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kernel/src/protected.c

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#include "protected.h"
#include "config.h"
#include "info.h"
#include "interrupts/main.h"
#include <kernaux/arch/i386.h>
#include <kernaux/asm/i386.h>
#include <kernaux/drivers/console.h>
#include <kernaux/drivers/intel_8259_pic.h>
#include <string.h>
struct GdtPointer {
unsigned short limit;
unsigned int base;
}
__attribute__((packed));
struct IdtPointer {
unsigned short limit;
unsigned int base;
}
__attribute__((packed));
struct IdtEntry {
unsigned short base_lo;
unsigned short sel;
unsigned char always0;
unsigned char flags;
unsigned short base_hi;
};
static struct GdtPointer gdt_pointer;
static struct IdtPointer idt_pointer;
static struct KernAux_Arch_I386_DTE gdt_entries[GDT_SIZE];
static struct IdtEntry idt_entries[IDT_SIZE];
static struct KernAux_Arch_I386_TSS tss;
static void gdt_set_gates();
static void idt_set_gates();
static void idt_set_gate(unsigned char num, unsigned int base, unsigned short sel, unsigned char flags);
void protected_initialize(const struct Kernel_Info *const kinfo)
{
kernaux_drivers_intel_8259_pic_remap(32, 40);
kernaux_drivers_intel_8259_pic_disable_all();
kernaux_drivers_console_print("[INFO] protected: Setup GDT.\n");
gdt_set_gates();
kernaux_drivers_console_print("[INFO] protected: Setup IDT.\n");
idt_set_gates();
kernaux_drivers_console_print("[INFO] protected: Setup TSS.\n");
memset(&tss, 0, sizeof(tss));
tss.ss0 = GDT_KERNEL_DS_SELECTOR;
tss.esp0 = kinfo->kernel_stack_start + kinfo->kernel_stack_size;
kernaux_drivers_console_print("[INFO] protected: Load GDT.\n");
gdt_pointer.limit = sizeof(struct KernAux_Arch_I386_DTE) * GDT_SIZE - 1;
gdt_pointer.base = (unsigned int)&gdt_entries;
kernaux_asm_i386_flush_gdt(
(uint32_t)&gdt_pointer,
GDT_KERNEL_DS_SELECTOR,
GDT_KERNEL_CS_SELECTOR
);
kernaux_drivers_console_print("[INFO] protected: Load IDT.\n");
idt_pointer.limit = sizeof(struct IdtEntry) * IDT_SIZE - 1;
idt_pointer.base = (unsigned int)&idt_entries;
kernaux_asm_i386_flush_idt((uint32_t)&idt_pointer);
kernaux_drivers_console_print("[INFO] protected: Load TSS.\n");
kernaux_asm_i386_flush_tss(GDT_TSS_SELECTOR);
kernaux_drivers_console_print("[INFO] protected: Enable interrupts.\n");
asm volatile ("sti");
kernaux_drivers_console_print("[INFO] protected: Finished.\n");
}
void gdt_set_gates()
{
memset(gdt_entries, 0, sizeof(gdt_entries));
gdt_entries[GDT_NULL_INDEX].always_1 = 1;
gdt_entries[GDT_KERNEL_CS_INDEX] = (struct KernAux_Arch_I386_DTE){
.base_low = 0,
.base_high = 0,
.limit_low = 0xFFFF,
.limit_high = 0xF,
.available = 0,
.always_0 = 0,
.big = 1,
.gran = 1,
.accessed = 0,
.read_write = 1,
.conforming_expand_down = 0,
.code = 1,
.always_1 = 1,
.DPL = 0,
.present = 1,
};
gdt_entries[GDT_KERNEL_DS_INDEX] = (struct KernAux_Arch_I386_DTE){
.base_low = 0,
.base_high = 0,
.limit_low = 0xFFFF,
.limit_high = 0xF,
.available = 0,
.always_0 = 0,
.big = 1,
.gran = 1,
.accessed = 0,
.read_write = 1,
.conforming_expand_down = 0,
.code = 0,
.always_1 = 1,
.DPL = 0,
.present = 1,
};
gdt_entries[GDT_USER_CS_INDEX] = (struct KernAux_Arch_I386_DTE){
.base_low = 0,
.base_high = 0,
.limit_low = 0xFFFF,
.limit_high = 0xF,
.available = 0,
.always_0 = 0,
.big = 1,
.gran = 1,
.accessed = 0,
.read_write = 1,
.conforming_expand_down = 0,
.code = 1,
.always_1 = 1,
.DPL = 3,
.present = 1,
};
gdt_entries[GDT_USER_DS_INDEX] = (struct KernAux_Arch_I386_DTE){
.base_low = 0,
.base_high = 0,
.limit_low = 0xFFFF,
.limit_high = 0xF,
.available = 0,
.always_0 = 0,
.big = 1,
.gran = 1,
.accessed = 0,
.read_write = 1,
.conforming_expand_down = 0,
.code = 0,
.always_1 = 1,
.DPL = 3,
.present = 1,
};
uint32_t base = (uint32_t)&tss;
