227cc19890
New features: - support of kernel tasks in 64bit mode - support of LwIP in 64bit mode Missing features in 64bit mode - user-level support - APIC support => SMP support To create a 64bit version of the MetalSVM kernel, the compiler flags “-m64 -mno-red-zone” and the assembler flags “-felf64” has to be used. Please use qemu-system-x86_64 as test platform. Notice, metalsvm.elf is a 32bit ELF file. However, it contains (beside the startup code) only 64bit code. This is required because GRUB doesn’t boot 64bit ELF kernels. Therefore, for disassembling via objdump the flag “-M x86-64” has to be used.
124 lines
3.2 KiB
C
124 lines
3.2 KiB
C
/*
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* Copyright 2010 Stefan Lankes, Chair for Operating Systems,
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* RWTH Aachen University
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of MetalSVM.
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*/
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/**
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* @file arch/x86/include/asm/gdt.h
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* @brief Definitions and functions related to segmentation
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* @author Stefan Lankes
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*
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* This file defines the interface for segmentation as like structures to describe segments.\n
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* There are also some other gdt-private functions in the gdt.c file defined.
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*/
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#ifndef __ARCH_GDT_H__
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#define __ARCH_GDT_H__
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#include <metalsvm/stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/// This segment is a data segment
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#define GDT_FLAG_DATASEG 0x02
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/// This segment is a code segment
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#define GDT_FLAG_CODESEG 0x0a
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#define GDT_FLAG_TSS 0x09
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#define GDT_FLAG_TSS_BUSY 0x02
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#define GDT_FLAG_SEGMENT 0x10
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/// Privilege level: Ring 0
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#define GDT_FLAG_RING0 0x00
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/// Privilege level: Ring 1
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#define GDT_FLAG_RING1 0x20
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/// Privilege level: Ring 2
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#define GDT_FLAG_RING2 0x40
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/// Privilege level: Ring 3
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#define GDT_FLAG_RING3 0x60
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/// Segment is present
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#define GDT_FLAG_PRESENT 0x80
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/**
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* @brief Granularity of segment limit
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* - set: segment limit unit is 4 KB (page size)
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* - not set: unit is bytes
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*/
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#define GDT_FLAG_4K_GRAN 0x80
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/**
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* @brief Default operand size
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* - set: 32 bit
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* - not set: 16 bit
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*/
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#define GDT_FLAG_16_BIT 0x00
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#define GDT_FLAG_32_BIT 0x40
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#define GDT_FLAG_64_BIT 0x20
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/** @brief Defines a GDT entry
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*
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* A global descriptor table entry consists of:
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* - 32 bit base address (chunkwise embedded into this structure)
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* - 20 bit limit
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*/
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typedef struct {
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/// Lower 16 bits of limit range
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uint16_t limit_low;
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/// Lower 16 bits of base address
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uint16_t base_low;
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/// middle 8 bits of base address
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uint8_t base_middle;
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/// Access bits
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uint8_t access;
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/// Granularity bits
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uint8_t granularity;
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/// Higher 8 bits of base address
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uint8_t base_high;
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} __attribute__ ((packed)) gdt_entry_t;
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/** @brief defines the GDT pointer structure
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*
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* This structure tells the address and size of the table.
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*/
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typedef struct {
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/// Size of the table in bytes (not the number of entries!)
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uint16_t limit;
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/// Address of the table
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size_t base;
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} __attribute__ ((packed)) gdt_ptr_t;
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/// Defines the maximum number of GDT entries
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#define GDT_ENTRIES (5+MAX_TASKS)
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#if GDT_ENTRIES > 8192
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#error Too many GDT entries!
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#endif
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/** @brief Installs the global descriptor table
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*
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* The installation involves the following steps:
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* - set up the special GDT pointer
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* - set up the entries in our GDT
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* - finally call gdt_flush() in our assembler file
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* in order to tell the processor where the new GDT is
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* - update the new segment registers
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*/
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void gdt_install(void);
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#ifdef __cplusplus
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}
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#endif
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#endif
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