[PATCH] i386: Relocatable kernel support

[safe/jmp/linux-2.6] / arch / i386 / boot / setup.S

diff --git a/arch/i386/boot/setup.S b/arch/i386/boot/setup.S
index 3aec453..9aa8b05 100644 (file)
--- 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