1 files changed, 62 insertions, 6 deletions

diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index be9d883c62ce..edef5084ce17 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -55,6 +55,12 @@
  */
 ENTRY(startup_32)
 
+#ifdef CONFIG_PARAVIRT
+        movl %cs, %eax
+        testl $0x3, %eax
+        jnz startup_paravirt
+#endif
+
 /*
  * Set segments to known values.
  */
@@ -302,6 +308,7 @@ is386:	movl $2,%ecx		# set MP
         movl %eax,%cr0
 
         call check_x87
+        call setup_pda
         lgdt cpu_gdt_descr
         lidt idt_descr
         ljmp $(__KERNEL_CS),$1f
@@ -312,12 +319,15 @@ is386:	movl $2,%ecx		# set MP
         movl %eax,%ds
         movl %eax,%es
 
-        xorl %eax,%eax                  # Clear FS/GS and LDT
+        xorl %eax,%eax                  # Clear FS and LDT
         movl %eax,%fs
-        movl %eax,%gs
         lldt %ax
+
+        movl $(__KERNEL_PDA),%eax
+        mov  %eax,%gs
+
         cld                     # gcc2 wants the direction flag cleared at all times
-        pushl %eax              # fake return address
+        pushl $0                # fake return address for unwinder
 #ifdef CONFIG_SMP
         movb ready, %cl
         movb $1, ready
@@ -346,6 +356,23 @@ check_x87:
         ret
 
 /*
+ * Point the GDT at this CPU's PDA.  On boot this will be
+ * cpu_gdt_table and boot_pda; for secondary CPUs, these will be
+ * that CPU's GDT and PDA.
+ */
+setup_pda:
+        /* get the PDA pointer */
+        movl start_pda, %eax
+
+        /* slot the PDA address into the GDT */
+        mov cpu_gdt_descr+2, %ecx
+        mov %ax, (__KERNEL_PDA+0+2)(%ecx)               /* base & 0x0000ffff */
+        shr $16, %eax
+        mov %al, (__KERNEL_PDA+4+0)(%ecx)               /* base & 0x00ff0000 */
+        mov %ah, (__KERNEL_PDA+4+3)(%ecx)               /* base & 0xff000000 */
+        ret
+
+/*
  *  setup_idt
  *
  *  sets up a idt with 256 entries pointing to
@@ -465,6 +492,33 @@ ignore_int:
 #endif
         iret
 
+#ifdef CONFIG_PARAVIRT
+startup_paravirt:
+        cld
+        movl $(init_thread_union+THREAD_SIZE),%esp
+
+        /* We take pains to preserve all the regs. */
+        pushl   %edx
+        pushl   %ecx
+        pushl   %eax
+
+        /* paravirt.o is last in link, and that probe fn never returns */
+        pushl   $__start_paravirtprobe
+1:
+        movl    0(%esp), %eax
+        pushl   (%eax)
+        movl    8(%esp), %eax
+        call    *(%esp)
+        popl    %eax
+
+        movl    4(%esp), %eax
+        movl    8(%esp), %ecx
+        movl    12(%esp), %edx
+
+        addl    $4, (%esp)
+        jmp     1b
+#endif
+
 /*
  * Real beginning of normal "text" segment
  */
@@ -484,6 +538,8 @@ ENTRY(empty_zero_page)
  * This starts the data section.
  */
 .data
+ENTRY(start_pda)
+        .long boot_pda
 
 ENTRY(stack_start)
         .long init_thread_union+THREAD_SIZE
@@ -525,7 +581,7 @@ idt_descr:
 
 # boot GDT descriptor (later on used by CPU#0):
         .word 0                         # 32 bit align gdt_desc.address
-cpu_gdt_descr:
+ENTRY(cpu_gdt_descr)
         .word GDT_ENTRIES*8-1
         .long cpu_gdt_table
 
@@ -584,8 +640,8 @@ ENTRY(cpu_gdt_table)
         .quad 0x00009a000000ffff        /* 0xc0 APM CS 16 code (16 bit) */
         .quad 0x004092000000ffff        /* 0xc8 APM DS    data */
 
-        .quad 0x0000920000000000        /* 0xd0 - ESPFIX 16-bit SS */
-        .quad 0x0000000000000000        /* 0xd8 - unused */
+        .quad 0x00c0920000000000        /* 0xd0 - ESPFIX SS */
+        .quad 0x00cf92000000ffff        /* 0xd8 - PDA */
         .quad 0x0000000000000000        /* 0xe0 - unused */
         .quad 0x0000000000000000        /* 0xe8 - unused */
         .quad 0x0000000000000000        /* 0xf0 - unused */