From b3ac891b67bd4b1fc728d1c784cad1212dea433d Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Wed, 24 Feb 2010 10:54:22 +0100
Subject: x86: Add support for lock prefix in alternatives

The current lock prefix UP/SMP alternative code doesn't allow
LOCK_PREFIX to be used in alternatives code.

This patch solves the problem by adding a new LOCK_PREFIX_ALTERNATIVE_PATCH
macro that only records the lock prefix location but does not emit
the prefix.

The user of this macro can then start any alternative sequence with
"lock" and have it UP/SMP patched.

To make this work, the UP/SMP alternative code is changed to do the
lock/DS prefix switching only if the byte actually contains a lock or
DS prefix.

Thus, if an alternative without the "lock" is selected, it will now do
nothing instead of clobbering the code.

Changes in v2:
- Naming change
- Change label to not conflict with alternatives

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-2-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/include/asm/alternative.h | 8 +++++---
 arch/x86/kernel/alternative.c      | 6 ++++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 3b5b828767b..55fee12cea6 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -28,12 +28,14 @@
  */
 
 #ifdef CONFIG_SMP
-#define LOCK_PREFIX \
+#define LOCK_PREFIX_HERE \
 		".section .smp_locks,\"a\"\n"	\
 		_ASM_ALIGN "\n"			\
-		_ASM_PTR "661f\n" /* address */	\
+		_ASM_PTR "671f\n" /* address */	\
 		".previous\n"			\
-		"661:\n\tlock; "
+		"671:"
+
+#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
 
 #else /* ! CONFIG_SMP */
 #define LOCK_PREFIX ""
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 2589ea4c60c..80b222ea4cf 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -244,7 +244,8 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
 		if (*ptr > text_end)
 			continue;
 		/* turn DS segment override prefix into lock prefix */
-		text_poke(*ptr, ((unsigned char []){0xf0}), 1);
+		if (**ptr == 0x3e)
+			text_poke(*ptr, ((unsigned char []){0xf0}), 1);
 	};
 	mutex_unlock(&text_mutex);
 }
@@ -263,7 +264,8 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end
 		if (*ptr > text_end)
 			continue;
 		/* turn lock prefix into DS segment override prefix */
-		text_poke(*ptr, ((unsigned char []){0x3E}), 1);
+		if (**ptr == 0xf0)
+			text_poke(*ptr, ((unsigned char []){0x3E}), 1);
 	};
 	mutex_unlock(&text_mutex);
 }
-- 
cgit v1.2.3-70-g09d2


From 9c76b38476b18c45f97098a10b0176b321eba3ea Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Wed, 24 Feb 2010 10:54:23 +0100
Subject: x86-32: Allow UP/SMP lock replacement in cmpxchg64

Use the functionality just introduced in the previous patch: mark the
lock prefixes in cmpxchg64 alternatives for UP removal.

Changes in v2:
- Naming change

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-3-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/include/asm/cmpxchg_32.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index ffb9bb6b6c3..8859e12dd3c 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -271,7 +271,8 @@ extern unsigned long long cmpxchg_486_u64(volatile void *, u64, u64);
 	__typeof__(*(ptr)) __ret;				\
 	__typeof__(*(ptr)) __old = (o);				\
 	__typeof__(*(ptr)) __new = (n);				\
-	alternative_io("call cmpxchg8b_emu",			\
+	alternative_io(LOCK_PREFIX_HERE				\
+			"call cmpxchg8b_emu",			\
 			"lock; cmpxchg8b (%%esi)" ,		\
 		       X86_FEATURE_CX8,				\
 		       "=A" (__ret),				\
-- 
cgit v1.2.3-70-g09d2


From 86a8938078a8bb518c5376de493e348c7490d506 Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Wed, 24 Feb 2010 10:54:24 +0100
Subject: lib: Add self-test for atomic64_t

This patch adds self-test on boot code for atomic64_t.

This has been used to test the later changes in this patchset.

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-4-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 lib/Kconfig.debug   |   7 +++
 lib/Makefile        |   2 +
 lib/atomic64_test.c | 158 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 lib/atomic64_test.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 25c3ed594c5..3676c517a07 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1054,6 +1054,13 @@ config DMA_API_DEBUG
 	  This option causes a performance degredation.  Use only if you want
 	  to debug device drivers. If unsure, say N.
 
+config ATOMIC64_SELFTEST
+	bool "Perform an atomic64_t self-test at boot"
+	help
+	  Enable this option to test the atomic64_t functions at boot.
+
+	  If unsure, say N.
+
 source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"
diff --git a/lib/Makefile b/lib/Makefile
index 347ad8db29d..4af4786fe28 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -99,6 +99,8 @@ obj-$(CONFIG_GENERIC_CSUM) += checksum.o
 
 obj-$(CONFIG_GENERIC_ATOMIC64) += atomic64.o
 
+obj-$(CONFIG_ATOMIC64_SELFTEST) += atomic64_test.o
+
 hostprogs-y	:= gen_crc32table
 clean-files	:= crc32table.h
 
diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
new file mode 100644
index 00000000000..4ff649e46ba
--- /dev/null
+++ b/lib/atomic64_test.c
@@ -0,0 +1,158 @@
+/*
+ * Testsuite for atomic64_t functions
+ *
+ * Copyright © 2010  Luca Barbieri
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/init.h>
+#include <asm/atomic.h>
+
+#define INIT(c) do { atomic64_set(&v, c); r = c; } while (0)
+static __init int test_atomic64(void)
+{
+	long long v0 = 0xaaa31337c001d00dLL;
+	long long v1 = 0xdeadbeefdeafcafeLL;
+	long long v2 = 0xfaceabadf00df001LL;
+	long long onestwos = 0x1111111122222222LL;
+	long long one = 1LL;
+
+	atomic64_t v = ATOMIC64_INIT(v0);
+	long long r = v0;
+	BUG_ON(v.counter != r);
+
+	atomic64_set(&v, v1);
+	r = v1;
+	BUG_ON(v.counter != r);
+	BUG_ON(atomic64_read(&v) != r);
+
+	INIT(v0);
+	atomic64_add(onestwos, &v);
+	r += onestwos;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	atomic64_add(-one, &v);
+	r += -one;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	r += onestwos;
+	BUG_ON(atomic64_add_return(onestwos, &v) != r);
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	r += -one;
+	BUG_ON(atomic64_add_return(-one, &v) != r);
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	atomic64_sub(onestwos, &v);
+	r -= onestwos;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	atomic64_sub(-one, &v);
+	r -= -one;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	r -= onestwos;
+	BUG_ON(atomic64_sub_return(onestwos, &v) != r);
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	r -= -one;
+	BUG_ON(atomic64_sub_return(-one, &v) != r);
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	atomic64_inc(&v);
+	r += one;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	r += one;
+	BUG_ON(atomic64_inc_return(&v) != r);
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	atomic64_dec(&v);
+	r -= one;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	r -= one;
+	BUG_ON(atomic64_dec_return(&v) != r);
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	BUG_ON(atomic64_xchg(&v, v1) != v0);
+	r = v1;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	BUG_ON(atomic64_cmpxchg(&v, v0, v1) != v0);
+	r = v1;
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	BUG_ON(atomic64_cmpxchg(&v, v2, v1) != v0);
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	BUG_ON(!atomic64_add_unless(&v, one, v0));
+	BUG_ON(v.counter != r);
+
+	INIT(v0);
+	BUG_ON(atomic64_add_unless(&v, one, v1));
+	r += one;
+	BUG_ON(v.counter != r);
+
+	INIT(onestwos);
+	BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
+	r -= one;
+	BUG_ON(v.counter != r);
+
+	INIT(0);
+	BUG_ON(atomic64_dec_if_positive(&v) != -one);
+	BUG_ON(v.counter != r);
+
+	INIT(-one);
+	BUG_ON(atomic64_dec_if_positive(&v) != (-one - one));
+	BUG_ON(v.counter != r);
+
+	INIT(onestwos);
+	BUG_ON(atomic64_inc_not_zero(&v));
+	r += one;
+	BUG_ON(v.counter != r);
+
+	INIT(0);
+	BUG_ON(!atomic64_inc_not_zero(&v));
+	BUG_ON(v.counter != r);
+
+	INIT(-one);
+	BUG_ON(atomic64_inc_not_zero(&v));
+	r += one;
+	BUG_ON(v.counter != r);
+
+#ifdef CONFIG_X86
+	printk(KERN_INFO "atomic64 test passed for %s+ platform %s CX8 and %s SSE\n",
+#ifdef CONFIG_X86_CMPXCHG64
+			"586",
+#else
+			"386",
+#endif
+			boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
+			boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
+#else
+	printk(KERN_INFO "atomic64 test passed\n");
+#endif
+
+	return 0;
+}
+
+core_initcall(test_atomic64);
-- 
cgit v1.2.3-70-g09d2


