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[PATCH v2 28/44] metag: Atomics, locks and bitops

From: James Hogan <hidden>
Date: 2012-12-05 16:15:46
Also in: lkml
Subsystem: atomic infrastructure, bitops api, locking primitives, the rest · Maintainers: Will Deacon, Peter Zijlstra, Boqun Feng, Yury Norov, Ingo Molnar, Linus Torvalds

Add header files to implement Meta hardware thread locks (used by some
other atomic operations), atomics, spinlocks, and bitops.

There are 2 main types of atomic primitives for metag (in addition to
IRQs off on UP):
 - LOCK instructions provide locking between hardware threads.
 - LNKGET/LNKSET instructions provide load-linked/store-conditional
   operations allowing for lighter weight atomics on Meta2)

LOCK instructions allow for hardware threads to acquire voluntary or
exclusive hardware thread locks:
 - LOCK0 releases exclusive and voluntary lock from the running hardware
   thread.
 - LOCK1 acquires the voluntary hardware lock, blocking until it becomes
   available.
 - LOCK2 implies LOCK1, and additionally acquires the exclusive hardware
   lock, blocking all other hardware threads from executing.

Signed-off-by: James Hogan <redacted>
---
 arch/metag/include/asm/atomic.h          |   53 ++++++
 arch/metag/include/asm/atomic_lnkget.h   |  245 ++++++++++++++++++++++++++++
 arch/metag/include/asm/atomic_lock1.h    |  160 ++++++++++++++++++
 arch/metag/include/asm/bitops.h          |  132 +++++++++++++++
 arch/metag/include/asm/cmpxchg.h         |   65 ++++++++
 arch/metag/include/asm/cmpxchg_irq.h     |   42 +++++
 arch/metag/include/asm/cmpxchg_lnkget.h  |   86 ++++++++++
 arch/metag/include/asm/cmpxchg_lock1.h   |   48 ++++++
 arch/metag/include/asm/lock.h            |   14 ++
 arch/metag/include/asm/spinlock.h        |   22 +++
 arch/metag/include/asm/spinlock_lnkget.h |  261 ++++++++++++++++++++++++++++++
 arch/metag/include/asm/spinlock_lock1.h  |  184 +++++++++++++++++++++
 arch/metag/include/asm/spinlock_types.h  |   20 +++
 13 files changed, 1332 insertions(+), 0 deletions(-)
 create mode 100644 arch/metag/include/asm/atomic.h
 create mode 100644 arch/metag/include/asm/atomic_lnkget.h
 create mode 100644 arch/metag/include/asm/atomic_lock1.h
 create mode 100644 arch/metag/include/asm/bitops.h
 create mode 100644 arch/metag/include/asm/cmpxchg.h
 create mode 100644 arch/metag/include/asm/cmpxchg_irq.h
 create mode 100644 arch/metag/include/asm/cmpxchg_lnkget.h
 create mode 100644 arch/metag/include/asm/cmpxchg_lock1.h
 create mode 100644 arch/metag/include/asm/lock.h
 create mode 100644 arch/metag/include/asm/spinlock.h
 create mode 100644 arch/metag/include/asm/spinlock_lnkget.h
 create mode 100644 arch/metag/include/asm/spinlock_lock1.h
 create mode 100644 arch/metag/include/asm/spinlock_types.h
diff --git a/arch/metag/include/asm/atomic.h b/arch/metag/include/asm/atomic.h
new file mode 100644
index 0000000..307ecd2
--- /dev/null
+++ b/arch/metag/include/asm/atomic.h
@@ -0,0 +1,53 @@
+#ifndef __ASM_METAG_ATOMIC_H
+#define __ASM_METAG_ATOMIC_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+#include <asm/cmpxchg.h>
+
+#if defined(CONFIG_METAG_ATOMICITY_IRQSOFF)
+/* The simple UP case. */
+#include <asm-generic/atomic.h>
+#else
+
+#if defined(CONFIG_METAG_ATOMICITY_LOCK1)
+#include <asm/atomic_lock1.h>
+#else
+#include <asm/atomic_lnkget.h>
+#endif
+
+#define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
+
+#define atomic_dec_return(v) atomic_sub_return(1, (v))
+#define atomic_inc_return(v) atomic_add_return(1, (v))
+
+/*
+ * atomic_inc_and_test - increment and test
+ * @v: pointer of type atomic_t
+ *
+ * Atomically increments @v by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
+
+#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
+#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
+
+#define atomic_inc(v) atomic_add(1, (v))
+#define atomic_dec(v) atomic_sub(1, (v))
+
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
+#define smp_mb__before_atomic_dec()	barrier()
+#define smp_mb__after_atomic_dec()	barrier()
+#define smp_mb__before_atomic_inc()	barrier()
+#define smp_mb__after_atomic_inc()	barrier()
+
+#endif
+
+#define atomic_dec_if_positive(v)       atomic_sub_if_positive(1, v)
+
+#include <asm-generic/atomic64.h>
+
+#endif /* __ASM_METAG_ATOMIC_H */
diff --git a/arch/metag/include/asm/atomic_lnkget.h b/arch/metag/include/asm/atomic_lnkget.h
new file mode 100644
index 0000000..b05be05
--- /dev/null
+++ b/arch/metag/include/asm/atomic_lnkget.h
@@ -0,0 +1,245 @@
+#ifndef __ASM_METAG_ATOMIC_LNKGET_H
+#define __ASM_METAG_ATOMIC_LNKGET_H
+
+#define ATOMIC_INIT(i)	{ (i) }
+
+#define atomic_set(v, i)		((v)->counter = (i))
+
+#include <linux/compiler.h>
+
+#include <asm/barrier.h>
+
+/*
+ * None of these asm statements clobber memory as LNKSET writes around
+ * the cache so the memory it modifies cannot safely be read by any means
+ * other than these accessors.
