4 files changed, 50 insertions, 8 deletions
diff --git a/arch/x86/kernel/acpi/realmode/Makefile b/arch/x86/kernel/acpi/realmode/Makefile
index 092900854ac..1c31cc0e9de 100644
--- a/arch/x86/kernel/acpi/realmode/Makefile
+++ b/arch/x86/kernel/acpi/realmode/Makefile
@@ -6,7 +6,8 @@
 # for more details.
 #
 
-targets		:= wakeup.bin wakeup.elf
+always		:= wakeup.bin
+targets		:= wakeup.elf wakeup.lds
 
 wakeup-y	+= wakeup.o wakemain.o video-mode.o copy.o
 
@@ -48,7 +49,7 @@ LDFLAGS_wakeup.elf	:= -T
 
 CPPFLAGS_wakeup.lds += -P -C
 
-$(obj)/wakeup.elf: $(src)/wakeup.lds $(WAKEUP_OBJS) FORCE
+$(obj)/wakeup.elf: $(obj)/wakeup.lds $(WAKEUP_OBJS) FORCE
 	$(call if_changed,ld)
 
 OBJCOPYFLAGS_wakeup.bin	:= -O binary
diff --git a/arch/x86/kernel/acpi/realmode/wakeup.S b/arch/x86/kernel/acpi/realmode/wakeup.S
index f9b77fb37e5..3355973b12a 100644
--- 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
diff --git a/arch/x86/kernel/acpi/realmode/wakeup.h b/arch/x86/kernel/acpi/realmode/wakeup.h
index ef8166fe802..69d38d0b2b6 100644
--- a/arch/x86/kernel/acpi/realmode/wakeup.h
+++ b/arch/x86/kernel/acpi/realmode/wakeup.h
@@ -24,6 +24,11 @@ struct wakeup_header {
 	u32 realmode_flags;
 	u32 real_magic;
 	u16 trampoline_segment;	/* segment with trampoline code, 64-bit only */
+	u8  _pad1;
+	u8  wakeup_jmp;
+	u16 wakeup_jmp_off;
+	u16 wakeup_jmp_seg;
+	u64 wakeup_gdt[3];
 	u32 signature;		/* To check we have correct structure */
 } __attribute__((__packed__));
 
diff --git a/arch/x86/kernel/acpi/realmode/wakeup.lds.S b/arch/x86/kernel/acpi/realmode/wakeup.lds.S
index 22fab6c4be1..7da00b799cd 100644
--- a/arch/x86/kernel/acpi/realmode/wakeup.lds.S
+++ b/arch/x86/kernel/acpi/realmode/wakeup.lds.S
@@ -12,11 +12,6 @@ ENTRY(_start)
 
 SECTIONS
 {
-	. = HEADER_OFFSET;
-	.header : {
-		 *(.header)
-	}
-
 	. = 0;
 	.text : {
 		 *(.text*)
@@ -50,6 +45,11 @@ SECTIONS
 		__bss_end = .;
 	}
 
+	. = HEADER_OFFSET;
+	.header : {
+		*(.header)
+	}
+
 	. = ALIGN(16);
 	_end = .;