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Paging: mapped kernel, fb, early-mem, HHDM

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xamidev
2026-01-02 13:40:44 +01:00
parent bb5fb9db33
commit c065df6ff3
4 changed files with 188 additions and 15 deletions
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26
src/mem/paging/paging.h
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@@ -5,8 +5,9 @@
#define BITS_PER_ROW 64
#include <stdint.h>
#include <limine.h>
void paging_init();
void paging_init(struct limine_kernel_address_response* kaddr, struct limine_framebuffer* fb);
extern uint64_t hhdm_off;
@@ -16,14 +17,27 @@ extern uint64_t hhdm_off;
// Stole it
#define ALIGN_UP(x, align) (((x) + ((align) - 1)) & ~((align) - 1))
#define ALIGN_DOWN(x, align) ((x) & ~((align) - 1))
#define PAGE_ALIGN_DOWN(x) ((x) & ~0xFFFULL)
#define PML4_INDEX(x) (((x) >> 39) & 0x1FF)
#define PDPT_INDEX(x) (((x) >> 30) & 0x1FF)
#define PD_INDEX(x) (((x) >> 21) & 0x1FF)
#define PT_INDEX(x) (((x) >> 12) & 0x1FF)
// Page entry special bits
// Bits set on a parent (directory, table) fall back to their children
#define PTE_PRESENT (1ULL << 0)
#define PTE_WRITE (1ULL << 1)
#define PTE_USER (1ULL << 2)
#define PTE_HUGE (1ULL << 7)
#define PTE_NOEXEC (1ULL << 63)
#define PTE_PRESENT (1ULL << 0)
#define PTE_WRITABLE (1ULL << 1)
#define PTE_USER (1ULL << 2)
#define PTE_PWT (1ULL << 3)
#define PTE_PCD (1ULL << 4)
#define PTE_HUGE (1ULL << 7)
#define PTE_NOEXEC (1ULL << 63)
// Specified in linker.ld
#define KERNEL_BASE 0xFFFFFFFF80000000ULL
// 2 MB should be enough (as of now, the whole kernel ELF is around 75kb)
#define KERNEL_SIZE 0x200000
#endif