+ */
+
+static inline int atomic_read(const atomic_t *v)
+{
+	int temp;
+
+	__asm__ __volatile__(
+		"LNKGETD %0, [%1]\n"
+		: "=da" (temp)
+		: "da" (&v->counter)
+	);
+
+	return temp;
+}
+
+static inline void atomic_add(int i, atomic_t *v)
+{
+	int temp;
+
+	__asm__ __volatile__(
+		"1:	LNKGETD %0, [%1]\n"
+		"	ADD	%0, %0, %2\n"
+		"	LNKSETD [%1], %0\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ	1b\n"
+		: "=&d" (temp)
+		: "da" (&v->counter), "bd" (i)
+		: "cc"
+	);
+}
+
+static inline void atomic_sub(int i, atomic_t *v)
+{
+	int temp;
+
+	__asm__ __volatile__(
+		"1:	LNKGETD %0, [%1]\n"
+		"	SUB	%0, %0, %2\n"
+		"	LNKSETD [%1], %0\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ 1b\n"
+		: "=&d" (temp)
+		: "da" (&v->counter), "bd" (i)
+		: "cc"
+	);
+}
+
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+	int result, temp;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+		"1:	LNKGETD %1, [%2]\n"
+		"	ADD	%1, %1, %3\n"
+		"	LNKSETD [%2], %1\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ 1b\n"
+		: "=&d" (temp), "=&da" (result)
+		: "da" (&v->counter), "bd" (i)
+		: "cc"
+	);
+
+	smp_mb();
+
+	return result;
+}
+
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+	int result, temp;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+		"1:	LNKGETD %1, [%2]\n"
+		"	SUB	%1, %1, %3\n"
+		"	LNKSETD [%2], %1\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ	1b\n"
+		: "=&d" (temp), "=&da" (result)
+		: "da" (&v->counter), "bd" (i)
+		: "cc"
+	);
+
+	smp_mb();
+
+	return result;
+}
+
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
+{
+	int temp;
+
+	__asm__ __volatile__(
+		"1:	LNKGETD %0, [%1]\n"
+		"	AND	%0, %0, %2\n"
+		"	LNKSETD	[%1] %0\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ	1b\n"
+		: "=&d" (temp)
+		: "da" (&v->counter), "bd" (~mask)
+		: "cc"
+	);
+}
+
+static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
+{
+	int temp;
+
+	__asm__ __volatile__(
+		"1:	LNKGETD %0, [%1]\n"
+		"	OR	%0, %0, %2\n"
+		"	LNKSETD	[%1], %0\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ	1b\n"
+		: "=&d" (temp)
+		: "da" (&v->counter), "bd" (mask)
+		: "cc"
+	);
+}
+
+static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+	int result, temp;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+		"1:	LNKGETD	%1, [%2]\n"
+		"	CMP	%1, %3\n"
+		"	LNKSETDEQ [%2], %4\n"
+		"	BNE	2f\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ	1b\n"
+		"2:\n"
+		: "=&d" (temp), "=&d" (result)
+		: "da" (&v->counter), "bd" (old), "da" (new)
+		: "cc"
+	);
+
+	smp_mb();
+
+	return result;
+}
+
+static inline int atomic_xchg(atomic_t *v, int new)
+{
+	int temp, old;
+
+	__asm__ __volatile__(
+			"1:	LNKGETD %1, [%2]\n"
+			"	LNKSETD	[%2], %3\n"
+			"	DEFR	%0, TXSTAT\n"
+			"	ANDT	%0, %0, #HI(0x3f000000)\n"
+			"	CMPT	%0, #HI(0x02000000)\n"
+			"	BNZ	1b\n"
+			: "=&d" (temp), "=&d" (old)
+			: "da" (&v->counter), "da" (new)
+			: "cc"
+	);
+
+	return old;
+}
+
+static inline int __atomic_add_unless(atomic_t *v, int a, int u)
+{
+	int result, temp;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+			"1:	LNKGETD %1, [%2]\n"
+			"	CMP	%1, %3\n"
+			"	ADD	%0, %1, %4\n"
+			"	LNKSETDNE [%2], %0\n"
+			"	BEQ	2f\n"
+			"	DEFR	%0, TXSTAT\n"
+			"	ANDT	%0, %0, #HI(0x3f000000)\n"
+			"	CMPT	%0, #HI(0x02000000)\n"
+			"	BNZ	1b\n"
+			"2:\n"
+			: "=&d" (temp), "=&d" (result)
+			: "da" (&v->counter), "bd" (u), "bd" (a)
+			: "cc"
+	);
+
+	smp_mb();
+
+	return result;
+}
+
+static inline int atomic_sub_if_positive(int i, atomic_t *v)
+{
+	int result, temp;
+
+	__asm__ __volatile__(
+			"1:	LNKGETD %1, [%2]\n"
+			"	SUBS	%1, %1, %3\n"
+			"	LNKSETDGE [%2], %1\n"
+			"	BLT	2f\n"
+			"	DEFR	%0, TXSTAT\n"
+			"	ANDT	%0, %0, #HI(0x3f000000)\n"
+			"	CMPT	%0, #HI(0x02000000)\n"
+			"	BNZ	1b\n"
+			"2:\n"
+			: "=&d" (temp), "=&da" (result)
