Stage 2

Makefile

@@ -68,6 +68,8 @@ SOURCES := \
     clks/kernel/log.c \
     clks/kernel/limine_requests.c \
     clks/kernel/tty.c \
+    clks/kernel/pmm.c \
+    clks/kernel/heap.c \
     clks/lib/string.c \
     clks/drivers/serial/serial.c \
     clks/drivers/video/framebuffer.c \

clks/include/clks/boot.h

@@ -6,5 +6,6 @@
 
 clks_bool clks_boot_base_revision_supported(void);
 const struct limine_framebuffer *clks_boot_get_framebuffer(void);
+const struct limine_memmap_response *clks_boot_get_memmap(void);
 
 #endif

clks/include/clks/heap.h

@@ -0,0 +1,19 @@
+#ifndef CLKS_HEAP_H
+#define CLKS_HEAP_H
+
+#include <clks/types.h>
+
+struct clks_heap_stats {
+    usize total_bytes;
+    usize used_bytes;
+    usize free_bytes;
+    u64 alloc_count;
+    u64 free_count;
+};
+
+void clks_heap_init(void);
+void *clks_kmalloc(usize size);
+void clks_kfree(void *ptr);
+struct clks_heap_stats clks_heap_get_stats(void);
+
+#endif

clks/include/clks/limine.h

@@ -23,6 +23,24 @@
         0xa3148604f6fab11bULL \
     }
 
+#define LIMINE_MEMMAP_REQUEST \
+    { \
+        LIMINE_COMMON_MAGIC, \
+        LIMINE_REQUEST_MAGIC, \
+        0x67cf3d9d378a806fULL, \
+        0xe304acdfc50c3c62ULL \
+    }
+
+#define LIMINE_MEMMAP_USABLE                 0ULL
+#define LIMINE_MEMMAP_RESERVED               1ULL
+#define LIMINE_MEMMAP_ACPI_RECLAIMABLE       2ULL
+#define LIMINE_MEMMAP_ACPI_NVS               3ULL
+#define LIMINE_MEMMAP_BAD_MEMORY             4ULL
+#define LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE 5ULL
+#define LIMINE_MEMMAP_EXECUTABLE_AND_MODULES 6ULL
+#define LIMINE_MEMMAP_FRAMEBUFFER            7ULL
+#define LIMINE_MEMMAP_RESERVED_MAPPED        8ULL
+
 struct limine_framebuffer {
     void *address;
     u64 width;
@@ -53,4 +71,22 @@ struct limine_framebuffer_request {
     struct limine_framebuffer_response *response;
 };
 
+struct limine_memmap_entry {
+    u64 base;
+    u64 length;
+    u64 type;
+};
+
+struct limine_memmap_response {
+    u64 revision;
+    u64 entry_count;
+    struct limine_memmap_entry **entries;
+};
+
+struct limine_memmap_request {
+    u64 id[4];
+    u64 revision;
+    struct limine_memmap_response *response;
+};
+
 #endif

clks/include/clks/pmm.h

@@ -0,0 +1,21 @@
+#ifndef CLKS_PMM_H
+#define CLKS_PMM_H
+
+#include <clks/limine.h>
+#include <clks/types.h>
+
+#define CLKS_PAGE_SIZE 4096ULL
+
+struct clks_pmm_stats {
+    u64 managed_pages;
+    u64 free_pages;
+    u64 used_pages;
+    u64 dropped_pages;
+};
+
+void clks_pmm_init(const struct limine_memmap_response *memmap);
+u64 clks_pmm_alloc_page(void);
+void clks_pmm_free_page(u64 phys_addr);
+struct clks_pmm_stats clks_pmm_get_stats(void);
+
+#endif