From a7e926abc3adfbd2e5e20d2b46177adb4e313915 Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Wed, 24 Feb 2010 10:54:25 +0100
Subject: x86-32: Rewrite 32-bit atomic64 functions in assembly

This patch replaces atomic64_32.c with two assembly implementations,
one for 386/486 machines using pushf/cli/popf and one for 586+ machines
using cmpxchg8b.

The cmpxchg8b implementation provides the following advantages over the
current one:

1. Implements atomic64_add_unless, atomic64_dec_if_positive and
   atomic64_inc_not_zero

2. Uses the ZF flag changed by cmpxchg8b instead of doing a comparison

3. Uses custom register calling conventions that reduce or eliminate
   register moves to suit cmpxchg8b

4. Reads the initial value instead of using cmpxchg8b to do that.
   Currently we use lock xaddl and movl, which seems the fastest.

5. Does not use the lock prefix for atomic64_set
   64-bit writes are already atomic, so we don't need that.
   We still need it for atomic64_read to avoid restoring a value
   changed in the meantime.

6. Allocates registers as well or better than gcc

The 386 implementation provides support for 386 and 486 machines.
386/486 SMP is not supported (we dropped it), but such support can be
added easily if desired.

A pure assembly implementation is required due to the custom calling
conventions, and desire to use %ebp in atomic64_add_return (we need
7 registers...), as well as the ability to use pushf/popf in the 386
code without an intermediate pop/push.

The parameter names are changed to match the convention in atomic_64.h

Changes in v3 (due to rebasing to tip/x86/asm):
- Patches atomic64_32.h instead of atomic_32.h
- Uses the CALL alternative mechanism from commit
  1b1d9258181bae199dc940f4bd0298126b9a73d9

Changes in v2:
- Merged 386 and cx8 support in the same patch
- 386 support now done in assembly, C code no longer used at all
- cmpxchg64 is used for atomic64_cmpxchg
- stop using macros, use one-line inline functions instead
- miscellanous changes and improvements

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-5-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/include/asm/atomic64_32.h | 278 ++++++++++++++++++++++++++++---------
 arch/x86/lib/Makefile              |   3 +-
 arch/x86/lib/atomic64_32.c         | 273 +++++++-----------------------------
 arch/x86/lib/atomic64_386_32.S     | 175 +++++++++++++++++++++++
 arch/x86/lib/atomic64_cx8_32.S     | 225 ++++++++++++++++++++++++++++++
 5 files changed, 664 insertions(+), 290 deletions(-)
 create mode 100644 arch/x86/lib/atomic64_386_32.S
 create mode 100644 arch/x86/lib/atomic64_cx8_32.S

diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 03027bf28de..2a934aa19a4 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -14,109 +14,193 @@ typedef struct {
 
 #define ATOMIC64_INIT(val)	{ (val) }
 
-extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);
+#ifdef CONFIG_X86_CMPXCHG64
+#define ATOMIC64_ALTERNATIVE_(f, g) "call atomic64_" #g "_cx8"
+#else
+#define ATOMIC64_ALTERNATIVE_(f, g) ALTERNATIVE("call atomic64_" #f "_386", "call atomic64_" #g "_cx8", X86_FEATURE_CX8)
+#endif
+
+#define ATOMIC64_ALTERNATIVE(f) ATOMIC64_ALTERNATIVE_(f, f)
+
+/**
+ * atomic64_cmpxchg - cmpxchg atomic64 variable
+ * @p: pointer to type atomic64_t
+ * @o: expected value
+ * @n: new value
+ *
+ * Atomically sets @v to @n if it was equal to @o and returns
+ * the old value.
+ */
+
+static inline long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)
+{
+	return cmpxchg64(&v->counter, o, n);
+}
 
 /**
  * atomic64_xchg - xchg atomic64 variable
- * @ptr:      pointer to type atomic64_t
- * @new_val:  value to assign
+ * @v: pointer to type atomic64_t
+ * @n: value to assign
  *
- * Atomically xchgs the value of @ptr to @new_val and returns
+ * Atomically xchgs the value of @v to @n and returns
  * the old value.
  */
-extern u64 atomic64_xchg(atomic64_t *ptr, u64 new_val);
+static inline long long atomic64_xchg(atomic64_t *v, long long n)
+{
+	long long o;
+	unsigned high = (unsigned)(n >> 32);
+	unsigned low = (unsigned)n;
+	asm volatile(ATOMIC64_ALTERNATIVE(xchg)
+		     : "=A" (o), "+b" (low), "+c" (high)
+		     : "S" (v)
+		     : "memory"
+		     );
+	return o;
+}
 
 /**
  * atomic64_set - set atomic64 variable
- * @ptr:      pointer to type atomic64_t
- * @new_val:  value to assign
+ * @v: pointer to type atomic64_t
+ * @n: value to assign
  *
- * Atomically sets the value of @ptr to @new_val.
+ * Atomically sets the value of @v to @n.
  */
-extern void atomic64_set(atomic64_t *ptr, u64 new_val);
+static inline void atomic64_set(atomic64_t *v, long long i)
+{
+	unsigned high = (unsigned)(i >> 32);
+	unsigned low = (unsigned)i;
+	asm volatile(ATOMIC64_ALTERNATIVE(set)
+		     : "+b" (low), "+c" (high)
+		     : "S" (v)
+		     : "eax", "edx", "memory"
+		     );
+}
 
