x86: merge 64 and 32 SMP percpu handling

Now that pda is allocated as part of percpu, percpu doesn't need to be
accessed through pda.  Unify x86_64 SMP percpu access with x86_32 SMP
one.  Other than the segment register, operand size and the base of
percpu symbols, they behave identical now.

This patch replaces now unnecessary pda->data_offset with a dummy
field which is necessary to keep stack_canary at its place.  This
patch also moves per_cpu_offset initialization out of init_gdt() into
setup_per_cpu_areas().  Note that this change also necessitates
explicit per_cpu_offset initializations in voyager_smp.c.

With this change, x86_OP_percpu()'s are as efficient on x86_64 as on
x86_32 and also x86_64 can use assembly PER_CPU macros.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/mach-voyager/voyager_smp.c b/arch/x86/mach-voyager/voyager_smp.c
index 9840b7ec749a..1a48368acb09 100644
--- a/arch/x86/mach-voyager/voyager_smp.c
+++ b/arch/x86/mach-voyager/voyager_smp.c
@@ -531,6 +531,7 @@ static void __init do_boot_cpu(__u8 cpu)
         stack_start.sp = (void *)idle->thread.sp;
 
         init_gdt(cpu);
+        per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
         per_cpu(current_task, cpu) = idle;
         early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
         irq_ctx_init(cpu);
@@ -1748,6 +1749,7 @@ static void __init voyager_smp_prepare_cpus(unsigned int max_cpus)
 static void __cpuinit voyager_smp_prepare_boot_cpu(void)
 {
         init_gdt(smp_processor_id());
+        per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
         switch_to_new_gdt();
 
         cpu_set(smp_processor_id(), cpu_online_map);