clks/kernel/heap.c

@@ -0,0 +1,176 @@
+#include <clks/heap.h>
+#include <clks/string.h>
+#include <clks/types.h>
+
+#define CLKS_HEAP_ARENA_SIZE (1024ULL * 1024ULL)
+#define CLKS_HEAP_ALIGN      16ULL
+#define CLKS_HEAP_MAGIC      0x434C454F4E4F534FULL
+
+struct clks_heap_block {
+    usize size;
+    clks_bool is_free;
+    struct clks_heap_block *next;
+    struct clks_heap_block *prev;
+    u64 magic;
+};
+
+static u8 clks_heap_arena[CLKS_HEAP_ARENA_SIZE] __attribute__((aligned(16)));
+static struct clks_heap_block *clks_heap_head = CLKS_NULL;
+static clks_bool clks_heap_ready = CLKS_FALSE;
+
+static usize clks_heap_used_bytes = 0;
+static u64 clks_heap_alloc_count = 0;
+static u64 clks_heap_free_count = 0;
+
+static usize clks_heap_align_up(usize value) {
+    return (value + (CLKS_HEAP_ALIGN - 1ULL)) & ~(CLKS_HEAP_ALIGN - 1ULL);
+}
+
+static void clks_heap_split_block(struct clks_heap_block *block, usize need_size) {
+    usize min_tail_size = sizeof(struct clks_heap_block) + CLKS_HEAP_ALIGN;
+
+    if (block->size < (need_size + min_tail_size)) {
+        return;
+    }
+
+    {
+        u8 *new_block_addr = (u8 *)block + sizeof(struct clks_heap_block) + need_size;
+        struct clks_heap_block *new_block = (struct clks_heap_block *)new_block_addr;
+
+        new_block->size = block->size - need_size - sizeof(struct clks_heap_block);
+        new_block->is_free = CLKS_TRUE;
+        new_block->next = block->next;
+        new_block->prev = block;
+        new_block->magic = CLKS_HEAP_MAGIC;
+
+        if (block->next != CLKS_NULL) {
+            block->next->prev = new_block;
+        }
+
+        block->next = new_block;
+        block->size = need_size;
+    }
+}
+
+static void clks_heap_merge_next(struct clks_heap_block *block) {
+    struct clks_heap_block *next = block->next;
+
+    if (next == CLKS_NULL) {
+        return;
+    }
+
+    if (next->is_free == CLKS_FALSE) {
+        return;
+    }
+
+    if (next->magic != CLKS_HEAP_MAGIC) {
+        return;
+    }
+
+    block->size += sizeof(struct clks_heap_block) + next->size;
+    block->next = next->next;
+
+    if (next->next != CLKS_NULL) {
+        next->next->prev = block;
+    }
+}
+
+void clks_heap_init(void) {
+    clks_memset(clks_heap_arena, 0, sizeof(clks_heap_arena));
+
+    clks_heap_head = (struct clks_heap_block *)clks_heap_arena;
+    clks_heap_head->size = CLKS_HEAP_ARENA_SIZE - sizeof(struct clks_heap_block);
+    clks_heap_head->is_free = CLKS_TRUE;
+    clks_heap_head->next = CLKS_NULL;
+    clks_heap_head->prev = CLKS_NULL;
+    clks_heap_head->magic = CLKS_HEAP_MAGIC;
+
+    clks_heap_used_bytes = 0;
+    clks_heap_alloc_count = 0;
+    clks_heap_free_count = 0;
+    clks_heap_ready = CLKS_TRUE;
+}
+
+void *clks_kmalloc(usize size) {
+    struct clks_heap_block *current;
+    usize aligned_size;
+
+    if (clks_heap_ready == CLKS_FALSE) {
+        return CLKS_NULL;
+    }
+
+    if (size == 0) {
+        return CLKS_NULL;
+    }
+
+    aligned_size = clks_heap_align_up(size);
+    current = clks_heap_head;
+
+    while (current != CLKS_NULL) {
+        if (current->magic != CLKS_HEAP_MAGIC) {
+            return CLKS_NULL;
+        }
+
+        if (current->is_free == CLKS_TRUE && current->size >= aligned_size) {
+            clks_heap_split_block(current, aligned_size);
+            current->is_free = CLKS_FALSE;
+            clks_heap_used_bytes += current->size;
+            clks_heap_alloc_count++;
+            return (void *)((u8 *)current + sizeof(struct clks_heap_block));
+        }
+
+        current = current->next;
+    }
+
+    return CLKS_NULL;
+}
+
+void clks_kfree(void *ptr) {
+    struct clks_heap_block *block;
+
+    if (clks_heap_ready == CLKS_FALSE) {
+        return;
+    }
+
+    if (ptr == CLKS_NULL) {
+        return;
+    }
+
+    block = (struct clks_heap_block *)((u8 *)ptr - sizeof(struct clks_heap_block));
+
+    if (block->magic != CLKS_HEAP_MAGIC) {
+        return;
+    }
+
+    if (block->is_free == CLKS_TRUE) {
+        return;
+    }
+
+    block->is_free = CLKS_TRUE;
+
+    if (clks_heap_used_bytes >= block->size) {
+        clks_heap_used_bytes -= block->size;
+    } else {
+        clks_heap_used_bytes = 0;
+    }
+
+    clks_heap_free_count++;
+
+    clks_heap_merge_next(block);
+
+    if (block->prev != CLKS_NULL && block->prev->is_free == CLKS_TRUE) {
+        clks_heap_merge_next(block->prev);
+    }
+}
+
+struct clks_heap_stats clks_heap_get_stats(void) {
+    struct clks_heap_stats stats;
+
+    stats.total_bytes = CLKS_HEAP_ARENA_SIZE - sizeof(struct clks_heap_block);
+    stats.used_bytes = clks_heap_used_bytes;
+    stats.free_bytes = stats.total_bytes - stats.used_bytes;
+    stats.alloc_count = clks_heap_alloc_count;
+    stats.free_count = clks_heap_free_count;
+
+    return stats;
+}