 /**
  * atomic64_read - read atomic64 variable
- * @ptr:      pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically reads the value of @ptr and returns it.
+ * Atomically reads the value of @v and returns it.
  */
-static inline u64 atomic64_read(atomic64_t *ptr)
+static inline long long atomic64_read(atomic64_t *v)
 {
-	u64 res;
-
-	/*
-	 * Note, we inline this atomic64_t primitive because
-	 * it only clobbers EAX/EDX and leaves the others
-	 * untouched. We also (somewhat subtly) rely on the
-	 * fact that cmpxchg8b returns the current 64-bit value
-	 * of the memory location we are touching:
-	 */
-	asm volatile(
-		"mov %%ebx, %%eax\n\t"
-		"mov %%ecx, %%edx\n\t"
-		LOCK_PREFIX "cmpxchg8b %1\n"
-			: "=&A" (res)
-			: "m" (*ptr)
-		);
-
-	return res;
-}
-
-extern u64 atomic64_read(atomic64_t *ptr);
+	long long r;
+	asm volatile(ATOMIC64_ALTERNATIVE(read)
+		     : "=A" (r), "+c" (v)
+		     : : "memory"
+		     );
+	return r;
+ }
 
 /**
  * atomic64_add_return - add and return
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to add
+ * @v: pointer to type atomic64_t
  *
- * Atomically adds @delta to @ptr and returns @delta + *@ptr
+ * Atomically adds @i to @v and returns @i + *@v
  */
-extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);
+static inline long long atomic64_add_return(long long i, atomic64_t *v)
+{
+	asm volatile(ATOMIC64_ALTERNATIVE(add_return)
+		     : "+A" (i), "+c" (v)
+		     : : "memory"
+		     );
+	return i;
+}
 
 /*
  * Other variants with different arithmetic operators:
  */
-extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);
-extern u64 atomic64_inc_return(atomic64_t *ptr);
-extern u64 atomic64_dec_return(atomic64_t *ptr);
+static inline long long atomic64_sub_return(long long i, atomic64_t *v)
+{
+	asm volatile(ATOMIC64_ALTERNATIVE(sub_return)
+		     : "+A" (i), "+c" (v)
+		     : : "memory"
+		     );
+	return i;
+}
+
+static inline long long atomic64_inc_return(atomic64_t *v)
+{
+	long long a;
+	asm volatile(ATOMIC64_ALTERNATIVE(inc_return)
+		     : "=A" (a)
+		     : "S" (v)
+		     : "memory", "ecx"
+		     );
+	return a;
+}
+
+static inline long long atomic64_dec_return(atomic64_t *v)
+{
+	long long a;
+	asm volatile(ATOMIC64_ALTERNATIVE(dec_return)
+		     : "=A" (a)
+		     : "S" (v)
+		     : "memory", "ecx"
+		     );
+	return a;
+}
 
 /**
  * atomic64_add - add integer to atomic64 variable
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to add
+ * @v: pointer to type atomic64_t
  *
- * Atomically adds @delta to @ptr.
+ * Atomically adds @i to @v.
  */
-extern void atomic64_add(u64 delta, atomic64_t *ptr);
+static inline long long atomic64_add(long long i, atomic64_t *v)
+{
+	asm volatile(ATOMIC64_ALTERNATIVE_(add, add_return)
+		     : "+A" (i), "+c" (v)
+		     : : "memory"
+		     );
+	return i;
+}
 
 /**
  * atomic64_sub - subtract the atomic64 variable
- * @delta: integer value to subtract
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to subtract
+ * @v: pointer to type atomic64_t
  *
- * Atomically subtracts @delta from @ptr.
+ * Atomically subtracts @i from @v.
  */
-extern void atomic64_sub(u64 delta, atomic64_t *ptr);
+static inline long long atomic64_sub(long long i, atomic64_t *v)
+{
+	asm volatile(ATOMIC64_ALTERNATIVE_(sub, sub_return)
+		     : "+A" (i), "+c" (v)
+		     : : "memory"
+		     );
+	return i;
+}
 
 /**
  * atomic64_sub_and_test - subtract value from variable and test result
- * @delta: integer value to subtract
- * @ptr:   pointer to type atomic64_t
- *
- * Atomically subtracts @delta from @ptr and returns
+ * @i: integer value to subtract
+ * @v: pointer to type atomic64_t
+  *
+ * Atomically subtracts @i from @v and returns
  * true if the result is zero, or false for all
  * other cases.
  */
-extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);
+static inline int atomic64_sub_and_test(long long i, atomic64_t *v)
+{
+	return atomic64_sub_return(i, v) == 0;
+}
 
 /**
  * atomic64_inc - increment atomic64 variable
- * @ptr: pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically increments @ptr by 1.
+ * Atomically increments @v by 1.
  */
-extern void atomic64_inc(atomic64_t *ptr);
+static inline void atomic64_inc(atomic64_t *v)
+{
+	asm volatile(ATOMIC64_ALTERNATIVE_(inc, inc_return)
+		     : : "S" (v)
+		     : "memory", "eax", "ecx", "edx"
+		     );
+}
 
 /**
  * atomic64_dec - decrement atomic64 variable
@@ -124,37 +208,97 @@ extern void atomic64_inc(atomic64_t *ptr);
  *
  * Atomically decrements @ptr by 1.
  */
-extern void atomic64_dec(atomic64_t *ptr);
+static inline void atomic64_dec(atomic64_t *v)
+{
+	asm volatile(ATOMIC64_ALTERNATIVE_(dec, dec_return)
+		     : : "S" (v)
+		     : "memory", "eax", "ecx", "edx"
+		     );
+}
 
 /**
  * atomic64_dec_and_test - decrement and test
- * @ptr: pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically decrements @ptr by 1 and
+ * Atomically decrements @v by 1 and
  * returns true if the result is 0, or false for all other
  * cases.
  */
-extern int atomic64_dec_and_test(atomic64_t *ptr);
+static inline int atomic64_dec_and_test(atomic64_t *v)
+{
+	return atomic64_dec_return(v) == 0;
+}
 
 /**
  * atomic64_inc_and_test - increment and test
- * @ptr: pointer to type atomic64_t
+ * @v: pointer to type atomic64_t
  *
- * Atomically increments @ptr by 1
+ * Atomically increments @v by 1
  * and returns true if the result is zero, or false for all
  * other cases.
  */
-extern int atomic64_inc_and_test(atomic64_t *ptr);
+static inline int atomic64_inc_and_test(atomic64_t *v)
+{
+	return atomic64_inc_return(v) == 0;
+}
 
