25 files changed, 744 insertions, 277 deletions

diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index daf866ed061..330ee807f89 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -161,6 +161,7 @@ extern int io_apic_set_pci_routing(struct device *dev, int irq,
 		 struct io_apic_irq_attr *irq_attr);
 extern int (*ioapic_renumber_irq)(int ioapic, int irq);
 extern void ioapic_init_mappings(void);
+extern void ioapic_insert_resources(void);
 
 extern struct IO_APIC_route_entry **alloc_ioapic_entries(void);
 extern void free_ioapic_entries(struct IO_APIC_route_entry **ioapic_entries);
@@ -180,6 +181,7 @@ extern void ioapic_write_entry(int apic, int pin,
 #define io_apic_assign_pci_irqs 0
 static const int timer_through_8259 = 0;
 static inline void ioapic_init_mappings(void)	{ }
+static inline void ioapic_insert_resources(void) { }
 
 static inline void probe_nr_irqs_gsi(void)	{ }
 #endif
diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h
index 313389cd50d..5136dad57cb 100644
--- a/arch/x86/include/asm/lguest.h
+++ b/arch/x86/include/asm/lguest.h
@@ -17,8 +17,7 @@
 /* Pages for switcher itself, then two pages per cpu */
 #define TOTAL_SWITCHER_PAGES (SHARED_SWITCHER_PAGES + 2 * nr_cpu_ids)
 
-/* We map at -4M (-2M when PAE is activated) for ease of mapping
- * into the guest (one PTE page). */
+/* We map at -4M (-2M for PAE) for ease of mapping (one PTE page). */
 #ifdef CONFIG_X86_PAE
 #define SWITCHER_ADDR 0xFFE00000
 #else
diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h
index d31c4a68407..ba0eed8aa1a 100644
--- a/arch/x86/include/asm/lguest_hcall.h
+++ b/arch/x86/include/asm/lguest_hcall.h
@@ -30,27 +30,27 @@
 #include <asm/hw_irq.h>
 #include <asm/kvm_para.h>
 
-/*G:031 But first, how does our Guest contact the Host to ask for privileged
+/*G:030
+ * But first, how does our Guest contact the Host to ask for privileged
  * operations?  There are two ways: the direct way is to make a "hypercall",
  * to make requests of the Host Itself.
  *
- * We use the KVM hypercall mechanism. Seventeen hypercalls are
- * available: the hypercall number is put in the %eax register, and the
- * arguments (when required) are placed in %ebx, %ecx, %edx and %esi.
- * If a return value makes sense, it's returned in %eax.
+ * We use the KVM hypercall mechanism, though completely different hypercall
+ * numbers. Seventeen hypercalls are available: the hypercall number is put in
+ * the %eax register, and the arguments (when required) are placed in %ebx,
+ * %ecx, %edx and %esi.  If a return value makes sense, it's returned in %eax.
  *
  * Grossly invalid calls result in Sudden Death at the hands of the vengeful
  * Host, rather than returning failure.  This reflects Winston Churchill's
- * definition of a gentleman: "someone who is only rude intentionally". */
-/*:*/
+ * definition of a gentleman: "someone who is only rude intentionally".
+:*/
 
 /* Can't use our min() macro here: needs to be a constant */
 #define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32)
 
 #define LHCALL_RING_SIZE 64
 struct hcall_args {
-	/* These map directly onto eax, ebx, ecx, edx and esi
-	 * in struct lguest_regs */
+	/* These map directly onto eax/ebx/ecx/edx/esi in struct lguest_regs */
 	unsigned long arg0, arg1, arg2, arg3, arg4;
 };
 
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h
index dd14c54ac71..0e8c2a0fd92 100644
--- a/arch/x86/include/asm/pgalloc.h
+++ b/arch/x86/include/asm/pgalloc.h
@@ -46,7 +46,13 @@ static inline void pte_free(struct mm_struct *mm, struct page *pte)
 	__free_page(pte);
 }
 
-extern void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte);
+extern void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte);
+
+static inline void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte,
+				  unsigned long address)
+{
+	___pte_free_tlb(tlb, pte);
+}
 
 static inline void pmd_populate_kernel(struct mm_struct *mm,
 				       pmd_t *pmd, pte_t *pte)
@@ -78,7 +84,13 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 	free_page((unsigned long)pmd);
 }
 
-extern void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd);
+extern void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd);
+
+static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
+				  unsigned long adddress)
+{
+	___pmd_free_tlb(tlb, pmd);
+}
 
 #ifdef CONFIG_X86_PAE
 extern void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd);
@@ -108,7 +120,14 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud)
 	free_page((unsigned long)pud);
 }
 
-extern void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pud);
+extern void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud);
+
+static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
+				  unsigned long address)
+{
+	___pud_free_tlb(tlb, pud);
+}
+
 #endif	/* PAGETABLE_LEVELS > 3 */
 #endif	/* PAGETABLE_LEVELS > 2 */
 
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 20e6a795e16..d2c6c930b49 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -212,9 +212,9 @@ extern int __get_user_bad(void);
 		     : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 #else
 #define __put_user_asm_u64(x, ptr, retval, errret) \
-	__put_user_asm(x, ptr, retval, "q", "", "Zr", errret)
+	__put_user_asm(x, ptr, retval, "q", "", "er", errret)
 #define __put_user_asm_ex_u64(x, addr)	\
-	__put_user_asm_ex(x, addr, "q", "", "Zr")
+	__put_user_asm_ex(x, addr, "q", "", "er")
 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
 #endif
 
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index 8cc687326eb..db24b215fc5 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -88,11 +88,11 @@ int __copy_to_user(void __user *dst, const void *src, unsigned size)
 			      ret, "l", "k", "ir", 4);
 		return ret;
 	case 8:__put_user_asm(*(u64 *)src, (u64 __user *)dst,
-			      ret, "q", "", "ir", 8);
+			      ret, "q", "", "er", 8);
 		return ret;
 	case 10:
 		__put_user_asm(*(u64 *)src, (u64 __user *)dst,
-			       ret, "q", "", "ir", 10);
+			       ret, "q", "", "er", 10);
 		if (unlikely(ret))
 			return ret;
 		asm("":::"memory");
@@ -101,12 +101,12 @@ int __copy_to_user(void __user *dst, const void *src, unsigned size)
 		return ret;
 	case 16:
 		__put_user_asm(*(u64 *)src, (u64 __user *)dst,
-			       ret, "q", "", "ir", 16);
+			       ret, "q", "", "er", 16);
 		if (unlikely(ret))
 			return ret;
 		asm("":::"memory");
 		__put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
-			       ret, "q", "", "ir", 8);
+			       ret, "q", "", "er", 8);
 		return ret;
 	default:
 		return copy_user_generic((__force void *)dst, src, size);
@@ -157,7 +157,7 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 			       ret, "q", "", "=r", 8);
 		if (likely(!ret))
 			__put_user_asm(tmp, (u64 __user *)dst,
-				       ret, "q", "", "ir", 8);
+				       ret, "q", "", "er", 8);
 		return ret;
 	}
 	default:
diff --git a/arch/x86/kernel/apic/es7000_32.c b/arch/x86/kernel/apic/es7000_32.c
index 69328ac8de9..8952a589028 100644
--- a/arch/x86/kernel/apic/es7000_32.c
+++ b/arch/x86/kernel/apic/es7000_32.c
@@ -652,7 +652,8 @@ static int es7000_mps_oem_check_cluster(struct mpc_table *mpc, char *oem,
 	return ret && es7000_apic_is_cluster();
 }
 
-struct apic apic_es7000_cluster = {
+/* We've been warned by a false positive warning.Use __refdata to keep calm. */
+struct apic __refdata apic_es7000_cluster = {
 
 	.name				= "es7000",
 	.probe				= probe_es7000,
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 90b5e6efa93..2284a4812b6 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -4181,28 +4181,20 @@ fake_ioapic_page:
 	}
 }
 
-static int __init ioapic_insert_resources(void)
+void __init ioapic_insert_resources(void)
 {
 	int i;
 	struct resource *r = ioapic_resources;
 
 	if (!r) {
-		if (nr_ioapics > 0) {
+		if (nr_ioapics > 0)
 			printk(KERN_ERR
 				"IO APIC resources couldn't be allocated.\n");
-			return -1;
-		}
-		return 0;
+		return;
 	}
 
 	for (i = 0; i < nr_ioapics; i++) {
 		insert_resource(&iomem_resource, r);
 		r++;
 	}
-
-	return 0;
 }
-
-/* Insert the IO APIC resources after PCI initialization has occured to handle
- * IO APICS that are mapped in on a BAR in PCI space. */
-late_initcall(ioapic_insert_resources);
diff --git a/arch/x86/kernel/apic/numaq_32.c b/arch/x86/kernel/apic/numaq_32.c
index 533e59c6fc8..ca96e68f0d2 100644
--- a/arch/x86/kernel/apic/numaq_32.c
+++ b/arch/x86/kernel/apic/numaq_32.c
@@ -493,7 +493,8 @@ static void numaq_setup_portio_remap(void)
 		(u_long) xquad_portio, (u_long) num_quads*XQUAD_PORTIO_QUAD);
 }
 
-struct apic apic_numaq = {
+/* Use __refdata to keep false positive warning calm.	*/
+struct apic __refdata apic_numaq = {
 
 	.name				= "NUMAQ",
 	.probe				= probe_numaq,
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 28e5f595604..e2485b03f1c 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -356,7 +356,7 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
 #endif
 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PCI)
 	/* check CPU config space for extended APIC ID */
-	if (c->x86 >= 0xf) {
+	if (cpu_has_apic && c->x86 >= 0xf) {
 		unsigned int val;
 		val = read_pci_config(0, 24, 0, 0x68);
 		if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18)))
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 484c1e5f658..1cfb623ce11 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1692,17 +1692,15 @@ static ssize_t set_trigger(struct sys_device *s, struct sysdev_attribute *attr,
 				const char *buf, size_t siz)
 {
 	char *p;
-	int len;
 
 	strncpy(mce_helper, buf, sizeof(mce_helper));
 	mce_helper[sizeof(mce_helper)-1] = 0;
-	len = strlen(mce_helper);
 	p = strchr(mce_helper, '\n');
 
-	if (*p)
+	if (p)
 		*p = 0;
 
-	return len;
+	return strlen(mce_helper) + !!p;
 }
 
 static ssize_t set_ignore_ce(struct sys_device *s,
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 36c3dc7b899..a7aa8f90095 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -66,6 +66,52 @@ static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters) = {
 };
 
