Merge tag 'stable/for-linus-3.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen fixes from David Vrabel:
 "Xen regression and bug fixes for 3.15-rc1:

   - fix completely broken 32-bit PV guests caused by x86 refactoring
     32-bit thread_info.
   - only enable ticketlock slow path on Xen (not bare metal)
   - fix two bugs with PV guests not shutting down when requested
   - fix a minor memory leak in xen-pciback error path"

* tag 'stable/for-linus-3.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/manage: Poweroff forcefully if user-space is not yet up.
  xen/xenbus: Avoid synchronous wait on XenBus stalling shutdown/restart.
  xen/spinlock: Don't enable them unconditionally.
  xen-pciback: silence an unwanted debug printk
  xen: fix memory leak in __xen_pcibk_add_pci_dev()
  x86/xen: Fix 32-bit PV guests's usage of kernel_stack

3 files changed, 23 insertions, 10 deletions

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index a18eadd8bb40..7005974c3ff3 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -441,10 +441,11 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
         irq_ctx_init(cpu);
 #else
         clear_tsk_thread_flag(idle, TIF_FORK);
+#endif
         per_cpu(kernel_stack, cpu) =
                 (unsigned long)task_stack_page(idle) -
                 KERNEL_STACK_OFFSET + THREAD_SIZE;
-#endif
+
         xen_setup_runstate_info(cpu);
         xen_setup_timer(cpu);
         xen_init_lock_cpu(cpu);
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 4d3acc34a998..0ba5f3b967f0 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -274,7 +274,7 @@ void __init xen_init_spinlocks(void)
                 printk(KERN_DEBUG "xen: PV spinlocks disabled\n");
                 return;
         }
-
+        printk(KERN_DEBUG "xen: PV spinlocks enabled\n");
         pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
         pv_lock_ops.unlock_kick = xen_unlock_kick;
 }
@@ -290,6 +290,9 @@ static __init int xen_init_spinlocks_jump(void)
         if (!xen_pvspin)
                 return 0;
 
+        if (!xen_domain())
+                return 0;
+
         static_key_slow_inc(&paravirt_ticketlocks_enabled);
         return 0;
 }
diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S
index 33ca6e42a4ca..fd92a64d748e 100644
--- a/arch/x86/xen/xen-asm_32.S
+++ b/arch/x86/xen/xen-asm_32.S
@@ -75,6 +75,17 @@ ENDPROC(xen_sysexit)
  * stack state in whatever form its in, we keep things simple by only
  * using a single register which is pushed/popped on the stack.
  */
+
+.macro POP_FS
+1:
+        popw %fs
+.pushsection .fixup, "ax"
+2:      movw $0, (%esp)
+        jmp 1b
+.popsection
+        _ASM_EXTABLE(1b,2b)
+.endm
+
 ENTRY(xen_iret)
         /* test eflags for special cases */
         testl $(X86_EFLAGS_VM | XEN_EFLAGS_NMI), 8(%esp)
@@ -83,15 +94,13 @@ ENTRY(xen_iret)
         push %eax
         ESP_OFFSET=4    # bytes pushed onto stack
 
-        /*
-         * Store vcpu_info pointer for easy access.  Do it this way to
-         * avoid having to reload %fs
-         */
+        /* Store vcpu_info pointer for easy access */
 #ifdef CONFIG_SMP
-        GET_THREAD_INFO(%eax)
-        movl %ss:TI_cpu(%eax), %eax
-        movl %ss:__per_cpu_offset(,%eax,4), %eax
-        mov %ss:xen_vcpu(%eax), %eax
+        pushw %fs
+        movl $(__KERNEL_PERCPU), %eax
+        movl %eax, %fs
+        movl %fs:xen_vcpu, %eax
+        POP_FS
 #else
         movl %ss:xen_vcpu, %eax
 #endif