 /**
  * atomic64_add_negative - add and test if negative
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
+ * @i: integer value to add
+ * @v: pointer to type atomic64_t
  *
- * Atomically adds @delta to @ptr and returns true
+ * Atomically adds @i to @v and returns true
  * if the result is negative, or false when
  * result is greater than or equal to zero.
  */
-extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);
+static inline int atomic64_add_negative(long long i, atomic64_t *v)
+{
+	return atomic64_add_return(i, v) < 0;
+}
+
+/**
+ * atomic64_add_unless - add unless the number is a given value
+ * @v: pointer of type atomic64_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, so long as it was not @u.
+ * Returns non-zero if @v was not @u, and zero otherwise.
+ */
+static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u)
+{
+	unsigned low = (unsigned)u;
+	unsigned high = (unsigned)(u >> 32);
+	asm volatile(ATOMIC64_ALTERNATIVE(add_unless) "\n\t"
+		     : "+A" (a), "+c" (v), "+S" (low), "+D" (high)
+		     : : "memory");
+	return (int)a;
+}
+
+
+static inline int atomic64_inc_not_zero(atomic64_t *v)
+{
+	int r;
+	asm volatile(ATOMIC64_ALTERNATIVE(inc_not_zero)
+		     : "=a" (r)
+		     : "S" (v)
+		     : "ecx", "edx", "memory"
+		     );
+	return r;
+}
+
+static inline long long atomic64_dec_if_positive(atomic64_t *v)
+{
+	long long r;
+	asm volatile(ATOMIC64_ALTERNATIVE(dec_if_positive)
+		     : "=A" (r)
+		     : "S" (v)
+		     : "ecx", "memory"
+		     );
+	return r;
+}
+
+#undef ATOMIC64_ALTERNATIVE
+#undef ATOMIC64_ALTERNATIVE_
 
 #endif /* _ASM_X86_ATOMIC64_32_H */
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index cffd754f303..05d686bbbe9 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -26,11 +26,12 @@ obj-y += msr.o msr-reg.o msr-reg-export.o
 
 ifeq ($(CONFIG_X86_32),y)
         obj-y += atomic64_32.o
+        lib-y += atomic64_cx8_32.o
         lib-y += checksum_32.o
         lib-y += strstr_32.o
         lib-y += semaphore_32.o string_32.o
 ifneq ($(CONFIG_X86_CMPXCHG64),y)
-        lib-y += cmpxchg8b_emu.o
+        lib-y += cmpxchg8b_emu.o atomic64_386_32.o
 endif
         lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o
 else
diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c
index 824fa0be55a..540179e8e9f 100644
--- a/arch/x86/lib/atomic64_32.c
+++ b/arch/x86/lib/atomic64_32.c
@@ -6,225 +6,54 @@
 #include <asm/cmpxchg.h>
 #include <asm/atomic.h>
 
