103 lines
2.5 KiB
C
103 lines
2.5 KiB
C
#include <kernel.h>
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#include <init/boot.h>
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#define PAGESIZE (4 * KB)
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// Page directory pointer offset
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typedef ulong pdpe_t;
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// Page directory offset
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typedef ulong pde_t;
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// Page table entry
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typedef ulong pte_t;
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// paging.asm
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void MmLoadPML4(void *);
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void MmEnableWriteProtect(void);
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void MmDisableWriteProtect(void);
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enum
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{
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MF_PRESENT = 1 << 0,
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MF_READWRITE = 1 << 1,
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MF_USERMODE = 1 << 2,
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MF_WRITETHR = 1 << 3,
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MF_CACHEDIS = 1 << 4,
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MF_ACCESSED = 1 << 5,
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MF_DIRTY = 1 << 6,
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MF_HUGE = 1 << 7,
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MF_NX = 1 << 31
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};
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#define RAM_MAX 16
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#define NB_4K 2
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//-----------
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volatile pdpe_t MmPML4[512] __attribute__((__aligned__(4096)));
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volatile pde_t MmPDP[512] __attribute__((__aligned__(4096)));
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volatile pde_t MmPD[512 * RAM_MAX] __attribute__((__aligned__(4096)));
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volatile pte_t MmPT[512 * NB_4K] __attribute__((__aligned__(4096)));
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volatile ulong MmStackGuards[2] = { 0 };
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//
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// Creates our new page table structure and loads it
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void MmInitPaging(void)
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{
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memzero((void *)&MmPML4[0], sizeof(MmPML4));
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memzero((void *)&MmPDP[0], sizeof(MmPDP));
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memzero((void *)&MmPD[0], sizeof(MmPD));
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memzero((void *)&MmPT[0], sizeof(MmPT));
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for (int i = 0; i < 512 * NB_4K; i++) {
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// STACK GUARD PAGE
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if ((ulong)i*4096 == (ulong)BtLoaderInfo.stackEndAddr) {
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MmPT[i] = ((ulong)i * 4096);
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MmStackGuards[0] = i;
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continue;
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}
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// STACK PAGES
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if (
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(ulong)i*4096 < (ulong)BtLoaderInfo.stackEndAddr &&
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(ulong)i*4096 > (ulong)BtLoaderInfo.kernelEndAddr
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) {
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MmPT[i] = ((ulong)i * 4096) | MF_PRESENT | MF_READWRITE;// | MF_NX;
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continue;
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}
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// STACK GARD PAGE
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if ((ulong)i*4096 == (ulong)BtLoaderInfo.kernelEndAddr) {
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MmPT[i] = ((ulong)i * 4096);
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MmStackGuards[1] = i;
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continue;
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}
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MmPT[i] = ((ulong)i * 4096) | MF_PRESENT | MF_READWRITE;
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}
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for (int i = 0; i < NB_4K; i++) {
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MmPD[i] = (ulong)(&MmPT[i*512])| MF_PRESENT | MF_READWRITE;
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}
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for (int i = NB_4K; i < 512 * RAM_MAX; i++) {
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MmPD[i] = ((ulong)i * 2048 * 1024) | MF_PRESENT | MF_READWRITE | MF_HUGE;
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}
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for (int i = 0; i < RAM_MAX; i++) {
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MmPDP[i] = (ulong)(&MmPD[i*512])| MF_PRESENT | MF_READWRITE;
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}
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MmPML4[0] = (ulong)(&MmPDP[0])| MF_PRESENT | MF_READWRITE;
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MmLoadPML4((void *)MmPML4);
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}
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