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-rw-r--r--arch/sparc64/lib/debuglocks.c376
1 files changed, 376 insertions, 0 deletions
diff --git a/arch/sparc64/lib/debuglocks.c b/arch/sparc64/lib/debuglocks.c
new file mode 100644
index 000000000000..c421e0c65325
--- /dev/null
+++ b/arch/sparc64/lib/debuglocks.c
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+/* $Id: debuglocks.c,v 1.9 2001/11/17 00:10:48 davem Exp $
+ * debuglocks.c: Debugging versions of SMP locking primitives.
+ *
+ * Copyright (C) 1998 David S. Miller (davem@redhat.com)
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_SMP
+
+#define GET_CALLER(PC) __asm__ __volatile__("mov %%i7, %0" : "=r" (PC))
+
+static inline void show (char *str, spinlock_t *lock, unsigned long caller)
+{
+ int cpu = smp_processor_id();
+
+ printk("%s(%p) CPU#%d stuck at %08x, owner PC(%08x):CPU(%x)\n",
+ str, lock, cpu, (unsigned int) caller,
+ lock->owner_pc, lock->owner_cpu);
+}
+
+static inline void show_read (char *str, rwlock_t *lock, unsigned long caller)
+{
+ int cpu = smp_processor_id();
+
+ printk("%s(%p) CPU#%d stuck at %08x, writer PC(%08x):CPU(%x)\n",
+ str, lock, cpu, (unsigned int) caller,
+ lock->writer_pc, lock->writer_cpu);
+}
+
+static inline void show_write (char *str, rwlock_t *lock, unsigned long caller)
+{
+ int cpu = smp_processor_id();
+ int i;
+
+ printk("%s(%p) CPU#%d stuck at %08x\n",
+ str, lock, cpu, (unsigned int) caller);
+ printk("Writer: PC(%08x):CPU(%x)\n",
+ lock->writer_pc, lock->writer_cpu);
+ printk("Readers:");
+ for (i = 0; i < NR_CPUS; i++)
+ if (lock->reader_pc[i])
+ printk(" %d[%08x]", i, lock->reader_pc[i]);
+ printk("\n");
+}
+
+#undef INIT_STUCK
+#define INIT_STUCK 100000000
+
+void _do_spin_lock(spinlock_t *lock, char *str)
+{
+ unsigned long caller, val;
+ int stuck = INIT_STUCK;
+ int cpu = get_cpu();
+ int shown = 0;
+
+ GET_CALLER(caller);
+again:
+ __asm__ __volatile__("ldstub [%1], %0"
+ : "=r" (val)
+ : "r" (&(lock->lock))
+ : "memory");
+ membar("#StoreLoad | #StoreStore");
+ if (val) {
+ while (lock->lock) {
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show(str, lock, caller);
+ stuck = INIT_STUCK;
+ }
+ membar("#LoadLoad");
+ }
+ goto again;
+ }
+ lock->owner_pc = ((unsigned int)caller);
+ lock->owner_cpu = cpu;
+ current->thread.smp_lock_count++;
+ current->thread.smp_lock_pc = ((unsigned int)caller);
+
+ put_cpu();
+}
+
+int _do_spin_trylock(spinlock_t *lock)
+{
+ unsigned long val, caller;
+ int cpu = get_cpu();
+
+ GET_CALLER(caller);
+ __asm__ __volatile__("ldstub [%1], %0"
+ : "=r" (val)
+ : "r" (&(lock->lock))
+ : "memory");
+ membar("#StoreLoad | #StoreStore");
+ if (!val) {
+ lock->owner_pc = ((unsigned int)caller);
+ lock->owner_cpu = cpu;
+ current->thread.smp_lock_count++;
+ current->thread.smp_lock_pc = ((unsigned int)caller);
+ }
+
+ put_cpu();
+
+ return val == 0;
+}
+
+void _do_spin_unlock(spinlock_t *lock)
+{
+ lock->owner_pc = 0;
