kernel: Add missing smp memory barrier calls. Set max cpu to 1

* Set max cpu to 1 for PPC until atomic functions are finished
* We have atomic functions inline in the kernel and assembly
  code in libroot post-scheduler merge... isn't that a lot of
  duplication?

headers/private/kernel/arch/atomic.h

@@ -15,6 +15,8 @@
 #	include <arch/x86/64/atomic.h>
 #elif __INTEL__
 #	include <arch/x86/32/atomic.h>
+#elif __POWERPC__
+#	include <arch/ppc/arch_atomic.h>
 #endif
 
 

headers/private/kernel/arch/ppc/arch_atomic.h

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2014, Paweł Dziepak, [email protected].
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *		Alexander von Gluck IV <[email protected]>
+ */
+#ifndef _KERNEL_ARCH_PPC_ATOMIC_H
+#define _KERNEL_ARCH_PPC_ATOMIC_H
+
+
+static inline void
+memory_read_barrier_inline(void)
+{
+	#ifdef __powerpc64__
+	asm volatile("lwsync" : : : "memory");
+	#else
+	asm volatile("sync" : : : "memory");
+	#endif
+}
+
+
+static inline void
+memory_write_barrier_inline(void)
+{
+	#ifdef __powerpc64__
+	asm volatile("lwsync" : : : "memory");
+	#else
+	asm volatile("eieio" : : : "memory");
+	#endif
+}
+
+
+static inline void
+memory_full_barrier_inline(void)
+{
+	asm volatile("sync" : : : "memory");
+}
+
+
+#define memory_read_barrier		memory_read_barrier_inline
+#define memory_write_barrier	memory_write_barrier_inline
+#define memory_full_barrier		memory_full_barrier_inline
+
+
+static inline void
+atomic_set_inline(int32* value, int32 newValue)
+{
+	memory_write_barrier();
+	*(volatile int32*)value = newValue;
+}
+
+
+static inline int32
+atomic_get_and_set_inline(int32* value, int32 newValue)
+{
+	// BIG TODO: PowerPC Atomic get and set
+//	asm volatile("xchgl %0, (%1)"
+//		: "+r" (newValue)
+//		: "r" (value)
+//		: "memory");
+	return newValue;
+}
+
+
+static inline int32
+atomic_test_and_set_inline(int32* value, int32 newValue, int32 testAgainst)
+{
+	// BIG TODO: PowerPC Atomic test and set inline
+//	asm volatile("lock; cmpxchgl %2, (%3)"
+//		: "=a" (newValue)
+//		: "0" (testAgainst), "r" (newValue), "r" (value)
+//		: "memory");
+	return newValue;
+}
+
+
+static inline int32
+atomic_add_inline(int32* value, int32 newValue)
+{
+	// BIG TODO: PowerPC Atomic add inline
+//	asm volatile("lock; xaddl %0, (%1)"
+//		: "+r" (newValue)
+//		: "r" (value)
+//		: "memory");
+	return newValue;
+}
+
+
+static inline int32
+atomic_get_inline(int32* value)
+{
+	int32 newValue = *(volatile int32*)value;
+	memory_read_barrier();
+	return newValue;
+}
+
+
+#define atomic_set				atomic_set_inline
+#define atomic_get_and_set		atomic_get_and_set_inline
+#ifndef atomic_test_and_set
+#	define atomic_test_and_set	atomic_test_and_set_inline
+#endif
+#ifndef atomic_add
+#	define atomic_add			atomic_add_inline
+#endif
+#define atomic_get				atomic_get_inline
+
+
+#endif	// _KERNEL_ARCH_PPC_ATOMIC_H

headers/private/kernel/boot/platform/openfirmware/platform_kernel_args.h

@@ -10,7 +10,8 @@
 #	error This file is included from <boot/kernel_args.h> only
 #endif
 
-#define SMP_MAX_CPUS 16
+#define SMP_MAX_CPUS 1
+	// TODO: Until inline kernel atomic code for ppc is fixed
 
 #define MAX_PHYSICAL_MEMORY_RANGE 4
 #define MAX_PHYSICAL_ALLOCATED_RANGE 8