1 files changed, 11 insertions, 4 deletions

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 2f0ab0089883..7a995d0e9f78 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -245,10 +245,13 @@ ENTRY(secondary_startup_64)
 
         /* Set up %gs.
          *
-         * %gs should point to the pda.  For initial boot, make %gs point
-         * to the _boot_cpu_pda in data section.  For a secondary CPU,
-         * initial_gs should be set to its pda address before the CPU runs
-         * this code.
+         * On SMP, %gs should point to the per-cpu area.  For initial
+         * boot, make %gs point to the init data section.  For a
+         * secondary CPU,initial_gs should be set to its pda address
+         * before the CPU runs this code.
+         *
+         * On UP, initial_gs points to _boot_cpu_pda and doesn't
+         * change.
          */
         movl    $MSR_GS_BASE,%ecx
         movq    initial_gs(%rip),%rax
@@ -278,7 +281,11 @@ ENTRY(secondary_startup_64)
         ENTRY(initial_code)
         .quad   x86_64_start_kernel
         ENTRY(initial_gs)
+#ifdef CONFIG_SMP
+        .quad   __per_cpu_load
+#else
         .quad   _boot_cpu_pda
+#endif
         __FINITDATA
 
         ENTRY(stack_start)