1 files changed, 21 insertions, 8 deletions

diff --git a/arch/i386/boot/setup.S b/arch/i386/boot/setup.S
index 3aec4538a113..9aa8b0518184 100644
--- a/arch/i386/boot/setup.S
+++ b/arch/i386/boot/setup.S
@@ -588,11 +588,6 @@ rmodeswtch_normal:
         call    default_switch
 
 rmodeswtch_end:
-# we get the code32 start address and modify the below 'jmpi'
-# (loader may have changed it)
-        movl    %cs:code32_start, %eax
-        movl    %eax, %cs:code32
-
 # Now we move the system to its rightful place ... but we check if we have a
 # big-kernel. In that case we *must* not move it ...
         testb   $LOADED_HIGH, %cs:loadflags
@@ -788,11 +783,12 @@ a20_err_msg:
 a20_done:
 
 #endif /* CONFIG_X86_VOYAGER */
-# set up gdt and idt
+# set up gdt and idt and 32bit start address
         lidt    idt_48                          # load idt with 0,0
         xorl    %eax, %eax                      # Compute gdt_base
         movw    %ds, %ax                        # (Convert %ds:gdt to a linear ptr)
         shll    $4, %eax
+        addl    %eax, code32
         addl    $gdt, %eax
         movl    %eax, (gdt_48+2)
         lgdt    gdt_48                          # load gdt with whatever is
@@ -851,9 +847,26 @@ flush_instr:
 #       Manual, Mixing 16-bit and 32-bit code, page 16-6)
 
         .byte 0x66, 0xea                        # prefix + jmpi-opcode
-code32: .long   0x1000                          # will be set to 0x100000
-                                                # for big kernels
+code32: .long   startup_32                      # will be set to %cs+startup_32
         .word   __BOOT_CS
+.code32
+startup_32:
+        movl $(__BOOT_DS), %eax
+        movl %eax, %ds
+        movl %eax, %es
+        movl %eax, %fs
+        movl %eax, %gs
+        movl %eax, %ss
+
+        xorl %eax, %eax
+1:      incl %eax                               # check that A20 really IS enabled
+        movl %eax, 0x00000000                   # loop forever if it isn't
+        cmpl %eax, 0x00100000
+        je 1b
+
+        # Jump to the 32bit entry point
+        jmpl *(code32_start - start + (DELTA_INITSEG << 4))(%esi)
+.code16
 
 # Here's a bunch of information about your current kernel..
 kernel_version: .ascii  UTS_RELEASE