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