-static noinline u64 cmpxchg8b(u64 *ptr, u64 old, u64 new)
-{
-	u32 low = new;
-	u32 high = new >> 32;
-
-	asm volatile(
-		LOCK_PREFIX "cmpxchg8b %1\n"
-		     : "+A" (old), "+m" (*ptr)
-		     :  "b" (low),  "c" (high)
-		     );
-	return old;
-}
-
-u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val)
-{
-	return cmpxchg8b(&ptr->counter, old_val, new_val);
-}
-EXPORT_SYMBOL(atomic64_cmpxchg);
-
-/**
- * atomic64_xchg - xchg atomic64 variable
- * @ptr:      pointer to type atomic64_t
- * @new_val:  value to assign
- *
- * Atomically xchgs the value of @ptr to @new_val and returns
- * the old value.
- */
-u64 atomic64_xchg(atomic64_t *ptr, u64 new_val)
-{
-	/*
-	 * Try first with a (possibly incorrect) assumption about
-	 * what we have there. We'll do two loops most likely,
-	 * but we'll get an ownership MESI transaction straight away
-	 * instead of a read transaction followed by a
-	 * flush-for-ownership transaction:
-	 */
-	u64 old_val, real_val = 0;
-
-	do {
-		old_val = real_val;
-
-		real_val = atomic64_cmpxchg(ptr, old_val, new_val);
-
-	} while (real_val != old_val);
-
-	return old_val;
-}
-EXPORT_SYMBOL(atomic64_xchg);
-
-/**
- * atomic64_set - set atomic64 variable
- * @ptr:      pointer to type atomic64_t
- * @new_val:  value to assign
- *
- * Atomically sets the value of @ptr to @new_val.
- */
-void atomic64_set(atomic64_t *ptr, u64 new_val)
-{
-	atomic64_xchg(ptr, new_val);
-}
-EXPORT_SYMBOL(atomic64_set);
-
-/**
-EXPORT_SYMBOL(atomic64_read);
- * atomic64_add_return - add and return
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
- *
- * Atomically adds @delta to @ptr and returns @delta + *@ptr
- */
-noinline u64 atomic64_add_return(u64 delta, atomic64_t *ptr)
-{
-	/*
-	 * Try first with a (possibly incorrect) assumption about
-	 * what we have there. We'll do two loops most likely,
-	 * but we'll get an ownership MESI transaction straight away
-	 * instead of a read transaction followed by a
-	 * flush-for-ownership transaction:
-	 */
-	u64 old_val, new_val, real_val = 0;
-
-	do {
-		old_val = real_val;
-		new_val = old_val + delta;
-
-		real_val = atomic64_cmpxchg(ptr, old_val, new_val);
-
-	} while (real_val != old_val);
-
-	return new_val;
-}
-EXPORT_SYMBOL(atomic64_add_return);
-
-u64 atomic64_sub_return(u64 delta, atomic64_t *ptr)
-{
-	return atomic64_add_return(-delta, ptr);
-}
-EXPORT_SYMBOL(atomic64_sub_return);
-
-u64 atomic64_inc_return(atomic64_t *ptr)
-{
-	return atomic64_add_return(1, ptr);
-}
-EXPORT_SYMBOL(atomic64_inc_return);
-
-u64 atomic64_dec_return(atomic64_t *ptr)
-{
-	return atomic64_sub_return(1, ptr);
-}
-EXPORT_SYMBOL(atomic64_dec_return);
-
-/**
- * atomic64_add - add integer to atomic64 variable
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
- *
- * Atomically adds @delta to @ptr.
- */
-void atomic64_add(u64 delta, atomic64_t *ptr)
-{
-	atomic64_add_return(delta, ptr);
-}
-EXPORT_SYMBOL(atomic64_add);
-
-/**
- * atomic64_sub - subtract the atomic64 variable
- * @delta: integer value to subtract
- * @ptr:   pointer to type atomic64_t
- *
- * Atomically subtracts @delta from @ptr.
- */
-void atomic64_sub(u64 delta, atomic64_t *ptr)
-{
-	atomic64_add(-delta, ptr);
-}
-EXPORT_SYMBOL(atomic64_sub);
-
-/**
- * atomic64_sub_and_test - subtract value from variable and test result
- * @delta: integer value to subtract
- * @ptr:   pointer to type atomic64_t
- *
- * Atomically subtracts @delta from @ptr and returns
- * true if the result is zero, or false for all
- * other cases.
- */
-int atomic64_sub_and_test(u64 delta, atomic64_t *ptr)
-{
-	u64 new_val = atomic64_sub_return(delta, ptr);
-
-	return new_val == 0;
-}
-EXPORT_SYMBOL(atomic64_sub_and_test);
-
-/**
- * atomic64_inc - increment atomic64 variable
- * @ptr: pointer to type atomic64_t
- *
- * Atomically increments @ptr by 1.
- */
-void atomic64_inc(atomic64_t *ptr)
-{
-	atomic64_add(1, ptr);
-}
-EXPORT_SYMBOL(atomic64_inc);
-
-/**
- * atomic64_dec - decrement atomic64 variable
- * @ptr: pointer to type atomic64_t
- *
- * Atomically decrements @ptr by 1.
- */
-void atomic64_dec(atomic64_t *ptr)
-{
-	atomic64_sub(1, ptr);
-}
-EXPORT_SYMBOL(atomic64_dec);
-
-/**
- * atomic64_dec_and_test - decrement and test
- * @ptr: pointer to type atomic64_t
- *
- * Atomically decrements @ptr by 1 and
- * returns true if the result is 0, or false for all other
- * cases.
- */
-int atomic64_dec_and_test(atomic64_t *ptr)
-{
-	return atomic64_sub_and_test(1, ptr);
-}
-EXPORT_SYMBOL(atomic64_dec_and_test);
-
-/**
- * atomic64_inc_and_test - increment and test
- * @ptr: pointer to type atomic64_t
- *
- * Atomically increments @ptr by 1
- * and returns true if the result is zero, or false for all
- * other cases.
- */
-int atomic64_inc_and_test(atomic64_t *ptr)
-{
-	return atomic64_sub_and_test(-1, ptr);
-}
-EXPORT_SYMBOL(atomic64_inc_and_test);
-
-/**
- * atomic64_add_negative - add and test if negative
- * @delta: integer value to add
- * @ptr:   pointer to type atomic64_t
- *
- * Atomically adds @delta to @ptr and returns true
- * if the result is negative, or false when
- * result is greater than or equal to zero.
- */
-int atomic64_add_negative(u64 delta, atomic64_t *ptr)
-{
-	s64 new_val = atomic64_add_return(delta, ptr);
-
-	return new_val < 0;
-}
-EXPORT_SYMBOL(atomic64_add_negative);
+long long atomic64_read_cx8(long long, const atomic64_t *v);
+EXPORT_SYMBOL(atomic64_read_cx8);
+long long atomic64_set_cx8(long long, const atomic64_t *v);
+EXPORT_SYMBOL(atomic64_set_cx8);
+long long atomic64_xchg_cx8(long long, unsigned high);
+EXPORT_SYMBOL(atomic64_xchg_cx8);
+long long atomic64_add_return_cx8(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_add_return_cx8);
+long long atomic64_sub_return_cx8(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_sub_return_cx8);
+long long atomic64_inc_return_cx8(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_inc_return_cx8);
+long long atomic64_dec_return_cx8(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_dec_return_cx8);
+long long atomic64_dec_if_positive_cx8(atomic64_t *v);
+EXPORT_SYMBOL(atomic64_dec_if_positive_cx8);
+int atomic64_inc_not_zero_cx8(atomic64_t *v);
+EXPORT_SYMBOL(atomic64_inc_not_zero_cx8);
+int atomic64_add_unless_cx8(atomic64_t *v, long long a, long long u);
+EXPORT_SYMBOL(atomic64_add_unless_cx8);
+
+#ifndef CONFIG_X86_CMPXCHG64
+long long atomic64_read_386(long long, const atomic64_t *v);
+EXPORT_SYMBOL(atomic64_read_386);
+long long atomic64_set_386(long long, const atomic64_t *v);
+EXPORT_SYMBOL(atomic64_set_386);
+long long atomic64_xchg_386(long long, unsigned high);
+EXPORT_SYMBOL(atomic64_xchg_386);
+long long atomic64_add_return_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_add_return_386);
+long long atomic64_sub_return_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_sub_return_386);
+long long atomic64_inc_return_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_inc_return_386);
