114 lines
2.9 KiB
C
114 lines
2.9 KiB
C
/**
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* @file kernel/arch/x86_64/gdt.c
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* @brief x86-64 GDT
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*
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* @copyright
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* This file is part of ToaruOS and is released under the terms
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* of the NCSA / University of Illinois License - see LICENSE.md
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* Copyright (C) 2021 K. Lange
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*/
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#include <kernel/printf.h>
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#include <kernel/string.h>
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#include <kernel/process.h>
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/**
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* @brief 64-bit TSS
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*/
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typedef struct tss_entry {
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uint32_t reserved_0;
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uint64_t rsp[3];
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uint64_t reserved_1;
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uint64_t ist[7];
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uint64_t reserved_2;
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uint16_t reserved_3;
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uint16_t iomap_base;
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} __attribute__ ((packed)) tss_entry_t;
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typedef struct {
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uint16_t limit_low;
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uint16_t base_low;
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uint8_t base_middle;
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uint8_t access;
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uint8_t granularity;
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uint8_t base_high;
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} __attribute__((packed)) gdt_entry_t;
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typedef struct {
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uint32_t base_highest;
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uint32_t reserved0;
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} __attribute__((packed)) gdt_entry_high_t;
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typedef struct {
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uint16_t limit;
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uintptr_t base;
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} __attribute__((packed)) gdt_pointer_t;
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typedef struct {
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gdt_entry_t entries[7];
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gdt_entry_high_t tss_extra;
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gdt_pointer_t pointer;
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tss_entry_t tss;
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} __attribute__((packed)) __attribute__((aligned(0x10))) FullGDT;
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FullGDT gdt[32] __attribute__((used)) = {{
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{
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{0x0000, 0x0000, 0x00, 0x00, 0x00, 0x00},
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{0xFFFF, 0x0000, 0x00, 0x9A, (1 << 5) | (1 << 7) | 0x0F, 0x00},
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{0xFFFF, 0x0000, 0x00, 0x92, (1 << 5) | (1 << 7) | 0x0F, 0x00},
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{0xFFFF, 0x0000, 0x00, 0xFA, (1 << 5) | (1 << 7) | 0x0F, 0x00},
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{0xFFFF, 0x0000, 0x00, 0xF2, (1 << 5) | (1 << 7) | 0x0F, 0x00},
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{0xFFFF, 0x0000, 0x00, 0xFA, (1 << 5) | (1 << 7) | 0x0F, 0x00},
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{0x0067, 0x0000, 0x00, 0xE9, 0x00, 0x00},
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},
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{0x00000000, 0x00000000},
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{0x0000, 0x0000000000000000},
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{0,{0,0,0},0,{0,0,0,0,0,0,0},0,0,0},
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}};
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void gdt_install(void) {
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for (int i = 1; i < 32; ++i) {
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memcpy(&gdt[i], &gdt[0], sizeof(*gdt));
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}
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for (int i = 0; i < 32; ++i) {
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gdt[i].pointer.limit = sizeof(gdt[i].entries)+sizeof(gdt[i].tss_extra)-1;
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gdt[i].pointer.base = (uintptr_t)&gdt[i].entries;
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uintptr_t addr = (uintptr_t)&gdt[i].tss;
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gdt[i].entries[6].limit_low = sizeof(gdt[i].tss);
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gdt[i].entries[6].base_low = (addr & 0xFFFF);
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gdt[i].entries[6].base_middle = (addr >> 16) & 0xFF;
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gdt[i].entries[6].base_high = (addr >> 24) & 0xFF;
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gdt[i].tss_extra.base_highest = (addr >> 32) & 0xFFFFFFFF;
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}
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extern void * stack_top;
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gdt[0].tss.rsp[0] = (uintptr_t)&stack_top;
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asm volatile (
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"mov %0, %%rdi\n"
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"lgdt (%%rdi)\n"
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"mov $0x10, %%ax\n"
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"mov %%ax, %%ds\n"
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"mov %%ax, %%es\n"
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"mov %%ax, %%ss\n"
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"mov $0x33, %%ax\n" /* TSS offset */
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"ltr %%ax\n"
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: : "r"(&gdt[0].pointer)
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);
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}
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void gdt_copy_to_trampoline(int ap, char * trampoline) {
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memcpy(trampoline, &gdt[ap].pointer, sizeof(gdt[ap].pointer));
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}
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void arch_set_kernel_stack(uintptr_t stack) {
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gdt[this_core->cpu_id].tss.rsp[0] = stack;
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this_core->syscall_stack = stack;
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}
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void arch_set_tls_base(uintptr_t tlsbase) {
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asm volatile ("wrmsr" : : "c"(0xc0000100), "d"((uint32_t)(tlsbase >> 32)), "a"((uint32_t)(tlsbase & 0xFFFFFFFF)));
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}
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