 /*
+ * Not sure about some of these
+ */
+static const u64 p6_perfmon_event_map[] =
+{
+  [PERF_COUNT_HW_CPU_CYCLES]		= 0x0079,
+  [PERF_COUNT_HW_INSTRUCTIONS]		= 0x00c0,
+  [PERF_COUNT_HW_CACHE_REFERENCES]	= 0x0000,
+  [PERF_COUNT_HW_CACHE_MISSES]		= 0x0000,
+  [PERF_COUNT_HW_BRANCH_INSTRUCTIONS]	= 0x00c4,
+  [PERF_COUNT_HW_BRANCH_MISSES]		= 0x00c5,
+  [PERF_COUNT_HW_BUS_CYCLES]		= 0x0062,
+};
+
+static u64 p6_pmu_event_map(int event)
+{
+	return p6_perfmon_event_map[event];
+}
+
+/*
+ * Counter setting that is specified not to count anything.
+ * We use this to effectively disable a counter.
+ *
+ * L2_RQSTS with 0 MESI unit mask.
+ */
+#define P6_NOP_COUNTER			0x0000002EULL
+
+static u64 p6_pmu_raw_event(u64 event)
+{
+#define P6_EVNTSEL_EVENT_MASK		0x000000FFULL
+#define P6_EVNTSEL_UNIT_MASK		0x0000FF00ULL
+#define P6_EVNTSEL_EDGE_MASK		0x00040000ULL
+#define P6_EVNTSEL_INV_MASK		0x00800000ULL
+#define P6_EVNTSEL_COUNTER_MASK		0xFF000000ULL
+
+#define P6_EVNTSEL_MASK			\
+	(P6_EVNTSEL_EVENT_MASK |	\
+	 P6_EVNTSEL_UNIT_MASK  |	\
+	 P6_EVNTSEL_EDGE_MASK  |	\
+	 P6_EVNTSEL_INV_MASK   |	\
+	 P6_EVNTSEL_COUNTER_MASK)
+
+	return event & P6_EVNTSEL_MASK;
+}
+
+
+/*
  * Intel PerfMon v3. Used on Core2 and later.
  */
 static const u64 intel_perfmon_event_map[] =
@@ -666,6 +712,7 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
 {
 	struct perf_counter_attr *attr = &counter->attr;
 	struct hw_perf_counter *hwc = &counter->hw;
+	u64 config;
 	int err;
 
 	if (!x86_pmu_initialized())
@@ -718,14 +765,40 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
 
 	if (attr->config >= x86_pmu.max_events)
 		return -EINVAL;
+
 	/*
 	 * The generic map:
 	 */
-	hwc->config |= x86_pmu.event_map(attr->config);
+	config = x86_pmu.event_map(attr->config);
+
+	if (config == 0)
+		return -ENOENT;
+
+	if (config == -1LL)
+		return -EINVAL;
+
+	hwc->config |= config;
 
 	return 0;
 }
 
+static void p6_pmu_disable_all(void)
+{
+	struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+	u64 val;
+
+	if (!cpuc->enabled)
+		return;
+
+	cpuc->enabled = 0;
+	barrier();
+
+	/* p6 only has one enable register */
+	rdmsrl(MSR_P6_EVNTSEL0, val);
+	val &= ~ARCH_PERFMON_EVENTSEL0_ENABLE;
+	wrmsrl(MSR_P6_EVNTSEL0, val);
+}
+
 static void intel_pmu_disable_all(void)
 {
 	wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
@@ -767,6 +840,23 @@ void hw_perf_disable(void)
 	return x86_pmu.disable_all();
 }
 
+static void p6_pmu_enable_all(void)
+{
+	struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+	unsigned long val;
+
+	if (cpuc->enabled)
+		return;
+
+	cpuc->enabled = 1;
+	barrier();
+
+	/* p6 only has one enable register */
+	rdmsrl(MSR_P6_EVNTSEL0, val);
+	val |= ARCH_PERFMON_EVENTSEL0_ENABLE;
+	wrmsrl(MSR_P6_EVNTSEL0, val);
+}
+
 static void intel_pmu_enable_all(void)
 {
 	wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl);
@@ -784,13 +874,13 @@ static void amd_pmu_enable_all(void)
 	barrier();
 
 	for (idx = 0; idx < x86_pmu.num_counters; idx++) {
+		struct perf_counter *counter = cpuc->counters[idx];
 		u64 val;
 
 		if (!test_bit(idx, cpuc->active_mask))
 			continue;
-		rdmsrl(MSR_K7_EVNTSEL0 + idx, val);
-		if (val & ARCH_PERFMON_EVENTSEL0_ENABLE)
-			continue;
+
+		val = counter->hw.config;
 		val |= ARCH_PERFMON_EVENTSEL0_ENABLE;
 		wrmsrl(MSR_K7_EVNTSEL0 + idx, val);
 	}
@@ -819,16 +909,13 @@ static inline void intel_pmu_ack_status(u64 ack)
 
 static inline void x86_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
 {
-	int err;
-	err = checking_wrmsrl(hwc->config_base + idx,
+	(void)checking_wrmsrl(hwc->config_base + idx,
 			      hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE);
 }
 
 static inline void x86_pmu_disable_counter(struct hw_perf_counter *hwc, int idx)
 {
-	int err;
-	err = checking_wrmsrl(hwc->config_base + idx,
-			      hwc->config);
+	(void)checking_wrmsrl(hwc->config_base + idx, hwc->config);
 }
 
 static inline void
@@ -836,13 +923,24 @@ intel_pmu_disable_fixed(struct hw_perf_counter *hwc, int __idx)
 {
 	int idx = __idx - X86_PMC_IDX_FIXED;
 	u64 ctrl_val, mask;
-	int err;
 
 	mask = 0xfULL << (idx * 4);
 
 	rdmsrl(hwc->config_base, ctrl_val);
 	ctrl_val &= ~mask;
-	err = checking_wrmsrl(hwc->config_base, ctrl_val);
+	(void)checking_wrmsrl(hwc->config_base, ctrl_val);
+}
+
+static inline void
+p6_pmu_disable_counter(struct hw_perf_counter *hwc, int idx)
+{
+	struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+	u64 val = P6_NOP_COUNTER;
+
+	if (cpuc->enabled)
+		val |= ARCH_PERFMON_EVENTSEL0_ENABLE;
+
+	(void)checking_wrmsrl(hwc->config_base + idx, val);
 }
 
 static inline void
@@ -943,6 +1041,19 @@ intel_pmu_enable_fixed(struct hw_perf_counter *hwc, int __idx)
 	err = checking_wrmsrl(hwc->config_base, ctrl_val);
 }
 
+static void p6_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
+{
+	struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+	u64 val;
+
+	val = hwc->config;
+	if (cpuc->enabled)
+		val |= ARCH_PERFMON_EVENTSEL0_ENABLE;
+
+	(void)checking_wrmsrl(hwc->config_base + idx, val);
+}
+
+
 static void intel_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
 {
 	if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) {
@@ -959,8 +1070,6 @@ static void amd_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)
 
 	if (cpuc->enabled)
 		x86_pmu_enable_counter(hwc, idx);
-	else
-		x86_pmu_disable_counter(hwc, idx);
 }
 
 static int
@@ -1176,6 +1285,49 @@ static void intel_pmu_reset(void)
 	local_irq_restore(flags);
 }
 
+static int p6_pmu_handle_irq(struct pt_regs *regs)
+{
+	struct perf_sample_data data;
+	struct cpu_hw_counters *cpuc;
+	struct perf_counter *counter;
+	struct hw_perf_counter *hwc;
+	int idx, handled = 0;
+	u64 val;
+
+	data.regs = regs;
+	data.addr = 0;
+
+	cpuc = &__get_cpu_var(cpu_hw_counters);
+
+	for (idx = 0; idx < x86_pmu.num_counters; idx++) {
+		if (!test_bit(idx, cpuc->active_mask))
+			continue;
+
+		counter = cpuc->counters[idx];
+		hwc = &counter->hw;
+
+		val = x86_perf_counter_update(counter, hwc, idx);
+		if (val & (1ULL << (x86_pmu.counter_bits - 1)))
+			continue;
+
+		/*
+		 * counter overflow
+		 */
+		handled		= 1;
+		data.period	= counter->hw.last_period;
+
+		if (!x86_perf_counter_set_period(counter, hwc, idx))
+			continue;
+
+		if (perf_counter_overflow(counter, 1, &data))
+			p6_pmu_disable_counter(hwc, idx);
+	}
+
+	if (handled)
+		inc_irq_stat(apic_perf_irqs);
+
+	return handled;
+}
 
 /*
  * This handler is triggered by the local APIC, so the APIC IRQ handling
@@ -1185,14 +1337,13 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 {
 	struct perf_sample_data data;
 	struct cpu_hw_counters *cpuc;
-	int bit, cpu, loops;
+	int bit, loops;
 	u64 ack, status;
 
 	data.regs = regs;
 	data.addr = 0;
 
-	cpu = smp_processor_id();
-	cpuc = &per_cpu(cpu_hw_counters, cpu);
+	cpuc = &__get_cpu_var(cpu_hw_counters);
 
 	perf_disable();
 	status = intel_pmu_get_status();
@@ -1249,14 +1400,13 @@ static int amd_pmu_handle_irq(struct pt_regs *regs)
 	struct cpu_hw_counters *cpuc;
 	struct perf_counter *counter;
 	struct hw_perf_counter *hwc;
-	int cpu, idx, handled = 0;
+	int idx, handled = 0;
 	u64 val;
 
 	data.regs = regs;
 	data.addr = 0;
 
-	cpu = smp_processor_id();
-	cpuc = &per_cpu(cpu_hw_counters, cpu);
+	cpuc = &__get_cpu_var(cpu_hw_counters);
 
 	for (idx = 0; idx < x86_pmu.num_counters; idx++) {
 		if (!test_bit(idx, cpuc->active_mask))
@@ -1353,6 +1503,32 @@ static __read_mostly struct notifier_block perf_counter_nmi_notifier = {
 	.priority		= 1
 };
 