+long long atomic64_dec_return_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_dec_return_386);
+long long atomic64_add_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_add_386);
+long long atomic64_sub_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_sub_386);
+long long atomic64_inc_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_inc_386);
+long long atomic64_dec_386(long long a, atomic64_t *v);
+EXPORT_SYMBOL(atomic64_dec_386);
+long long atomic64_dec_if_positive_386(atomic64_t *v);
+EXPORT_SYMBOL(atomic64_dec_if_positive_386);
+int atomic64_inc_not_zero_386(atomic64_t *v);
+EXPORT_SYMBOL(atomic64_inc_not_zero_386);
+int atomic64_add_unless_386(atomic64_t *v, long long a, long long u);
+EXPORT_SYMBOL(atomic64_add_unless_386);
+#endif
diff --git a/arch/x86/lib/atomic64_386_32.S b/arch/x86/lib/atomic64_386_32.S
new file mode 100644
index 00000000000..5db07fe4a0c
--- /dev/null
+++ b/arch/x86/lib/atomic64_386_32.S
@@ -0,0 +1,175 @@
+/*
+ * atomic64_t for 386/486
+ *
+ * Copyright © 2010  Luca Barbieri
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/linkage.h>
+#include <asm/alternative-asm.h>
+#include <asm/dwarf2.h>
+
+/* if you want SMP support, implement these with real spinlocks */
+.macro LOCK reg
+	pushfl
+	CFI_ADJUST_CFA_OFFSET 4
+	cli
+.endm
+
+.macro UNLOCK reg
+	popfl
+	CFI_ADJUST_CFA_OFFSET -4
+.endm
+
+.macro BEGIN func reg
+$v = \reg
+
+ENTRY(atomic64_\func\()_386)
+	CFI_STARTPROC
+	LOCK $v
+
+.macro RETURN
+	UNLOCK $v
+	ret
+.endm
+
+.macro END_
+	CFI_ENDPROC
+ENDPROC(atomic64_\func\()_386)
+.purgem RETURN
+.purgem END_
+.purgem END
+.endm
+
+.macro END
+RETURN
+END_
+.endm
+.endm
+
+BEGIN read %ecx
+	movl  ($v), %eax
+	movl 4($v), %edx
+END
+
+BEGIN set %esi
+	movl %ebx,  ($v)
+	movl %ecx, 4($v)
+END
+
+BEGIN xchg %esi
+	movl  ($v), %eax
+	movl 4($v), %edx
+	movl %ebx,  ($v)
+	movl %ecx, 4($v)
+END
+
+BEGIN add %ecx
+	addl %eax,  ($v)
+	adcl %edx, 4($v)
+END
+
+BEGIN add_return %ecx
+	addl  ($v), %eax
+	adcl 4($v), %edx
+	movl %eax,  ($v)
+	movl %edx, 4($v)
+END
+
+BEGIN sub %ecx
+	subl %eax,  ($v)
+	sbbl %edx, 4($v)
+END
+
+BEGIN sub_return %ecx
+	negl %edx
+	negl %eax
+	sbbl $0, %edx
+	addl  ($v), %eax
+	adcl 4($v), %edx
+	movl %eax,  ($v)
+	movl %edx, 4($v)
+END
+
+BEGIN inc %esi
+	addl $1,  ($v)
+	adcl $0, 4($v)
+END
+
+BEGIN inc_return %esi
+	movl  ($v), %eax
+	movl 4($v), %edx
+	addl $1, %eax
+	adcl $0, %edx
+	movl %eax,  ($v)
+	movl %edx, 4($v)
+END
+
+BEGIN dec %esi
+	subl $1,  ($v)
+	sbbl $0, 4($v)
+END
+
+BEGIN dec_return %esi
+	movl  ($v), %eax
+	movl 4($v), %edx
+	subl $1, %eax
+	sbbl $0, %edx
+	movl %eax,  ($v)
+	movl %edx, 4($v)
+END
+
+BEGIN add_unless %ecx
+	addl %eax, %esi
+	adcl %edx, %edi
+	addl  ($v), %eax
+	adcl 4($v), %edx
+	cmpl %eax, %esi
+	je 3f
+1:
+	movl %eax,  ($v)
+	movl %edx, 4($v)
+	xorl %eax, %eax
+2:
+RETURN
+3:
+	cmpl %edx, %edi
+	jne 1b
+	movl $1, %eax
+	jmp 2b
+END_
+
+BEGIN inc_not_zero %esi
+	movl  ($v), %eax
+	movl 4($v), %edx
+	testl %eax, %eax
+	je 3f
+1:
+	addl $1, %eax
+	adcl $0, %edx
+	movl %eax,  ($v)
+	movl %edx, 4($v)
+	xorl %eax, %eax
+2:
+RETURN
+3:
+	testl %edx, %edx
+	jne 1b
+	movl $1, %eax
+	jmp 2b
+END_
+
+BEGIN dec_if_positive %esi
+	movl  ($v), %eax
+	movl 4($v), %edx
+	subl $1, %eax
+	sbbl $0, %edx
+	js 1f
+	movl %eax,  ($v)
+	movl %edx, 4($v)
+1:
+END
diff --git a/arch/x86/lib/atomic64_cx8_32.S b/arch/x86/lib/atomic64_cx8_32.S
new file mode 100644
index 00000000000..e49c4ebca9f
--- /dev/null
+++ b/arch/x86/lib/atomic64_cx8_32.S
@@ -0,0 +1,225 @@
+/*
+ * atomic64_t for 586+
+ *
+ * Copyright © 2010  Luca Barbieri
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/linkage.h>
+#include <asm/alternative-asm.h>
+#include <asm/dwarf2.h>
+
+.macro SAVE reg
+	pushl %\reg
+	CFI_ADJUST_CFA_OFFSET 4
+	CFI_REL_OFFSET \reg, 0
+.endm
+
+.macro RESTORE reg
+	popl %\reg
+	CFI_ADJUST_CFA_OFFSET -4
+	CFI_RESTORE \reg
+.endm
+
+.macro read64 reg
+	movl %ebx, %eax
+	movl %ecx, %edx
+/* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */
+	LOCK_PREFIX
+	cmpxchg8b (\reg)
+.endm
+
+ENTRY(atomic64_read_cx8)
+	CFI_STARTPROC
+
+	read64 %ecx
+	ret
+	CFI_ENDPROC
+ENDPROC(atomic64_read_cx8)
+
+ENTRY(atomic64_set_cx8)
+	CFI_STARTPROC
+
+1:
+/* we don't need LOCK_PREFIX since aligned 64-bit writes
+ * are atomic on 586 and newer */
+	cmpxchg8b (%esi)
+	jne 1b
+
+	ret
+	CFI_ENDPROC
+ENDPROC(atomic64_set_cx8)
+
+ENTRY(atomic64_xchg_cx8)
+	CFI_STARTPROC
+
+	movl %ebx, %eax
+	movl %ecx, %edx
+1:
+	LOCK_PREFIX
+	cmpxchg8b (%esi)
+	jne 1b
+
+	ret
+	CFI_ENDPROC
+ENDPROC(atomic64_xchg_cx8)
+
+.macro addsub_return func ins insc
+ENTRY(atomic64_\func\()_return_cx8)
+	CFI_STARTPROC
+	SAVE ebp
+	SAVE ebx
+	SAVE esi
+	SAVE edi
+
+	movl %eax, %esi
+	movl %edx, %edi
+	movl %ecx, %ebp
+
+	read64 %ebp
+1:
+	movl %eax, %ebx
+	movl %edx, %ecx
+	\ins\()l %esi, %ebx
+	\insc\()l %edi, %ecx
+	LOCK_PREFIX
+	cmpxchg8b (%ebp)
+	jne 1b
+
+10:
+	movl %ebx, %eax
+	movl %ecx, %edx
+	RESTORE edi
+	RESTORE esi
+	RESTORE ebx
+	RESTORE ebp
+	ret
+	CFI_ENDPROC
+ENDPROC(atomic64_\func\()_return_cx8)
+.endm
+
+addsub_return add add adc
+addsub_return sub sub sbb
+
+.macro incdec_return func ins insc
+ENTRY(atomic64_\func\()_return_cx8)
+	CFI_STARTPROC
+	SAVE ebx
+
+	read64 %esi
+1:
+	movl %eax, %ebx
+	movl %edx, %ecx
+	\ins\()l $1, %ebx
+	\insc\()l $0, %ecx
+	LOCK_PREFIX
+	cmpxchg8b (%esi)
+	jne 1b
+
+10:
+	movl %ebx, %eax
+	movl %ecx, %edx
+	RESTORE ebx
+	ret
+	CFI_ENDPROC
+ENDPROC(atomic64_\func\()_return_cx8)
+.endm
+
+incdec_return inc add adc
+incdec_return dec sub sbb
+
+ENTRY(atomic64_dec_if_positive_cx8)
+	CFI_STARTPROC
+	SAVE ebx
+
+	read64 %esi
+1:
+	movl %eax, %ebx
+	movl %edx, %ecx
+	subl $1, %ebx
+	sbb $0, %ecx
+	js 2f
+	LOCK_PREFIX
+	cmpxchg8b (%esi)
+	jne 1b
+
+2:
+	movl %ebx, %eax
+	movl %ecx, %edx
+	RESTORE ebx
+	ret
+	CFI_ENDPROC
+ENDPROC(atomic64_dec_if_positive_cx8)
+
+ENTRY(atomic64_add_unless_cx8)
+	CFI_STARTPROC
+	SAVE ebp
+	SAVE ebx
+/* these just push these two parameters on the stack */
+	SAVE edi
+	SAVE esi
+
+	movl %ecx, %ebp
+	movl %eax, %esi
+	movl %edx, %edi
+
+	read64 %ebp
+1:
+	cmpl %eax, 0(%esp)
+	je 4f
+2:
+	movl %eax, %ebx
+	movl %edx, %ecx
+	addl %esi, %ebx
+	adcl %edi, %ecx
+	LOCK_PREFIX
+	cmpxchg8b (%ebp)
+	jne 1b
+
+	xorl %eax, %eax
+3:
+	addl $8, %esp
+	CFI_ADJUST_CFA_OFFSET -8
+	RESTORE ebx
+	RESTORE ebp
+	ret
+4:
+	cmpl %edx, 4(%esp)
+	jne 2b
+	movl $1, %eax
+	jmp 3b
+	CFI_ENDPROC
+ENDPROC(atomic64_add_unless_cx8)
+
+ENTRY(atomic64_inc_not_zero_cx8)
+	CFI_STARTPROC
+	SAVE ebx
+
+	read64 %esi
+1:
+	testl %eax, %eax
+	je 4f
+2:
+	movl %eax, %ebx
+	movl %edx, %ecx
+	addl $1, %ebx
+	adcl $0, %ecx
+	LOCK_PREFIX
+	cmpxchg8b (%esi)
+	jne 1b
+
+	xorl %eax, %eax
+3:
+	RESTORE ebx
+	ret
+4:
+	testl %edx, %edx
+	jne 2b
+	movl $1, %eax
+	jmp 3b
+	CFI_ENDPROC
+ENDPROC(atomic64_inc_not_zero_cx8)
-- 
cgit v1.2.3-70-g09d2