+ lock->owner_cpu = NO_PROC_ID;
+ membar("#StoreStore | #LoadStore");
+ lock->lock = 0;
+ current->thread.smp_lock_count--;
+}
+
+/* Keep INIT_STUCK the same... */
+
+void _do_read_lock (rwlock_t *rw, char *str)
+{
+ unsigned long caller, val;
+ int stuck = INIT_STUCK;
+ int cpu = get_cpu();
+ int shown = 0;
+
+ GET_CALLER(caller);
+wlock_again:
+ /* Wait for any writer to go away. */
+ while (((long)(rw->lock)) < 0) {
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show_read(str, rw, caller);
+ stuck = INIT_STUCK;
+ }
+ membar("#LoadLoad");
+ }
+ /* Try once to increment the counter. */
+ __asm__ __volatile__(
+" ldx [%0], %%g1\n"
+" brlz,a,pn %%g1, 2f\n"
+" mov 1, %0\n"
+" add %%g1, 1, %%g7\n"
+" casx [%0], %%g1, %%g7\n"
+" sub %%g1, %%g7, %0\n"
+"2:" : "=r" (val)
+ : "0" (&(rw->lock))
+ : "g1", "g7", "memory");
+ membar("#StoreLoad | #StoreStore");
+ if (val)
+ goto wlock_again;
+ rw->reader_pc[cpu] = ((unsigned int)caller);
+ current->thread.smp_lock_count++;
+ current->thread.smp_lock_pc = ((unsigned int)caller);
+
+ put_cpu();
+}
+
+void _do_read_unlock (rwlock_t *rw, char *str)
+{
+ unsigned long caller, val;
+ int stuck = INIT_STUCK;
+ int cpu = get_cpu();
+ int shown = 0;
+
+ GET_CALLER(caller);
+
+ /* Drop our identity _first_. */
+ rw->reader_pc[cpu] = 0;
+ current->thread.smp_lock_count--;
+runlock_again:
+ /* Spin trying to decrement the counter using casx. */
+ __asm__ __volatile__(
+" membar #StoreLoad | #LoadLoad\n"
+" ldx [%0], %%g1\n"
+" sub %%g1, 1, %%g7\n"
+" casx [%0], %%g1, %%g7\n"
+" membar #StoreLoad | #StoreStore\n"
+" sub %%g1, %%g7, %0\n"
+ : "=r" (val)
+ : "0" (&(rw->lock))
+ : "g1", "g7", "memory");
+ if (val) {
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show_read(str, rw, caller);
+ stuck = INIT_STUCK;
+ }
+ goto runlock_again;
+ }
+
+ put_cpu();
+}
+
+void _do_write_lock (rwlock_t *rw, char *str)
+{
+ unsigned long caller, val;
+ int stuck = INIT_STUCK;
+ int cpu = get_cpu();
+ int shown = 0;
+
+ GET_CALLER(caller);
+wlock_again:
+ /* Spin while there is another writer. */
+ while (((long)rw->lock) < 0) {
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show_write(str, rw, caller);
+ stuck = INIT_STUCK;
+ }
+ membar("#LoadLoad");
+ }
+
+ /* Try to acuire the write bit. */
+ __asm__ __volatile__(
+" mov 1, %%g3\n"
+" sllx %%g3, 63, %%g3\n"
+" ldx [%0], %%g1\n"
+" brlz,pn %%g1, 1f\n"
+" or %%g1, %%g3, %%g7\n"
+" casx [%0], %%g1, %%g7\n"
+" membar #StoreLoad | #StoreStore\n"
+" ba,pt %%xcc, 2f\n"
+" sub %%g1, %%g7, %0\n"
+"1: mov 1, %0\n"
+"2:" : "=r" (val)
+ : "0" (&(rw->lock))
+ : "g3", "g1", "g7", "memory");
+ if (val) {
+ /* We couldn't get the write bit. */
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show_write(str, rw, caller);
+ stuck = INIT_STUCK;
+ }
+ goto wlock_again;
+ }
+ if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) {
+ /* Readers still around, drop the write
+ * lock, spin, and try again.
