mirror of
https://github.com/0Nera/BMOSP.git
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114 lines
3.4 KiB
C
114 lines
3.4 KiB
C
/**
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* arch.c
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* Инициализация архитектуры
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*
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* Настройка архитектурнозависимых функций
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*
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*/
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#include <LOG.h>
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#include <arch.h>
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typedef struct __attribute__((packed)) {
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uint16_t limit;
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uint64_t base;
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} gdt_reg_t;
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struct gdt_desc {
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uint16_t limit;
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uint16_t base_low;
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uint8_t base_mid;
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uint8_t access;
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uint8_t granularity;
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uint8_t base_hi;
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} __attribute__((packed));
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static uint64_t kernel_start_ticks = 0;
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static uint64_t kernel_ticks = 0;
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static gdt_reg_t gdtr;
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static struct gdt_desc gdt_descs[] = { { 0 },
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{ .limit = 0xffff,
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.base_low = 0x0000,
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.base_mid = 0x00,
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.access = 0b10011011,
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.granularity = 0b00000000,
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.base_hi = 0x00 },
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{ .limit = 0xffff,
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.base_low = 0x0000,
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.base_mid = 0x00,
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.access = 0b10010011,
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.granularity = 0b00000000,
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.base_hi = 0x00 },
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{ .limit = 0xffff,
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.base_low = 0x0000,
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.base_mid = 0x00,
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.access = 0b10011011,
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.granularity = 0b11001111,
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.base_hi = 0x00 },
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{ .limit = 0xffff,
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.base_low = 0x0000,
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.base_mid = 0x00,
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.access = 0b10010011,
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.granularity = 0b11001111,
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.base_hi = 0x00 },
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{ .limit = 0x0000,
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.base_low = 0x0000,
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.base_mid = 0x00,
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.access = 0b10011011,
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.granularity = 0b00100000,
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.base_hi = 0x00 },
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{ .limit = 0x0000,
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.base_low = 0x0000,
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.base_mid = 0x00,
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.access = 0b10010011,
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.granularity = 0b00000000,
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.base_hi = 0x00 } };
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extern void load_gdt(uint64_t gdtr);
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uint64_t rdtsc( ) {
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unsigned int lo, hi;
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asm volatile("rdtsc" : "=a"(lo), "=d"(hi));
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return ((uint64_t)hi << 32) | lo;
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}
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uint64_t arch_get_tick( ) {
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if (kernel_start_ticks == 0) {
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kernel_start_ticks = rdtsc( );
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return 0;
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}
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kernel_ticks = rdtsc( ) - kernel_start_ticks;
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return kernel_ticks;
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}
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uint64_t arch_get_tick_b( ) {
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uint64_t tick = arch_get_tick( ) + 1;
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return tick / 1000000;
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}
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uint64_t arch_get_tick_l( ) {
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uint64_t tick = arch_get_tick( ) + 1;
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return tick % 1000000;
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}
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void arch_init( ) {
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LOG("Установка сегментов\n");
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gdtr.limit = (sizeof(gdt_descs) - 1);
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gdtr.base = (uint64_t)&gdt_descs;
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load_gdt((uint64_t)&gdtr);
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LOG("Установка сегментов успешна!\n");
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pic_init( );
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idt_init( );
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cpu_init( );
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} |