descriptor.h File Reference

cpu segment descriptors for long mode. More...

#include <types.h>

Classes
struct	descriptor_gdt_null
	null segment descriptor for gdt More...
struct	descriptor_gdt_code
	code segment descriptor for gdt More...
struct	descriptor_gdt_data
	data segment descriptor for gdt More...
struct	descriptor_gdt
	general segment descriptor for gdt More...
struct	descriptor_idt
	idt table descriptor More...
struct	descriptor_register
	common register value for gdtr, idtr, ldtr, tr More...

Macros
#define	___CPU_DESCRIPTOR_H   0
#define	DPL_RING0   0
#define	DPL_RING1   1
#define	DPL_RING2   2
#define	DPL_RING3   3
#define	DPL_KERNEL   DPL_RING0
#define	DPL_USER   DPL_RING3
#define	KERNEL_CODE_SEG   0x08
#define	KERNEL_DATA_SEG   0x10
#define	KERNEL_TSS_SEG   0x18
#define	DESCRIPTOR_BUILD_GDT_NULL_SEG(seg)
	null segment builder macro
#define	DESCRIPTOR_BUILD_GDT_CODE_SEG(seg, DPL)
	code segment builder macro with privilage level
#define	DESCRIPTOR_BUILD_GDT_DATA_SEG(seg, DPL)
	data segment builder macro
#define	IDT_BASE_ADDRESS   (1 << 20)
#define	SYSTEM_SEGMENT_TYPE_IDT   0x02
#define	SYSTEM_SEGMENT_TYPE_TSS_A   0x09
#define	SYSTEM_SEGMENT_TYPE_TSS_B   0x0B
#define	SYSTEM_SEGMENT_TYPE_GATE_CALL   0x0C
#define	SYSTEM_SEGMENT_TYPE_GATE_INT   0x0E
#define	SYSTEM_SEGMENT_TYPE_GATE_TRAP   0x0F
#define	DESCRIPTOR_BUILD_IDT_SEG(IE, FUNC_ADDR, SELECTOR, IST, DPL)
	assign a function to interrupt nomber

Typedefs
typedef struct descriptor_gdt_null	descriptor_gdt_null_t
	struct short hand
typedef struct descriptor_gdt_code	descriptor_gdt_code_t
	struct short hand
typedef struct descriptor_gdt_data	descriptor_gdt_data_t
	struct short hand
typedef struct descriptor_gdt	descriptor_gdt_t
	struct short hand
typedef struct descriptor_idt	descriptor_idt_t
	struct short hand
typedef struct descriptor_register	descriptor_register_t
	struct short hand

Functions
uint8_t	descriptor_build_gdt_register (void)
	builds a default gdt
uint8_t	descriptor_build_idt_register (void)
	builds a default idt
uint8_t	descriptor_build_ap_descriptors_register (void)
	builds gdt and tss for application processor

Variables
descriptor_register_t *	GDT_REGISTER
	static address of gdt for lgdtr/sgdtr
descriptor_register_t *	IDT_REGISTER
	static address of idt for lidtr/sidtr

Detailed Description

cpu segment descriptors for long mode.

This work is licensed under TURNSTONE OS Public License. Please read and understand latest version of Licence.

Macro Definition Documentation

___CPU_DESCRIPTOR_H

#define ___CPU_DESCRIPTOR_H   0

prevent duplicate header error macro

DESCRIPTOR_BUILD_GDT_CODE_SEG

#define DESCRIPTOR_BUILD_GDT_CODE_SEG	(		seg,
			DPL )

Value:

                                                 {seg.code.unused1 = 0; \
                                                 seg.code.unused2 = 0; \
                                                 seg.code.unused3 = 0; \
                                                 seg.code.readable = 1; \
                                                 seg.code.conforming = 0; \
                                                 seg.code.always1 = 3; \
                                                 seg.code.dpl = DPL; \
                                                 seg.code.present = 1; \
                                                 seg.code.unused4 = 0; \
                                                 seg.code.avl = 0; \
                                                 seg.code.long_mode = 1; \
                                                 seg.code.default_opsize = 0; \
                                                 seg.code.unused5 = 0; \
                                                 seg.code.unused6 = 0;}

code segment builder macro with privilage level

Parameters

seg	segment to build as code
DPL	privilage level to build as code

DESCRIPTOR_BUILD_GDT_DATA_SEG

#define DESCRIPTOR_BUILD_GDT_DATA_SEG	(		seg,
			DPL )

