gdt.h File Reference

#include <stdint.h>
#include <hardware/context.h>
#include <process/thread.h>

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Classes
struct	GDTTable
struct	GDTEntry
struct	IDTTable
struct	IDTEntry

Macros
#define	KERNELSTACK_SIZE   PAGE_SIZE
#define	USERMODE_KERNELSTACK_ADDRESS   0xFF800000
#define	USERMODE_GDT_ADDRESS   0xFF801000
#define	USERMODE_IDT_ADDRESS   0xFF811000
#define	USERMODE_INTJMP_ADDRESS   0xFF812000
#define	USERMODE_TASK_ADDRESS   0xFF813000
#define	USERMODE_KERNELSTACK_LIMIT   (USERMODE_KERNELSTACK_ADDRESS + KERNELSTACK_SIZE)
#define	USERMODE_INTJMP_ENABLE_FPU   (USERMODE_INTJMP_ADDRESS + 2048)
GDT Privileges
#define	GDT_CPL_MASK   3
#define	GDT_CPL_RING0   0
#define	GDT_CPL_RING3   3
Interrupt types
For more information take a look at http://wiki.osdev.org/Interrupt_Descriptor_Table
#define	INT_TYPE_TASK32   0x5
#define	INT_TYPE_INT16   0x6
#define	INT_TYPE_TRAP16   0x7
#define	INT_TYPE_INT32   0xE
#define	INT_TYPE_TRAP32   0xF
GDT Size
#define	GDT_MAX_SIZE   0x10000
#define	GDT_MAX_PAGES   ((GDT_MAX_SIZE + PAGE_MASK) >> PAGE_BITS)
#define	GDT_MAX_COUNT   (GDT_MAX_SIZE / sizeof(struct GDTEntry))
IDT Size
#define	IDT_MAX_SIZE   PAGE_SIZE
#define	IDT_MAX_COUNT   256

Functions
struct GDTTable	__attribute__ ((packed))
void	gdtInit ()
	Initializes the GDT, task registers, and sets up everything required for multiprocessing. More...
struct GDTEntry *	gdtGetFreeEntry ()
	Get a free entry in the GDT. More...
uint32_t	gdtGetEntryOffset (struct GDTEntry *entry, uint32_t ring)
	Determines the offset of a GDT entry. More...
void	gdtEntrySetAddress (struct GDTEntry *entry, uint32_t address)
	Helper function to set the address inside a GDTEntry. More...
void	gdtEntrySetLimit (struct GDTEntry *entry, uint64_t length)
	Helper function to set the length inside a GDTEntry. More...
void	gdtReleaseEntry (struct GDTEntry *entry)
	Mark a GDTEntry as free. More...
uint32_t	tssRunUsermodeThread (struct thread *t)
	Run a thread. More...
void	__attribute__ ((cdecl))

Variables
void *	kernelStack
void *	intJmpTable_kernel
void *	intJmpTable_user
struct GDTEntry *	codeRing0
struct GDTEntry *	dataRing0
struct GDTEntry *	codeRing3
struct GDTEntry *	dataRing3
struct GDTEntry *	kernelTask
struct GDTEntry *	usermodeTask
uint16_t	limit
uint32_t	address
uint16_t	limit1
uint16_t	address1
uint8_t	address2
union {
uint8_t   access
struct {
uint8_t   accessed: 1
uint8_t   readWrite: 1
uint8_t   dc: 1
uint8_t   execute: 1
uint8_t   isSystem: 1
uint8_t   privlevel: 2
uint8_t   present: 1
}   accessBits
};
uint8_t	limit2
uint8_t	user
uint8_t	reserved
uint8_t	is32bit
uint8_t	granularity
uint8_t	address3
uint16_t	addressLow
union {
uint16_t   csSelector
uint16_t   taskSelector
};
uint8_t	zero
union {
uint8_t   typeAttr
struct {
uint8_t   type: 4
uint8_t   storageSegment: 1
uint8_t   dpl: 2
uint8_t   present: 1
}   typeBits
};
uint16_t	addressHigh

Macro Definition Documentation

USERMODE_GDT_ADDRESS

#define USERMODE_GDT_ADDRESS   0xFF801000

Definition at line 94 of file gdt.h.

USERMODE_IDT_ADDRESS

#define USERMODE_IDT_ADDRESS   0xFF811000

Definition at line 95 of file gdt.h.

USERMODE_INTJMP_ADDRESS

#define USERMODE_INTJMP_ADDRESS   0xFF812000

Definition at line 96 of file gdt.h.

USERMODE_INTJMP_ENABLE_FPU

#define USERMODE_INTJMP_ENABLE_FPU   (USERMODE_INTJMP_ADDRESS + 2048)

Definition at line 102 of file gdt.h.

USERMODE_KERNELSTACK_ADDRESS

#define USERMODE_KERNELSTACK_ADDRESS   0xFF800000

Definition at line 93 of file gdt.h.

USERMODE_KERNELSTACK_LIMIT

#define USERMODE_KERNELSTACK_LIMIT   (USERMODE_KERNELSTACK_ADDRESS + KERNELSTACK_SIZE)

Definition at line 99 of file gdt.h.

USERMODE_TASK_ADDRESS

#define USERMODE_TASK_ADDRESS   0xFF813000

Definition at line 97 of file gdt.h.

Variable Documentation

@11

union { ... }

@13

union { ... }

@3

union { ... }

access

uint8_t access

Definition at line 121 of file gdt.h.

accessBits

struct { ... } accessBits

accessed

uint8_t accessed

Definition at line 123 of file gdt.h.

address

uint32_t address

Definition at line 118 of file gdt.h.

address1

uint16_t address1

Definition at line 118 of file gdt.h.

address2

uint8_t address2

Definition at line 119 of file gdt.h.

address3

uint8_t address3

Definition at line 137 of file gdt.h.

addressHigh

uint16_t addressHigh

Definition at line 132 of file gdt.h.

addressLow

uint16_t addressLow

Definition at line 117 of file gdt.h.

csSelector

uint16_t csSelector

Definition at line 119 of file gdt.h.

dc

uint8_t dc

Definition at line 125 of file gdt.h.

dpl

uint8_t dpl

Definition at line 128 of file gdt.h.

execute

uint8_t execute

Definition at line 126 of file gdt.h.

granularity

uint8_t granularity

Definition at line 136 of file gdt.h.

is32bit

uint8_t is32bit

Definition at line 135 of file gdt.h.

isSystem

uint8_t isSystem

Definition at line 127 of file gdt.h.

limit

uint16_t limit

Definition at line 117 of file gdt.h.

limit1

uint16_t limit1

Definition at line 117 of file gdt.h.

limit2

uint8_t limit2

Definition at line 132 of file gdt.h.

present

uint8_t present

Definition at line 129 of file gdt.h.

privlevel

uint8_t privlevel

Definition at line 128 of file gdt.h.

readWrite

uint8_t readWrite

Definition at line 124 of file gdt.h.

reserved

uint8_t reserved

Definition at line 134 of file gdt.h.

storageSegment

uint8_t storageSegment

Definition at line 127 of file gdt.h.

taskSelector

uint16_t taskSelector

Definition at line 120 of file gdt.h.

type

uint8_t type

Definition at line 126 of file gdt.h.

typeAttr

uint8_t typeAttr

Definition at line 124 of file gdt.h.

typeBits

struct { ... } typeBits

user

uint8_t user

Definition at line 133 of file gdt.h.

zero

uint8_t zero

Definition at line 122 of file gdt.h.