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

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);

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;
 }

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