xen: setup percpu data pointers

We need to access percpu data fairly early, so set up the percpu
registers as soon as possible.  We only need to load the appropriate
segment register.  We already have a GDT, but its hard to change it
early because we need to manipulate the pagetable to do so, and that
hasn't been set up yet.

Also, set the kernel stack when bringing up secondary CPUs.  If we
don't they all end up sharing the same stack...

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 88d5d5ec6beb..035582ae815d 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -170,8 +170,7 @@ static void __init xen_smp_prepare_boot_cpu(void)
 
         /* We've switched to the "real" per-cpu gdt, so make sure the
            old memory can be recycled */
-        make_lowmem_page_readwrite(__per_cpu_load +
-                                   (unsigned long)&per_cpu_var(gdt_page));
+        make_lowmem_page_readwrite(xen_initial_gdt);
 
         xen_setup_vcpu_info_placement();
 }
@@ -287,6 +286,9 @@ static int __cpuinit xen_cpu_up(unsigned int cpu)
         irq_ctx_init(cpu);
 #else
         clear_tsk_thread_flag(idle, TIF_FORK);
+        per_cpu(kernel_stack, cpu) =
+                (unsigned long)task_stack_page(idle) -
+                KERNEL_STACK_OFFSET + THREAD_SIZE;
 #endif
         xen_setup_timer(cpu);
         xen_init_lock_cpu(cpu);