Merge with Linux 2.4.0-pre3-test6.

4 files changed, 50 insertions, 0 deletions

diff --git a/arch/i386/config.in b/arch/i386/config.in
index 7344e802c..a2252d7af 100644
--- a/arch/i386/config.in
+++ b/arch/i386/config.in
@@ -34,6 +34,7 @@ choice 'Processor family' \
 # Define implied options from the CPU selection here
 #
 if [ "$CONFIG_M386" = "y" ]; then
+   define_bool CONFIG_X86_CMPXCHG n
    define_int  CONFIG_X86_L1_CACHE_BYTES 16
 else
    define_bool CONFIG_X86_WP_WORKS_OK y
@@ -139,6 +140,9 @@ if [ "$CONFIG_SMP" != "y" ]; then
        define_bool CONFIG_X86_LOCAL_APIC y
     fi
 fi
+if [ "$CONFIG_SMP" = "y" -a "$CONFIG_X86_CMPXCHG" = "y" ]; then
+    define_bool CONFIG_HAVE_DEC_LOCK y
+fi
 endmenu
 
 mainmenu_option next_comment
diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index c78a8f512..6a4eedf72 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -660,6 +660,7 @@ static void apm_power_off(void)
 #endif
 }
 
+#ifdef CONFIG_APM_DO_ENABLE
 static int apm_enable_power_management(int enable)
 {
 	u32	eax;
@@ -675,6 +676,7 @@ static int apm_enable_power_management(int enable)
 		apm_bios_info.flags |= APM_BIOS_DISABLED;
 	return APM_SUCCESS;
 }
+#endif
 
 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
 {
diff --git a/arch/i386/lib/Makefile b/arch/i386/lib/Makefile
index 2394245a6..be8fcec0a 100644
--- a/arch/i386/lib/Makefile
+++ b/arch/i386/lib/Makefile
@@ -13,4 +13,8 @@ ifdef CONFIG_X86_USE_3DNOW
 L_OBJS += mmx.o
 endif
 
+ifdef CONFIG_HAVE_DEC_LOCK
+L_OBJS += dec_and_lock.o
+endif
+
 include $(TOPDIR)/Rules.make
diff --git a/arch/i386/lib/dec_and_lock.c b/arch/i386/lib/dec_and_lock.c
new file mode 100644
index 000000000..ffd486900
--- /dev/null
+++ b/arch/i386/lib/dec_and_lock.c
@@ -0,0 +1,40 @@
+/*
+ * x86 version of "atomic_dec_and_lock()" using
+ * the atomic "cmpxchg" instruction.
+ *
+ * (For CPU's lacking cmpxchg, we use the slow
+ * generic version, and this one never even gets
+ * compiled).
+ */
+
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+
+int atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
+{
+	int counter;
+	int newcount;
+
+repeat:
+	counter = atomic_read(atomic);
+	newcount = counter-1;
+
+	if (!newcount)
+		goto slow_path;
+
+	asm volatile("lock; cmpxchgl %1,%2"
+		:"=a" (newcount)
+		:"r" (newcount), "m" (atomic->counter), "0" (counter));
+
+	/* If the above failed, "eax" will have changed */
+	if (newcount != counter)
+		goto repeat;
+	return 0;
+
+slow_path:
+	spin_lock(lock);
+	if (atomic_dec_and_test(atomic))
+		return 1;
+	spin_unlock(lock);
+	return 0;
+}