1 files changed, 23 insertions, 1 deletions

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 0e275d495563..7ee0363871e8 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -204,6 +204,23 @@ ENTRY(secondary_startup_64)
         pushq $0
         popfq
 
+#ifdef CONFIG_SMP
+        /*
+         * early_gdt_base should point to the gdt_page in static percpu init
+         * data area.  Computing this requires two symbols - __per_cpu_load
+         * and per_cpu__gdt_page.  As linker can't do no such relocation, do
+         * it by hand.  As early_gdt_descr is manipulated by C code for
+         * secondary CPUs, this should be done only once for the boot CPU
+         * when early_gdt_descr_base contains zero.
+         */
+        movq    early_gdt_descr_base(%rip), %rax
+        testq   %rax, %rax
+        jnz     1f
+        movq    $__per_cpu_load, %rax
+        addq    $per_cpu__gdt_page, %rax
+        movq    %rax, early_gdt_descr_base(%rip)
+1:
+#endif
         /*
          * We must switch to a new descriptor in kernel space for the GDT
          * because soon the kernel won't have access anymore to the userspace
@@ -401,7 +418,12 @@ NEXT_PAGE(level2_spare_pgt)
         .globl early_gdt_descr
 early_gdt_descr:
         .word   GDT_ENTRIES*8-1
-        .quad   per_cpu__gdt_page
+#ifdef CONFIG_SMP
+early_gdt_descr_base:
+        .quad   0x0000000000000000
+#else
+        .quad   per_cpu__gdt_page
+#endif
 
 ENTRY(phys_base)
         /* This must match the first entry in level2_kernel_pgt */