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sortix--sortix/sortix/descriptor_tables.h
Jonas 'Sortie' Termansen 9b79673dcb Initial version of Sortix.
2011-08-05 14:25:00 +02:00

181 lines
5.8 KiB
C++

/******************************************************************************
COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
This file is part of Sortix.
Sortix is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public License along
with Sortix. If not, see <http://www.gnu.org/licenses/>.
descriptor_tables.cpp
Initializes and handles the GDT, TSS and IDT.
******************************************************************************/
#ifndef SORTIX_DESCRIPTOR_TABLES_H
#define SORTIX_DESCRIPTOR_TABLES_H
namespace Sortix
{
namespace GDT
{
// This structure contains the value of one GDT entry.
// We use the attribute 'packed' to tell GCC not to change
// any of the alignment in the structure.
struct gdt_entry_struct
{
uint16_t limit_low; // The lower 16 bits of the limit.
uint16_t base_low; // The lower 16 bits of the base.
uint8_t base_middle; // The next 8 bits of the base.
uint8_t access; // Access flags, determine what ring this segment can be used in.
uint8_t granularity;
uint8_t base_high; // The last 8 bits of the base.
} __attribute__((packed));
typedef struct gdt_entry_struct gdt_entry_t;
// This struct describes a GDT pointer. It points to the start of
// our array of GDT entries, and is in the format required by the
// lgdt instruction.
struct gdt_ptr_struct
{
uint16_t limit; // The upper 16 bits of all selector limits.
addr_t base; // The address of the first gdt_entry_t struct.
} __attribute__((packed));
typedef struct gdt_ptr_struct gdt_ptr_t;
// A struct describing a Task State Segment.
struct tss_entry_struct
{
uint32_t prev_tss; // The previous TSS - if we used hardware task switching this would form a linked list.
uint32_t esp0; // The stack pointer to load when we change to kernel mode.
uint32_t ss0; // The stack segment to load when we change to kernel mode.
uint32_t esp1; // Unused...
uint32_t ss1;
uint32_t esp2;
uint32_t ss2;
uint32_t cr3;
uint32_t eip;
uint32_t eflags;
uint32_t eax;
uint32_t ecx;
uint32_t edx;
uint32_t ebx;
uint32_t esp;
uint32_t ebp;
uint32_t esi;
uint32_t edi;
uint32_t es; // The value to load into ES when we change to kernel mode.
uint32_t cs; // The value to load into CS when we change to kernel mode.
uint32_t ss; // The value to load into SS when we change to kernel mode.
uint32_t ds; // The value to load into DS when we change to kernel mode.
uint32_t fs; // The value to load into FS when we change to kernel mode.
uint32_t gs; // The value to load into GS when we change to kernel mode.
uint32_t ldt; // Unused...
uint16_t trap;
uint16_t iomap_base;
} __attribute__((packed));
typedef struct tss_entry_struct tss_entry_t;
void Init();
void SetGate(int32_t num, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran);
void WriteTSS(int32_t num, uint16_t ss0, uint32_t esp0);
void SetKernelStack(size_t* stack);
}
namespace IDT
{
// A struct describing an interrupt gate.
struct idt_entry_struct
{
uint16_t base_lo; // The lower 16 bits of the address to jump to when this interrupt fires.
uint16_t sel; // Kernel segment selector.
uint8_t always0; // This must always be zero.
uint8_t flags; // More flags. See documentation.
uint16_t base_hi; // The upper 16 bits of the address to jump to.
} __attribute__((packed));
typedef struct idt_entry_struct idt_entry_t;
// A struct describing a pointer to an array of interrupt handlers.
// This is in a format suitable for giving to 'lidt'.
struct idt_ptr_struct
{
uint16_t limit;
addr_t base; // The address of the first element in our idt_entry_t array.
} __attribute__((packed));
typedef struct idt_ptr_struct idt_ptr_t;
void Init();
void SetGate(uint8_t num, uint32_t base, uint16_t sel, uint8_t flags);
}
}
// These extern directives let us access the addresses of our ASM ISR handlers.
extern "C" void isr0 ();
extern "C" void isr1 ();
extern "C" void isr2 ();
extern "C" void isr3 ();
extern "C" void isr4 ();
extern "C" void isr5 ();
extern "C" void isr6 ();
extern "C" void isr7 ();
extern "C" void isr8 ();
extern "C" void isr9 ();
extern "C" void isr10();
extern "C" void isr11();
extern "C" void isr12();
extern "C" void isr13();
extern "C" void isr14();
extern "C" void isr15();
extern "C" void isr16();
extern "C" void isr17();
extern "C" void isr18();
extern "C" void isr19();
extern "C" void isr20();
extern "C" void isr21();
extern "C" void isr22();
extern "C" void isr23();
extern "C" void isr24();
extern "C" void isr25();
extern "C" void isr26();
extern "C" void isr27();
extern "C" void isr28();
extern "C" void isr29();
extern "C" void isr30();
extern "C" void isr31();
extern "C" void isr128();
extern "C" void isr177();
extern "C" void irq0 ();
extern "C" void irq1 ();
extern "C" void irq2 ();
extern "C" void irq3 ();
extern "C" void irq4 ();
extern "C" void irq5 ();
extern "C" void irq6 ();
extern "C" void irq7 ();
extern "C" void irq8 ();
extern "C" void irq9 ();
extern "C" void irq10();
extern "C" void irq11();
extern "C" void irq12();
extern "C" void irq13();
extern "C" void irq14();
extern "C" void irq15();
#endif