+			: "da" (&v->counter), "bd" (i)
+			: "cc"
+	);
+
+	return result;
+}
+
+#endif /* __ASM_METAG_ATOMIC_LNKGET_H */
diff --git a/arch/metag/include/asm/atomic_lock1.h b/arch/metag/include/asm/atomic_lock1.h
new file mode 100644
index 0000000..0ce2a9d
--- /dev/null
+++ b/arch/metag/include/asm/atomic_lock1.h
@@ -0,0 +1,160 @@
+#ifndef __ASM_METAG_ATOMIC_LOCK1_H
+#define __ASM_METAG_ATOMIC_LOCK1_H
+
+#define ATOMIC_INIT(i)	{ (i) }
+
+#include <linux/compiler.h>
+
+#include <asm/barrier.h>
+#include <asm/lock.h>
+
+static inline int atomic_read(const atomic_t *v)
+{
+	return (v)->counter;
+}
+
+/*
+ * atomic_set needs to be take the lock to protect atomic_add_unless from a
+ * possible race, as it reads the counter twice:
+ *
+ *  CPU0                               CPU1
+ *  atomic_add_unless(1, 0)
+ *    ret = v->counter (non-zero)
+ *    if (ret != u)                    v->counter = 0
+ *      v->counter += 1 (counter set to 1)
+ *
+ * Making atomic_set take the lock ensures that ordering and logical
+ * consistency is preserved.
+ */
+static inline int atomic_set(atomic_t *v, int i)
+{
+	unsigned long flags;
+
+	__global_lock1(flags);
+	fence();
+	v->counter = i;
+	__global_unlock1(flags);
+	return i;
+}
+
+static inline void atomic_add(int i, atomic_t *v)
+{
+	unsigned long flags;
+
+	__global_lock1(flags);
+	fence();
+	v->counter += i;
+	__global_unlock1(flags);
+}
+
+static inline void atomic_sub(int i, atomic_t *v)
+{
+	unsigned long flags;
+
+	__global_lock1(flags);
+	fence();
+	v->counter -= i;
+	__global_unlock1(flags);
+}
+
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+	unsigned long result;
+	unsigned long flags;
+
+	__global_lock1(flags);
+	result = v->counter;
+	result += i;
+	fence();
+	v->counter = result;
+	__global_unlock1(flags);
+
+	return result;
+}
+
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+	unsigned long result;
+	unsigned long flags;
+
+	__global_lock1(flags);
+	result = v->counter;
+	result -= i;
+	fence();
+	v->counter = result;
+	__global_unlock1(flags);
+
+	return result;
+}
+
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
+{
+	unsigned long flags;
+
+	__global_lock1(flags);
+	fence();
+	v->counter &= ~mask;
+	__global_unlock1(flags);
+}
+
+static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
+{
+	unsigned long flags;
+
+	__global_lock1(flags);
+	fence();
+	v->counter |= mask;
+	__global_unlock1(flags);
+}
+
+static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+	int ret;
+	unsigned long flags;
+
+	__global_lock1(flags);
+	ret = v->counter;
+	if (ret == old) {
+		fence();
+		v->counter = new;
+	}
+	__global_unlock1(flags);
+
+	return ret;
+}
+
+#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
+
+static inline int __atomic_add_unless(atomic_t *v, int a, int u)
+{
+	int ret;
+	unsigned long flags;
+
+	__global_lock1(flags);
+	ret = v->counter;
+	if (ret != u) {
+		fence();
+		v->counter += a;
+	}
+	__global_unlock1(flags);
+
+	return ret;
+}
+
+static inline int atomic_sub_if_positive(int i, atomic_t *v)
+{
+	int ret;
+	unsigned long flags;
+
+	__global_lock1(flags);
+	ret = v->counter - 1;
+	if (ret >= 0) {
+		fence();
+		v->counter = ret;
+	}
+	__global_unlock1(flags);
+
+	return ret;
+}
+
+#endif /* __ASM_METAG_ATOMIC_LOCK1_H */
diff --git a/arch/metag/include/asm/bitops.h b/arch/metag/include/asm/bitops.h
new file mode 100644
index 0000000..638a364
--- /dev/null
+++ b/arch/metag/include/asm/bitops.h
@@ -0,0 +1,132 @@
+#ifndef __ASM_METAG_BITOPS_H
+#define __ASM_METAG_BITOPS_H
+
+#include <linux/compiler.h>
+#include <asm/barrier.h>
+#include <asm/lock.h>
+
+/*
+ * clear_bit() doesn't provide any barrier for the compiler.
+ */
+#define smp_mb__before_clear_bit()	barrier()
+#define smp_mb__after_clear_bit()	barrier()
+
+#ifdef CONFIG_SMP
+/*
+ * These functions are the basis of our bit ops.
