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authorLinus Torvalds <torvalds@linux-foundation.org>2011-05-25 15:35:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-25 15:35:32 -0700
commit0798b1dbfbd9ff2a370c5968c5f0621ef0075fe0 (patch)
treec7f61ab9683786a070da0933b9981fc74a4d865f /arch/tile/include/asm/spinlock_64.h
parentad363e0916423b2e6cdfcdc30ae707ec709f0a65 (diff)
parent6738d3210aabe3016a1b03cd98a7fc479c229197 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: (26 commits) arch/tile: prefer "tilepro" as the name of the 32-bit architecture compat: include aio_abi.h for aio_context_t arch/tile: cleanups for tilegx compat mode arch/tile: allocate PCI IRQs later in boot arch/tile: support signal "exception-trace" hook arch/tile: use better definitions of xchg() and cmpxchg() include/linux/compat.h: coding-style fixes tile: add an RTC driver for the Tilera hypervisor arch/tile: finish enabling support for TILE-Gx 64-bit chip compat: fixes to allow working with tile arch arch/tile: update defconfig file to something more useful tile: do_hardwall_trap: do not play with task->sighand tile: replace mm->cpu_vm_mask with mm_cpumask() tile,mn10300: add device parameter to dma_cache_sync() audit: support the "standard" <asm-generic/unistd.h> arch/tile: clarify flush_buffer()/finv_buffer() function names arch/tile: kernel-related cleanups from removing static page size arch/tile: various header improvements for building drivers arch/tile: disable GX prefetcher during cache flush arch/tile: tolerate disabling CONFIG_BLK_DEV_INITRD ...
Diffstat (limited to 'arch/tile/include/asm/spinlock_64.h')
-rw-r--r--arch/tile/include/asm/spinlock_64.h161
1 files changed, 161 insertions, 0 deletions
diff --git a/arch/tile/include/asm/spinlock_64.h b/arch/tile/include/asm/spinlock_64.h
new file mode 100644
index 000000000000..72be5904e020
--- /dev/null
+++ b/arch/tile/include/asm/spinlock_64.h
@@ -0,0 +1,161 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ * 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, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ *
+ * 64-bit SMP ticket spinlocks, allowing only a single CPU anywhere
+ * (the type definitions are in asm/spinlock_types.h)
+ */
+
+#ifndef _ASM_TILE_SPINLOCK_64_H
+#define _ASM_TILE_SPINLOCK_64_H
+
+/* Shifts and masks for the various fields in "lock". */
+#define __ARCH_SPIN_CURRENT_SHIFT 17
+#define __ARCH_SPIN_NEXT_MASK 0x7fff
+#define __ARCH_SPIN_NEXT_OVERFLOW 0x8000
+
+/*
+ * Return the "current" portion of a ticket lock value,
+ * i.e. the number that currently owns the lock.
+ */
+static inline int arch_spin_current(u32 val)
+{
+ return val >> __ARCH_SPIN_CURRENT_SHIFT;
+}
+
+/*
+ * Return the "next" portion of a ticket lock value,
+ * i.e. the number that the next task to try to acquire the lock will get.
+ */
+static inline int arch_spin_next(u32 val)
+{
+ return val & __ARCH_SPIN_NEXT_MASK;
+}
+
+/* The lock is locked if a task would have to wait to get it. */
+static inline int arch_spin_is_locked(arch_spinlock_t *lock)
+{
+ u32 val = lock->lock;
+ return arch_spin_current(val) != arch_spin_next(val);
+}
+
+/* Bump the current ticket so the next task owns the lock. */
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+ wmb(); /* guarantee anything modified under the lock is visible */
+ __insn_fetchadd4(&lock->lock, 1U << __ARCH_SPIN_CURRENT_SHIFT);
+}
+
+void arch_spin_unlock_wait(arch_spinlock_t *lock);
+
+void arch_spin_lock_slow(arch_spinlock_t *lock, u32 val);
+
+/* Grab the "next" ticket number and bump it atomically.
+ * If the current ticket is not ours, go to the slow path.
+ * We also take the slow path if the "next" value overflows.
+ */
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+ u32 val = __insn_fetchadd4(&lock->lock, 1);
+ u32 ticket = val & (__ARCH_SPIN_NEXT_MASK | __ARCH_SPIN_NEXT_OVERFLOW);
+ if (unlikely(arch_spin_current(val) != ticket))
+ arch_spin_lock_slow(lock, ticket);
+}
+
+/* Try to get the lock, and return whether we succeeded. */
+int arch_spin_trylock(arch_spinlock_t *lock);
+
+/* We cannot take an interrupt after getting a ticket, so don't enable them. */
+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
+
+/*
+ * Read-write spinlocks, allowing multiple readers
+ * but only one writer.
+ *
+ * We use fetchadd() for readers, and fetchor() with the sign bit
+ * for writers.
+ */
+
+#define __WRITE_LOCK_BIT (1 << 31)
+
+static inline int arch_write_val_locked(int val)
+{
+ return val < 0; /* Optimize "val & __WRITE_LOCK_BIT". */
+}
+
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static inline int arch_read_can_lock(arch_rwlock_t *rw)
+{
+ return !arch_write_val_locked(rw->lock);
+}
+
+/**
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static inline int arch_write_can_lock(arch_rwlock_t *rw)
+{
+ return rw->lock == 0;
+}
+
+extern void __read_lock_failed(arch_rwlock_t *rw);
+
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+ u32 val = __insn_fetchaddgez4(&rw->lock, 1);
+ if (unlikely(arch_write_val_locked(val)))
+ __read_lock_failed(rw);
+}
+
+extern void __write_lock_failed(arch_rwlock_t *rw, u32 val);
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+ u32 val = __insn_fetchor4(&rw->lock, __WRITE_LOCK_BIT);
+ if (unlikely(val != 0))
+ __write_lock_failed(rw, val);
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+ __insn_mf();
+ __insn_fetchadd4(&rw->lock, -1);
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+ __insn_mf();
+ rw->lock = 0;
+}
+
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+ return !arch_write_val_locked(__insn_fetchaddgez4(&rw->lock, 1));
+}
+
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+ u32 val = __insn_fetchor4(&rw->lock, __WRITE_LOCK_BIT);
+ if (likely(val == 0))
+ return 1;
+ if (!arch_write_val_locked(val))
+ __insn_fetchand4(&rw->lock, ~__WRITE_LOCK_BIT);
+ return 0;
+}
+
+#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
+#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
+
+#endif /* _ASM_TILE_SPINLOCK_64_H */