arch/x86/realmode/rm/wakeup/wakeup_asm.S

   1 /*
   2  * ACPI wakeup real mode startup stub
   3  */
   4 #include <linux/linkage.h>
   5 #include <asm/segment.h>
   6 #include <asm/msr-index.h>
   7 #include <asm/page_types.h>
   8 #include <asm/pgtable_types.h>
   9 #include <asm/processor-flags.h>
  10 #include "../realmode.h"
  11 #include "wakeup.h"
  12
  13         .code16
  14
  15 /* This should match the structure in wakeup.h */
  16         .section ".data", "aw"
  17
  18         .balign 16
  19 GLOBAL(wakeup_header)
  20         video_mode:     .short  0       /* Video mode number */
  21         pmode_entry:    .long   0
  22         pmode_cs:       .short  __KERNEL_CS
  23         pmode_cr0:      .long   0       /* Saved %cr0 */
  24         pmode_cr3:      .long   0       /* Saved %cr3 */
  25         pmode_cr4:      .long   0       /* Saved %cr4 */
  26         pmode_efer:     .quad   0       /* Saved EFER */
  27         pmode_gdt:      .quad   0
  28         pmode_misc_en:  .quad   0       /* Saved MISC_ENABLE MSR */
  29         pmode_behavior: .long   0       /* Wakeup behavior flags */
  30         realmode_flags: .long   0
  31         real_magic:     .long   0
  32         signature:      .long   WAKEUP_HEADER_SIGNATURE
  33 END(wakeup_header)
  34
  35         .text
  36         .code16
  37
  38         .balign 16
  39 ENTRY(wakeup_start)
  40         cli
  41         cld
  42
  43         LJMPW_RM(3f)
  44 3:
  45         /* Apparently some dimwit BIOS programmers don't know how to
  46            program a PM to RM transition, and we might end up here with
  47            junk in the data segment descriptor registers.  The only way
  48            to repair that is to go into PM and fix it ourselves... */
  49         movw    $16, %cx
  50         lgdtl   %cs:wakeup_gdt
  51         movl    %cr0, %eax
  52         orb     $X86_CR0_PE, %al
  53         movl    %eax, %cr0
  54         ljmpw   $8, $2f
  55 2:
  56         movw    %cx, %ds
  57         movw    %cx, %es
  58         movw    %cx, %ss
  59         movw    %cx, %fs
  60         movw    %cx, %gs
  61
  62         andb    $~X86_CR0_PE, %al
  63         movl    %eax, %cr0
  64         LJMPW_RM(3f)
  65 3:
  66         /* Set up segments */
  67         movw    %cs, %ax
  68         movw    %ax, %ss
  69         movl    $rm_stack_end, %esp
  70         movw    %ax, %ds
  71         movw    %ax, %es
  72         movw    %ax, %fs
  73         movw    %ax, %gs
  74
  75         lidtl   wakeup_idt
  76
  77         /* Clear the EFLAGS */
  78         pushl   $0
  79         popfl
  80
  81         /* Check header signature... */
  82         movl    signature, %eax
  83         cmpl    $WAKEUP_HEADER_SIGNATURE, %eax
  84         jne     bogus_real_magic
  85
  86         /* Check we really have everything... */
  87         movl    end_signature, %eax
  88         cmpl    $WAKEUP_END_SIGNATURE, %eax
  89         jne     bogus_real_magic
  90
  91         /* Call the C code */
  92         calll   main
  93
  94         /* Restore MISC_ENABLE before entering protected mode, in case
  95            BIOS decided to clear XD_DISABLE during S3. */
  96         movl    pmode_behavior, %eax
  97         btl     $WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE, %eax
  98         jnc     1f
  99
 100         movl    pmode_misc_en, %eax
 101         movl    pmode_misc_en + 4, %edx
 102         movl    $MSR_IA32_MISC_ENABLE, %ecx
 103         wrmsr
 104 1:
 105
 106         /* Do any other stuff... */
 107
 108 #ifndef CONFIG_64BIT
 109         /* This could also be done in C code... */
 110         movl    pmode_cr3, %eax
 111         movl    %eax, %cr3
 112
 113         movl    pmode_cr4, %ecx
 114         jecxz   1f
 115         movl    %ecx, %cr4
 116 1:
 117         movl    pmode_efer, %eax
 118         movl    pmode_efer + 4, %edx
 119         movl    %eax, %ecx
 120         orl     %edx, %ecx
 121         jz      1f
 122         movl    $MSR_EFER, %ecx
 123         wrmsr
 124 1:
 125
 126         lgdtl   pmode_gdt
 127
 128         /* This really couldn't... */
 129         movl    pmode_entry, %eax
 130         movl    pmode_cr0, %ecx
 131         movl    %ecx, %cr0
 132         ljmpl   $__KERNEL_CS, $pa_startup_32
 133         /* -> jmp *%eax in trampoline_32.S */
 134 #else
 135         jmp     trampoline_data
 136 #endif
 137
 138 bogus_real_magic:
 139 1:
 140         hlt
 141         jmp     1b
 142
 143         .section ".rodata","a"
 144
 145         /*
 146          * Set up the wakeup GDT.  We set these up as Big Real Mode,
 147          * that is, with limits set to 4 GB.  At least the Lenovo
 148          * Thinkpad X61 is known to need this for the video BIOS
 149          * initialization quirk to work; this is likely to also
 150          * be the case for other laptops or integrated video devices.
 151          */
 152
 153         .balign 16
 154 GLOBAL(wakeup_gdt)
 155         .word   3*8-1           /* Self-descriptor */
 156         .long   pa_wakeup_gdt
 157         .word   0
 158
 159         .word   0xffff          /* 16-bit code segment @ real_mode_base */
 160         .long   0x9b000000 + pa_real_mode_base
 161         .word   0x008f          /* big real mode */
 162
 163         .word   0xffff          /* 16-bit data segment @ real_mode_base */
 164         .long   0x93000000 + pa_real_mode_base
 165         .word   0x008f          /* big real mode */
 166 END(wakeup_gdt)
 167
 168         .section ".rodata","a"
 169         .balign 8
 170
 171         /* This is the standard real-mode IDT */
 172         .balign 16
 173 GLOBAL(wakeup_idt)
 174         .word   0xffff          /* limit */
 175         .long   0               /* address */
 176         .word   0
 177 END(wakeup_idt)
 178
 179         .section ".signature","a"
 180 end_signature:
 181         .long   WAKEUP_END_SIGNATURE