+static struct x86_pmu p6_pmu = {
+	.name			= "p6",
+	.handle_irq		= p6_pmu_handle_irq,
+	.disable_all		= p6_pmu_disable_all,
+	.enable_all		= p6_pmu_enable_all,
+	.enable			= p6_pmu_enable_counter,
+	.disable		= p6_pmu_disable_counter,
+	.eventsel		= MSR_P6_EVNTSEL0,
+	.perfctr		= MSR_P6_PERFCTR0,
+	.event_map		= p6_pmu_event_map,
+	.raw_event		= p6_pmu_raw_event,
+	.max_events		= ARRAY_SIZE(p6_perfmon_event_map),
+	.max_period		= (1ULL << 31) - 1,
+	.version		= 0,
+	.num_counters		= 2,
+	/*
+	 * Counters have 40 bits implemented. However they are designed such
+	 * that bits [32-39] are sign extensions of bit 31. As such the
+	 * effective width of a counter for P6-like PMU is 32 bits only.
+	 *
+	 * See IA-32 Intel Architecture Software developer manual Vol 3B
+	 */
+	.counter_bits		= 32,
+	.counter_mask		= (1ULL << 32) - 1,
+};
+
 static struct x86_pmu intel_pmu = {
 	.name			= "Intel",
 	.handle_irq		= intel_pmu_handle_irq,
@@ -1392,6 +1568,37 @@ static struct x86_pmu amd_pmu = {
 	.max_period		= (1ULL << 47) - 1,
 };
 
+static int p6_pmu_init(void)
+{
+	switch (boot_cpu_data.x86_model) {
+	case 1:
+	case 3:  /* Pentium Pro */
+	case 5:
+	case 6:  /* Pentium II */
+	case 7:
+	case 8:
+	case 11: /* Pentium III */
+		break;
+	case 9:
+	case 13:
+		/* Pentium M */
+		break;
+	default:
+		pr_cont("unsupported p6 CPU model %d ",
+			boot_cpu_data.x86_model);
+		return -ENODEV;
+	}
+
+	if (!cpu_has_apic) {
+		pr_info("no Local APIC, try rebooting with lapic");
+		return -ENODEV;
+	}
+
+	x86_pmu				= p6_pmu;
+
+	return 0;
+}
+
 static int intel_pmu_init(void)
 {
 	union cpuid10_edx edx;
@@ -1400,8 +1607,14 @@ static int intel_pmu_init(void)
 	unsigned int ebx;
 	int version;
 
-	if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+	if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
+		/* check for P6 processor family */
+	   if (boot_cpu_data.x86 == 6) {
+		return p6_pmu_init();
+	   } else {
 		return -ENODEV;
+	   }
+	}
 
 	/*
 	 * Check whether the Architectural PerfMon supports
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index 696f0e475c2..92b7703d3d5 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -187,7 +187,7 @@ static void __init apic_intr_init(void)
 #ifdef CONFIG_X86_THERMAL_VECTOR
 	alloc_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
 #endif
-#ifdef CONFIG_X86_THRESHOLD
+#ifdef CONFIG_X86_MCE_THRESHOLD
 	alloc_intr_gate(THRESHOLD_APIC_VECTOR, threshold_interrupt);
 #endif
 #if defined(CONFIG_X86_NEW_MCE) && defined(CONFIG_X86_LOCAL_APIC)
diff --git a/arch/x86/kernel/mfgpt_32.c b/arch/x86/kernel/mfgpt_32.c
index 846510b78a0..2a62d843f01 100644
--- a/arch/x86/kernel/mfgpt_32.c
+++ b/arch/x86/kernel/mfgpt_32.c
@@ -347,7 +347,7 @@ static irqreturn_t mfgpt_tick(int irq, void *dev_id)
 
 static struct irqaction mfgptirq  = {
 	.handler = mfgpt_tick,
-	.flags = IRQF_DISABLED | IRQF_NOBALANCING,
+	.flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_TIMER,
 	.name = "mfgpt-timer"
 };
 
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 4f9c55f3a7c..03801f2f761 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -60,7 +60,7 @@ static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
 		"adc  %5,%%edx ; "
 		: "=A" (product), "=r" (tmp1), "=r" (tmp2)
 		: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
-#elif __x86_64__
+#elif defined(__x86_64__)
 	__asm__ (
 		"mul %%rdx ; shrd $32,%%rdx,%%rax"
 		: "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index d2d1ce8170f..508e982dd07 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -249,6 +249,14 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
 		},
 	},
+	{	/* Handle problems with rebooting on CompuLab SBC-FITPC2 */
+		.callback = set_bios_reboot,
+		.ident = "CompuLab SBC-FITPC2",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"),
+		},
+	},
 	{ }
 };
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index de2cab13284..63f32d220ef 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -672,6 +672,19 @@ static struct dmi_system_id __initdata bad_bios_dmi_table[] = {
 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies"),
 		},
 	},
+	{
+	/*
+	 * AMI BIOS with low memory corruption was found on Intel DG45ID board.
+	 * It hase different DMI_BIOS_VENDOR = "Intel Corp.", for now we will
+	 * match only DMI_BOARD_NAME and see if there is more bad products
+	 * with this vendor.
+	 */
+		.callback = dmi_low_memory_corruption,
+		.ident = "AMI BIOS",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_NAME, "DG45ID"),
+		},
+	},
 #endif
 	{}
 };
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 367e8788204..59f31d2dd43 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -112,11 +112,6 @@ SECTIONS
 		_sdata = .;
 		DATA_DATA
 		CONSTRUCTORS
-
-#ifdef CONFIG_X86_64
-		/* End of data section */
-		_edata = .;
-#endif
 	} :data
 
 #ifdef CONFIG_X86_32
@@ -156,10 +151,8 @@ SECTIONS
 	.data.read_mostly : AT(ADDR(.data.read_mostly) - LOAD_OFFSET) {
 		*(.data.read_mostly)
 
-#ifdef CONFIG_X86_32
 		/* End of data section */
 		_edata = .;
-#endif
 	}
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 7bc65f0f62c..d677fa9ca65 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -22,7 +22,8 @@
  *
  * So how does the kernel know it's a Guest?  We'll see that later, but let's
  * just say that we end up here where we replace the native functions various
- * "paravirt" structures with our Guest versions, then boot like normal. :*/
+ * "paravirt" structures with our Guest versions, then boot like normal.
+:*/
 
 /*
  * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation.
@@ -74,7 +75,8 @@
  *
  * The Guest in our tale is a simple creature: identical to the Host but
  * behaving in simplified but equivalent ways.  In particular, the Guest is the
- * same kernel as the Host (or at least, built from the same source code). :*/
+ * same kernel as the Host (or at least, built from the same source code).
+:*/
 
 struct lguest_data lguest_data = {
 	.hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF },
@@ -85,7 +87,8 @@ struct lguest_data lguest_data = {
 	.syscall_vec = SYSCALL_VECTOR,
 };
 
-/*G:037 async_hcall() is pretty simple: I'm quite proud of it really.  We have a
+/*G:037
+ * async_hcall() is pretty simple: I'm quite proud of it really.  We have a
  * ring buffer of stored hypercalls which the Host will run though next time we
  * do a normal hypercall.  Each entry in the ring has 5 slots for the hypercall
  * arguments, and a "hcall_status" word which is 0 if the call is ready to go,
@@ -94,7 +97,8 @@ struct lguest_data lguest_data = {
  * If we come around to a slot which hasn't been finished, then the table is
  * full and we just make the hypercall directly.  This has the nice side
  * effect of causing the Host to run all the stored calls in the ring buffer
- * which empties it for next time! */
+ * which empties it for next time!
+ */
 static void async_hcall(unsigned long call, unsigned long arg1,
 			unsigned long arg2, unsigned long arg3,
 			unsigned long arg4)
@@ -103,9 +107,11 @@ static void async_hcall(unsigned long call, unsigned long arg1,
 	static unsigned int next_call;
 	unsigned long flags;
 
-	/* Disable interrupts if not already disabled: we don't want an
+	/*
+	 * Disable interrupts if not already disabled: we don't want an
 	 * interrupt handler making a hypercall while we're already doing
-	 * one! */
+	 * one!
+	 */
 	local_irq_save(flags);
 	if (lguest_data.hcall_status[next_call] != 0xFF) {
 		/* Table full, so do normal hcall which will flush table. */
@@ -125,8 +131,9 @@ static void async_hcall(unsigned long call, unsigned long arg1,
 	local_irq_restore(flags);
 }
 
-/*G:035 Notice the lazy_hcall() above, rather than hcall().  This is our first
- * real optimization trick!
+/*G:035
+ * Notice the lazy_hcall() above, rather than hcall().  This is our first real
+ * optimization trick!
  *
  * When lazy_mode is set, it means we're allowed to defer all hypercalls and do
  * them as a batch when lazy_mode is eventually turned off.  Because hypercalls
@@ -136,7 +143,8 @@ static void async_hcall(unsigned long call, unsigned long arg1,
  * lguest_leave_lazy_mode().
  *
  * So, when we're in lazy mode, we call async_hcall() to store the call for
- * future processing: */
+ * future processing:
+ */
 static void lazy_hcall1(unsigned long call,
 		       unsigned long arg1)
 {
@@ -146,6 +154,7 @@ static void lazy_hcall1(unsigned long call,
 		async_hcall(call, arg1, 0, 0, 0);
 }
 
+/* You can imagine what lazy_hcall2, 3 and 4 look like. :*/
 static void lazy_hcall2(unsigned long call,
 		       unsigned long arg1,
 		       unsigned long arg2)
@@ -181,8 +190,10 @@ static void lazy_hcall4(unsigned long call,
 }
 #endif
 
-/* When lazy mode is turned off reset the per-cpu lazy mode variable and then
- * issue the do-nothing hypercall to flush any stored calls. */
+/*G:036
+ * When lazy mode is turned off reset the per-cpu lazy mode variable and then
+ * issue the do-nothing hypercall to flush any stored calls.
+:*/
 static void lguest_leave_lazy_mmu_mode(void)
 {
 	kvm_hypercall0(LHCALL_FLUSH_ASYNC);
@@ -208,9 +219,11 @@ static void lguest_end_context_switch(struct task_struct *next)
  * check there before it tries to deliver an interrupt.
  */
 
-/* save_flags() is expected to return the processor state (ie. "flags").  The
+/*
+ * save_flags() is expected to return the processor state (ie. "flags").  The
  * flags word contains all kind of stuff, but in practice Linux only cares
- * about the interrupt flag.  Our "save_flags()" just returns that. */
+ * about the interrupt flag.  Our "save_flags()" just returns that.
+ */
 static unsigned long save_fl(void)
 {
 	return lguest_data.irq_enabled;
@@ -222,13 +235,15 @@ static void irq_disable(void)
 	lguest_data.irq_enabled = 0;
 }
 
