| ;; @file | |
| ; This is the code that goes from real-mode to protected mode. | |
| ; It consumes the reset vector, configures the stack. | |
| ; | |
| ; Copyright (c) 2015 - 2022, Intel Corporation. All rights reserved.<BR> | |
| ; SPDX-License-Identifier: BSD-2-Clause-Patent | |
| ;; | |
| ; | |
| ; Define assembler characteristics | |
| ; | |
| extern ASM_PFX(TempRamInitApi) | |
| SECTION .text | |
| %macro RET_ESI 0 | |
| movd esi, mm7 ; restore EIP from MM7 | |
| jmp esi | |
| %endmacro | |
| ; | |
| ; Perform early platform initialization | |
| ; | |
| global ASM_PFX(SecPlatformInit) | |
| ASM_PFX(SecPlatformInit): | |
| RET_ESI | |
| ; | |
| ; Protected mode portion initializes stack, configures cache, and calls C entry point | |
| ; | |
| ;---------------------------------------------------------------------------- | |
| ; | |
| ; Procedure: ProtectedModeEntryPoint | |
| ; | |
| ; Input: Executing in 32 Bit Protected (flat) mode | |
| ; cs: 0-4GB | |
| ; ds: 0-4GB | |
| ; es: 0-4GB | |
| ; fs: 0-4GB | |
| ; gs: 0-4GB | |
| ; ss: 0-4GB | |
| ; | |
| ; Output: This function never returns | |
| ; | |
| ; Destroys: | |
| ; ecx | |
| ; edi | |
| ; esi | |
| ; esp | |
| ; | |
| ; Description: | |
| ; Perform any essential early platform initialisation | |
| ; Setup a stack | |
| ; | |
| ;---------------------------------------------------------------------------- | |
| global ASM_PFX(ProtectedModeEntryPoint) | |
| ASM_PFX(ProtectedModeEntryPoint): | |
| ; | |
| ; Dummy function. Consume 2 API to make sure they can be linked. | |
| ; | |
| mov eax, ASM_PFX(TempRamInitApi) | |
| ; Should never return | |
| jmp $ | |
| ; | |
| ; ROM-based Global-Descriptor Table for the PEI Phase | |
| ; | |
| align 16 | |
| global ASM_PFX(BootGdtTable) | |
| ; | |
| ; GDT[0]: 0x00: Null entry, never used. | |
| ; | |
| NULL_SEL equ $ - GDT_BASE ; Selector [0] | |
| GDT_BASE: | |
| ASM_PFX(BootGdtTable): DD 0 | |
| DD 0 | |
| ; | |
| ; Linear code segment descriptor | |
| ; | |
| LINEAR_CODE_SEL equ $ - GDT_BASE ; Selector [0x8] | |
| DW 0FFFFh ; limit 0xFFFF | |
| DW 0 ; base 0 | |
| DB 0 | |
| DB 09Bh ; present, ring 0, data, expand-up, not-writable | |
| DB 0CFh ; page-granular, 32-bit | |
| DB 0 | |
| ; | |
| ; System data segment descriptor | |
| ; | |
| SYS_DATA_SEL equ $ - GDT_BASE ; Selector [0x10] | |
| DW 0FFFFh ; limit 0xFFFF | |
| DW 0 ; base 0 | |
| DB 0 | |
| DB 093h ; present, ring 0, data, expand-up, not-writable | |
| DB 0CFh ; page-granular, 32-bit | |
| DB 0 | |
| GDT_SIZE EQU $ - GDT_BASE ; Size, in bytes | |
| ; | |
| ; GDT Descriptor | |
| ; | |
| GdtDesc: ; GDT descriptor | |
| DW GDT_SIZE - 1 ; GDT limit | |
| DD GDT_BASE ; GDT base address | |
| global ASM_PFX(ProtectedModeEntryLinearAddress) | |
| global ASM_PFX(ProtectedModeEntryLinearOffset) | |
| ASM_PFX(ProtectedModeEntryLinearAddress): | |
| ASM_PFX(ProtectedModeEntryLinearOffset): | |
| DD ASM_PFX(ProtectedModeEntryPoint) ; Offset of our 32 bit code | |
| DW LINEAR_CODE_SEL | |