gdt.c File Reference

GDT configuration. More...

#include "gdt.h"
#include "libc.h"
#include "debug.h"
#include "pipcall.h"
#include "segment_selectors.h"

Macros
#define	GDT_N_ENTRY   (LAST_PIPCALL + 1)

Functions
void	set_segment_descriptor (uint32_t num, uint32_t base, uint32_t limit, unsigned char type, unsigned char dpl, unsigned char granularity)
void	set_callgate_descriptor (int num, void *handler, uint8_t args, uint8_t dpl, uint16_t segment)
	Installs a call gate entry into the GDT. More...
void	set_tss_descriptor (uint32_t num, tss_t *tss_ptr, uint32_t limit, unsigned char type, unsigned char dpl, unsigned char granularity)
void	set_tss (uint16_t kernel_code_segment, uint16_t kernel_data_segment, uint16_t kernel_stack_segment)
void	setKernelStack (uint32_t stack)
	Updates the kernel stack address into the TSS. More...
void	load_gdt (void *base, uint16_t limit)
void	load_tss ()
void	gdt_init (void)
	Installs the GDT into the CPU. More...

Variables
gdt_entry_t	gdt [GDT_N_ENTRY]
	Our GDT. More...
tss_t	tss
	Generic TSS for userland-to-kernel switch. More...
void *	cg_outbGlue
void *	cg_inbGlue
void *	cg_outwGlue
void *	cg_inwGlue
void *	cg_outlGlue
void *	cg_inlGlue
void *	cg_outaddrlGlue
void *	cg_createPartition
void *	cg_countToMap
void *	cg_prepare
void *	cg_addVAddr
void *	cg_get_int_state
void *	cg_set_int_state
void *	cg_removeVAddr
void *	cg_mappedInChild
void *	cg_deletePartition
void *	cg_collect
void *	cg_yieldGlue

Detailed Description

GDT configuration.

Macro Definition Documentation

GDT_N_ENTRY

#define GDT_N_ENTRY   (LAST_PIPCALL + 1)

Function Documentation

gdt_init()

void gdt_init

(

void

)

Installs the GDT into the CPU.

Callgate setup (Syscalls)

load_gdt()

void load_gdt	(	void *	base,
		uint16_t	limit
	)

< Pointer to our GDT

load_tss()

void load_tss

(

)

set_callgate_descriptor()

void set_callgate_descriptor	(	int	num,
		void *	handler,
		uint8_t	args,
		uint8_t	dpl,
		uint16_t	segment
	)

Installs a call gate entry into the GDT.

Parameters

num	The index of the segment into the GDT
handler	The function pointer
args	Argument count
dpl	Descriptor Privilege Level (Caller Privilege Level must be numerically less or equal to DPL)
segment	The segment to switch to

set_segment_descriptor()

void set_segment_descriptor	(	uint32_t	num,
		uint32_t	base,
		uint32_t	limit,
		unsigned char	type,
		unsigned char	dpl,
		unsigned char	granularity
	)

set_tss()

void set_tss	(	uint16_t	kernel_code_segment,
		uint16_t	kernel_data_segment,
		uint16_t	kernel_stack_segment
	)

< Pointer to the previous TSS entry (updated on a task switch)

< Kernel-mode ESP (static)

< Kernel-mode stack segment (static)

< Ring-1 ESP (static)

< Ring-1 stack segment (static)

< Ring-2 ESP (static)

< Ring-2 stack segment (static)

< Page directory address (static)

< Execution pointer (prior to task switch)

< CPU flags (prior to task switch)

< General register EAX (prior to task switch)

< General register ECX (prior to task switch)

< General register EDX (prior to task switch)

< General register EBX (prior to task switch)

< User-mode ESP (prior to task switch)

< User-mode EBP (prior to task switch)

< General register ESI (prior to task switch)

< General register EDI (prior to task switch)

< Segment selector ES (prior to task switch)

< Segment selector CS (prior to task switch)

< Segment selector SS (prior to task switch)

< Segment selector DS (prior to task switch)

< Segment selector FS (prior to task switch)

< Segment selector GS (prior to task switch)

< Pointer to the LDT (static)

< Flag to raise an exception when a task switch to this task occurs (static)

< IOMMU base

set_tss_descriptor()

void set_tss_descriptor	(	uint32_t	num,
		tss_t *	tss_ptr,
		uint32_t	limit,
		unsigned char	type,
		unsigned char	dpl,
		unsigned char	granularity
	)

setKernelStack()

void setKernelStack

(

uint32_t

stack

)

Updates the kernel stack address into the TSS.

Parameters

stack

The stack address

Variable Documentation

cg_addVAddr

void* cg_addVAddr

cg_collect

void* cg_collect

cg_countToMap

void* cg_countToMap

cg_createPartition

void* cg_createPartition

cg_deletePartition

void* cg_deletePartition

cg_get_int_state

void* cg_get_int_state

cg_inbGlue

void* cg_inbGlue

cg_inlGlue

void* cg_inlGlue

cg_inwGlue

void* cg_inwGlue

cg_mappedInChild

void* cg_mappedInChild

cg_outaddrlGlue

void* cg_outaddrlGlue

cg_outbGlue

void* cg_outbGlue

cg_outlGlue

void* cg_outlGlue

cg_outwGlue

void* cg_outwGlue

cg_prepare

void* cg_prepare

cg_removeVAddr

void* cg_removeVAddr

cg_set_int_state

void* cg_set_int_state

cg_yieldGlue

void* cg_yieldGlue

gdt

gdt_entry_t gdt[GDT_N_ENTRY]

Our GDT.

tss

tss_t tss

Generic TSS for userland-to-kernel switch.