-/* Let's pause a moment.  Remember how I said these are called so often?
+/*
+ * Let's pause a moment.  Remember how I said these are called so often?
  * Jeremy Fitzhardinge optimized them so hard early in 2009 that he had to
  * break some rules.  In particular, these functions are assumed to save their
  * own registers if they need to: normal C functions assume they can trash the
  * eax register.  To use normal C functions, we use
  * PV_CALLEE_SAVE_REGS_THUNK(), which pushes %eax onto the stack, calls the
- * C function, then restores it. */
+ * C function, then restores it.
+ */
 PV_CALLEE_SAVE_REGS_THUNK(save_fl);
 PV_CALLEE_SAVE_REGS_THUNK(irq_disable);
 /*:*/
@@ -237,18 +252,18 @@ PV_CALLEE_SAVE_REGS_THUNK(irq_disable);
 extern void lg_irq_enable(void);
 extern void lg_restore_fl(unsigned long flags);
 
-/*M:003 Note that we don't check for outstanding interrupts when we re-enable
- * them (or when we unmask an interrupt).  This seems to work for the moment,
- * since interrupts are rare and we'll just get the interrupt on the next timer
- * tick, but now we can run with CONFIG_NO_HZ, we should revisit this.  One way
- * would be to put the "irq_enabled" field in a page by itself, and have the
- * Host write-protect it when an interrupt comes in when irqs are disabled.
- * There will then be a page fault as soon as interrupts are re-enabled.
+/*M:003
+ * We could be more efficient in our checking of outstanding interrupts, rather
+ * than using a branch.  One way would be to put the "irq_enabled" field in a
+ * page by itself, and have the Host write-protect it when an interrupt comes
+ * in when irqs are disabled.  There will then be a page fault as soon as
+ * interrupts are re-enabled.
  *
  * A better method is to implement soft interrupt disable generally for x86:
  * instead of disabling interrupts, we set a flag.  If an interrupt does come
  * in, we then disable them for real.  This is uncommon, so we could simply use
- * a hypercall for interrupt control and not worry about efficiency. :*/
+ * a hypercall for interrupt control and not worry about efficiency.
+:*/
 
 /*G:034
  * The Interrupt Descriptor Table (IDT).
@@ -261,10 +276,12 @@ extern void lg_restore_fl(unsigned long flags);
 static void lguest_write_idt_entry(gate_desc *dt,
 				   int entrynum, const gate_desc *g)
 {
-	/* The gate_desc structure is 8 bytes long: we hand it to the Host in
+	/*
+	 * The gate_desc structure is 8 bytes long: we hand it to the Host in
 	 * two 32-bit chunks.  The whole 32-bit kernel used to hand descriptors
 	 * around like this; typesafety wasn't a big concern in Linux's early
-	 * years. */
+	 * years.
+	 */
 	u32 *desc = (u32 *)g;
 	/* Keep the local copy up to date. */
 	native_write_idt_entry(dt, entrynum, g);
@@ -272,9 +289,11 @@ static void lguest_write_idt_entry(gate_desc *dt,
 	kvm_hypercall3(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1]);
 }
 
-/* Changing to a different IDT is very rare: we keep the IDT up-to-date every
+/*
+ * Changing to a different IDT is very rare: we keep the IDT up-to-date every
  * time it is written, so we can simply loop through all entries and tell the
- * Host about them. */
+ * Host about them.
+ */
 static void lguest_load_idt(const struct desc_ptr *desc)
 {
 	unsigned int i;
@@ -305,9 +324,11 @@ static void lguest_load_gdt(const struct desc_ptr *desc)
 		kvm_hypercall3(LHCALL_LOAD_GDT_ENTRY, i, gdt[i].a, gdt[i].b);
 }
 
-/* For a single GDT entry which changes, we do the lazy thing: alter our GDT,
+/*
+ * For a single GDT entry which changes, we do the lazy thing: alter our GDT,
  * then tell the Host to reload the entire thing.  This operation is so rare
- * that this naive implementation is reasonable. */
+ * that this naive implementation is reasonable.
+ */
 static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
 				   const void *desc, int type)
 {
@@ -317,29 +338,36 @@ static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
 		       dt[entrynum].a, dt[entrynum].b);
 }
 
-/* OK, I lied.  There are three "thread local storage" GDT entries which change
+/*
+ * OK, I lied.  There are three "thread local storage" GDT entries which change
  * on every context switch (these three entries are how glibc implements
- * __thread variables).  So we have a hypercall specifically for this case. */
+ * __thread variables).  So we have a hypercall specifically for this case.
+ */
 static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
 {
-	/* There's one problem which normal hardware doesn't have: the Host
+	/*
+	 * There's one problem which normal hardware doesn't have: the Host
 	 * can't handle us removing entries we're currently using.  So we clear
-	 * the GS register here: if it's needed it'll be reloaded anyway. */
+	 * the GS register here: if it's needed it'll be reloaded anyway.
+	 */
 	lazy_load_gs(0);
 	lazy_hcall2(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu);
 }
 
-/*G:038 That's enough excitement for now, back to ploughing through each of
- * the different pv_ops structures (we're about 1/3 of the way through).
+/*G:038
+ * That's enough excitement for now, back to ploughing through each of the
+ * different pv_ops structures (we're about 1/3 of the way through).
  *
  * This is the Local Descriptor Table, another weird Intel thingy.  Linux only
  * uses this for some strange applications like Wine.  We don't do anything
- * here, so they'll get an informative and friendly Segmentation Fault. */
+ * here, so they'll get an informative and friendly Segmentation Fault.
+ */
 static void lguest_set_ldt(const void *addr, unsigned entries)
 {
 }
 
-/* This loads a GDT entry into the "Task Register": that entry points to a
+/*
+ * This loads a GDT entry into the "Task Register": that entry points to a
  * structure called the Task State Segment.  Some comments scattered though the
  * kernel code indicate that this used for task switching in ages past, along
  * with blood sacrifice and astrology.
@@ -347,19 +375,21 @@ static void lguest_set_ldt(const void *addr, unsigned entries)
  * Now there's nothing interesting in here that we don't get told elsewhere.
  * But the native version uses the "ltr" instruction, which makes the Host
  * complain to the Guest about a Segmentation Fault and it'll oops.  So we
- * override the native version with a do-nothing version. */
+ * override the native version with a do-nothing version.
+ */
 static void lguest_load_tr_desc(void)
 {
 }
 
-/* The "cpuid" instruction is a way of querying both the CPU identity
+/*
+ * The "cpuid" instruction is a way of querying both the CPU identity
  * (manufacturer, model, etc) and its features.  It was introduced before the
  * Pentium in 1993 and keeps getting extended by both Intel, AMD and others.
  * As you might imagine, after a decade and a half this treatment, it is now a
  * giant ball of hair.  Its entry in the current Intel manual runs to 28 pages.
  *
  * This instruction even it has its own Wikipedia entry.  The Wikipedia entry
- * has been translated into 4 languages.  I am not making this up!
+ * has been translated into 5 languages.  I am not making this up!
  *
  * We could get funky here and identify ourselves as "GenuineLguest", but
  * instead we just use the real "cpuid" instruction.  Then I pretty much turned
@@ -371,7 +401,8 @@ static void lguest_load_tr_desc(void)
  * Replacing the cpuid so we can turn features off is great for the kernel, but
  * anyone (including userspace) can just use the raw "cpuid" instruction and
  * the Host won't even notice since it isn't privileged.  So we try not to get
- * too worked up about it. */
+ * too worked up about it.
+ */
 static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
 			 unsigned int *cx, unsigned int *dx)
 {
@@ -379,38 +410,63 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
 
 	native_cpuid(ax, bx, cx, dx);
 	switch (function) {
-	case 1:	/* Basic feature request. */
-		/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
+	/*
+	 * CPUID 0 gives the highest legal CPUID number (and the ID string).
+	 * We futureproof our code a little by sticking to known CPUID values.
+	 */
+	case 0:
+		if (*ax > 5)
+			*ax = 5;
+		break;
+
+	/*
+	 * CPUID 1 is a basic feature request.
+	 *
+	 * CX: we only allow kernel to see SSE3, CMPXCHG16B and SSSE3
+	 * DX: SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU and PAE.
+	 */
+	case 1:
 		*cx &= 0x00002201;
-		/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU, PAE. */
 		*dx &= 0x07808151;
-		/* The Host can do a nice optimization if it knows that the
+		/*
+		 * The Host can do a nice optimization if it knows that the
 		 * kernel mappings (addresses above 0xC0000000 or whatever
 		 * PAGE_OFFSET is set to) haven't changed.  But Linux calls
 		 * flush_tlb_user() for both user and kernel mappings unless
-		 * the Page Global Enable (PGE) feature bit is set. */
+		 * the Page Global Enable (PGE) feature bit is set.
+		 */
 		*dx |= 0x00002000;
-		/* We also lie, and say we're family id 5.  6 or greater
+		/*
+		 * We also lie, and say we're family id 5.  6 or greater
 		 * leads to a rdmsr in early_init_intel which we can't handle.
-		 * Family ID is returned as bits 8-12 in ax. */
+		 * Family ID is returned as bits 8-12 in ax.
+		 */
 		*ax &= 0xFFFFF0FF;
 		*ax |= 0x00000500;
 		break;
+	/*
+	 * 0x80000000 returns the highest Extended Function, so we futureproof
+	 * like we do above by limiting it to known fields.
+	 */
 	case 0x80000000:
-		/* Futureproof this a little: if they ask how much extended
-		 * processor information there is, limit it to known fields. */
 		if (*ax > 0x80000008)
 			*ax = 0x80000008;
 		break;
+
+	/*
+	 * PAE systems can mark pages as non-executable.  Linux calls this the
+	 * NX bit.  Intel calls it XD (eXecute Disable), AMD EVP (Enhanced
+	 * Virus Protection).  We just switch turn if off here, since we don't
+	 * support it.
+	 */
 	case 0x80000001:
-		/* Here we should fix nx cap depending on host. */
-		/* For this version of PAE, we just clear NX bit. */
 		*dx &= ~(1 << 20);
 		break;
 	}
 }
 
-/* Intel has four control registers, imaginatively named cr0, cr2, cr3 and cr4.
+/*
+ * Intel has four control registers, imaginatively named cr0, cr2, cr3 and cr4.
  * I assume there's a cr1, but it hasn't bothered us yet, so we'll not bother
  * it.  The Host needs to know when the Guest wants to change them, so we have
  * a whole series of functions like read_cr0() and write_cr0().
@@ -425,7 +481,8 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
  * name like "FPUTRAP bit" be a little less cryptic?
  *
  * We store cr0 locally because the Host never changes it.  The Guest sometimes
- * wants to read it and we'd prefer not to bother the Host unnecessarily. */
+ * wants to read it and we'd prefer not to bother the Host unnecessarily.
+ */
 static unsigned long current_cr0;
 static void lguest_write_cr0(unsigned long val)
 {
@@ -438,18 +495,22 @@ static unsigned long lguest_read_cr0(void)
 	return current_cr0;
 }
 
