Memory heap and allocator

memory.h

@@ -0,0 +1,75 @@
+#ifndef MEMORY_H
+#define MEMORY_H
+
+#include <efi.h>
+#include "boot_info.h"
+
+/* Page size constants */
+#define PAGE_SIZE       4096
+#define PAGE_SHIFT      12
+#define PAGE_MASK       (~(UINT64)(PAGE_SIZE - 1))
+
+/* Page table entry flags */
+#define PTE_PRESENT     (1ULL << 0)
+#define PTE_WRITABLE    (1ULL << 1)
+#define PTE_USER        (1ULL << 2)
+#define PTE_WRITETHROUGH (1ULL << 3)
+#define PTE_NOCACHE     (1ULL << 4)
+#define PTE_ACCESSED    (1ULL << 5)
+#define PTE_DIRTY       (1ULL << 6)
+#define PTE_HUGE        (1ULL << 7)
+#define PTE_GLOBAL      (1ULL << 8)
+#define PTE_NX          (1ULL << 63)
+
+#define PTE_ADDR_MASK   0x000FFFFFFFFFF000ULL
+
+/* PMM pool: 16 MB managed by the kernel */
+#define PMM_POOL_SIZE   (16ULL * 1024 * 1024)
+#define PMM_POOL_PAGES  (PMM_POOL_SIZE / PAGE_SIZE)
+
+/* Heap constants */
+#define HEAP_INITIAL_PAGES  64   /* 256 KB initial heap */
+#define HEAP_BLOCK_MAGIC    0xDEADBEEFU
+#define HEAP_BLOCK_FREE     0
+#define HEAP_BLOCK_USED     1
+#define HEAP_ALIGN          16
+
+/* -------- Physical Memory Manager -------- */
+
+void    pmm_init(BootInfo *Boot);
+UINT64  pmm_alloc_page(void);
+void    pmm_free_page(UINT64 phys_addr);
+UINT64  pmm_alloc_pages(UINTN count);
+void    pmm_free_pages(UINT64 phys_addr, UINTN count);
+UINTN   pmm_get_free_pages(void);
+UINTN   pmm_get_total_pages(void);
+
+/* -------- Paging -------- */
+
+void    paging_init(BootInfo *Boot);
+BOOLEAN paging_map_page(UINT64 virt, UINT64 phys, UINT64 flags);
+void    paging_unmap_page(UINT64 virt);
+UINT64  paging_get_phys(UINT64 virt);
+
+/* -------- Heap Allocator -------- */
+
+typedef struct HeapBlock {
+    UINT32 magic;
+    UINT32 state;
+    UINTN  size;              /* usable bytes (excludes header) */
+    struct HeapBlock *next;
+    struct HeapBlock *prev;
+} HeapBlock;
+
+void  heap_init(BootInfo *Boot);
+void *kmalloc(UINTN size);
+void  kfree(void *ptr);
+void  heap_get_stats(UINTN *total, UINTN *used, UINTN *free_mem,
+                     UINTN *num_blocks);
+
+/* -------- Top-level helpers -------- */
+
+void memory_init(BootInfo *Boot);
+void memory_print_stats(BootInfo *Boot);
+
+#endif