6 files changed, 86 insertions, 19 deletions
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index b1942e222768..18e329ca108e 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -302,7 +302,7 @@ static efi_status_t setup_efi_pci(struct boot_params *params)
 		if (status != EFI_SUCCESS)
 			continue;
 
-		if (!attributes & EFI_PCI_IO_ATTRIBUTE_EMBEDDED_ROM)
+		if (!(attributes & EFI_PCI_IO_ATTRIBUTE_EMBEDDED_ROM))
 			continue;
 
 		if (!pci->romimage || !pci->romsize)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 4428fd178bce..6774c17a5576 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -340,9 +340,6 @@ int x86_setup_perfctr(struct perf_event *event)
 		/* BTS is currently only allowed for user-mode. */
 		if (!attr->exclude_kernel)
 			return -EOPNOTSUPP;
-
-		if (!attr->exclude_guest)
-			return -EOPNOTSUPP;
 	}
 
 	hwc->config |= config;
@@ -385,9 +382,6 @@ int x86_pmu_hw_config(struct perf_event *event)
 	if (event->attr.precise_ip) {
 		int precise = 0;
 
-		if (!event->attr.exclude_guest)
-			return -EOPNOTSUPP;
-
 		/* Support for constant skid */
 		if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) {
 			precise++;
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index ff84d5469d77..6ed91d9980e2 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1065,7 +1065,6 @@ ENTRY(xen_failsafe_callback)
 	lea 16(%esp),%esp
 	CFI_ADJUST_CFA_OFFSET -16
 	jz 5f
-	addl $16,%esp
 	jmp iret_exc
 5:	pushl_cfi $-1 /* orig_ax = -1 => not a system call */
 	SAVE_ALL
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 23ddd558fbd5..00f6c1472b85 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -610,6 +610,83 @@ static __init void reserve_ibft_region(void)
 
 static unsigned reserve_low = CONFIG_X86_RESERVE_LOW << 10;
 
+static bool __init snb_gfx_workaround_needed(void)
+{
+#ifdef CONFIG_PCI
+	int i;
+	u16 vendor, devid;
+	static const __initconst u16 snb_ids[] = {
+		0x0102,
+		0x0112,
+		0x0122,
+		0x0106,
+		0x0116,
+		0x0126,
+		0x010a,
+	};
+
+	/* Assume no if something weird is going on with PCI */
+	if (!early_pci_allowed())
+		return false;
+
+	vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
+	if (vendor != 0x8086)
+		return false;
+
+	devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
+	for (i = 0; i < ARRAY_SIZE(snb_ids); i++)
+		if (devid == snb_ids[i])
+			return true;
+#endif
+
+	return false;
+}
+
+/*
+ * Sandy Bridge graphics has trouble with certain ranges, exclude
+ * them from allocation.
+ */
+static void __init trim_snb_memory(void)
+{
+	static const __initconst unsigned long bad_pages[] = {
+		0x20050000,
+		0x20110000,
+		0x20130000,
+		0x20138000,
+		0x40004000,
+	};
+	int i;
+
+	if (!snb_gfx_workaround_needed())
+		return;
+
+	printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");
+
+	/*
+	 * Reserve all memory below the 1 MB mark that has not
+	 * already been reserved.
+	 */
+	memblock_reserve(0, 1<<20);
+	
+	for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
+		if (memblock_reserve(bad_pages[i], PAGE_SIZE))
+			printk(KERN_WARNING "failed to reserve 0x%08lx\n",
+			       bad_pages[i]);
+	}
+}
+
+/*
+ * Here we put platform-specific memory range workarounds, i.e.
+ * memory known to be corrupt or otherwise in need to be reserved on
+ * specific platforms.
+ *
+ * If this gets used more widely it could use a real dispatch mechanism.
+ */
+static void __init trim_platform_memory_ranges(void)
+{
+	trim_snb_memory();
+}
+
 static void __init trim_bios_range(void)
 {
 	/*
@@ -630,6 +707,7 @@ static void __init trim_bios_range(void)
 	 * take them out.
 	 */
 	e820_remove_range(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_RAM, 1);
+
 	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
 }
 
@@ -908,6 +986,8 @@ void __init setup_arch(char **cmdline_p)
 
 	setup_real_mode();
 
+	trim_platform_memory_ranges();
+
 	init_gbpages();
 
 	/* max_pfn_mapped is updated here */
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index cd3b2438a980..9b4d51d0c0d0 100644
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -165,10 +165,11 @@ void set_task_blockstep(struct task_struct *task, bool on)
 	 * Ensure irq/preemption can't change debugctl in between.
 	 * Note also that both TIF_BLOCKSTEP and debugctl should
 	 * be changed atomically wrt preemption.
-	 * FIXME: this means that set/clear TIF_BLOCKSTEP is simply
-	 * wrong if task != current, SIGKILL can wakeup the stopped
-	 * tracee and set/clear can play with the running task, this
-	 * can confuse the next __switch_to_xtra().
+	 *
+	 * NOTE: this means that set/clear TIF_BLOCKSTEP is only safe if
+	 * task is current or it can't be running, otherwise we can race
+	 * with __switch_to_xtra(). We rely on ptrace_freeze_traced() but
+	 * PTRACE_KILL is not safe.
 	 */
 	local_irq_disable();
 	debugctl = get_debugctlmsr();
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 4f7d2599b484..34bc4cee8887 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -432,13 +432,6 @@ static void __cpuinit xen_play_dead(void) /* used only with HOTPLUG_CPU */
 	play_dead_common();
 	HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
 	cpu_bringup();
-	/*
-	 * Balance out the preempt calls - as we are running in cpu_idle
-	 * loop which has been called at bootup from cpu_bringup_and_idle.
-	 * The cpucpu_bringup_and_idle called cpu_bringup which made a
-	 * preempt_disable() So this preempt_enable will balance it out.
-	 */
-	preempt_enable();
 }
 
 #else /* !CONFIG_HOTPLUG_CPU */