-/* Intel provided a special instruction to clear the TS bit for people too cool
+/*
+ * Intel provided a special instruction to clear the TS bit for people too cool
  * to use write_cr0() to do it.  This "clts" instruction is faster, because all
- * the vowels have been optimized out. */
+ * the vowels have been optimized out.
+ */
 static void lguest_clts(void)
 {
 	lazy_hcall1(LHCALL_TS, 0);
 	current_cr0 &= ~X86_CR0_TS;
 }
 
-/* cr2 is the virtual address of the last page fault, which the Guest only ever
+/*
+ * cr2 is the virtual address of the last page fault, which the Guest only ever
  * reads.  The Host kindly writes this into our "struct lguest_data", so we
- * just read it out of there. */
+ * just read it out of there.
+ */
 static unsigned long lguest_read_cr2(void)
 {
 	return lguest_data.cr2;
@@ -458,10 +519,12 @@ static unsigned long lguest_read_cr2(void)
 /* See lguest_set_pte() below. */
 static bool cr3_changed = false;
 
-/* cr3 is the current toplevel pagetable page: the principle is the same as
+/*
+ * cr3 is the current toplevel pagetable page: the principle is the same as
  * cr0.  Keep a local copy, and tell the Host when it changes.  The only
  * difference is that our local copy is in lguest_data because the Host needs
- * to set it upon our initial hypercall. */
+ * to set it upon our initial hypercall.
+ */
 static void lguest_write_cr3(unsigned long cr3)
 {
 	lguest_data.pgdir = cr3;
@@ -506,7 +569,7 @@ static void lguest_write_cr4(unsigned long val)
  * cr3 ---> +---------+
  *	    |  	   --------->+---------+
  *	    |	      |	     | PADDR1  |
- *	  Top-level   |	     | PADDR2  |
+ *	  Mid-level   |	     | PADDR2  |
  *	  (PMD) page  |	     | 	       |
  *	    |	      |	   Lower-level |
  *	    |	      |	   (PTE) page  |
@@ -526,21 +589,62 @@ static void lguest_write_cr4(unsigned long val)
  *    Index into top     Index into second      Offset within page
  *  page directory page    pagetable page
  *
- * The kernel spends a lot of time changing both the top-level page directory
- * and lower-level pagetable pages.  The Guest doesn't know physical addresses,
- * so while it maintains these page tables exactly like normal, it also needs
- * to keep the Host informed whenever it makes a change: the Host will create
- * the real page tables based on the Guests'.
+ * Now, unfortunately, this isn't the whole story: Intel added Physical Address
+ * Extension (PAE) to allow 32 bit systems to use 64GB of memory (ie. 36 bits).
+ * These are held in 64-bit page table entries, so we can now only fit 512
+ * entries in a page, and the neat three-level tree breaks down.
+ *
+ * The result is a four level page table:
+ *
+ * cr3 --> [ 4 Upper  ]
+ *	   [   Level  ]
+ *	   [  Entries ]
+ *	   [(PUD Page)]---> +---------+
+ *	 		    |  	   --------->+---------+
+ *	 		    |	      |	     | PADDR1  |
+ *	 		  Mid-level   |	     | PADDR2  |
+ *	 		  (PMD) page  |	     | 	       |
+ *	 		    |	      |	   Lower-level |
+ *	 		    |	      |	   (PTE) page  |
+ *	 		    |	      |	     |	       |
+ *	 		      ....    	     	 ....
+ *
+ *
+ * And the virtual address is decoded as:
+ *
+ *         1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ *      |<-2->|<--- 9 bits ---->|<---- 9 bits --->|<------ 12 bits ------>|
+ * Index into    Index into mid    Index into lower    Offset within page
+ * top entries   directory page     pagetable page
+ *
+ * It's too hard to switch between these two formats at runtime, so Linux only
+ * supports one or the other depending on whether CONFIG_X86_PAE is set.  Many
+ * distributions turn it on, and not just for people with silly amounts of
+ * memory: the larger PTE entries allow room for the NX bit, which lets the
+ * kernel disable execution of pages and increase security.
+ *
+ * This was a problem for lguest, which couldn't run on these distributions;
+ * then Matias Zabaljauregui figured it all out and implemented it, and only a
+ * handful of puppies were crushed in the process!
+ *
+ * Back to our point: the kernel spends a lot of time changing both the
+ * top-level page directory and lower-level pagetable pages.  The Guest doesn't
+ * know physical addresses, so while it maintains these page tables exactly
+ * like normal, it also needs to keep the Host informed whenever it makes a
+ * change: the Host will create the real page tables based on the Guests'.
  */
 
-/* The Guest calls this to set a second-level entry (pte), ie. to map a page
- * into a process' address space.  We set the entry then tell the Host the
- * toplevel and address this corresponds to.  The Guest uses one pagetable per
- * process, so we need to tell the Host which one we're changing (mm->pgd). */
+/*
+ * The Guest calls this after it has set a second-level entry (pte), ie. to map
+ * a page into a process' address space.  Wetell the Host the toplevel and
+ * address this corresponds to.  The Guest uses one pagetable per process, so
+ * we need to tell the Host which one we're changing (mm->pgd).
+ */
 static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
 			       pte_t *ptep)
 {
 #ifdef CONFIG_X86_PAE
+	/* PAE needs to hand a 64 bit page table entry, so it uses two args. */
 	lazy_hcall4(LHCALL_SET_PTE, __pa(mm->pgd), addr,
 		    ptep->pte_low, ptep->pte_high);
 #else
@@ -548,6 +652,7 @@ static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
 #endif
 }
 
+/* This is the "set and update" combo-meal-deal version. */
 static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
 			      pte_t *ptep, pte_t pteval)
 {
@@ -555,10 +660,13 @@ static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
 	lguest_pte_update(mm, addr, ptep);
 }
 
-/* The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd
+/*
+ * The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd
  * to set a middle-level entry when PAE is activated.
+ *
  * Again, we set the entry then tell the Host which page we changed,
- * and the index of the entry we changed. */
+ * and the index of the entry we changed.
+ */
 #ifdef CONFIG_X86_PAE
 static void lguest_set_pud(pud_t *pudp, pud_t pudval)
 {
@@ -577,8 +685,7 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
 }
 #else
 
-/* The Guest calls lguest_set_pmd to set a top-level entry when PAE is not
- * activated. */
+/* The Guest calls lguest_set_pmd to set a top-level entry when !PAE. */
 static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
 {
 	native_set_pmd(pmdp, pmdval);
@@ -587,7 +694,8 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
 }
 #endif
 
-/* There are a couple of legacy places where the kernel sets a PTE, but we
+/*
+ * There are a couple of legacy places where the kernel sets a PTE, but we
  * don't know the top level any more.  This is useless for us, since we don't
  * know which pagetable is changing or what address, so we just tell the Host
  * to forget all of them.  Fortunately, this is very rare.
@@ -595,7 +703,8 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
  * ... except in early boot when the kernel sets up the initial pagetables,
  * which makes booting astonishingly slow: 1.83 seconds!  So we don't even tell
  * the Host anything changed until we've done the first page table switch,
- * which brings boot back to 0.25 seconds. */
+ * which brings boot back to 0.25 seconds.
+ */
 static void lguest_set_pte(pte_t *ptep, pte_t pteval)
 {
 	native_set_pte(ptep, pteval);
@@ -604,6 +713,11 @@ static void lguest_set_pte(pte_t *ptep, pte_t pteval)
 }
 
 #ifdef CONFIG_X86_PAE
+/*
+ * With 64-bit PTE values, we need to be careful setting them: if we set 32
+ * bits at a time, the hardware could see a weird half-set entry.  These
+ * versions ensure we update all 64 bits at once.
+ */
 static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte)
 {
 	native_set_pte_atomic(ptep, pte);
@@ -611,19 +725,21 @@ static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte)
 		lazy_hcall1(LHCALL_FLUSH_TLB, 1);
 }
 
-void lguest_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+static void lguest_pte_clear(struct mm_struct *mm, unsigned long addr,
+			     pte_t *ptep)
 {
 	native_pte_clear(mm, addr, ptep);
 	lguest_pte_update(mm, addr, ptep);
 }
 
-void lguest_pmd_clear(pmd_t *pmdp)
+static void lguest_pmd_clear(pmd_t *pmdp)
 {
 	lguest_set_pmd(pmdp, __pmd(0));
 }
 #endif
 
-/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
+/*
+ * Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
  * native page table operations.  On native hardware you can set a new page
  * table entry whenever you want, but if you want to remove one you have to do
  * a TLB flush (a TLB is a little cache of page table entries kept by the CPU).
@@ -632,24 +748,29 @@ void lguest_pmd_clear(pmd_t *pmdp)
  * called when a valid entry is written, not when it's removed (ie. marked not
  * present).  Instead, this is where we come when the Guest wants to remove a
  * page table entry: we tell the Host to set that entry to 0 (ie. the present
- * bit is zero). */
+ * bit is zero).
+ */
 static void lguest_flush_tlb_single(unsigned long addr)
 {
 	/* Simply set it to zero: if it was not, it will fault back in. */
 	lazy_hcall3(LHCALL_SET_PTE, lguest_data.pgdir, addr, 0);
 }
 
-/* This is what happens after the Guest has removed a large number of entries.
+/*
+ * This is what happens after the Guest has removed a large number of entries.
  * This tells the Host that any of the page table entries for userspace might
- * have changed, ie. virtual addresses below PAGE_OFFSET. */
+ * have changed, ie. virtual addresses below PAGE_OFFSET.
+ */
 static void lguest_flush_tlb_user(void)
 {
 	lazy_hcall1(LHCALL_FLUSH_TLB, 0);
 }
 
-/* This is called when the kernel page tables have changed.  That's not very
+/*
+ * This is called when the kernel page tables have changed.  That's not very
  * common (unless the Guest is using highmem, which makes the Guest extremely
- * slow), so it's worth separating this from the user flushing above. */
+ * slow), so it's worth separating this from the user flushing above.
+ */
 static void lguest_flush_tlb_kernel(void)
 {
 	lazy_hcall1(LHCALL_FLUSH_TLB, 1);
@@ -686,26 +807,38 @@ static struct irq_chip lguest_irq_controller = {
 	.unmask		= enable_lguest_irq,
 };
 
