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os-k/kaleid/kernel/mm/paging.c

72 lines
1.6 KiB
C

#include <kernel.h>
#define PAGESIZE (4 * KB)
// Page directory pointer offset
typedef ulong pdpe_t;
// Page directory offset
typedef ulong pde_t;
// Page table entry
typedef ulong pte_t;
// paging.asm
void MmLoadPML4(void *);
void MmEnableWriteProtect(void);
void MmDisableWriteProtect(void);
enum
{
MF_PRESENT = 1 << 0,
MF_READWRITE = 1 << 1,
MF_USERMODE = 1 << 2,
MF_WRITETHR = 1 << 3,
MF_CACHEDIS = 1 << 4,
MF_ACCESSED = 1 << 5,
MF_DIRTY = 1 << 6,
MF_HUGE = 1 << 7
};
#define RAM 8
#define NB_4K 2
//-----------
volatile pdpe_t PML4[512] __attribute__((__aligned__(4096)));
volatile pde_t PDP[512] __attribute__((__aligned__(4096)));
volatile pde_t PD[512 * RAM] __attribute__((__aligned__(4096)));
volatile pte_t PT[512 * NB_4K] __attribute__((__aligned__(4096)));
void MmInitPaging(void)
{
memzero((void *)&PML4[0], sizeof(PML4));
memzero((void *)&PDP[0], sizeof(PDP));
memzero((void *)&PD[0], sizeof(PD));
memzero((void *)&PT[0], sizeof(PT));
for (int i = 0; i < 512 * NB_4K; i++) {
PT[i] = ((ulong)i * 4096) | MF_PRESENT | MF_READWRITE;
}
for (int i = 0; i < NB_4K; i++) {
PD[i] = (ulong)(&PT[i*512])| MF_PRESENT | MF_READWRITE;
}
for (int i = NB_4K; i < 512 * RAM; i++) {
PD[i] = ((ulong)i * 2048 * 1024) | MF_PRESENT | MF_READWRITE | MF_HUGE;
}
for (int i = 0; i < RAM; i++) {
PDP[i] = (ulong)(&PD[i*512])| MF_PRESENT | MF_READWRITE;
}
PML4[0] = (ulong)(&PDP[0])| MF_PRESENT | MF_READWRITE;
MmLoadPML4((void *)PML4);
}