uint32_t limit = sizeof(tss);
gdt_entries[GDT_TSS_INDEX] = (struct KernAux_Arch_I386_DTE){
.base_low = base & 0xFFFFFF,
.base_high = (base & 0xFF000000) >> 24,
.limit_low = limit & 0xFFFF,
.limit_high = (limit & 0xF0000) >> 16,
.available = 0,
.always_0 = 0,
.big = 0,
.gran = 0,
.accessed = 1,
.read_write = 0,
.conforming_expand_down = 0,
.code = 1,
.always_1 = 1, // was 0
.DPL = 3,
.present = 1,
};
}
void idt_set_gates()
{
memset(idt_entries, 0, sizeof(idt_entries));
// exception
idt_set_gate(0, (unsigned int)interrupt_0, 0x08, 0x8E);
idt_set_gate(1, (unsigned int)interrupt_1, 0x08, 0x8E);
idt_set_gate(2, (unsigned int)interrupt_2, 0x08, 0x8E);
idt_set_gate(3, (unsigned int)interrupt_3, 0x08, 0x8E);
idt_set_gate(4, (unsigned int)interrupt_4, 0x08, 0x8E);
idt_set_gate(5, (unsigned int)interrupt_5, 0x08, 0x8E);
idt_set_gate(6, (unsigned int)interrupt_6, 0x08, 0x8E);
idt_set_gate(7, (unsigned int)interrupt_7, 0x08, 0x8E);
idt_set_gate(8, (unsigned int)interrupt_8, 0x08, 0x8E);
idt_set_gate(9, (unsigned int)interrupt_9, 0x08, 0x8E);
idt_set_gate(10, (unsigned int)interrupt_10, 0x08, 0x8E);
idt_set_gate(11, (unsigned int)interrupt_11, 0x08, 0x8E);
idt_set_gate(12, (unsigned int)interrupt_12, 0x08, 0x8E);
idt_set_gate(13, (unsigned int)interrupt_13, 0x08, 0x8E);
idt_set_gate(14, (unsigned int)interrupt_14, 0x08, 0x8E);
idt_set_gate(15, (unsigned int)interrupt_15, 0x08, 0x8E);
idt_set_gate(16, (unsigned int)interrupt_16, 0x08, 0x8E);
idt_set_gate(17, (unsigned int)interrupt_17, 0x08, 0x8E);
idt_set_gate(18, (unsigned int)interrupt_18, 0x08, 0x8E);
idt_set_gate(19, (unsigned int)interrupt_19, 0x08, 0x8E);
idt_set_gate(20, (unsigned int)interrupt_20, 0x08, 0x8E);
idt_set_gate(21, (unsigned int)interrupt_21, 0x08, 0x8E);
idt_set_gate(22, (unsigned int)interrupt_22, 0x08, 0x8E);
idt_set_gate(23, (unsigned int)interrupt_23, 0x08, 0x8E);
idt_set_gate(24, (unsigned int)interrupt_24, 0x08, 0x8E);
idt_set_gate(25, (unsigned int)interrupt_25, 0x08, 0x8E);
idt_set_gate(26, (unsigned int)interrupt_26, 0x08, 0x8E);
idt_set_gate(27, (unsigned int)interrupt_27, 0x08, 0x8E);
idt_set_gate(28, (unsigned int)interrupt_28, 0x08, 0x8E);
idt_set_gate(29, (unsigned int)interrupt_29, 0x08, 0x8E);
idt_set_gate(30, (unsigned int)interrupt_30, 0x08, 0x8E);
idt_set_gate(31, (unsigned int)interrupt_31, 0x08, 0x8E);
// hwint: master PIC
idt_set_gate(32, (unsigned int)interrupt_32, 0x08, 0x8E);
idt_set_gate(33, (unsigned int)interrupt_33, 0x08, 0x8E);
idt_set_gate(34, (unsigned int)interrupt_34, 0x08, 0x8E);
idt_set_gate(35, (unsigned int)interrupt_35, 0x08, 0x8E);
idt_set_gate(36, (unsigned int)interrupt_36, 0x08, 0x8E);
idt_set_gate(37, (unsigned int)interrupt_37, 0x08, 0x8E);
idt_set_gate(38, (unsigned int)interrupt_38, 0x08, 0x8E);
idt_set_gate(39, (unsigned int)interrupt_39, 0x08, 0x8E);
// hwint: slave PIC
idt_set_gate(40, (unsigned int)interrupt_40, 0x08, 0x8E);
idt_set_gate(41, (unsigned int)interrupt_41, 0x08, 0x8E);
idt_set_gate(42, (unsigned int)interrupt_42, 0x08, 0x8E);
idt_set_gate(43, (unsigned int)interrupt_43, 0x08, 0x8E);
idt_set_gate(44, (unsigned int)interrupt_44, 0x08, 0x8E);
idt_set_gate(45, (unsigned int)interrupt_45, 0x08, 0x8E);
idt_set_gate(46, (unsigned int)interrupt_46, 0x08, 0x8E);
idt_set_gate(47, (unsigned int)interrupt_47, 0x08, 0x8E);
// syscall
idt_set_gate(INT_SYSCALL, (unsigned int)interrupt_0x80, 0x08, 0x8E | 0x60);
}
void idt_set_gate(unsigned char num, unsigned int base, unsigned short sel, unsigned char flags)
{
idt_entries[num].base_lo = base & 0xFFFF;
idt_entries[num].base_hi = (base >> 16) & 0xFFFF;
idt_entries[num].sel = sel;
idt_entries[num].always0 = 0;
idt_entries[num].flags = flags;
}
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