-/* This sets up the Interrupt Descriptor Table (IDT) entry for each hardware
+/*
+ * This sets up the Interrupt Descriptor Table (IDT) entry for each hardware
  * interrupt (except 128, which is used for system calls), and then tells the
  * Linux infrastructure that each interrupt is controlled by our level-based
- * lguest interrupt controller. */
+ * lguest interrupt controller.
+ */
 static void __init lguest_init_IRQ(void)
 {
 	unsigned int i;
 
 	for (i = FIRST_EXTERNAL_VECTOR; i < NR_VECTORS; i++) {
-		/* Some systems map "vectors" to interrupts weirdly.  Lguest has
-		 * a straightforward 1 to 1 mapping, so force that here. */
+		/* Some systems map "vectors" to interrupts weirdly.  Not us! */
 		__get_cpu_var(vector_irq)[i] = i - FIRST_EXTERNAL_VECTOR;
 		if (i != SYSCALL_VECTOR)
 			set_intr_gate(i, interrupt[i - FIRST_EXTERNAL_VECTOR]);
 	}
-	/* This call is required to set up for 4k stacks, where we have
-	 * separate stacks for hard and soft interrupts. */
+
+	/*
+	 * This call is required to set up for 4k stacks, where we have
+	 * separate stacks for hard and soft interrupts.
+	 */
 	irq_ctx_init(smp_processor_id());
 }
 
+/*
+ * With CONFIG_SPARSE_IRQ, interrupt descriptors are allocated as-needed, so
+ * rather than set them in lguest_init_IRQ we are called here every time an
+ * lguest device needs an interrupt.
+ *
+ * FIXME: irq_to_desc_alloc_node() can fail due to lack of memory, we should
+ * pass that up!
+ */
 void lguest_setup_irq(unsigned int irq)
 {
 	irq_to_desc_alloc_node(irq, 0);
@@ -724,31 +857,39 @@ static unsigned long lguest_get_wallclock(void)
 	return lguest_data.time.tv_sec;
 }
 
-/* The TSC is an Intel thing called the Time Stamp Counter.  The Host tells us
+/*
+ * The TSC is an Intel thing called the Time Stamp Counter.  The Host tells us
  * what speed it runs at, or 0 if it's unusable as a reliable clock source.
  * This matches what we want here: if we return 0 from this function, the x86
- * TSC clock will give up and not register itself. */
+ * TSC clock will give up and not register itself.
+ */
 static unsigned long lguest_tsc_khz(void)
 {
 	return lguest_data.tsc_khz;
 }
 
-/* If we can't use the TSC, the kernel falls back to our lower-priority
- * "lguest_clock", where we read the time value given to us by the Host. */
+/*
+ * If we can't use the TSC, the kernel falls back to our lower-priority
+ * "lguest_clock", where we read the time value given to us by the Host.
+ */
 static cycle_t lguest_clock_read(struct clocksource *cs)
 {
 	unsigned long sec, nsec;
 
-	/* Since the time is in two parts (seconds and nanoseconds), we risk
+	/*
+	 * Since the time is in two parts (seconds and nanoseconds), we risk
 	 * reading it just as it's changing from 99 & 0.999999999 to 100 and 0,
 	 * and getting 99 and 0.  As Linux tends to come apart under the stress
-	 * of time travel, we must be careful: */
+	 * of time travel, we must be careful:
+	 */
 	do {
 		/* First we read the seconds part. */
 		sec = lguest_data.time.tv_sec;
-		/* This read memory barrier tells the compiler and the CPU that
+		/*
+		 * This read memory barrier tells the compiler and the CPU that
 		 * this can't be reordered: we have to complete the above
-		 * before going on. */
+		 * before going on.
+		 */
 		rmb();
 		/* Now we read the nanoseconds part. */
 		nsec = lguest_data.time.tv_nsec;
@@ -772,9 +913,11 @@ static struct clocksource lguest_clock = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-/* We also need a "struct clock_event_device": Linux asks us to set it to go
+/*
+ * We also need a "struct clock_event_device": Linux asks us to set it to go
  * off some time in the future.  Actually, James Morris figured all this out, I
- * just applied the patch. */
+ * just applied the patch.
+ */
 static int lguest_clockevent_set_next_event(unsigned long delta,
                                            struct clock_event_device *evt)
 {
@@ -824,8 +967,10 @@ static struct clock_event_device lguest_clockevent = {
 	.max_delta_ns           = LG_CLOCK_MAX_DELTA,
 };
 
-/* This is the Guest timer interrupt handler (hardware interrupt 0).  We just
- * call the clockevent infrastructure and it does whatever needs doing. */
+/*
+ * This is the Guest timer interrupt handler (hardware interrupt 0).  We just
+ * call the clockevent infrastructure and it does whatever needs doing.
+ */
 static void lguest_time_irq(unsigned int irq, struct irq_desc *desc)
 {
 	unsigned long flags;
@@ -836,10 +981,12 @@ static void lguest_time_irq(unsigned int irq, struct irq_desc *desc)
 	local_irq_restore(flags);
 }
 
-/* At some point in the boot process, we get asked to set up our timing
+/*
+ * At some point in the boot process, we get asked to set up our timing
  * infrastructure.  The kernel doesn't expect timer interrupts before this, but
  * we cleverly initialized the "blocked_interrupts" field of "struct
- * lguest_data" so that timer interrupts were blocked until now. */
+ * lguest_data" so that timer interrupts were blocked until now.
+ */
 static void lguest_time_init(void)
 {
 	/* Set up the timer interrupt (0) to go to our simple timer routine */
@@ -863,14 +1010,16 @@ static void lguest_time_init(void)
  * to work.  They're pretty simple.
  */
 
-/* The Guest needs to tell the Host what stack it expects traps to use.  For
+/*
+ * The Guest needs to tell the Host what stack it expects traps to use.  For
  * native hardware, this is part of the Task State Segment mentioned above in
  * lguest_load_tr_desc(), but to help hypervisors there's this special call.
  *
  * We tell the Host the segment we want to use (__KERNEL_DS is the kernel data
  * segment), the privilege level (we're privilege level 1, the Host is 0 and
  * will not tolerate us trying to use that), the stack pointer, and the number
- * of pages in the stack. */
+ * of pages in the stack.
+ */
 static void lguest_load_sp0(struct tss_struct *tss,
 			    struct thread_struct *thread)
 {
@@ -884,7 +1033,8 @@ static void lguest_set_debugreg(int regno, unsigned long value)
 	/* FIXME: Implement */
 }
 
-/* There are times when the kernel wants to make sure that no memory writes are
+/*
+ * There are times when the kernel wants to make sure that no memory writes are
  * caught in the cache (that they've all reached real hardware devices).  This
  * doesn't matter for the Guest which has virtual hardware.
  *
@@ -898,11 +1048,13 @@ static void lguest_wbinvd(void)
 {
 }
 
-/* If the Guest expects to have an Advanced Programmable Interrupt Controller,
+/*
+ * If the Guest expects to have an Advanced Programmable Interrupt Controller,
  * we play dumb by ignoring writes and returning 0 for reads.  So it's no
  * longer Programmable nor Controlling anything, and I don't think 8 lines of
  * code qualifies for Advanced.  It will also never interrupt anything.  It
- * does, however, allow us to get through the Linux boot code. */
+ * does, however, allow us to get through the Linux boot code.
+ */
 #ifdef CONFIG_X86_LOCAL_APIC
 static void lguest_apic_write(u32 reg, u32 v)
 {
@@ -951,11 +1103,13 @@ static void lguest_safe_halt(void)
 	kvm_hypercall0(LHCALL_HALT);
 }
 
-/* The SHUTDOWN hypercall takes a string to describe what's happening, and
+/*
+ * The SHUTDOWN hypercall takes a string to describe what's happening, and
  * an argument which says whether this to restart (reboot) the Guest or not.
  *
  * Note that the Host always prefers that the Guest speak in physical addresses
- * rather than virtual addresses, so we use __pa() here. */
+ * rather than virtual addresses, so we use __pa() here.
+ */
 static void lguest_power_off(void)
 {
 	kvm_hypercall2(LHCALL_SHUTDOWN, __pa("Power down"),
@@ -986,8 +1140,10 @@ static __init char *lguest_memory_setup(void)
 	 * nice to move it back to lguest_init.  Patch welcome... */
 	atomic_notifier_chain_register(&panic_notifier_list, &paniced);
 
-	/* The Linux bootloader header contains an "e820" memory map: the
-	 * Launcher populated the first entry with our memory limit. */
+	/*
+	 *The Linux bootloader header contains an "e820" memory map: the
+	 * Launcher populated the first entry with our memory limit.
+	 */
 	e820_add_region(boot_params.e820_map[0].addr,
 			  boot_params.e820_map[0].size,
 			  boot_params.e820_map[0].type);
@@ -996,16 +1152,17 @@ static __init char *lguest_memory_setup(void)
 	return "LGUEST";
 }
 
-/* We will eventually use the virtio console device to produce console output,
+/*
+ * We will eventually use the virtio console device to produce console output,
  * but before that is set up we use LHCALL_NOTIFY on normal memory to produce
- * console output. */
+ * console output.
+ */
 static __init int early_put_chars(u32 vtermno, const char *buf, int count)
 {
 	char scratch[17];
 	unsigned int len = count;
 
-	/* We use a nul-terminated string, so we have to make a copy.  Icky,
-	 * huh? */
+	/* We use a nul-terminated string, so we make a copy.  Icky, huh? */
 	if (len > sizeof(scratch) - 1)
 		len = sizeof(scratch) - 1;
 	scratch[len] = '\0';
@@ -1016,8 +1173,10 @@ static __init int early_put_chars(u32 vtermno, const char *buf, int count)
 	return len;
 }
 
-/* Rebooting also tells the Host we're finished, but the RESTART flag tells the
- * Launcher to reboot us. */
+/*
+ * Rebooting also tells the Host we're finished, but the RESTART flag tells the
+ * Launcher to reboot us.
+ */
 static void lguest_restart(char *reason)
 {
 	kvm_hypercall2(LHCALL_SHUTDOWN, __pa(reason), LGUEST_SHUTDOWN_RESTART);
@@ -1044,7 +1203,8 @@ static void lguest_restart(char *reason)
  * fit comfortably.
  *
  * First we need assembly templates of each of the patchable Guest operations,
- * and these are in i386_head.S. */
+ * and these are in i386_head.S.
+ */
 
 /*G:060 We construct a table from the assembler templates: */
 static const struct lguest_insns
@@ -1055,9 +1215,11 @@ static const struct lguest_insns
 	[PARAVIRT_PATCH(pv_irq_ops.save_fl)] = { lgstart_pushf, lgend_pushf },
 };
 
