Index: kernel/generic/src/cpu/cpu.c
===================================================================
--- kernel/generic/src/cpu/cpu.c	(revision cd3b3802ee73ed2b2467458eb3b06bd7d0bf0879)
+++ kernel/generic/src/cpu/cpu.c	(revision ad05baf7d73a916fc6e4f10a51198319da11ea31)
@@ -50,4 +50,5 @@
 #include <sysinfo/sysinfo.h>
 #include <arch/cycle.h>
+#include <synch/rcu.h>
 
 cpu_t *cpus;
@@ -105,4 +106,5 @@
 	cpu_identify();
 	cpu_arch_init();
+	rcu_cpu_init();
 }
 
Index: kernel/generic/src/cpu/cpu_mask.c
===================================================================
--- kernel/generic/src/cpu/cpu_mask.c	(revision ad05baf7d73a916fc6e4f10a51198319da11ea31)
+++ kernel/generic/src/cpu/cpu_mask.c	(revision ad05baf7d73a916fc6e4f10a51198319da11ea31)
@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2012 Adam Hraska
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup generic
+ * @{
+ */
+
+/**
+ * @file
+ * @brief CPU mask manipulation functions.
+ */
+#include <cpu/cpu_mask.h>
+#include <cpu.h>
+#include <config.h>
+
+static const size_t word_size = sizeof(unsigned int);
+static const size_t word_bit_cnt = 8 * sizeof(unsigned int);
+
+/** Returns the size of cpu_mask_t for the detected number of cpus in bytes. */
+size_t cpu_mask_size(void)
+{
+	size_t word_cnt = (config.cpu_count + word_bit_cnt - 1) / word_bit_cnt;
+	return word_cnt * word_size;
+}
+
+/** Add first cpu_cnt cpus to the mask, ie sets the first cpu_cnt bits. */
+static void cpu_mask_count(cpu_mask_t *cpus, size_t cpu_cnt)
+{
+	ASSERT(NULL != cpus);
+	ASSERT(cpu_cnt <= config.cpu_count);
+	
+	for (size_t active_word = 0; 
+		(active_word + 1) * word_bit_cnt <= cpu_cnt;
+		++active_word) {
+		/* Set all bits in the cell/word. */
+		cpus->mask[active_word] = -1;
+	}
+	
+	size_t remaining_bits = (cpu_cnt % word_bit_cnt);
+	if (0 < remaining_bits) {
+		/* Set lower remaining_bits of the last word. */
+		cpus->mask[cpu_cnt / word_bit_cnt] = (1 << remaining_bits) - 1;
+	}
+}
+
+/** Sets bits corresponding to the active cpus, ie the first 
+ * config.cpu_active cpus. 
+ */
+void cpu_mask_active(cpu_mask_t *cpus)
+{
+	cpu_mask_none(cpus);
+	cpu_mask_count(cpus, config.cpu_active);
+}
+
+/** Sets bits for all cpus of the mask. */
+void cpu_mask_all(cpu_mask_t *cpus)
+{
+	cpu_mask_count(cpus, config.cpu_count);
+}
+
+/** Resets/removes all bits. */
+void cpu_mask_none(cpu_mask_t *cpus)
+{
+	ASSERT(cpus);
+	
+	size_t word_cnt = cpu_mask_size() / word_size;
+		
+	for (size_t word = 0; word < word_cnt; ++word) {
+		cpus->mask[word] = 0;
+	}
+}
+
+/** Sets the bit corresponding to cpu_id to true. */
+void cpu_mask_set(cpu_mask_t *cpus, unsigned int cpu_id)
+{
+	size_t word = cpu_id / word_bit_cnt;
+	size_t word_pos = cpu_id % word_bit_cnt;
+	
+	cpus->mask[word] |= (1U << word_pos);
+}
+
+/** Resets the bit corresponding to cpu_id to false. */
+void cpu_mask_reset(cpu_mask_t *cpus, unsigned int cpu_id)
+{
+	size_t word = cpu_id / word_bit_cnt;
+	size_t word_pos = cpu_id % word_bit_cnt;
+	
+	cpus->mask[word] &= ~(1U << word_pos);
+}
+
+/** Returns true if the bit corresponding to cpu_id is set. */
+bool cpu_mask_is_set(cpu_mask_t *cpus, unsigned int cpu_id)
+{
+	size_t word = cpu_id / word_bit_cnt;
+	size_t word_pos = cpu_id % word_bit_cnt;
+	
+	return 0 != (cpus->mask[word] & (1U << word_pos));
+}
+
+/** Returns true if no bits are set. */
+bool cpu_mask_is_none(cpu_mask_t *cpus)
+{
+	size_t word_cnt = cpu_mask_size() / word_size;
+
+	for (size_t word = 0; word < word_cnt; ++word) {
+		if (cpus->mask[word])
+			return false;
+	}
+	
+	return true;
+}
+
+/** @}
+ */