+ */
+static inline void set_bit(unsigned int bit, volatile unsigned long *p)
+{
+	unsigned long flags;
+	unsigned long mask = 1UL << (bit & 31);
+
+	p += bit >> 5;
+
+	__global_lock1(flags);
+	fence();
+	*p |= mask;
+	__global_unlock1(flags);
+}
+
+static inline void clear_bit(unsigned int bit, volatile unsigned long *p)
+{
+	unsigned long flags;
+	unsigned long mask = 1UL << (bit & 31);
+
+	p += bit >> 5;
+
+	__global_lock1(flags);
+	fence();
+	*p &= ~mask;
+	__global_unlock1(flags);
+}
+
+static inline void change_bit(unsigned int bit, volatile unsigned long *p)
+{
+	unsigned long flags;
+	unsigned long mask = 1UL << (bit & 31);
+
+	p += bit >> 5;
+
+	__global_lock1(flags);
+	fence();
+	*p ^= mask;
+	__global_unlock1(flags);
+}
+
+static inline int test_and_set_bit(unsigned int bit, volatile unsigned long *p)
+{
+	unsigned long flags;
+	unsigned long old;
+	unsigned long mask = 1UL << (bit & 31);
+
+	p += bit >> 5;
+
+	__global_lock1(flags);
+	old = *p;
+	if (!(old & mask)) {
+		fence();
+		*p = old | mask;
+	}
+	__global_unlock1(flags);
+
+	return (old & mask) != 0;
+}
+
+static inline int test_and_clear_bit(unsigned int bit,
+				     volatile unsigned long *p)
+{
+	unsigned long flags;
+	unsigned long old;
+	unsigned long mask = 1UL << (bit & 31);
+
+	p += bit >> 5;
+
+	__global_lock1(flags);
+	old = *p;
+	if (old & mask) {
+		fence();
+		*p = old & ~mask;
+	}
+	__global_unlock1(flags);
+
+	return (old & mask) != 0;
+}
+
+static inline int test_and_change_bit(unsigned int bit,
+				      volatile unsigned long *p)
+{
+	unsigned long flags;
+	unsigned long old;
+	unsigned long mask = 1UL << (bit & 31);
+
+	p += bit >> 5;
+
+	__global_lock1(flags);
+	fence();
+	old = *p;
+	*p = old ^ mask;
+	__global_unlock1(flags);
+
+	return (old & mask) != 0;
+}
+
+#else
+#include <asm-generic/bitops/atomic.h>
+#endif /* CONFIG_SMP */
+
+#include <asm-generic/bitops/non-atomic.h>
+#include <asm-generic/bitops/find.h>
+#include <asm-generic/bitops/ffs.h>
+#include <asm-generic/bitops/__ffs.h>
+#include <asm-generic/bitops/ffz.h>
+#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
+#include <asm-generic/bitops/fls64.h>
+#include <asm-generic/bitops/hweight.h>
+#include <asm-generic/bitops/lock.h>
+#include <asm-generic/bitops/sched.h>
+#include <asm-generic/bitops/le.h>
+#include <asm-generic/bitops/ext2-atomic.h>
+
+#endif /* __ASM_METAG_BITOPS_H */
diff --git a/arch/metag/include/asm/cmpxchg.h b/arch/metag/include/asm/cmpxchg.h
new file mode 100644
index 0000000..b1bc1be
--- /dev/null
+++ b/arch/metag/include/asm/cmpxchg.h
@@ -0,0 +1,65 @@
+#ifndef __ASM_METAG_CMPXCHG_H
+#define __ASM_METAG_CMPXCHG_H
+
+#include <asm/barrier.h>
+
+#if defined(CONFIG_METAG_ATOMICITY_IRQSOFF)
+#include <asm/cmpxchg_irq.h>
+#elif defined(CONFIG_METAG_ATOMICITY_LOCK1)
+#include <asm/cmpxchg_lock1.h>
+#elif defined(CONFIG_METAG_ATOMICITY_LNKGET)
+#include <asm/cmpxchg_lnkget.h>
+#endif
+
+extern void __xchg_called_with_bad_pointer(void);
+
+#define __xchg(ptr, x, size)				\
+({							\
+	unsigned long __xchg__res;			\
+	volatile void *__xchg_ptr = (ptr);		\
+	switch (size) {					\
+	case 4:						\
+		__xchg__res = xchg_u32(__xchg_ptr, x);	\
+		break;					\
+	case 1:						\
+		__xchg__res = xchg_u8(__xchg_ptr, x);	\
+		break;					\
+	default:					\
+		__xchg_called_with_bad_pointer();	\
+		__xchg__res = x;			\
+		break;					\
+	}						\
+							\
+	__xchg__res;					\
+})
+
+#define xchg(ptr, x)	\
+	((__typeof__(*(ptr)))__xchg((ptr), (unsigned long)(x), sizeof(*(ptr))))
+
+/* This function doesn't exist, so you'll get a linker error
+ * if something tries to do an invalid cmpxchg(). */
+extern void __cmpxchg_called_with_bad_pointer(void);
+
+static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
+				      unsigned long new, int size)
+{
+	switch (size) {
+	case 4:
+		return __cmpxchg_u32(ptr, old, new);
+	}
+	__cmpxchg_called_with_bad_pointer();
+	return old;