-/* Now our patch routine is fairly simple (based on the native one in
+/*
+ * Now our patch routine is fairly simple (based on the native one in
  * paravirt.c).  If we have a replacement, we copy it in and return how much of
- * the available space we used. */
+ * the available space we used.
+ */
 static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf,
 			     unsigned long addr, unsigned len)
 {
@@ -1069,8 +1231,7 @@ static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf,
 
 	insn_len = lguest_insns[type].end - lguest_insns[type].start;
 
-	/* Similarly if we can't fit replacement (shouldn't happen, but let's
-	 * be thorough). */
+	/* Similarly if it can't fit (doesn't happen, but let's be thorough). */
 	if (len < insn_len)
 		return paravirt_patch_default(type, clobber, ibuf, addr, len);
 
@@ -1079,22 +1240,28 @@ static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf,
 	return insn_len;
 }
 
-/*G:030 Once we get to lguest_init(), we know we're a Guest.  The various
+/*G:029
+ * Once we get to lguest_init(), we know we're a Guest.  The various
  * pv_ops structures in the kernel provide points for (almost) every routine we
- * have to override to avoid privileged instructions. */
+ * have to override to avoid privileged instructions.
+ */
 __init void lguest_init(void)
 {
-	/* We're under lguest, paravirt is enabled, and we're running at
-	 * privilege level 1, not 0 as normal. */
+	/* We're under lguest. */
 	pv_info.name = "lguest";
+	/* Paravirt is enabled. */
 	pv_info.paravirt_enabled = 1;
+	/* We're running at privilege level 1, not 0 as normal. */
 	pv_info.kernel_rpl = 1;
+	/* Everyone except Xen runs with this set. */
 	pv_info.shared_kernel_pmd = 1;
 
-	/* We set up all the lguest overrides for sensitive operations.  These
-	 * are detailed with the operations themselves. */
+	/*
+	 * We set up all the lguest overrides for sensitive operations.  These
+	 * are detailed with the operations themselves.
+	 */
 
-	/* interrupt-related operations */
+	/* Interrupt-related operations */
 	pv_irq_ops.init_IRQ = lguest_init_IRQ;
 	pv_irq_ops.save_fl = PV_CALLEE_SAVE(save_fl);
 	pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(lg_restore_fl);
@@ -1102,11 +1269,11 @@ __init void lguest_init(void)
 	pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(lg_irq_enable);
 	pv_irq_ops.safe_halt = lguest_safe_halt;
 
-	/* init-time operations */
+	/* Setup operations */
 	pv_init_ops.memory_setup = lguest_memory_setup;
 	pv_init_ops.patch = lguest_patch;
 
-	/* Intercepts of various cpu instructions */
+	/* Intercepts of various CPU instructions */
 	pv_cpu_ops.load_gdt = lguest_load_gdt;
 	pv_cpu_ops.cpuid = lguest_cpuid;
 	pv_cpu_ops.load_idt = lguest_load_idt;
@@ -1127,7 +1294,7 @@ __init void lguest_init(void)
 	pv_cpu_ops.start_context_switch = paravirt_start_context_switch;
 	pv_cpu_ops.end_context_switch = lguest_end_context_switch;
 
-	/* pagetable management */
+	/* Pagetable management */
 	pv_mmu_ops.write_cr3 = lguest_write_cr3;
 	pv_mmu_ops.flush_tlb_user = lguest_flush_tlb_user;
 	pv_mmu_ops.flush_tlb_single = lguest_flush_tlb_single;
@@ -1149,54 +1316,71 @@ __init void lguest_init(void)
 	pv_mmu_ops.pte_update_defer = lguest_pte_update;
 
 #ifdef CONFIG_X86_LOCAL_APIC
-	/* apic read/write intercepts */
+	/* APIC read/write intercepts */
 	set_lguest_basic_apic_ops();
 #endif
 
-	/* time operations */
+	/* Time operations */
 	pv_time_ops.get_wallclock = lguest_get_wallclock;
 	pv_time_ops.time_init = lguest_time_init;
 	pv_time_ops.get_tsc_khz = lguest_tsc_khz;
 
-	/* Now is a good time to look at the implementations of these functions
-	 * before returning to the rest of lguest_init(). */
+	/*
+	 * Now is a good time to look at the implementations of these functions
+	 * before returning to the rest of lguest_init().
+	 */
 
-	/*G:070 Now we've seen all the paravirt_ops, we return to
+	/*G:070
+	 * Now we've seen all the paravirt_ops, we return to
 	 * lguest_init() where the rest of the fairly chaotic boot setup
-	 * occurs. */
+	 * occurs.
+	 */
 
-	/* The stack protector is a weird thing where gcc places a canary
+	/*
+	 * The stack protector is a weird thing where gcc places a canary
 	 * value on the stack and then checks it on return.  This file is
 	 * compiled with -fno-stack-protector it, so we got this far without
 	 * problems.  The value of the canary is kept at offset 20 from the
 	 * %gs register, so we need to set that up before calling C functions
-	 * in other files. */
+	 * in other files.
+	 */
 	setup_stack_canary_segment(0);
-	/* We could just call load_stack_canary_segment(), but we might as
-	 * call switch_to_new_gdt() which loads the whole table and sets up
-	 * the per-cpu segment descriptor register %fs as well. */
+
+	/*
+	 * We could just call load_stack_canary_segment(), but we might as well
+	 * call switch_to_new_gdt() which loads the whole table and sets up the
+	 * per-cpu segment descriptor register %fs as well.
+	 */
 	switch_to_new_gdt(0);
 
-	/* As described in head_32.S, we map the first 128M of memory. */
+	/* We actually boot with all memory mapped, but let's say 128MB. */
 	max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT;
 
-	/* The Host<->Guest Switcher lives at the top of our address space, and
+	/*
+	 * The Host<->Guest Switcher lives at the top of our address space, and
 	 * the Host told us how big it is when we made LGUEST_INIT hypercall:
-	 * it put the answer in lguest_data.reserve_mem  */
+	 * it put the answer in lguest_data.reserve_mem
+	 */
 	reserve_top_address(lguest_data.reserve_mem);
 
-	/* If we don't initialize the lock dependency checker now, it crashes
-	 * paravirt_disable_iospace. */
+	/*
+	 * If we don't initialize the lock dependency checker now, it crashes
+	 * paravirt_disable_iospace.
+	 */
 	lockdep_init();
 
-	/* The IDE code spends about 3 seconds probing for disks: if we reserve
+	/*
+	 * The IDE code spends about 3 seconds probing for disks: if we reserve
 	 * all the I/O ports up front it can't get them and so doesn't probe.
 	 * Other device drivers are similar (but less severe).  This cuts the
-	 * kernel boot time on my machine from 4.1 seconds to 0.45 seconds. */
+	 * kernel boot time on my machine from 4.1 seconds to 0.45 seconds.
+	 */
 	paravirt_disable_iospace();
 
-	/* This is messy CPU setup stuff which the native boot code does before
-	 * start_kernel, so we have to do, too: */
+	/*
+	 * This is messy CPU setup stuff which the native boot code does before
+	 * start_kernel, so we have to do, too:
+	 */
 	cpu_detect(&new_cpu_data);
 	/* head.S usually sets up the first capability word, so do it here. */
 	new_cpu_data.x86_capability[0] = cpuid_edx(1);
@@ -1213,22 +1397,28 @@ __init void lguest_init(void)
 	acpi_ht = 0;
 #endif
 
-	/* We set the preferred console to "hvc".  This is the "hypervisor
+	/*
+	 * We set the preferred console to "hvc".  This is the "hypervisor
 	 * virtual console" driver written by the PowerPC people, which we also
-	 * adapted for lguest's use. */
+	 * adapted for lguest's use.
+	 */
 	add_preferred_console("hvc", 0, NULL);
 
 	/* Register our very early console. */
 	virtio_cons_early_init(early_put_chars);
 
-	/* Last of all, we set the power management poweroff hook to point to
+	/*
+	 * Last of all, we set the power management poweroff hook to point to
 	 * the Guest routine to power off, and the reboot hook to our restart
-	 * routine. */
+	 * routine.
+	 */
 	pm_power_off = lguest_power_off;
 	machine_ops.restart = lguest_restart;
 
-	/* Now we're set up, call i386_start_kernel() in head32.c and we proceed
-	 * to boot as normal.  It never returns. */
+	/*
+	 * Now we're set up, call i386_start_kernel() in head32.c and we proceed
+	 * to boot as normal.  It never returns.
+	 */
 	i386_start_kernel();
 }
 /*
diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S
index a9c8cfe61cd..27eac0faee4 100644
--- a/arch/x86/lguest/i386_head.S
+++ b/arch/x86/lguest/i386_head.S
@@ -5,7 +5,8 @@
 #include <asm/thread_info.h>
 #include <asm/processor-flags.h>
 
-/*G:020 Our story starts with the kernel booting into startup_32 in
+/*G:020
+ * Our story starts with the kernel booting into startup_32 in
  * arch/x86/kernel/head_32.S.  It expects a boot header, which is created by
  * the bootloader (the Launcher in our case).
  *
@@ -21,11 +22,14 @@
  * data without remembering to subtract __PAGE_OFFSET!
  *
  * The .section line puts this code in .init.text so it will be discarded after
- * boot. */
+ * boot.
+ */
 .section .init.text, "ax", @progbits
 ENTRY(lguest_entry)
-	/* We make the "initialization" hypercall now to tell the Host about
-	 * us, and also find out where it put our page tables. */
+	/*
+	 * We make the "initialization" hypercall now to tell the Host about
+	 * us, and also find out where it put our page tables.
+	 */
 	movl $LHCALL_LGUEST_INIT, %eax
 	movl $lguest_data - __PAGE_OFFSET, %ebx
 	.byte 0x0f,0x01,0xc1 /* KVM_HYPERCALL */
@@ -33,13 +37,14 @@ ENTRY(lguest_entry)
 	/* Set up the initial stack so we can run C code. */
 	movl $(init_thread_union+THREAD_SIZE),%esp
 
-	/* Jumps are relative, and we're running __PAGE_OFFSET too low at the
-	 * moment. */
+	/* Jumps are relative: we're running __PAGE_OFFSET too low. */
 	jmp lguest_init+__PAGE_OFFSET
 
