EdkCompatibilityPkg/Foundation/Library/Thunk16/X64/Thunk16.S

   1 #*****************************************************************************
   2 #*
   3 #*   Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>
   4 #*   This program and the accompanying materials
   5 #*   are licensed and made available under the terms and conditions of the BSD License
   6 #*   which accompanies this distribution.  The full text of the license may be found at
   7 #*   http://opensource.org/licenses/bsd-license.php
   8 #*
   9 #*   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 #*   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #*
  12 #*   Module Name:
  13 #*
  14 #*    Thunk.S
  15 #*
  16 #*   Abstract:
  17 #*
  18 #*    Real mode thunk
  19 #*
  20 #*****************************************************************************
  21 #include <EfiBind.h>
  22
  23
  24
  25     .data
  26
  27 .globl ASM_PFX(mCode16Size)
  28
  29 .data
  30 mCode16Size:    .long   _Code16End - _Code16Addr
  31
  32
  33 NullSegSel:     .quad   0
  34 _16CsSegSel:
  35                 .word   -1
  36                 .word   0
  37                 .byte   0
  38                 .byte   0x9b
  39                 .byte   0x8f            #16-bit segment
  40                 .byte   0
  41 _16DsSegSel:
  42                 .word   -1
  43                 .word   0
  44                 .byte   0
  45                 .byte   0x93
  46                 .byte   0x8f           #16-bit segment
  47                 .byte   0
  48
  49 _16Gdtr:
  50                 .word      _16Gdtr - NullSegSel - 1
  51                 .long      NullSegSel
  52     .code:
  53
  54 #IA32_REGS   STRUC   4t
  55 #_EDI        DD      ?
  56 #_ESI        DD      ?
  57 #_EBP        DD      ?
  58 #_ESP        DD      ?
  59 #_EBX        DD      ?
  60 #_EDX        DD      ?
  61 #_ECX        DD      ?
  62 #_EAX        DD      ?
  63 #_DS         DW      ?
  64 #_ES         DW      ?
  65 #_FS         DW      ?
  66 #_GS         DW      ?
  67 #_RFLAGS     DQ      ?
  68 #_EIP        DD      ?
  69 #_CS         DW      ?
  70 #_SS         DW      ?
  71 #IA32_REGS   ENDS
  72
  73 #_STK16      STRUC   1t
  74 #RetEip      DD      ?
  75 #RetCs       DW      ?
  76 #ThunkFlags  DW      ?
  77 #SavedGdtr   FWORD   ?
  78 #Resvd1      DW      ?
  79 #SavedCr0    DD      ?
  80 #SavedCr4    DD      ?
  81 #_STK16      ENDS
  82
  83 ASM_PFX(Thunk16):
  84       push   %rbp
  85       push   %rbx
  86       push   %rsi
  87       push   %rdi
  88       push   %r12
  89       push   %r13
  90       push   %r14
  91       push   %r15
  92       pushq  %fs
  93       pushq  %gs
  94       movl   %ds,%r12d
  95       movl   %es,%r13d
  96       movl   %ss,%r14d
  97       mov    %rsp,%r15
  98       mov    %rcx,%rsi
  99       movzwq 0x36(%rsi),%r10            #movzx   r10, (IA32_REGS ptr [rsi])._SS
 100       xor    %rdi,%rdi
 101       mov    0xc(%rsi),%edi             #mov     edi, (IA32_REGS ptr [rsi])._ESP
 102       add    $0xffffffffffffffb0,%rdi   #add     rdi, - sizeof (IA32_REGS) - sizeof (_STK16)
 103       push   %rdi
 104       imul   $0x10,%r10,%rax
 105       add    %rax,%rdi
 106       pushq  $0xe                       #push    sizeof (IA32_REGS) / 4
 107       pop    %rcx
 108       rep movsl %ds:(%rsi),%es:(%rdi)
 109       pop    %rbx                       #rbx <- 16-bit stack offset
 110       lea    Label,%eax                 #42 <_Thunk16+0x42>
 111       stos   %eax,%es:(%rdi)
 112       movl   %cs,%eax                   #return segment
 113       stos   %ax,%es:(%rdi)
 114       mov    %edx,%eax                  #THUNK Flags
 115       stos   %ax,%es:(%rdi)
 116       sgdt  0x58(%rsp)                  #save GDTR
 117       mov    0x58(%rsp),%rax
 118       stos   %rax,%es:(%rdi)
 119       mov    %cr0,%rax                  #save CR0
 120       mov    %eax,%esi                  #esi <- CR0 to set
 121       stos   %eax,%es:(%rdi)
 122       mov    %cr4,%rax                  #save CR4
 123       stos   %eax,%es:(%rdi)
 124       sidt   0x58(%rsp)                 #save IDTR
 125       and    $0x7ffffffe,%esi           #clear PE & PG bits
 126       mov    %r10,%rdi                  #rdi <- 16-bit stack segment
 127       shl    $0x10,%r8
 128       push   %r8                        #far jmp address
 129       lea    Label_16Bit,%eax
 130       push   %rax
 131       movw   $0x8,0x4(%rsp)
 132       lgdt   _16Gdtr                    #bugbug: may not match.
