[IA64] Fix CONFIG_PRINTK_TIME

There were two problems with enabling the PRINTK_TIME config
option:
1) The first calls to printk() occur before per-cpu data virtual
address is pinned into the TLB, so sched_clock() can fault.
2) sched_clock() is based on ar.itc, which may not be synchronized
across cpus.

Ken Chen started this patch, Tony Luck tinkered with it, and Jes
Sorensen perfected it.

Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S
index fbc7ea35dd57..f1778a84ea61 100644
--- a/arch/ia64/kernel/head.S
+++ b/arch/ia64/kernel/head.S
@@ -352,6 +352,7 @@ start_ap:
         mov ar.rsc=0            // place RSE in enforced lazy mode
         ;;
         loadrs                  // clear the dirty partition
+        mov IA64_KR(PER_CPU_DATA)=r0    // clear physical per-CPU base
         ;;
         mov ar.bspstore=r2      // establish the new RSE stack
         ;;