+}
+
+#define __HAVE_ARCH_CMPXCHG 1
+
+#define cmpxchg(ptr, o, n)						\
+	({								\
+		__typeof__(*(ptr)) _o_ = (o);				\
+		__typeof__(*(ptr)) _n_ = (n);				\
+		(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
+					       (unsigned long)_n_,	\
+					       sizeof(*(ptr)));		\
+	})
+
+#endif /* __ASM_METAG_CMPXCHG_H */
diff --git a/arch/metag/include/asm/cmpxchg_irq.h b/arch/metag/include/asm/cmpxchg_irq.h
new file mode 100644
index 0000000..6495731
--- /dev/null
+++ b/arch/metag/include/asm/cmpxchg_irq.h
@@ -0,0 +1,42 @@
+#ifndef __ASM_METAG_CMPXCHG_IRQ_H
+#define __ASM_METAG_CMPXCHG_IRQ_H
+
+#include <linux/irqflags.h>
+
+static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
+{
+	unsigned long flags, retval;
+
+	local_irq_save(flags);
+	retval = *m;
+	*m = val;
+	local_irq_restore(flags);
+	return retval;
+}
+
+static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
+{
+	unsigned long flags, retval;
+
+	local_irq_save(flags);
+	retval = *m;
+	*m = val & 0xff;
+	local_irq_restore(flags);
+	return retval;
+}
+
+static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
+					  unsigned long new)
+{
+	__u32 retval;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	retval = *m;
+	if (retval == old)
+		*m = new;
+	local_irq_restore(flags);       /* implies memory barrier  */
+	return retval;
+}
+
+#endif /* __ASM_METAG_CMPXCHG_IRQ_H */
diff --git a/arch/metag/include/asm/cmpxchg_lnkget.h b/arch/metag/include/asm/cmpxchg_lnkget.h
new file mode 100644
index 0000000..3a44b28
--- /dev/null
+++ b/arch/metag/include/asm/cmpxchg_lnkget.h
@@ -0,0 +1,86 @@
+#ifndef __ASM_METAG_CMPXCHG_LNKGET_H
+#define __ASM_METAG_CMPXCHG_LNKGET_H
+
+static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
+{
+	int temp, old;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+			"1:	LNKGETD %1, [%2]\n"
+			"	LNKSETD	[%2], %3\n"
+			"	DEFR	%0, TXSTAT\n"
+			"	ANDT	%0, %0, #HI(0x3f000000)\n"
+			"	CMPT	%0, #HI(0x02000000)\n"
+			"	BNZ	1b\n"
+#ifdef CONFIG_METAG_LNKGET_AROUND_CACHE
+			"	DCACHE	[%2], %0\n"
+#endif
+			: "=&d" (temp), "=&d" (old)
+			: "da" (m), "da" (val)
+			: "cc"
+	);
+
+	smp_mb();
+
+	return old;
+}
+
+static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
+{
+	int temp, old;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+			"1:	LNKGETD %1, [%2]\n"
+			"	LNKSETD	[%2], %3\n"
+			"	DEFR	%0, TXSTAT\n"
+			"	ANDT	%0, %0, #HI(0x3f000000)\n"
+			"	CMPT	%0, #HI(0x02000000)\n"
+			"	BNZ	1b\n"
+#ifdef CONFIG_METAG_LNKGET_AROUND_CACHE
+			"	DCACHE	[%2], %0\n"
+#endif
+			: "=&d" (temp), "=&d" (old)
+			: "da" (m), "da" (val & 0xff)
+			: "cc"
+	);
+
+	smp_mb();
+
+	return old;
+}
+
+static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
+					  unsigned long new)
+{
+	__u32 retval, temp;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+		"1:	LNKGETD	%1, [%2]\n"
+		"	CMP	%1, %3\n"
+		"	LNKSETDEQ [%2], %4\n"
+		"	BNE	2f\n"
+		"	DEFR	%0, TXSTAT\n"
+		"	ANDT	%0, %0, #HI(0x3f000000)\n"
+		"	CMPT	%0, #HI(0x02000000)\n"
+		"	BNZ	1b\n"
+#ifdef CONFIG_METAG_LNKGET_AROUND_CACHE
+		"	DCACHE	[%2], %0\n"
+#endif
+		"2:\n"
+		: "=&d" (temp), "=&da" (retval)
+		: "da" (m), "bd" (old), "da" (new)
+		: "cc"
+	);
+
+	smp_mb();
+
+	return retval;
+}
+
+#endif /* __ASM_METAG_CMPXCHG_LNKGET_H */
diff --git a/arch/metag/include/asm/cmpxchg_lock1.h b/arch/metag/include/asm/cmpxchg_lock1.h
new file mode 100644
index 0000000..7fb4e1c
--- /dev/null
+++ b/arch/metag/include/asm/cmpxchg_lock1.h
@@ -0,0 +1,48 @@
+#ifndef __ASM_METAG_CMPXCHG_LOCK1_H
+#define __ASM_METAG_CMPXCHG_LOCK1_H
+
+#include <asm/lock.h>
+
+/* Use LOCK2 as these have to be atomic w.r.t. ordinary accesses. */
+
+static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
+{
+	unsigned long flags, retval;
+
+	__global_lock2(flags);
+	fence();
+	retval = *m;
+	*m = val;
+	__global_unlock2(flags);
+	return retval;
+}
+
+static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
