4 files changed, 175 insertions, 2 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 930a9e5eae08..d85be90d5888 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1098,6 +1098,13 @@ 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 0d4015205c64..af759f39d4ae 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -101,6 +101,8 @@ 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.c b/lib/atomic64.c
index 8bee16ec7524..a21c12bc727c 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;
diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
new file mode 100644
index 000000000000..65e482caf5e9
--- /dev/null
+++ b/lib/atomic64_test.c
@@ -0,0 +1,164 @@
+/*
+ * 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);
+
+#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;
+        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);
+#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));
+        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_64
+               "x86-64",
+#elif defined(CONFIG_X86_CMPXCHG64)
+               "i586+",
+#else
+               "i386+",
+#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);