root/arch/x86/platform/olpc/xo1-wakeup.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 .text
   3 #include <linux/linkage.h>
   4 #include <asm/segment.h>
   5 #include <asm/page.h>
   6 #include <asm/pgtable_32.h>
   7 
   8         .macro writepost,value
   9                 movb $0x34, %al
  10                 outb %al, $0x70
  11                 movb $\value, %al
  12                 outb %al, $0x71
  13         .endm
  14 
  15 wakeup_start:
  16         # OFW lands us here, running in protected mode, with a
  17         # kernel-compatible GDT already setup.
  18 
  19         # Clear any dangerous flags
  20         pushl $0
  21         popfl
  22 
  23         writepost 0x31
  24 
  25         # Set up %cr3
  26         movl $initial_page_table - __PAGE_OFFSET, %eax
  27         movl %eax, %cr3
  28 
  29         movl saved_cr4, %eax
  30         movl %eax, %cr4
  31 
  32         movl saved_cr0, %eax
  33         movl %eax, %cr0
  34 
  35         # Control registers were modified, pipeline resync is needed
  36         jmp 1f
  37 1:
  38 
  39         movw    $__KERNEL_DS, %ax
  40         movw    %ax, %ss
  41         movw    %ax, %ds
  42         movw    %ax, %es
  43         movw    %ax, %fs
  44         movw    %ax, %gs
  45 
  46         lgdt    saved_gdt
  47         lidt    saved_idt
  48         lldt    saved_ldt
  49         ljmp    $(__KERNEL_CS),$1f
  50 1:
  51         movl    %cr3, %eax
  52         movl    %eax, %cr3
  53         wbinvd
  54 
  55         # Go back to the return point
  56         jmp ret_point
  57 
  58 save_registers:
  59         sgdt  saved_gdt
  60         sidt  saved_idt
  61         sldt  saved_ldt
  62 
  63         pushl %edx
  64         movl %cr4, %edx
  65         movl %edx, saved_cr4
  66 
  67         movl %cr0, %edx
  68         movl %edx, saved_cr0
  69 
  70         popl %edx
  71 
  72         movl %ebx, saved_context_ebx
  73         movl %ebp, saved_context_ebp
  74         movl %esi, saved_context_esi
  75         movl %edi, saved_context_edi
  76 
  77         pushfl
  78         popl saved_context_eflags
  79 
  80         ret
  81 
  82 restore_registers:
  83         movl saved_context_ebp, %ebp
  84         movl saved_context_ebx, %ebx
  85         movl saved_context_esi, %esi
  86         movl saved_context_edi, %edi
  87 
  88         pushl saved_context_eflags
  89         popfl
  90 
  91         ret
  92 
  93 ENTRY(do_olpc_suspend_lowlevel)
  94         call    save_processor_state
  95         call    save_registers
  96 
  97         # This is the stack context we want to remember
  98         movl %esp, saved_context_esp
  99 
 100         pushl   $3
 101         call    xo1_do_sleep
 102 
 103         jmp     wakeup_start
 104         .p2align 4,,7
 105 ret_point:
 106         movl    saved_context_esp, %esp
 107 
 108         writepost 0x32
 109 
 110         call    restore_registers
 111         call    restore_processor_state
 112         ret
 113 
 114 .data
 115 saved_gdt:             .long   0,0
 116 saved_idt:             .long   0,0
 117 saved_ldt:             .long   0
 118 saved_cr4:             .long   0
 119 saved_cr0:             .long   0
 120 saved_context_esp:     .long   0
 121 saved_context_edi:     .long   0
 122 saved_context_esi:     .long   0
 123 saved_context_ebx:     .long   0
 124 saved_context_ebp:     .long   0
 125 saved_context_eflags:  .long   0