+{
+	unsigned long flags, retval;
+
+	__global_lock2(flags);
+	fence();
+	retval = *m;
+	*m = val & 0xff;
+	__global_unlock2(flags);
+	return retval;
+}
+
+static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
+					  unsigned long new)
+{
+	__u32 retval;
+	unsigned long flags;
+
+	__global_lock2(flags);
+	retval = *m;
+	if (retval == old) {
+		fence();
+		*m = new;
+	}
+	__global_unlock2(flags);
+	return retval;
+}
+
+#endif /* __ASM_METAG_CMPXCHG_LOCK1_H */
diff --git a/arch/metag/include/asm/lock.h b/arch/metag/include/asm/lock.h
new file mode 100644
index 0000000..360ca21
--- /dev/null
+++ b/arch/metag/include/asm/lock.h
@@ -0,0 +1,14 @@
+#ifndef __ASM_METAG_LOCK_H
+#define __ASM_METAG_LOCK_H
+
+#include <linux/compiler.h>
+
+#include <asm/tbx.h>
+
+#define __global_lock1(flags) { TBI_CRITON(flags); barrier(); }
+#define __global_unlock1(flags) { barrier(); TBI_CRITOFF(flags); }
+
+#define __global_lock2(flags) { TBI_LOCK(flags); barrier(); }
+#define __global_unlock2(flags) { barrier(); TBI_UNLOCK(flags); }
+
+#endif /* __ASM_METAG_LOCK_H */
diff --git a/arch/metag/include/asm/spinlock.h b/arch/metag/include/asm/spinlock.h
new file mode 100644
index 0000000..86a7cf3
--- /dev/null
+++ b/arch/metag/include/asm/spinlock.h
@@ -0,0 +1,22 @@
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#ifdef CONFIG_METAG_ATOMICITY_LOCK1
+#include <asm/spinlock_lock1.h>
+#else
+#include <asm/spinlock_lnkget.h>
+#endif
+
+#define arch_spin_unlock_wait(lock) \
+	do { while (arch_spin_is_locked(lock)) cpu_relax(); } while (0)
+
+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
+
+#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_SPINLOCK_H */
diff --git a/arch/metag/include/asm/spinlock_lnkget.h b/arch/metag/include/asm/spinlock_lnkget.h
new file mode 100644
index 0000000..0990e39
--- /dev/null
+++ b/arch/metag/include/asm/spinlock_lnkget.h
@@ -0,0 +1,261 @@
+#ifndef __ASM_SPINLOCK_LNKGET_H
+#define __ASM_SPINLOCK_LNKGET_H
+
+/*
+ * None of these asm statements clobber memory as LNKSET writes around
+ * the cache so the memory it modifies cannot safely be read by any means
+ * other than these accessors.
+ */
+
+static inline int arch_spin_is_locked(arch_spinlock_t *lock)
+{
+	int ret;
+
+	__asm__ __volatile__(
+			     "LNKGETD	%0, [%1]\n"
+			     "TST	%0, #1\n"
+			     "MOV	%0, #1\n"
+			     "XORZ      %0, %0, %0\n"
+			     : "=&d" (ret)
+			     : "da" (&lock->lock)
+			     : "cc");
+	return ret;
+}
+
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			     "1:     LNKGETD %0,[%1]\n"
+			     "       TST     %0, #1\n"
+			     "       ADD     %0, %0, #1\n"
+			     "       LNKSETDZ [%1], %0\n"
+			     "       BNZ     1b\n"
+			     "       DEFR    %0, TXSTAT\n"
+			     "       ANDT    %0, %0, #HI(0x3f000000)\n"
+			     "       CMPT    %0, #HI(0x02000000)\n"
+			     "       BNZ     1b\n"
+			     : "=&d" (tmp)
+			     : "da" (&lock->lock)
+			     : "cc");
+
+	smp_mb();
+}
+
+/* Returns 0 if failed to acquire lock */
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			     "       LNKGETD %0,[%1]\n"
+			     "       TST     %0, #1\n"
+			     "       ADD     %0, %0, #1\n"
+			     "       LNKSETDZ [%1], %0\n"
+			     "       BNZ     1f\n"
+			     "       DEFR    %0, TXSTAT\n"
+			     "       ANDT    %0, %0, #HI(0x3f000000)\n"
+			     "       CMPT    %0, #HI(0x02000000)\n"
+			     "       MOV     %0, #1\n"
+			     "1:     XORNZ   %0, %0, %0\n"
+			     : "=&d" (tmp)
+			     : "da" (&lock->lock)
+			     : "cc");
+
+	smp_mb();
+
+	return tmp;
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+	smp_mb();
+
+	__asm__ __volatile__(
+			     "       SETD    [%0], %1\n"
+			     :
+			     : "da" (&lock->lock), "da" (0)
+			     : "memory");
+}
+
+/*
+ * RWLOCKS
+ *
+ *
+ * Write locks are easy - we just set bit 31.  When unlocking, we can
+ * just write zero since the lock is exclusively held.
