projects / mirror_edk2.git / blame
| Commit | Line | Data |
|---|---|---|
| e1f414b6 | 1 | #------------------------------------------------------------------------------\r |
| 2 | #\r | |
| c577049a | 3 | # Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>\r |
| bb817c56 | 4 | # This program and the accompanying materials\r |
| e1f414b6 | 5 | # are licensed and made available under the terms and conditions of the BSD License\r |
| 6 | # which accompanies this distribution. The full text of the license may be found at\r | |
| e4a34497 | 7 | # http://opensource.org/licenses/bsd-license.php.\r |
| e1f414b6 | 8 | #\r |
| 9 | # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
| 10 | # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
| 11 | #\r | |
| 12 | # Module Name:\r | |
| 13 | #\r | |
| 14 | # Thunk16.S\r | |
| 15 | #\r | |
| 16 | # Abstract:\r | |
| 17 | #\r | |
| 18 | # Real mode thunk\r | |
| 19 | #\r | |
| 20 | #------------------------------------------------------------------------------\r | |
| 21 | \r | |
| bff2467a | 22 | #include <Library/BaseLib.h>\r |
| 23 | \r | |
| 132f41f0 | 24 | ASM_GLOBAL ASM_PFX(m16Start), ASM_PFX(m16Size), ASM_PFX(mThunk16Attr), ASM_PFX(m16Gdt), ASM_PFX(m16GdtrBase), ASM_PFX(mTransition)\r |
| 25 | ASM_GLOBAL ASM_PFX(InternalAsmThunk16)\r | |
| e1f414b6 | 26 | \r |
| 27 | ASM_PFX(m16Start):\r | |
| 28 | \r | |
| 29 | SavedGdt: .space 6\r | |
| 30 | \r | |
| 31 | ASM_PFX(BackFromUserCode):\r | |
| 32 | push %ss\r | |
| 33 | push %cs\r | |
| 34 | .byte 0x66\r | |
| 35 | call L_Base1 # push eip\r | |
| 36 | L_Base1:\r | |
| 37 | pushfw # pushfd actually\r | |
| 38 | cli # disable interrupts\r | |
| 39 | push %gs\r | |
| 40 | push %fs\r | |
| 41 | push %es\r | |
| 42 | push %ds\r | |
| 43 | pushaw # pushad actually\r | |
| 44 | .byte 0x66, 0xba # mov edx, imm32\r | |
| 45 | ASM_PFX(ThunkAttr): .space 4\r | |
| 46 | testb $THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15, %dl\r | |
| 47 | jz 1f\r | |
| 48 | movl $0x15cd2401, %eax # mov ax, 2401h & int 15h\r | |
| 49 | cli # disable interrupts\r | |
| 50 | jnc 2f\r | |
| 51 | 1:\r | |
| 52 | testb $THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL, %dl\r | |
| 53 | jz 2f\r | |
| 54 | inb $0x92, %al\r | |
| 55 | orb $2, %al\r | |
| 56 | outb %al, $0x92 # deactivate A20M#\r | |
| 57 | 2:\r | |
| c577049a LG |
58 | xorw %ax, %ax # xor eax, eax\r |
| 59 | movl %ss, %eax # mov ax, ss\r | |
| e1f414b6 | 60 | .byte 0x67, 0x66, 0x8d, 0x6c, 0x24, 0x34, 0x66\r |
| 61 | mov %ebp, 0xffffffd8(%esi)\r | |
| 62 | mov 0xfffffff8(%esi), %ebx\r | |
| 63 | shlw $4, %ax # shl eax, 4\r | |
| 64 | addw %ax, %bp # add ebp, eax\r | |
| 65 | .byte 0x66, 0xb8 # mov eax, imm32\r | |
| 66 | SavedCr4: .space 4\r | |
| 67 | movl %eax, %cr4\r | |
| 68 | lgdtw %cs:0xfffffff2(%edi)\r | |
| 69 | .byte 0x66, 0xb8 # mov eax, imm32\r | |
| 70 | SavedCr0: .space 4\r | |
| 71 | movl %eax, %cr0\r | |
| 72 | .byte 0xb8 # mov ax, imm16\r | |
| 73 | SavedSs: .space 2\r | |
| 74 | movl %eax, %ss\r | |
| 75 | .byte 0x66, 0xbc # mov esp, imm32\r | |
| 76 | SavedEsp: .space 4\r | |
| 77 | .byte 0x66\r | |
| 78 | lret # return to protected mode\r | |
| 79 | \r | |
| 80 | _EntryPoint: .long ASM_PFX(ToUserCode) - ASM_PFX(m16Start)\r | |
| 81 | .word 0x8\r | |
| 82 | _16Idtr: .word 0x3ff\r | |
| 83 | .long 0\r | |
| 84 | _16Gdtr: .word GdtEnd - _NullSegDesc - 1\r | |
| 85 | _16GdtrBase: .long _NullSegDesc\r | |
| 86 | \r | |
| 87 | ASM_PFX(ToUserCode):\r | |
| 88 | movl %ss, %edx\r | |
| 89 | movl %ecx, %ss # set new segment selectors\r | |
| 90 | movl %ecx, %ds\r | |
| 91 | movl %ecx, %es\r | |
| 92 | movl %ecx, %fs\r | |
| 93 | movl %ecx, %gs\r | |
| 94 | movl %eax, %cr0\r | |
| 95 | movl %ebp, %cr4 # real mode starts at next instruction\r | |
| 96 | movl %esi, %ss # set up 16-bit stack segment\r | |
