int_test_spin, flags);
+		} else {
+			printk("ITW %2d %5d: spin_lock_irqing   (%lx)\n", id, it, flags2);
+			spin_lock_irq(&int_test_spin);
+		}
+
+		__save_flags(flags2);
+		printk("ITW %2d %5d: locked, sv_waiting (%lx).\n", id, it, flags2);
+		sv_wait(&int_test_sv, 0, 0);
+
+		__save_flags(flags2);
+		printk("ITW %2d %5d: wait finished      (%lx), pausing\n", id, it, flags2);
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(jiffies & 0xf);
+		if(current->state != TASK_RUNNING)
+		  printk("ITW:  current->state isn't RUNNING after schedule!\n");
+		it++;
+	}
+}
+
+static void interrupt_test(void) 
+{
+	int i;
+
+	printk("interrupt_test: initing sv.\n");
+	sv_init(&int_test_sv, &int_test_spin, SV_MON_SPIN | SV_INTS);
+
+	for(i = 0; i < SV_INTERRUPT_TEST_WORKERS; i++) {
+		printk("interrupt_test: starting test thread %d.\n", i);
+		kernel_thread(interrupt_test_worker, 0, 0);
+	}
+	printk("interrupt_test: done with init part.\n");
+	int_test_ready = 1;
+}
+
+int sv_test(void) 
+{
+	spinlock_t s = SPIN_LOCK_UNLOCKED;
+
+	sv_init(&sv, &s, SV_MON_SPIN);
+	printk("sv_test: starting sv_test_1_w.\n");
+	kernel_thread(sv_test_1_w, &s, 0);
+	printk("sv_test: starting sv_test_1_s.\n");
+	kernel_thread(sv_test_1_s, &s, 0);
+
+	printk("sv_test: waiting for talkback.\n");
+	down(&talkback); down(&talkback);
+	printk("sv_test: talkback happened, sv_destroying.\n");
+	sv_destroy(&sv);
+
+	count = 0;
+
+	printk("sv_test: beginning big_test on sv.\n");
+
+	sv_init(&sv, &monitor, SV_MON_SEMA);
+	big_test(&sv);
+	sv_destroy(&sv);
+
+	printk("sv_test: beginning big_test on sv_filo.\n");
+	sv_init(&sv_filo, &monitor, SV_MON_SEMA | SV_ORDER_FILO);
+	big_test(&sv_filo);
+	sv_destroy(&sv_filo);
+
+	interrupt_test();
+
+	printk("sv_test: done.\n");
+	return 0;
+}
+
+__initcall(sv_test);
+
+#endif /* RUN_SV_TEST */