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authorRich Felker <dalias@libc.org>2016-02-12 21:59:39 +0000
committerRich Felker <dalias@libc.org>2016-04-28 20:48:23 +0000
commit91a5a8b1e30f5136052873073f28efe30a0bf6ff (patch)
treea3b1779bff1fae708a1435931a81fdf80ab5c3f4 /arch/sh/include/asm/spinlock-llsc.h
parentbc5d710f8d251116f5d3e569aafefa78523b5fcc (diff)
downloadlinux-sh-91a5a8b1e30f5136052873073f28efe30a0bf6ff.tar.gz
sh: add J2 atomics using the cas.l instruction
Signed-off-by: Rich Felker <dalias@libc.org>
Diffstat (limited to 'arch/sh/include/asm/spinlock-llsc.h')
-rw-r--r--arch/sh/include/asm/spinlock-llsc.h218
1 files changed, 218 insertions, 0 deletions
diff --git a/arch/sh/include/asm/spinlock-llsc.h b/arch/sh/include/asm/spinlock-llsc.h
new file mode 100644
index 000000000000..238ef6f54dcc
--- /dev/null
+++ b/arch/sh/include/asm/spinlock-llsc.h
@@ -0,0 +1,218 @@
+/*
+ * include/asm-sh/spinlock-llsc.h
+ *
+ * Copyright (C) 2002, 2003 Paul Mundt
+ * Copyright (C) 2006, 2007 Akio Idehara
+ *
+ * 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.
+ */
+#ifndef __ASM_SH_SPINLOCK_LLSC_H
+#define __ASM_SH_SPINLOCK_LLSC_H
+
+/*
+ * Your basic SMP spinlocks, allowing only a single CPU anywhere
+ */
+
+#define arch_spin_is_locked(x) ((x)->lock <= 0)
+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
+#define arch_spin_unlock_wait(x) \
+ do { while (arch_spin_is_locked(x)) cpu_relax(); } while (0)
+
+/*
+ * Simple spin lock operations. There are two variants, one clears IRQ's
+ * on the local processor, one does not.
+ *
+ * We make no fairness assumptions. They have a cost.
+ */
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+ unsigned long tmp;
+ unsigned long oldval;
+
+ __asm__ __volatile__ (
+ "1: \n\t"
+ "movli.l @%2, %0 ! arch_spin_lock \n\t"
+ "mov %0, %1 \n\t"
+ "mov #0, %0 \n\t"
+ "movco.l %0, @%2 \n\t"
+ "bf 1b \n\t"
+ "cmp/pl %1 \n\t"
+ "bf 1b \n\t"
+ : "=&z" (tmp), "=&r" (oldval)
+ : "r" (&lock->lock)
+ : "t", "memory"
+ );
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+ unsigned long tmp;
+
+ __asm__ __volatile__ (
+ "mov #1, %0 ! arch_spin_unlock \n\t"
+ "mov.l %0, @%1 \n\t"
+ : "=&z" (tmp)
+ : "r" (&lock->lock)
+ : "t", "memory"
+ );
+}
+
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+ unsigned long tmp, oldval;
+
+ __asm__ __volatile__ (
+ "1: \n\t"
+ "movli.l @%2, %0 ! arch_spin_trylock \n\t"
+ "mov %0, %1 \n\t"
+ "mov #0, %0 \n\t"
+ "movco.l %0, @%2 \n\t"
+ "bf 1b \n\t"
+ "synco \n\t"
+ : "=&z" (tmp), "=&r" (oldval)
+ : "r" (&lock->lock)
+ : "t", "memory"
+ );
+
+ return oldval;
+}
+
+/*
+ * 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.
+ */
+
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define arch_read_can_lock(x) ((x)->lock > 0)
+
+/**
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define arch_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
+
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+ unsigned long tmp;
+
+ __asm__ __volatile__ (
+ "1: \n\t"
+ "movli.l @%1, %0 ! arch_read_lock \n\t"
+ "cmp/pl %0 \n\t"
+ "bf 1b \n\t"
+ "add #-1, %0 \n\t"
+ "movco.l %0, @%1 \n\t"
+ "bf 1b \n\t"
+ : "=&z" (tmp)
+ : "r" (&rw->lock)
+ : "t", "memory"
+ );
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+ unsigned long tmp;
+
+ __asm__ __volatile__ (
+ "1: \n\t"
+ "movli.l @%1, %0 ! arch_read_unlock \n\t"
+ "add #1, %0 \n\t"
+ "movco.l %0, @%1 \n\t"
+ "bf 1b \n\t"
+ : "=&z" (tmp)
+ : "r" (&rw->lock)
+ : "t", "memory"
+ );
+}
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+ unsigned long tmp;
+
+ __asm__ __volatile__ (
+ "1: \n\t"
+ "movli.l @%1, %0 ! arch_write_lock \n\t"
+ "cmp/hs %2, %0 \n\t"
+ "bf 1b \n\t"
+ "sub %2, %0 \n\t"
+ "movco.l %0, @%1 \n\t"
+ "bf 1b \n\t"
+ : "=&z" (tmp)
+ : "r" (&rw->lock), "r" (RW_LOCK_BIAS)
+ : "t", "memory"
+ );
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+ __asm__ __volatile__ (
+ "mov.l %1, @%0 ! arch_write_unlock \n\t"
+ :
+ : "r" (&rw->lock), "r" (RW_LOCK_BIAS)
+ : "t", "memory"
+ );
+}
+
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+ unsigned long tmp, oldval;
+
+ __asm__ __volatile__ (
+ "1: \n\t"
+ "movli.l @%2, %0 ! arch_read_trylock \n\t"
+ "mov %0, %1 \n\t"
+ "cmp/pl %0 \n\t"
+ "bf 2f \n\t"
+ "add #-1, %0 \n\t"
+ "movco.l %0, @%2 \n\t"
+ "bf 1b \n\t"
+ "2: \n\t"
+ "synco \n\t"
+ : "=&z" (tmp), "=&r" (oldval)
+ : "r" (&rw->lock)
+ : "t", "memory"
+ );
+
+ return (oldval > 0);
+}
+
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+ unsigned long tmp, oldval;
+
+ __asm__ __volatile__ (
+ "1: \n\t"
+ "movli.l @%2, %0 ! arch_write_trylock \n\t"
+ "mov %0, %1 \n\t"
+ "cmp/hs %3, %0 \n\t"
+ "bf 2f \n\t"
+ "sub %3, %0 \n\t"
+ "2: \n\t"
+ "movco.l %0, @%2 \n\t"
+ "bf 1b \n\t"
+ "synco \n\t"
+ : "=&z" (tmp), "=&r" (oldval)
+ : "r" (&rw->lock), "r" (RW_LOCK_BIAS)
+ : "t", "memory"
+ );
+
+ return (oldval > (RW_LOCK_BIAS - 1));
+}
+
+#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
+#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
+
+#define arch_spin_relax(lock) cpu_relax()
+#define arch_read_relax(lock) cpu_relax()
+#define arch_write_relax(lock) cpu_relax()
+
+#endif /* __ASM_SH_SPINLOCK_LLSC_H */