67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
#include <sys/gdt.h>
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__attribute__((noreturn)) void linux_spinup(void *entry, void *boot_params) {
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struct gdt_desc linux_gdt_descs[4];
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linux_gdt_descs[0] = (struct gdt_desc){0};
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linux_gdt_descs[1] = (struct gdt_desc){0};
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linux_gdt_descs[2] = (struct gdt_desc){
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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 = 0b10011010,
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.granularity = 0b11001111,
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.base_hi = 0x00
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};
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linux_gdt_descs[3] = (struct gdt_desc){
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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 = 0b10010010,
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.granularity = 0b11001111,
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.base_hi = 0x00
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};
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struct gdtr linux_gdt;
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linux_gdt.limit = sizeof(linux_gdt_descs) - 1;
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linux_gdt.ptr = (uintptr_t)linux_gdt_descs;
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// Load invalid IDT
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uint64_t invalid_idt[2] = {0, 0};
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asm volatile (
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"lidt %0"
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:
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: "m" (invalid_idt)
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: "memory"
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);
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asm volatile (
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"lgdt %0\n\t"
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"pushl $0x10\n\t"
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"call 1f\n\t"
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"1:\n\t"
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"addl $5, (%%esp)\n\t"
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"lret\n\t"
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"movl $0x18, %%eax\n\t"
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"movl %%eax, %%ds\n\t"
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"movl %%eax, %%es\n\t"
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"movl %%eax, %%fs\n\t"
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"movl %%eax, %%gs\n\t"
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"movl %%eax, %%ss\n\t"
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"xorl %%ebp, %%ebp\n\t"
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"xorl %%edi, %%edi\n\t"
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"xorl %%ebx, %%ebx\n\t"
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"jmp *%%ecx\n\t"
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:
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: "m"(linux_gdt), "c"(entry), "S"(boot_params)
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: "memory"
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);
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__builtin_unreachable();
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}
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