78 lines
2.2 KiB
C
78 lines
2.2 KiB
C
#include <lcrash/mm/virt.h>
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#include <lcrash/mm/kmalloc.h>
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#include <lcrash/debug/debug.h>
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u64 (*VmemOriginalPML4)[512] = 0;
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u64 (*VmemPML4)[512] = 0;
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void VmemInitialize() {
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// Copy control registers
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u64 CR3;
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asm ("mov %%cr3, %0" : "=r" (CR3));
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u64 CR4;
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asm ("mov %%cr4, %0" : "=r" (CR4));
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if (CR4 & 0x800) Panic("5 Level paging not supported");
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u64 (*OriginalPML4)[512] = (u64(*)[512])(CR3 & 0x0007fffffffff000);
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u64 (*NewPML4)[512] = KernelHeapAlloc(sizeof(u64) * 512, 0x1000, 0);
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for (int i = 0; i < 512; i++) {
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if ((*OriginalPML4)[i] & 1) {
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u64 (*OriginalPDPT)[512] = (u64(*)[512])(((*OriginalPML4)[i] & 0x0007fffffffff000));
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u64 (*NewPDPT)[512] = KernelHeapAlloc(sizeof(u64) * 512, 0x1000, 0);
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for (int j = 0; j < 512; j++) {
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if ((*OriginalPDPT)[j] & 1) {
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if ((*OriginalPDPT)[j] & 128) {
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(*NewPDPT)[j] = (*OriginalPDPT)[j];
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} else {
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u64 (*OriginalPD)[512] = (u64(*)[512])(((*OriginalPDPT)[j] & 0x000ffffffffff000));
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u64 (*NewPD)[512] = KernelHeapAlloc(sizeof(u64) * 512, 0x1000, 0);
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for (int k = 0; k < 512; k++) {
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if ((*OriginalPD)[k] & 1) {
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if ((*OriginalPD)[k] & 128) {
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(*NewPD)[k] = (*OriginalPD)[k];
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} else {
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u64 (*OriginalPT)[512] = (u64(*)[512])(((*OriginalPD)[k] & 0x000ffffffffff000));
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u64 (*NewPT)[512] = KernelHeapAlloc(sizeof(u64) * 512, 0x1000, 0);
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if ((s64)NewPT <= 0) Panic("Failed to allocate memory");
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for (int l = 0; l < 512; l++) {
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(*NewPT)[l] = (*OriginalPT)[l];
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}
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NewPT = (void*)((u64)OriginalPT | (((*OriginalPD)[k] & ~0x000ffffffffff000)));
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(*NewPD)[k] = (u64)NewPT;
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}
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} else (*NewPD)[k] = 0;
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}
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NewPD = (void*)((uptr)NewPD | (((*OriginalPDPT)[j]) & ~0x0007fffffffff000));
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(*NewPDPT)[j] = (u64)NewPD;
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}
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} else (*NewPDPT)[j] = 0;
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}
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NewPDPT = (void*)((uptr)NewPDPT | (((*OriginalPML4)[i]) & ~0x0007fffffffff000));
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(*NewPML4)[i] = (u64)NewPDPT;
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} else (*NewPML4)[i] = 0;
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}
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// Save these
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VmemOriginalPML4 = OriginalPML4;
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VmemPML4 = NewPML4;
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// Load our new page table
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CR3 ^= (u64)VmemOriginalPML4;
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CR3 |= ((u64)VmemPML4) & 0x0007fffffffff000;
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asm volatile ("mov %q0, %%cr3" : : "r" (CR3));
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}
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