Value:

                                                 {seg.data.unused1 = 0; \
                                                 seg.data.unused2 = 0; \
                                                 seg.data.unused3 = 0; \
                                                 seg.data.rw = 1; \
                                                 seg.data.unused4 = 0; \
                                                 seg.data.always0 = 0; \
                                                 seg.data.always1 = 1; \
                                                 seg.data.dpl = DPL; \
                                                 seg.data.present = 1; \
                                                 seg.data.unused5 = 0; \
                                                 seg.data.long_mode = 1; \
                                                 seg.data.unused6 = 0;}

data segment builder macro

Parameters

seg	segment to build as data

DESCRIPTOR_BUILD_GDT_NULL_SEG

#define DESCRIPTOR_BUILD_GDT_NULL_SEG

(

seg

)

Value:

{seg.null.unused1 = 0; seg.null.unused2 = 0;}

null segment builder macro

Parameters

seg	segment to build as null

DESCRIPTOR_BUILD_IDT_SEG

#define DESCRIPTOR_BUILD_IDT_SEG	(		IE,
			FUNC_ADDR,
			SELECTOR,
			IST,
			DPL )

Value:

            { \
            IE.selector = SELECTOR; \
            IE.ist = IST; \
            IE.always0_1 = 0; \
            IE.type = 0xE; \
            IE.always0_2 = 0; \
            IE.dpl = DPL; \
            IE.present = 1; \
            IE.zero = 0; \
            IE.offset_1 = (FUNC_ADDR >> 0) & 0xFFFF; \
            IE.offset_2 = (FUNC_ADDR >> 16) & 0xFFFF; \
            IE.offset_3 = (FUNC_ADDR >> 32) & 0xFFFFFFFF; \
}

assign a function to interrupt nomber

Parameters

[in]	IE	interrupt vector
[in]	FUNC_ADDR	interrupt vector's function address
[in]	SELECTOR	gdt code selector for interrupt vector
[in]	IST	ist number for vector, if ist is zero not ist mechanism, else use ist at tss
[in]	DPL	privilage level of interrupt

DPL_KERNEL

#define DPL_KERNEL   DPL_RING0

a short hand for ring0 aka kernel space

DPL_RING0

#define DPL_RING0   0

cpu privilage level 0 for kernel space

DPL_RING1

#define DPL_RING1   1

cpu privilage level 1 for kernel additional space

DPL_RING2

#define DPL_RING2   2

cpu privilage level 2 for kernel additional space

DPL_RING3

#define DPL_RING3   3

cpu privilage level 3 for user space

DPL_USER

#define DPL_USER   DPL_RING3

a short hand for ring3 aka user space

KERNEL_CODE_SEG

#define KERNEL_CODE_SEG   0x08

hard coded gdt code segment value

KERNEL_DATA_SEG

#define KERNEL_DATA_SEG   0x10

hard coded gdt data segment value

KERNEL_TSS_SEG

#define KERNEL_TSS_SEG   0x18

hard coded gdt tss segment value

SYSTEM_SEGMENT_TYPE_GATE_CALL

#define SYSTEM_SEGMENT_TYPE_GATE_CALL   0x0C

Call Gate segment type

SYSTEM_SEGMENT_TYPE_GATE_INT

#define SYSTEM_SEGMENT_TYPE_GATE_INT   0x0E

Interrupt Gate segment type

SYSTEM_SEGMENT_TYPE_GATE_TRAP

#define SYSTEM_SEGMENT_TYPE_GATE_TRAP   0x0F

Trap Gate segment type

SYSTEM_SEGMENT_TYPE_IDT

#define SYSTEM_SEGMENT_TYPE_IDT   0x02

IDT segment type

SYSTEM_SEGMENT_TYPE_TSS_A

#define SYSTEM_SEGMENT_TYPE_TSS_A   0x09

Active TSS segment type

SYSTEM_SEGMENT_TYPE_TSS_B

#define SYSTEM_SEGMENT_TYPE_TSS_B   0x0B

Busy TSS segment type

Function Documentation

descriptor_build_ap_descriptors_register()

uint8_t descriptor_build_ap_descriptors_register

(

void

)

builds gdt and tss for application processor

Returns

0 at success.

descriptor_build_gdt_register()

uint8_t descriptor_build_gdt_register

(

void

)

builds a default gdt

Returns

0 at success.

descriptor_build_idt_register()

uint8_t descriptor_build_idt_register

(

void

)

builds a default idt

Returns

0 at success.