+ */
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show_write(str, rw, caller);
+ stuck = INIT_STUCK;
+ }
+ __asm__ __volatile__(
+" mov 1, %%g3\n"
+" sllx %%g3, 63, %%g3\n"
+"1: ldx [%0], %%g1\n"
+" andn %%g1, %%g3, %%g7\n"
+" casx [%0], %%g1, %%g7\n"
+" cmp %%g1, %%g7\n"
+" bne,pn %%xcc, 1b\n"
+" membar #StoreLoad | #StoreStore"
+ : /* no outputs */
+ : "r" (&(rw->lock))
+ : "g3", "g1", "g7", "cc", "memory");
+ while(rw->lock != 0) {
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show_write(str, rw, caller);
+ stuck = INIT_STUCK;
+ }
+ membar("#LoadLoad");
+ }
+ goto wlock_again;
+ }
+
+ /* We have it, say who we are. */
+ rw->writer_pc = ((unsigned int)caller);
+ rw->writer_cpu = cpu;
+ current->thread.smp_lock_count++;
+ current->thread.smp_lock_pc = ((unsigned int)caller);
+
+ put_cpu();
+}
+
+void _do_write_unlock(rwlock_t *rw)
+{
+ unsigned long caller, val;
+ int stuck = INIT_STUCK;
+ int shown = 0;
+
+ GET_CALLER(caller);
+
+ /* Drop our identity _first_ */
+ rw->writer_pc = 0;
+ rw->writer_cpu = NO_PROC_ID;
+ current->thread.smp_lock_count--;
+wlock_again:
+ __asm__ __volatile__(
+" membar #StoreLoad | #LoadLoad\n"
+" mov 1, %%g3\n"
+" sllx %%g3, 63, %%g3\n"
+" ldx [%0], %%g1\n"
+" andn %%g1, %%g3, %%g7\n"
+" casx [%0], %%g1, %%g7\n"
+" membar #StoreLoad | #StoreStore\n"
+" sub %%g1, %%g7, %0\n"
+ : "=r" (val)
+ : "0" (&(rw->lock))
+ : "g3", "g1", "g7", "memory");
+ if (val) {
+ if (!--stuck) {
+ if (shown++ <= 2)
+ show_write("write_unlock", rw, caller);
+ stuck = INIT_STUCK;
+ }
+ goto wlock_again;
+ }
+}
+
+int _do_write_trylock (rwlock_t *rw, char *str)
+{
+ unsigned long caller, val;
+ int cpu = get_cpu();
+
+ GET_CALLER(caller);
+
+ /* Try to acuire the write bit. */
+ __asm__ __volatile__(
+" mov 1, %%g3\n"
+" sllx %%g3, 63, %%g3\n"
+" ldx [%0], %%g1\n"
+" brlz,pn %%g1, 1f\n"
+" or %%g1, %%g3, %%g7\n"
+" casx [%0], %%g1, %%g7\n"
+" membar #StoreLoad | #StoreStore\n"
+" ba,pt %%xcc, 2f\n"
+" sub %%g1, %%g7, %0\n"
+"1: mov 1, %0\n"
+"2:" : "=r" (val)
+ : "0" (&(rw->lock))
+ : "g3", "g1", "g7", "memory");
+
+ if (val) {
+ put_cpu();
+ return 0;
+ }
+
+ if ((rw->lock & ((1UL<<63)-1UL)) != 0UL) {
+ /* Readers still around, drop the write
+ * lock, return failure.
+ */
+ __asm__ __volatile__(
+" mov 1, %%g3\n"
+" sllx %%g3, 63, %%g3\n"
+"1: ldx [%0], %%g1\n"
+" andn %%g1, %%g3, %%g7\n"
+" casx [%0], %%g1, %%g7\n"
+" cmp %%g1, %%g7\n"
+" bne,pn %%xcc, 1b\n"
+" membar #StoreLoad | #StoreStore"
+ : /* no outputs */
+ : "r" (&(rw->lock))
+ : "g3", "g1", "g7", "cc", "memory");
+
+ put_cpu();
+
+ return 0;
+ }
+
+ /* We have it, say who we are. */
+ rw->writer_pc = ((unsigned int)caller);
+ rw->writer_cpu = cpu;
+ current->thread.smp_lock_count++;
+ current->thread.smp_lock_pc = ((unsigned int)caller);
+
+ put_cpu();
+
+ return 1;
+}
+
+#endif /* CONFIG_SMP */
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