From 8f4f202b335144bf5be5c9e5b1bc9477ecdae958 Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Fri, 26 Feb 2010 12:22:40 +0100
Subject: lib: Only test atomic64_dec_if_positive on archs having it

Currently atomic64_dec_if_positive() is only supported by PowerPC,
MIPS and x86-32.

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267183361-20775-1-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 lib/atomic64_test.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index 4ff649e46ba..0effcacbebd 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -112,6 +112,7 @@ static __init int test_atomic64(void)
 	r += one;
 	BUG_ON(v.counter != r);
 
+#if defined(CONFIG_X86_32) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || defined(_ASM_GENERIC_ATOMIC64_H)
 	INIT(onestwos);
 	BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
 	r -= one;
@@ -124,6 +125,9 @@ static __init int test_atomic64(void)
 	INIT(-one);
 	BUG_ON(atomic64_dec_if_positive(&v) != (-one - one));
 	BUG_ON(v.counter != r);
+#else
+#warning Please implement atomic64_dec_if_positive for your architecture, and add it to the IF above
+#endif
 
 	INIT(onestwos);
 	BUG_ON(atomic64_inc_not_zero(&v));
-- 
cgit v1.2.3-70-g09d2


From d7f6de1e9c4a12e11ba7186c70f0f40caa76f590 Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Fri, 26 Feb 2010 12:22:41 +0100
Subject: x86: Implement atomic[64]_dec_if_positive()

Add support for atomic_dec_if_positive(), and
atomic64_dec_if_positive() for x86-64.

atomic64_dec_if_positive() for x86-32 was already implemented in a previous patch.

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267183361-20775-2-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/include/asm/atomic.h      | 23 +++++++++++++++++++++++
 arch/x86/include/asm/atomic64_64.h | 23 +++++++++++++++++++++++
 lib/atomic64_test.c                |  2 +-
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index 8f8217b9bda..706c69492c1 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -246,6 +246,29 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
 
 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 
+/*
+ * atomic_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+static inline int atomic_dec_if_positive(atomic_t *v)
+{
+	int c, old, dec;
+	c = atomic_read(v);
+	for (;;) {
+		dec = c - 1;
+		if (unlikely(dec < 0))
+			break;
+		old = atomic_cmpxchg((v), c, dec);
+		if (likely(old == c))
+			break;
+		c = old;
+	}
+	return dec;
+}
+
 /**
  * atomic_inc_short - increment of a short integer
  * @v: pointer to type int
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 51c5b405692..4d6e2cd6c88 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -221,4 +221,27 @@ static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
 
 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 
+/*
+ * atomic64_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+static inline long atomic64_dec_if_positive(atomic64_t *v)
+{
+	long c, old, dec;
+	c = atomic64_read(v);
+	for (;;) {
+		dec = c - 1;
+		if (unlikely(dec < 0))
+			break;
+		old = atomic64_cmpxchg((v), c, dec);
+		if (likely(old == c))
+			break;
+		c = old;
+	}
+	return dec;
+}
+
 #endif /* _ASM_X86_ATOMIC64_64_H */
diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index 0effcacbebd..58efdabb384 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -112,7 +112,7 @@ static __init int test_atomic64(void)
 	r += one;
 	BUG_ON(v.counter != r);
 
-#if defined(CONFIG_X86_32) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || defined(_ASM_GENERIC_ATOMIC64_H)
+#if defined(CONFIG_X86) || defined(CONFIG_MIPS) || defined(CONFIG_PPC) || defined(_ASM_GENERIC_ATOMIC64_H)
 	INIT(onestwos);
 	BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
 	r -= one;
-- 
cgit v1.2.3-70-g09d2


From 9efbcd590243045111670c171a951923b877b57d Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Mon, 1 Mar 2010 19:55:45 +0100
Subject: lib: Fix atomic64_add_unless test

atomic64_add_unless must return 1 if it perfomed the add and 0 otherwise.
The test assumed the opposite convention.

Reported-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267469749-11878-2-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 lib/atomic64_test.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index 58efdabb384..ee8e6de8b41 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -104,11 +104,11 @@ static __init int test_atomic64(void)
 	BUG_ON(v.counter != r);
 
 	INIT(v0);
-	BUG_ON(!atomic64_add_unless(&v, one, v0));
+	BUG_ON(atomic64_add_unless(&v, one, v0));
 	BUG_ON(v.counter != r);
 
 	INIT(v0);
-	BUG_ON(atomic64_add_unless(&v, one, v1));
+	BUG_ON(!atomic64_add_unless(&v, one, v1));
 	r += one;
 	BUG_ON(v.counter != r);
 
-- 
cgit v1.2.3-70-g09d2


From 6e6104fe085026e6ef82cc5cc303d6c8ceb7e411 Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Mon, 1 Mar 2010 19:55:46 +0100
Subject: x86-32: Fix atomic64_add_unless return value convention

atomic64_add_unless must return 1 if it perfomed the add and 0 otherwise.
The implementation did the opposite thing.

Reported-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267469749-11878-3-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/lib/atomic64_386_32.S | 4 ++--
 arch/x86/lib/atomic64_cx8_32.S | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/lib/atomic64_386_32.S b/arch/x86/lib/atomic64_386_32.S
index 5db07fe4a0c..a2f847c88b8 100644
--- a/arch/x86/lib/atomic64_386_32.S
+++ b/arch/x86/lib/atomic64_386_32.S
@@ -133,13 +133,13 @@ BEGIN add_unless %ecx
 1:
 	movl %eax,  ($v)
 	movl %edx, 4($v)
-	xorl %eax, %eax
+	movl $1, %eax
 2:
 RETURN
 3:
 	cmpl %edx, %edi
 	jne 1b
-	movl $1, %eax
+	xorl %eax, %eax
 	jmp 2b
 END_
 
diff --git a/arch/x86/lib/atomic64_cx8_32.S b/arch/x86/lib/atomic64_cx8_32.S
index e49c4ebca9f..d0e37b189f8 100644
--- a/arch/x86/lib/atomic64_cx8_32.S
+++ b/arch/x86/lib/atomic64_cx8_32.S
@@ -180,7 +180,7 @@ ENTRY(atomic64_add_unless_cx8)
 	cmpxchg8b (%ebp)
 	jne 1b
 
-	xorl %eax, %eax
+	movl $1, %eax
 3:
 	addl $8, %esp
 	CFI_ADJUST_CFA_OFFSET -8
@@ -190,7 +190,7 @@ ENTRY(atomic64_add_unless_cx8)
 4:
 	cmpl %edx, 4(%esp)
 	jne 2b
-	movl $1, %eax
+	xorl %eax, %eax
 	jmp 3b
 	CFI_ENDPROC
 ENDPROC(atomic64_add_unless_cx8)
-- 
cgit v1.2.3-70-g09d2


From 97577896f6b9c056fa0a5e9f6a608110cb3dcd33 Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Mon, 1 Mar 2010 19:55:47 +0100
Subject: lib: Fix atomic64_add_unless return value convention

atomic64_add_unless must return 1 if it perfomed the add and 0 otherwise.
The generic implementation did the opposite thing.

