Merge branch 'core/topology' of git://git.kernel.org/pub/scm/linux/kernel/git/tip...

[pandora-kernel.git] / arch / x86 / kernel / acpi / realmode / wakeup.S

diff --git a/arch/x86/kernel/acpi/realmode/wakeup.S b/arch/x86/kernel/acpi/realmode/wakeup.S
index f9b77fb..3355973 100644 (file)
--- a/arch/x86/kernel/acpi/realmode/wakeup.S
+++ b/arch/x86/kernel/acpi/realmode/wakeup.S
@@ -5,6 +5,7 @@
 #include <asm/msr-index.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
+#include <asm/processor-flags.h>
 
        .code16
        .section ".header", "a"
@@ -24,6 +25,11 @@ pmode_gdt:   .quad   0
 realmode_flags:        .long   0
 real_magic:    .long   0
 trampoline_segment:    .word 0
+_pad1:         .byte   0
+wakeup_jmp:    .byte   0xea    /* ljmpw */
+wakeup_jmp_off:        .word   3f
+wakeup_jmp_seg:        .word   0
+wakeup_gdt:    .quad   0, 0, 0
 signature:     .long   0x51ee1111
 
        .text
@@ -34,11 +40,34 @@ _start:
        cli
        cld
 
+       /* Apparently some dimwit BIOS programmers don't know how to
+          program a PM to RM transition, and we might end up here with
+          junk in the data segment descriptor registers.  The only way
+          to repair that is to go into PM and fix it ourselves... */
+       movw    $16, %cx
+       lgdtl   %cs:wakeup_gdt
+       movl    %cr0, %eax
+       orb     $X86_CR0_PE, %al
+       movl    %eax, %cr0
+       jmp     1f
+1:     ljmpw   $8, $2f
+2:
+       movw    %cx, %ds
+       movw    %cx, %es
+       movw    %cx, %ss
+       movw    %cx, %fs
+       movw    %cx, %gs
+
+       andb    $~X86_CR0_PE, %al
+       movl    %eax, %cr0
+       jmp     wakeup_jmp
+3:
        /* Set up segments */
        movw    %cs, %ax
        movw    %ax, %ds
        movw    %ax, %es
        movw    %ax, %ss
+       lidtl   wakeup_idt
 
        movl    $wakeup_stack_end, %esp
 
@@ -98,7 +127,14 @@ bogus_real_magic:
        jmp     1b
 
        .data
-       .balign 4
+       .balign 8
+
+       /* This is the standard real-mode IDT */
+wakeup_idt:
+       .word   0xffff          /* limit */
+       .long   0               /* address */
+       .word   0
+
        .globl  HEAP, heap_end
 HEAP:
        .long   wakeup_heap