1 ;------------------------------------------------------------------------------ ; 2 ; Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR> 3 ; This program and the accompanying materials 4 ; are licensed and made available under the terms and conditions of the BSD License 5 ; which accompanies this distribution. The full text of the license may be found at 6 ; http://opensource.org/licenses/bsd-license.php. 7 ; 8 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 9 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 10 ; 11 ; Module Name: 12 ; 13 ; SmiEntry.asm 14 ; 15 ; Abstract: 16 ; 17 ; Code template of the SMI handler for a particular processor 18 ; 19 ;------------------------------------------------------------------------------- 20 21 ; 22 ; Variables referenced by C code 23 ; 24 EXTERNDEF SmiRendezvous:PROC 25 EXTERNDEF CpuSmmDebugEntry:PROC 26 EXTERNDEF CpuSmmDebugExit:PROC 27 EXTERNDEF gcSmiHandlerTemplate:BYTE 28 EXTERNDEF gcSmiHandlerSize:WORD 29 EXTERNDEF gSmiCr3:DWORD 30 EXTERNDEF gSmiStack:DWORD 31 EXTERNDEF gSmbase:DWORD 32 EXTERNDEF gSmiHandlerIdtr:FWORD 33 34 35 ; 36 ; Constants relating to PROCESSOR_SMM_DESCRIPTOR 37 ; 38 DSC_OFFSET EQU 0fb00h 39 DSC_GDTPTR EQU 30h 40 DSC_GDTSIZ EQU 38h 41 DSC_CS EQU 14 42 DSC_DS EQU 16 43 DSC_SS EQU 18 44 DSC_OTHERSEG EQU 20 45 ; 46 ; Constants relating to CPU State Save Area 47 ; 48 SSM_DR6 EQU 0ffd0h 49 SSM_DR7 EQU 0ffc8h 50 51 PROTECT_MODE_CS EQU 08h 52 PROTECT_MODE_DS EQU 20h 53 LONG_MODE_CS EQU 38h 54 TSS_SEGMENT EQU 40h 55 GDT_SIZE EQU 50h 56 57 .code 58 59 gcSmiHandlerTemplate LABEL BYTE 60 61 _SmiEntryPoint: 62 ; 63 ; The encoding of BX in 16-bit addressing mode is the same as of RDI in 64- 64 ; bit addressing mode. And that coincidence has been used in the following 65 ; "64-bit like" 16-bit code. Be aware that once RDI is referenced as a 66 ; base address register, it is actually BX that is referenced. 67 ; 68 DB 0bbh ; mov bx, imm16 69 DW offset _GdtDesc - _SmiEntryPoint + 8000h ; bx = GdtDesc offset 70 ; fix GDT descriptor 71 DB 2eh, 0a1h ; mov ax, cs:[offset16] 72 DW DSC_OFFSET + DSC_GDTSIZ 73 DB 48h ; dec ax 74 DB 2eh 75 mov [rdi], eax ; mov cs:[bx], ax 76 DB 66h, 2eh, 0a1h ; mov eax, cs:[offset16] 77 DW DSC_OFFSET + DSC_GDTPTR 78 DB 2eh 79 mov [rdi + 2], ax ; mov cs:[bx + 2], eax 80 DB 66h, 2eh 81 lgdt fword ptr [rdi] ; lgdt fword ptr cs:[bx] 82 ; Patch ProtectedMode Segment 83 DB 0b8h ; mov ax, imm16 84 DW PROTECT_MODE_CS ; set AX for segment directly 85 DB 2eh 86 mov [rdi - 2], eax ; mov cs:[bx - 2], ax 87 ; Patch ProtectedMode entry 88 DB 66h, 0bfh ; mov edi, SMBASE 89 gSmbase DD ? 90 lea ax, [edi + (@ProtectedMode - _SmiEntryPoint) + 8000h] 91 DB 2eh 92 mov [rdi - 6], ax ; mov cs:[bx - 6], eax 93 ; Switch into @ProtectedMode 94 mov rbx, cr0 95 DB 66h 96 and ebx, 9ffafff3h 97 DB 66h 98 or ebx, 00000023h 99 100 mov cr0, rbx 101 DB 66h, 0eah 102 DD ? 103 DW ? 104 105 _GdtDesc FWORD ? 106 @ProtectedMode: 107 mov ax, PROTECT_MODE_DS 108 mov ds, ax 109 mov es, ax 110 mov fs, ax 111 mov gs, ax 112 mov ss, ax 113 DB 0bch ; mov esp, imm32 114 gSmiStack DD ? 115 jmp ProtFlatMode 116 117 ProtFlatMode: 118 DB 0b8h ; mov eax, offset gSmiCr3 119 gSmiCr3 DD ? 120 mov cr3, rax 121 mov eax, 668h ; as cr4.PGE is not set here, refresh cr3 122 mov cr4, rax ; in PreModifyMtrrs() to flush TLB. 123 ; Load TSS 124 sub esp, 8 ; reserve room in stack 125 sgdt fword ptr [rsp] 126 mov eax, [rsp + 2] ; eax = GDT base 127 add esp, 8 128 mov dl, 89h 129 mov [rax + TSS_SEGMENT + 5], dl ; clear busy flag 130 mov eax, TSS_SEGMENT 131 ltr ax 132 133 ; Switch into @LongMode 134 push LONG_MODE_CS ; push cs hardcore here 135 call Base ; push return address for retf later 136 Base: 137 add dword ptr [rsp], @LongMode - Base; offset for far retf, seg is the 1st arg 138 mov ecx, 0c0000080h 139 rdmsr 140 or ah, 1 141 wrmsr 142 mov rbx, cr0 143 or ebx, 080010000h ; enable paging + WP 144 mov cr0, rbx 145 retf 146 @LongMode: ; long mode (64-bit code) starts here 147 mov rax, offset gSmiHandlerIdtr 148 lidt fword ptr [rax] 149 lea ebx, [rdi + DSC_OFFSET] 150 mov ax, [rbx + DSC_DS] 151 mov ds, eax 152 mov ax, [rbx + DSC_OTHERSEG] 153 mov es, eax 154 mov fs, eax 155 mov gs, eax 156 mov ax, [rbx + DSC_SS] 157 mov ss, eax 158 ; jmp _SmiHandler ; instruction is not needed 159 160 _SmiHandler: 161 mov rbx, [rsp] ; rbx <- CpuIndex 162 163 ; 164 ; Save FP registers 165 ; 166 sub rsp, 208h 167 DB 48h ; FXSAVE64 168 fxsave [rsp] 169 170 add rsp, -20h 171 172 mov rcx, rbx 173 mov rax, CpuSmmDebugEntry 174 call rax 175 176 mov rcx, rbx 177 mov rax, SmiRendezvous ; rax <- absolute addr of SmiRedezvous 178 call rax 179 180 mov rcx, rbx 181 mov rax, CpuSmmDebugExit 182 call rax 183 184 add rsp, 20h 185 186 ; 187 ; Restore FP registers 188 ; 189 DB 48h ; FXRSTOR64 190 fxrstor [rsp] 191 192 rsm 193 194 gcSmiHandlerSize DW $ - _SmiEntryPoint 195 196 END 197