-/*G:055 We create a macro which puts the assembler code between lgstart_ and
- * lgend_ markers.  These templates are put in the .text section: they can't be
- * discarded after boot as we may need to patch modules, too. */
+/*G:055
+ * We create a macro which puts the assembler code between lgstart_ and lgend_
+ * markers.  These templates are put in the .text section: they can't be
+ * discarded after boot as we may need to patch modules, too.
+ */
 .text
 #define LGUEST_PATCH(name, insns...)			\
 	lgstart_##name:	insns; lgend_##name:;		\
@@ -48,83 +53,103 @@ ENTRY(lguest_entry)
 LGUEST_PATCH(cli, movl $0, lguest_data+LGUEST_DATA_irq_enabled)
 LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax)
 
-/*G:033 But using those wrappers is inefficient (we'll see why that doesn't
- * matter for save_fl and irq_disable later).  If we write our routines
- * carefully in assembler, we can avoid clobbering any registers and avoid
- * jumping through the wrapper functions.
+/*G:033
+ * But using those wrappers is inefficient (we'll see why that doesn't matter
+ * for save_fl and irq_disable later).  If we write our routines carefully in
+ * assembler, we can avoid clobbering any registers and avoid jumping through
+ * the wrapper functions.
  *
  * I skipped over our first piece of assembler, but this one is worth studying
- * in a bit more detail so I'll describe in easy stages.  First, the routine
- * to enable interrupts: */
+ * in a bit more detail so I'll describe in easy stages.  First, the routine to
+ * enable interrupts:
+ */
 ENTRY(lg_irq_enable)
-	/* The reverse of irq_disable, this sets lguest_data.irq_enabled to
-	 * X86_EFLAGS_IF (ie. "Interrupts enabled"). */
+	/*
+	 * The reverse of irq_disable, this sets lguest_data.irq_enabled to
+	 * X86_EFLAGS_IF (ie. "Interrupts enabled").
+	 */
 	movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled
-	/* But now we need to check if the Host wants to know: there might have
+	/*
+	 * But now we need to check if the Host wants to know: there might have
 	 * been interrupts waiting to be delivered, in which case it will have
 	 * set lguest_data.irq_pending to X86_EFLAGS_IF.  If it's not zero, we
-	 * jump to send_interrupts, otherwise we're done. */
+	 * jump to send_interrupts, otherwise we're done.
+	 */
 	testl $0, lguest_data+LGUEST_DATA_irq_pending
 	jnz send_interrupts
-	/* One cool thing about x86 is that you can do many things without using
+	/*
+	 * One cool thing about x86 is that you can do many things without using
 	 * a register.  In this case, the normal path hasn't needed to save or
-	 * restore any registers at all! */
+	 * restore any registers at all!
+	 */
 	ret
 send_interrupts:
-	/* OK, now we need a register: eax is used for the hypercall number,
+	/*
+	 * OK, now we need a register: eax is used for the hypercall number,
 	 * which is LHCALL_SEND_INTERRUPTS.
 	 *
 	 * We used not to bother with this pending detection at all, which was
 	 * much simpler.  Sooner or later the Host would realize it had to
 	 * send us an interrupt.  But that turns out to make performance 7
 	 * times worse on a simple tcp benchmark.  So now we do this the hard
-	 * way. */
+	 * way.
+	 */
 	pushl %eax
 	movl $LHCALL_SEND_INTERRUPTS, %eax
-	/* This is a vmcall instruction (same thing that KVM uses).  Older
+	/*
+	 * This is a vmcall instruction (same thing that KVM uses).  Older
 	 * assembler versions might not know the "vmcall" instruction, so we
-	 * create one manually here. */
+	 * create one manually here.
+	 */
 	.byte 0x0f,0x01,0xc1 /* KVM_HYPERCALL */
+	/* Put eax back the way we found it. */
 	popl %eax
 	ret
 
-/* Finally, the "popf" or "restore flags" routine.  The %eax register holds the
+/*
+ * Finally, the "popf" or "restore flags" routine.  The %eax register holds the
  * flags (in practice, either X86_EFLAGS_IF or 0): if it's X86_EFLAGS_IF we're
- * enabling interrupts again, if it's 0 we're leaving them off. */
+ * enabling interrupts again, if it's 0 we're leaving them off.
+ */
 ENTRY(lg_restore_fl)
 	/* This is just "lguest_data.irq_enabled = flags;" */
 	movl %eax, lguest_data+LGUEST_DATA_irq_enabled
-	/* Now, if the %eax value has enabled interrupts and
+	/*
+	 * Now, if the %eax value has enabled interrupts and
 	 * lguest_data.irq_pending is set, we want to tell the Host so it can
 	 * deliver any outstanding interrupts.  Fortunately, both values will
 	 * be X86_EFLAGS_IF (ie. 512) in that case, and the "testl"
 	 * instruction will AND them together for us.  If both are set, we
-	 * jump to send_interrupts. */
+	 * jump to send_interrupts.
+	 */
 	testl lguest_data+LGUEST_DATA_irq_pending, %eax
 	jnz send_interrupts
 	/* Again, the normal path has used no extra registers.  Clever, huh? */
 	ret
+/*:*/
 
 /* These demark the EIP range where host should never deliver interrupts. */
 .global lguest_noirq_start
 .global lguest_noirq_end
 
-/*M:004 When the Host reflects a trap or injects an interrupt into the Guest,
- * it sets the eflags interrupt bit on the stack based on
- * lguest_data.irq_enabled, so the Guest iret logic does the right thing when
- * restoring it.  However, when the Host sets the Guest up for direct traps,
- * such as system calls, the processor is the one to push eflags onto the
- * stack, and the interrupt bit will be 1 (in reality, interrupts are always
- * enabled in the Guest).
+/*M:004
+ * When the Host reflects a trap or injects an interrupt into the Guest, it
+ * sets the eflags interrupt bit on the stack based on lguest_data.irq_enabled,
+ * so the Guest iret logic does the right thing when restoring it.  However,
+ * when the Host sets the Guest up for direct traps, such as system calls, the
+ * processor is the one to push eflags onto the stack, and the interrupt bit
+ * will be 1 (in reality, interrupts are always enabled in the Guest).
  *
  * This turns out to be harmless: the only trap which should happen under Linux
  * with interrupts disabled is Page Fault (due to our lazy mapping of vmalloc
  * regions), which has to be reflected through the Host anyway.  If another
  * trap *does* go off when interrupts are disabled, the Guest will panic, and
- * we'll never get to this iret! :*/
+ * we'll never get to this iret!
+:*/
 
-/*G:045 There is one final paravirt_op that the Guest implements, and glancing
- * at it you can see why I left it to last.  It's *cool*!  It's in *assembler*!
+/*G:045
+ * There is one final paravirt_op that the Guest implements, and glancing at it
+ * you can see why I left it to last.  It's *cool*!  It's in *assembler*!
  *
  * The "iret" instruction is used to return from an interrupt or trap.  The
  * stack looks like this:
@@ -148,15 +173,18 @@ ENTRY(lg_restore_fl)
  * return to userspace or wherever.  Our solution to this is to surround the
  * code with lguest_noirq_start: and lguest_noirq_end: labels.  We tell the
  * Host that it is *never* to interrupt us there, even if interrupts seem to be
- * enabled. */
+ * enabled.
+ */
 ENTRY(lguest_iret)
 	pushl	%eax
 	movl	12(%esp), %eax
 lguest_noirq_start:
-	/* Note the %ss: segment prefix here.  Normal data accesses use the
+	/*
+	 * Note the %ss: segment prefix here.  Normal data accesses use the
 	 * "ds" segment, but that will have already been restored for whatever
 	 * we're returning to (such as userspace): we can't trust it.  The %ss:
-	 * prefix makes sure we use the stack segment, which is still valid. */
+	 * prefix makes sure we use the stack segment, which is still valid.
+	 */
 	movl	%eax,%ss:lguest_data+LGUEST_DATA_irq_enabled
 	popl	%eax
 	iret
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 85307cc6e45..bfae139182f 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -697,7 +697,7 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code,
 	if (!printk_ratelimit())
 		return;
 
-	printk(KERN_CONT "%s%s[%d]: segfault at %lx ip %p sp %p error %lx",
+	printk("%s%s[%d]: segfault at %lx ip %p sp %p error %lx",
 		task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
 		tsk->comm, task_pid_nr(tsk), address,
 		(void *)regs->ip, (void *)regs->sp, error_code);
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
index 58f621e8191..2112ed55e7e 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -103,6 +103,7 @@ EXPORT_SYMBOL(kmap);
 EXPORT_SYMBOL(kunmap);
 EXPORT_SYMBOL(kmap_atomic);
 EXPORT_SYMBOL(kunmap_atomic);
+EXPORT_SYMBOL(kmap_atomic_prot);
 
 void __init set_highmem_pages_init(void)
 {
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 8e43bdd4545..af8f9650058 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -25,7 +25,7 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 	return pte;
 }
 
-void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
+void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
 {
 	pgtable_page_dtor(pte);
 	paravirt_release_pte(page_to_pfn(pte));
@@ -33,14 +33,14 @@ void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
 }
 
 #if PAGETABLE_LEVELS > 2
-void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
+void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
 {
 	paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
 	tlb_remove_page(tlb, virt_to_page(pmd));
 }
 
 #if PAGETABLE_LEVELS > 3
-void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
+void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
 {
 	paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
 	tlb_remove_page(tlb, virt_to_page(pud));
diff --git a/arch/x86/mm/srat_64.c b/arch/x86/mm/srat_64.c
index 2dfcbf9df2a..dbb5381f7b3 100644
--- a/arch/x86/mm/srat_64.c
+++ b/arch/x86/mm/srat_64.c
@@ -79,8 +79,10 @@ static __init void bad_srat(void)
 	acpi_numa = -1;
 	for (i = 0; i < MAX_LOCAL_APIC; i++)
 		apicid_to_node[i] = NUMA_NO_NODE;
-	for (i = 0; i < MAX_NUMNODES; i++)
-		nodes_add[i].start = nodes[i].end = 0;
+	for (i = 0; i < MAX_NUMNODES; i++) {
+		nodes[i].start = nodes[i].end = 0;
+		nodes_add[i].start = nodes_add[i].end = 0;
+	}
 	remove_all_active_ranges();
 }
 
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 0fb56db16d1..52e62e57fed 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -35,6 +35,7 @@
 #include <asm/pat.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
+#include <asm/io_apic.h>
 
 
 static int
@@ -227,6 +228,12 @@ void __init pcibios_resource_survey(void)
 	pcibios_allocate_resources(1);
 
 	e820_reserve_resources_late();
+	/*
+	 * Insert the IO APIC resources after PCI initialization has
+	 * occured to handle IO APICS that are mapped in on a BAR in
+	 * PCI space, but before trying to assign unassigned pci res.
+	 */
+	ioapic_insert_resources();
 }
 
 /**