Reported-by: H. Peter Anvin <hpa@zytor.com>
Confirmed-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267469749-11878-4-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 lib/atomic64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/atomic64.c b/lib/atomic64.c
index 8bee16ec752..a21c12bc727 100644
--- a/lib/atomic64.c
+++ b/lib/atomic64.c
@@ -162,12 +162,12 @@ int atomic64_add_unless(atomic64_t *v, long long a, long long u)
 {
 	unsigned long flags;
 	spinlock_t *lock = lock_addr(v);
-	int ret = 1;
+	int ret = 0;
 
 	spin_lock_irqsave(lock, flags);
 	if (v->counter != u) {
 		v->counter += a;
-		ret = 0;
+		ret = 1;
 	}
 	spin_unlock_irqrestore(lock, flags);
 	return ret;
-- 
cgit v1.2.3-70-g09d2


From 25a304f277ad70166eeae25a4958d2049005c33a Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Mon, 1 Mar 2010 19:55:48 +0100
Subject: lib: Fix atomic64_inc_not_zero test

atomic64_inc_not_zero must return 1 if it perfomed the add and 0 otherwise.
The test assumed the opposite convention.

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267469749-11878-5-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 lib/atomic64_test.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index ee8e6de8b41..f7bb706c9c3 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -130,16 +130,16 @@ static __init int test_atomic64(void)
 #endif
 
 	INIT(onestwos);
-	BUG_ON(atomic64_inc_not_zero(&v));
+	BUG_ON(!atomic64_inc_not_zero(&v));
 	r += one;
 	BUG_ON(v.counter != r);
 
 	INIT(0);
-	BUG_ON(!atomic64_inc_not_zero(&v));
+	BUG_ON(atomic64_inc_not_zero(&v));
 	BUG_ON(v.counter != r);
 
 	INIT(-one);
-	BUG_ON(atomic64_inc_not_zero(&v));
+	BUG_ON(!atomic64_inc_not_zero(&v));
 	r += one;
 	BUG_ON(v.counter != r);
 
-- 
cgit v1.2.3-70-g09d2


From f3e83131469e29032a700217aa394996107b8fc5 Mon Sep 17 00:00:00 2001
From: Luca Barbieri <luca@luca-barbieri.com>
Date: Mon, 1 Mar 2010 19:55:49 +0100
Subject: x86-32: Fix atomic64_inc_not_zero return value convention

atomic64_inc_not_zero must return 1 if it perfomed the add and 0 otherwise.
It was doing the opposite thing.

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267469749-11878-6-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/lib/atomic64_386_32.S | 3 +--
 arch/x86/lib/atomic64_cx8_32.S | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/lib/atomic64_386_32.S b/arch/x86/lib/atomic64_386_32.S
index a2f847c88b8..4a5979aa688 100644
--- a/arch/x86/lib/atomic64_386_32.S
+++ b/arch/x86/lib/atomic64_386_32.S
@@ -153,13 +153,12 @@ BEGIN inc_not_zero %esi
 	adcl $0, %edx
 	movl %eax,  ($v)
 	movl %edx, 4($v)
-	xorl %eax, %eax
+	movl $1, %eax
 2:
 RETURN
 3:
 	testl %edx, %edx
 	jne 1b
-	movl $1, %eax
 	jmp 2b
 END_
 
diff --git a/arch/x86/lib/atomic64_cx8_32.S b/arch/x86/lib/atomic64_cx8_32.S
index d0e37b189f8..71e080de335 100644
--- a/arch/x86/lib/atomic64_cx8_32.S
+++ b/arch/x86/lib/atomic64_cx8_32.S
@@ -212,14 +212,13 @@ ENTRY(atomic64_inc_not_zero_cx8)
 	cmpxchg8b (%esi)
 	jne 1b
 
-	xorl %eax, %eax
+	movl $1, %eax
 3:
 	RESTORE ebx
 	ret
 4:
 	testl %edx, %edx
 	jne 2b
-	movl $1, %eax
 	jmp 3b
 	CFI_ENDPROC
 ENDPROC(atomic64_inc_not_zero_cx8)
-- 
cgit v1.2.3-70-g09d2


From a5c9161f27c3e1ae6c0094d262f03a7e98262181 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Mon, 1 Mar 2010 11:49:23 -0800
Subject: x86, atomic64: In selftest, distinguish x86-64 from 586+

The x86-64 implementation of the atomics is totally different from the
i586+ implementation, which makes it quite confusing to call it
"586+".  Also fix indentation, and add "i" for "i386" and "i586" as
used elsewhere in the kernel.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-4-git-send-email-luca@luca-barbieri.com>
---
 lib/atomic64_test.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index f7bb706c9c3..65e482caf5e 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -144,14 +144,16 @@ static __init int test_atomic64(void)
 	BUG_ON(v.counter != r);
 
 #ifdef CONFIG_X86
-	printk(KERN_INFO "atomic64 test passed for %s+ platform %s CX8 and %s SSE\n",
-#ifdef CONFIG_X86_CMPXCHG64
-			"586",
+	printk(KERN_INFO "atomic64 test passed for %s platform %s CX8 and %s SSE\n",
+#ifdef CONFIG_X86_64
+	       "x86-64",
+#elif defined(CONFIG_X86_CMPXCHG64)
+	       "i586+",
 #else
-			"386",
+	       "i386+",
 #endif
-			boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
-			boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
+	       boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without",
+	       boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without");
 #else
 	printk(KERN_INFO "atomic64 test passed\n");
 #endif
-- 
cgit v1.2.3-70-g09d2


From b701a47ba48b698976fb2fe05fb285b0edc1d26a Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Thu, 29 Apr 2010 16:03:57 -0700
Subject: x86: Fix LOCK_PREFIX_HERE for uniprocessor build

Checkin b3ac891b67bd4b1fc728d1c784cad1212dea433d:
x86: Add support for lock prefix in alternatives

... did not define LOCK_PREFIX_HERE in the case of a uniprocessor
build.  As a result, it would cause any of the usages of this macro to
fail on a uniprocessor build.  Fix this by defining LOCK_PREFIX_HERE
as a null string.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-2-git-send-email-luca@luca-barbieri.com>
---
 arch/x86/include/asm/alternative.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 55fee12cea6..e29a6c9bba0 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -38,6 +38,7 @@
 #define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
 
 #else /* ! CONFIG_SMP */
+#define LOCK_PREFIX_HERE ""
 #define LOCK_PREFIX ""
 #endif
 
-- 
cgit v1.2.3-70-g09d2