| 97 | xchgw %bx, %sp # set up 16-bit stack pointer\r | |
| 98 | .byte 0x66\r | |
| 99 | call L_Base # push eip\r | |
| 100 | L_Base:\r | |
| 101 | popw %bp # ebp <- offset L_Base\r | |
| 9e77c2c3 | 102 | .byte 0x67; # address size override\r |
| 103 | push 54(%esp)\r | |
| e1f414b6 | 104 | lea 0xc(%esi), %eax\r |
| 105 | push %eax\r | |
| 106 | lret\r | |
| 107 | \r | |
| 108 | L_RealMode:\r | |
| 109 | mov %edx, %cs:0xffffffc5(%esi)\r | |
| 110 | mov %bx, %cs:0xffffffcb(%esi)\r | |
| 111 | lidtw %cs:0xffffffd7(%esi)\r | |
| 112 | popaw # popad actually\r | |
| 113 | pop %ds\r | |
| 114 | pop %es\r | |
| 115 | pop %fs\r | |
| 116 | pop %gs\r | |
| 117 | popfw # popfd\r | |
| 118 | lretw # transfer control to user code\r | |
| 119 | \r | |
| 120 | _NullSegDesc: .quad 0\r | |
| 121 | _16CsDesc:\r | |
| 122 | .word -1\r | |
| 123 | .word 0\r | |
| 124 | .byte 0\r | |
| 125 | .byte 0x9b\r | |
| 126 | .byte 0x8f # 16-bit segment, 4GB limit\r | |
| 127 | .byte 0\r | |
| 128 | _16DsDesc:\r | |
| 129 | .word -1\r | |
| 130 | .word 0\r | |
| 131 | .byte 0\r | |
| 132 | .byte 0x93\r | |
| 133 | .byte 0x8f # 16-bit segment, 4GB limit\r | |
| 134 | .byte 0\r | |
| 135 | GdtEnd:\r | |
| 136 | \r | |
| 137 | #\r | |
| 2fc59a00 | 138 | # @param RegSet The pointer to a IA32_DWORD_REGS structure\r |
| 139 | # @param Transition The pointer to the transition code\r | |
| e1f414b6 | 140 | # @return The address of the 16-bit stack after returning from user code\r |
| 141 | #\r | |
| 142 | ASM_PFX(InternalAsmThunk16):\r | |
| 143 | push %ebp\r | |
| 144 | push %ebx\r | |
| 145 | push %esi\r | |
| 146 | push %edi\r | |
| 147 | push %ds\r | |
| 148 | push %es\r | |
| 149 | push %fs\r | |
| 150 | push %gs\r | |
| 151 | movl 36(%esp), %esi # esi <- RegSet\r | |
| 152 | movzwl 0x32(%esi), %edx\r | |
| 153 | mov 0xc(%esi), %edi\r | |
| 154 | add $0xffffffc8, %edi\r | |
| 155 | movl %edi, %ebx # ebx <- stack offset\r | |
| 156 | imul $0x10, %edx, %eax\r | |
| 157 | push $0xd\r | |
| 158 | addl %eax, %edi # edi <- linear address of 16-bit stack\r | |
| 159 | pop %ecx\r | |
| 160 | rep\r | |
| 161 | movsl # copy RegSet\r | |
| 162 | movl 40(%esp), %eax # eax <- address of transition code\r | |
| 163 | movl %edx, %esi # esi <- 16-bit stack segment\r | |
| dccf78f0 | 164 | lea 0x5f(%eax), %edx\r |
| e1f414b6 | 165 | movl %eax, %ecx\r |
| 166 | andl $0xf, %ecx\r | |
| 167 | shll $12, %eax\r | |
| 168 | lea 0x6(%ecx), %ecx\r | |
| 169 | movw %cx, %ax\r | |
| 170 | stosl # [edi] <- return address of user code\r | |
| dccf78f0 | 171 | sgdtl 0xffffffa1(%edx)\r |
| e1f414b6 | 172 | sidtl 0x24(%esp)\r |
| 173 | movl %cr0, %eax\r | |
| 174 | movl %eax, (%edx) # save CR0 in SavedCr0\r | |
| 175 | andl $0x7ffffffe, %eax # clear PE, PG bits\r | |
| 176 | movl %cr4, %ebp\r | |
| 177 | mov %ebp, 0xfffffff1(%edx)\r | |
| 178 | andl $0x300, %ebp # clear all but PCE and OSFXSR bits\r | |
| 179 | pushl $0x10\r | |
| 180 | pop %ecx # ecx <- selector for data segments\r | |
| 181 | lgdtl 0x20(%edx)\r | |
| 182 | pushfl\r | |
| 183 | lcall *0x14(%edx)\r | |
| 184 | popfl\r | |
| 185 | lidtl 0x24(%esp)\r | |
| 186 | lea 0xffffffcc(%ebp), %eax\r | |
| 6f890d5b | 187 | pop %gs\r |
| 188 | pop %fs\r | |
| 189 | pop %es\r | |
| 190 | pop %ds\r | |
| 191 | pop %edi\r | |
| 192 | pop %esi\r | |
| 193 | pop %ebx\r | |
| 194 | pop %ebp\r | |
| e1f414b6 | 195 | ret\r |
| 196 | \r | |
| 197 | .const:\r | |
| 198 | \r | |
| 6a8e44d9 | 199 | ASM_PFX(m16Size): .word ASM_PFX(InternalAsmThunk16) - ASM_PFX(m16Start)\r |
| 200 | ASM_PFX(mThunk16Attr): .word ASM_PFX(ThunkAttr) - ASM_PFX(m16Start)\r | |
| e1f414b6 | 201 | ASM_PFX(m16Gdt): .word _NullSegDesc - ASM_PFX(m16Start)\r |
| 202 | ASM_PFX(m16GdtrBase): .word _16GdtrBase - ASM_PFX(m16Start)\r | |
| 203 | ASM_PFX(mTransition): .word _EntryPoint - ASM_PFX(m16Start)\r |