Merge tag 'stable/for-linus-3.6-rc0-tag' of git://git.kernel.org/pub/…

…scm/linux/kernel/git/konrad/xen

Pull Xen update from Konrad Rzeszutek Wilk:
 "Features:
   * Performance improvement to lower the amount of traps the hypervisor
     has to do 32-bit guests.  Mainly for setting PTE entries and
     updating TLS descriptors.
   * MCE polling driver to collect hypervisor MCE buffer and present
     them to /dev/mcelog.
   * Physical CPU online/offline support.  When an privileged guest is
     booted it is present with virtual CPUs, which might have an 1:1 to
     physical CPUs but usually don't.  This provides mechanism to
     offline/online physical CPUs.
  Bug-fixes for:
   * Coverity found fixes in the console and ACPI processor driver.
   * PVonHVM kexec fixes along with some cleanups.
   * Pages that fall within E820 gaps and non-RAM regions (and had been
     released to hypervisor) would be populated back, but potentially in
     non-RAM regions."

* tag 'stable/for-linus-3.6-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: populate correct number of pages when across mem boundary (v2)
  xen PVonHVM: move shared_info to MMIO before kexec
  xen: simplify init_hvm_pv_info
  xen: remove cast from HYPERVISOR_shared_info assignment
  xen: enable platform-pci only in a Xen guest
  xen/pv-on-hvm kexec: shutdown watches from old kernel
  xen/x86: avoid updating TLS descriptors if they haven't changed
  xen/x86: add desc_equal() to compare GDT descriptors
  xen/mm: zero PTEs for non-present MFNs in the initial page table
  xen/mm: do direct hypercall in xen_set_pte() if batching is unavailable
  xen/hvc: Fix up checks when the info is allocated.
  xen/acpi: Fix potential memory leak.
  xen/mce: add .poll method for mcelog device driver
  xen/mce: schedule a workqueue to avoid sleep in atomic context
  xen/pcpu: Xen physical cpus online/offline sys interface
  xen/mce: Register native mce handler as vMCE bounce back point
  x86, MCE, AMD: Adjust initcall sequence for xen
  xen/mce: Add mcelog support for Xen platform

Documentation/ABI/testing/sysfs-devices-system-xen_cpu

@@ -0,0 +1,20 @@
+What:		/sys/devices/system/xen_cpu/
+Date:		May 2012
+Contact:	Liu, Jinsong <jinsong.liu@intel.com>
+Description:
+		A collection of global/individual Xen physical cpu attributes
+
+		Individual physical cpu attributes are contained in
+		subdirectories named by the Xen's logical cpu number, e.g.:
+		/sys/devices/system/xen_cpu/xen_cpu#/
+
+
+What:		/sys/devices/system/xen_cpu/xen_cpu#/online
+Date:		May 2012
+Contact:	Liu, Jinsong <jinsong.liu@intel.com>
+Description:
+		Interface to online/offline Xen physical cpus
+
+		When running under Xen platform, it provide user interface
+		to online/offline physical cpus, except cpu0 due to several
+		logic restrictions and assumptions.

arch/x86/include/asm/xen/hypercall.h

@@ -48,6 +48,7 @@
 #include <xen/interface/sched.h>
 #include <xen/interface/physdev.h>
 #include <xen/interface/platform.h>
+#include <xen/interface/xen-mca.h>
 
 /*
  * The hypercall asms have to meet several constraints:
@@ -301,6 +302,13 @@ HYPERVISOR_set_timer_op(u64 timeout)
 	return _hypercall2(long, set_timer_op, timeout_lo, timeout_hi);
 }
 
+static inline int
+HYPERVISOR_mca(struct xen_mc *mc_op)
+{
+	mc_op->interface_version = XEN_MCA_INTERFACE_VERSION;
+	return _hypercall1(int, mca, mc_op);
+}
+
 static inline int
 HYPERVISOR_dom0_op(struct xen_platform_op *platform_op)
 {

arch/x86/kernel/cpu/mcheck/mce.c

@@ -60,8 +60,6 @@ static DEFINE_MUTEX(mce_chrdev_read_mutex);
 
 int mce_disabled __read_mostly;
 
-#define MISC_MCELOG_MINOR	227
-
 #define SPINUNIT 100	/* 100ns */
 
 atomic_t mce_entry;
@@ -2346,7 +2344,7 @@ static __init int mcheck_init_device(void)
 
 	return err;
 }
-device_initcall(mcheck_init_device);
+device_initcall_sync(mcheck_init_device);
 
 /*
  * Old style boot options parsing. Only for compatibility.

arch/x86/kernel/cpu/mcheck/mce_amd.c

@@ -759,4 +759,24 @@ static __init int threshold_init_device(void)
 
 	return 0;
 }
-device_initcall(threshold_init_device);
+/*
+ * there are 3 funcs which need to be _initcalled in a logic sequence:
+ * 1. xen_late_init_mcelog
+ * 2. mcheck_init_device
+ * 3. threshold_init_device
+ *
+ * xen_late_init_mcelog must register xen_mce_chrdev_device before
+ * native mce_chrdev_device registration if running under xen platform;
+ *
+ * mcheck_init_device should be inited before threshold_init_device to
+ * initialize mce_device, otherwise a NULL ptr dereference will cause panic.
+ *
+ * so we use following _initcalls
+ * 1. device_initcall(xen_late_init_mcelog);
+ * 2. device_initcall_sync(mcheck_init_device);
+ * 3. late_initcall(threshold_init_device);
+ *
+ * when running under xen, the initcall order is 1,2,3;
+ * on baremetal, we skip 1 and we do only 2 and 3.
+ */
+late_initcall(threshold_init_device);