105 lines
3.6 KiB
C
105 lines
3.6 KiB
C
/*
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* memory.h – Memory management subsystem declarations.
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*
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* Three layers:
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* PMM – bitmap-based physical page-frame allocator (16 MB pool)
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* Paging – walks / creates 4-level x86-64 page tables
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* Heap – first-fit free-list allocator with block coalescing
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*/
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#ifndef MEMORY_H
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#define MEMORY_H
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#include "kernel_types.h"
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#include "boot_info.h"
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/* ================================================================
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* Page-level constants
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* ================================================================ */
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#define PAGE_SIZE 4096
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#define PAGE_SHIFT 12
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#define PAGE_MASK (~(UINT64)(PAGE_SIZE - 1))
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/* ================================================================
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* Page-table entry flags (x86-64 4-level paging)
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* ================================================================ */
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#define PTE_PRESENT (1ULL << 0)
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#define PTE_WRITABLE (1ULL << 1)
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#define PTE_USER (1ULL << 2)
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#define PTE_WRITETHROUGH (1ULL << 3)
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#define PTE_NOCACHE (1ULL << 4)
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#define PTE_ACCESSED (1ULL << 5)
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#define PTE_DIRTY (1ULL << 6)
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#define PTE_HUGE (1ULL << 7) /* 2 MB or 1 GB page */
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#define PTE_GLOBAL (1ULL << 8)
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#define PTE_NX (1ULL << 63) /* No-Execute */
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#define PTE_ADDR_MASK 0x000FFFFFFFFFF000ULL
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/* ================================================================
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* Physical Memory Manager (PMM)
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* ================================================================ */
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/* Size of the PMM-managed pool (allocated from UEFI at boot). */
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#define PMM_POOL_SIZE (16ULL * 1024 * 1024) /* 16 MB */
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#define PMM_POOL_PAGES (PMM_POOL_SIZE / PAGE_SIZE)
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void pmm_init(BootInfo *Boot);
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UINT64 pmm_alloc_page(void);
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void pmm_free_page(UINT64 phys_addr);
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UINT64 pmm_alloc_pages(UINTN count);
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void pmm_free_pages(UINT64 phys_addr, UINTN count);
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UINTN pmm_get_free_pages(void);
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UINTN pmm_get_total_pages(void);
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/* ================================================================
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* Paging
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* ================================================================ */
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void paging_init(BootInfo *Boot);
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BOOLEAN paging_map_page(UINT64 virt, UINT64 phys, UINT64 flags);
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void paging_unmap_page(UINT64 virt);
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UINT64 paging_get_phys(UINT64 virt);
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/* ================================================================
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* Heap allocator
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* ================================================================ */
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#define HEAP_INITIAL_PAGES 64 /* 256 KB initial heap */
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#define HEAP_BLOCK_MAGIC 0xDEADBEEFU /* corruption-detection canary */
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#define HEAP_BLOCK_FREE 0
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#define HEAP_BLOCK_USED 1
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#define HEAP_ALIGN 16 /* minimum allocation alignment */
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/*
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* HeapBlock – header placed immediately before each allocation.
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* Blocks form a doubly-linked free-list.
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*/
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typedef struct HeapBlock {
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UINT32 magic; /* must be HEAP_BLOCK_MAGIC */
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UINT32 state; /* HEAP_BLOCK_FREE / _USED */
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UINTN size; /* usable bytes (excludes hdr) */
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struct HeapBlock *next;
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struct HeapBlock *prev;
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} HeapBlock;
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void heap_init(BootInfo *Boot);
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void *kmalloc(UINTN size);
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void kfree(void *ptr);
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void heap_get_stats(UINTN *total, UINTN *used, UINTN *free_mem,
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UINTN *num_blocks);
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/* ================================================================
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* Top-level helpers
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* ================================================================ */
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/* Initialise all memory subsystems (PMM → paging → heap). */
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void memory_init(BootInfo *Boot);
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/* Print PMM, heap, and paging statistics to the console. */
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void memory_print_stats(BootInfo *Boot);
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#endif /* MEMORY_H */
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