diff options
Diffstat (limited to 'arch/x86/kernel/acpi/realmode/wakeup.S')
| -rw-r--r-- | arch/x86/kernel/acpi/realmode/wakeup.S | 38 |
1 files changed, 37 insertions, 1 deletions
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 |