 133       lret
 134 Label_16Bit:
 135       .byte  0x66
 136       movl   $0xc0000080,%ecx
 137       mov    %rsi,%cr0                  #disable PE & PG
 138       rdmsr
 139       and    $0xfe,%ah
 140       wrmsr                             #clear LME bit
 141       mov    %cr4,%rax
 142       and    $0xcf,%al                  #clear PAE & PSE
 143       mov    %rax,%cr4
 144       lret
 145
 146 Label:
 147       xor    %rax,%rax
 148       movl   %ss,%eax
 149       shl    $0x4,%eax
 150       add    %esp,%eax
 151       mov    %r15,%rsp
 152       lidt   0x58(%rsp)
 153       movl   %r12d,%ds
 154       movl   %r13d,%es
 155       movl   %r14d,%ss
 156       popq   %gs
 157       popq   %fs
 158       pop    %r15
 159       pop    %r14
 160       pop    %r13
 161       pop    %r12
 162       pop    %rdi
 163       pop    %rsi
 164       pop    %rbx
 165       pop    %rbp
 166       retq
 167
 168
 169     .p2align 4
 170
 171 _Code16Addr:
 172 ASM_PFX(RealMode):
 173     movl   %edi,%ss
 174     mov    %bx,%sp                     #set up 16-bit stack
 175    .byte   0x2e
 176    .byte   0x0f
 177    .byte   0x01
 178    .byte   0x1e
 179    .word   _16Idtr - _Code16Addr       #lidt _16Idtr
 180    .byte   0x66
 181    .byte   0x61                        #popad
 182    .byte   0x1f                        #pop ds
 183    .byte   0x07                        #pop es
 184     popq   %fs
 185     popq   %gs
 186     add    $0x8,%esp                   #skip RFLAGS
 187    .byte   0x67                        #test [esp + 0eh], 1
 188    .byte   0xf7
 189    .byte   0x44
 190    .byte   0x24
 191    .byte   0x0e
 192    .byte   0x01
 193    .byte   0x00
 194     jz      1f
 195     pushfq                             #pushf, actually
 196 1:
 197    .byte   0x0e                        #push cs
 198    .byte   0x68                        #push /iw
 199    .word   FarCallRet - _Code16Addr
 200     jz     2f
 201    .byte   0x66
 202     ljmp   *6(%esp)
 203 2:
 204    .byte   0x66
 205     ljmp   *4(%esp)
 206 FarCallRet:
 207    .byte   0x66
 208     push   $0x00                       #push a dword of zero
 209    .byte   0x66
 210     pushf                              #pushfd, actually
 211     pushq  %gs
 212     pushq  %fs
 213    .byte   0x06                        #push %es
 214    .byte   0x1e                        #push %ds
 215    .byte   0x66
 216    .byte   0x60
 217     cli
 218    .byte   0x66                        #sizeof (IA32_REGS) = 13 * 4 = 52
 219     lgdt   64(%esp)                    #lgdt    (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedGdtr
 220    .byte   0x66
 221     mov    76(%esp), %eax
 222     mov    %rax, %cr4
 223    .byte   0x66
 224     mov    $0xc0000080, %ecx
 225     rdmsr
 226     orb    $1, %ah
 227     wrmsr
 228    .byte   0x66
 229     mov    72(%esp), %eax
 230     mov    %rax, %cr0                   #restore CR0
 231    .byte   0x66
 232     ljmpl  *52(%esp)
 233
 234 _16Idtr:
 235    .word 0x3ff                          #FWORD   (1 SHL 10) - 1
 236    .byte 0x00