+ */
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			     "1:     LNKGETD %0,[%1]\n"
+			     "       CMP     %0, #0\n"
+			     "       ADD     %0, %0, %2\n"
+			     "       LNKSETDZ [%1], %0\n"
+			     "       BNZ     1b\n"
+			     "       DEFR    %0, TXSTAT\n"
+			     "       ANDT    %0, %0, #HI(0x3f000000)\n"
+			     "       CMPT    %0, #HI(0x02000000)\n"
+			     "       BNZ     1b\n"
+			     : "=&d" (tmp)
+			     : "da" (&rw->lock), "bd" (0x80000000)
+			     : "cc");
+
+	smp_mb();
+}
+
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			     "       LNKGETD %0,[%1]\n"
+			     "       CMP     %0, #0\n"
+			     "       ADD     %0, %0, %2\n"
+			     "       LNKSETDZ [%1], %0\n"
+			     "       BNZ     1f\n"
+			     "       DEFR    %0, TXSTAT\n"
+			     "       ANDT    %0, %0, #HI(0x3f000000)\n"
+			     "       CMPT    %0, #HI(0x02000000)\n"
+			     "       MOV     %0,#1\n"
+			     "1:     XORNZ   %0, %0, %0\n"
+			     : "=&d" (tmp)
+			     : "da" (&rw->lock), "bd" (0x80000000)
+			     : "cc");
+
+	smp_mb();
+
+	return tmp;
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+	smp_mb();
+
+	__asm__ __volatile__(
+			     "       SETD    [%0], %1\n"
+			     :
+			     : "da" (&rw->lock), "da" (0)
+			     : "memory");
+}
+
+/* write_can_lock - would write_trylock() succeed? */
+static inline int arch_write_can_lock(arch_rwlock_t *rw)
+{
+	int ret;
+
+	__asm__ __volatile__(
+			     "LNKGETD	%0, [%1]\n"
+			     "CMP	%0, #0\n"
+			     "MOV	%0, #1\n"
+			     "XORNZ     %0, %0, %0\n"
+			     : "=&d" (ret)
+			     : "da" (&rw->lock)
+			     : "cc");
+	return ret;
+}
+
+/*
+ * Read locks are a bit more hairy:
+ *  - Exclusively load the lock value.
+ *  - Increment it.
+ *  - Store new lock value if positive, and we still own this location.
+ *    If the value is negative, we've already failed.
+ *  - If we failed to store the value, we want a negative result.
+ *  - If we failed, try again.
+ * Unlocking is similarly hairy.  We may have multiple read locks
+ * currently active.  However, we know we won't have any write
+ * locks.
+ */
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			     "1:     LNKGETD %0,[%1]\n"
+			     "       ADDS    %0, %0, #1\n"
+			     "       LNKSETDPL [%1], %0\n"
+			     "       BMI     1b\n"
+			     "       DEFR    %0, TXSTAT\n"
+			     "       ANDT    %0, %0, #HI(0x3f000000)\n"
+			     "       CMPT    %0, #HI(0x02000000)\n"
+			     "       BNZ     1b\n"
+			     : "=&d" (tmp)
+			     : "da" (&rw->lock)
+			     : "cc");
+
+	smp_mb();
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+	int tmp;
+
+	smp_mb();
+
+	__asm__ __volatile__(
+			     "1:     LNKGETD %0,[%1]\n"
+			     "       SUB     %0, %0, #1\n"
+			     "       LNKSETD [%1], %0\n"
+			     "       DEFR    %0, TXSTAT\n"
+			     "       ANDT    %0, %0, #HI(0x3f000000)\n"
+			     "       CMPT    %0, #HI(0x02000000)\n"
+			     "       BNZ     1b\n"
+			     : "=&d" (tmp)
+			     : "da" (&rw->lock)
+			     : "cc", "memory");
+}
+
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			     "       LNKGETD %0,[%1]\n"
+			     "       ADDS    %0, %0, #1\n"
+			     "       LNKSETDPL [%1], %0\n"
+			     "       BMI     1f\n"
+			     "       DEFR    %0, TXSTAT\n"
+			     "       ANDT    %0, %0, #HI(0x3f000000)\n"
+			     "       CMPT    %0, #HI(0x02000000)\n"
+			     "       MOV     %0,#1\n"
+			     "       BZ      2f\n"
+			     "1:     MOV     %0,#0\n"
+			     "2:\n"
+			     : "=&d" (tmp)
+			     : "da" (&rw->lock)
+			     : "cc");
+
+	smp_mb();
+
+	return tmp;
+}
+
+/* read_can_lock - would read_trylock() succeed? */
+static inline int arch_read_can_lock(arch_rwlock_t *rw)
+{
+	int tmp;
+
+	__asm__ __volatile__(
+			     "LNKGETD	%0, [%1]\n"
+			     "CMP	%0, %2\n"
+			     "MOV	%0, #1\n"
+			     "XORZ	%0, %0, %0\n"
+			     : "=&d" (tmp)
+			     : "da" (&rw->lock), "bd" (0x80000000)
+			     : "cc");
+	return tmp;
+}
+
+#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_SPINLOCK_LNKGET_H */
diff --git a/arch/metag/include/asm/spinlock_lock1.h b/arch/metag/include/asm/spinlock_lock1.h
new file mode 100644
index 0000000..e9f27df
--- /dev/null
+++ b/arch/metag/include/asm/spinlock_lock1.h
@@ -0,0 +1,184 @@
+#ifndef __ASM_SPINLOCK_LOCK1_H
+#define __ASM_SPINLOCK_LOCK1_H
+
+#include <asm/bug.h>
+#include <asm/lock.h>
+
+static inline int arch_spin_is_locked(arch_spinlock_t *lock)
+{
+	int ret;
+
+	barrier();
+	ret = lock->lock;
+	WARN_ON(ret != 0 && ret != 1);
+	return ret;
+}
+
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+	unsigned int we_won = 0;
+	unsigned long flags;
+
+again:
+	__global_lock1(flags);
+	if (lock->lock == 0) {
+		fence();
+		lock->lock = 1;
+		we_won = 1;
+	}
+	__global_unlock1(flags);
+	if (we_won == 0)
+		goto again;
+	WARN_ON(lock->lock != 1);
+}
+
+/* Returns 0 if failed to acquire lock */
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+	unsigned long flags;
+	unsigned int ret;
+
+	__global_lock1(flags);
+	ret = lock->lock;
+	if (ret == 0) {
+		fence();
+		lock->lock = 1;
+	}
+	__global_unlock1(flags);
+	return (ret == 0);
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+	barrier();
+	WARN_ON(!lock->lock);
+	lock->lock = 0;
+}
+
+/*
+ * RWLOCKS
+ *
+ *
+ * Write locks are easy - we just set bit 31.  When unlocking, we can
+ * just write zero since the lock is exclusively held.
+ */
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+	unsigned long flags;
+	unsigned int we_won = 0;
+
+again:
+	__global_lock1(flags);
+	if (rw->lock == 0) {
+		fence();
+		rw->lock = 0x80000000;
+		we_won = 1;
+	}
+	__global_unlock1(flags);
+	if (we_won == 0)
+		goto again;
+	WARN_ON(rw->lock != 0x80000000);
+}
+
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+	unsigned long flags;
+	unsigned int ret;
+
+	__global_lock1(flags);
+	ret = rw->lock;
+	if (ret == 0) {
+		fence();
+		rw->lock = 0x80000000;
+	}
+	__global_unlock1(flags);
+
+	return (ret == 0);
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+	barrier();
+	WARN_ON(rw->lock != 0x80000000);
+	rw->lock = 0;
+}
+
+/* write_can_lock - would write_trylock() succeed? */
+static inline int arch_write_can_lock(arch_rwlock_t *rw)
+{
+	unsigned int ret;
+
+	barrier();
+	ret = rw->lock;
+	return (ret == 0);
+}
+
+/*
+ * Read locks are a bit more hairy:
+ *  - Exclusively load the lock value.
+ *  - Increment it.
+ *  - Store new lock value if positive, and we still own this location.
+ *    If the value is negative, we've already failed.
+ *  - If we failed to store the value, we want a negative result.
+ *  - If we failed, try again.
+ * Unlocking is similarly hairy.  We may have multiple read locks
+ * currently active.  However, we know we won't have any write
+ * locks.
+ */
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+	unsigned long flags;
+	unsigned int we_won = 0, ret;
+
+again:
+	__global_lock1(flags);
+	ret = rw->lock;
+	if (ret < 0x80000000) {
+		fence();
+		rw->lock = ret + 1;
+		we_won = 1;
+	}
+	__global_unlock1(flags);
+	if (!we_won)
+		goto again;
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+	unsigned long flags;
+	unsigned int ret;
+
+	__global_lock1(flags);
+	fence();
+	ret = rw->lock--;
+	__global_unlock1(flags);
+	WARN_ON(ret == 0);
+}
+
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+	unsigned long flags;
+	unsigned int ret;
+
+	__global_lock1(flags);
+	ret = rw->lock;
+	if (ret < 0x80000000) {
+		fence();
+		rw->lock = ret + 1;
+	}
+	__global_unlock1(flags);
+	return (ret < 0x80000000);
+}
+
+/* read_can_lock - would read_trylock() succeed? */
+static inline int arch_read_can_lock(arch_rwlock_t *rw)
+{
+	unsigned int ret;
+
+	barrier();
+	ret = rw->lock;
+	return (ret < 0x80000000);
+}
+
+#endif /* __ASM_SPINLOCK_LOCK1_H */
diff --git a/arch/metag/include/asm/spinlock_types.h b/arch/metag/include/asm/spinlock_types.h
new file mode 100644
index 0000000..b763914
--- /dev/null
+++ b/arch/metag/include/asm/spinlock_types.h
@@ -0,0 +1,20 @@
+#ifndef _ASM_METAG_SPINLOCK_TYPES_H
+#define _ASM_METAG_SPINLOCK_TYPES_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+# error "please don't include this file directly"
+#endif
+
+typedef struct {
+	volatile unsigned int lock;
+} arch_spinlock_t;
+
+#define __ARCH_SPIN_LOCK_UNLOCKED	{ 0 }
+
+typedef struct {
+	volatile unsigned int lock;
+} arch_rwlock_t;
+
+#define __ARCH_RW_LOCK_UNLOCKED		{ 0 }
+
+#endif /* _ASM_METAG_SPINLOCK_TYPES_H */
-- 
1.7.7.6
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