clks/kernel/kmain.c

@@ -1,14 +1,20 @@
 #include <clks/boot.h>
 #include <clks/cpu.h>
 #include <clks/framebuffer.h>
+#include <clks/heap.h>
 #include <clks/kernel.h>
 #include <clks/log.h>
+#include <clks/pmm.h>
 #include <clks/serial.h>
 #include <clks/tty.h>
 #include <clks/types.h>
 
 void clks_kernel_main(void) {
     const struct limine_framebuffer *boot_fb;
+    const struct limine_memmap_response *boot_memmap;
+    struct clks_pmm_stats pmm_stats;
+    struct clks_heap_stats heap_stats;
+    void *heap_probe = CLKS_NULL;
 
     clks_serial_init();
 
@@ -24,7 +30,7 @@ void clks_kernel_main(void) {
         clks_tty_init();
     }
 
-    clks_log(CLKS_LOG_INFO, "BOOT", "CLEONOS STAGE1 START");
+    clks_log(CLKS_LOG_INFO, "BOOT", "CLEONOS STAGE2 START");
 
     if (boot_fb == CLKS_NULL) {
         clks_log(CLKS_LOG_WARN, "VIDEO", "NO FRAMEBUFFER FROM LIMINE");
@@ -41,6 +47,36 @@ void clks_kernel_main(void) {
     clks_log(CLKS_LOG_INFO, "ARCH", "AARCH64 ONLINE");
 #endif
 
+    boot_memmap = clks_boot_get_memmap();
+
+    if (boot_memmap == CLKS_NULL) {
+        clks_log(CLKS_LOG_ERROR, "MEM", "NO LIMINE MEMMAP RESPONSE");
+        clks_cpu_halt_forever();
+    }
+
+    clks_pmm_init(boot_memmap);
+    pmm_stats = clks_pmm_get_stats();
+
+    clks_log_hex(CLKS_LOG_INFO, "PMM", "MANAGED_PAGES", pmm_stats.managed_pages);
+    clks_log_hex(CLKS_LOG_INFO, "PMM", "FREE_PAGES", pmm_stats.free_pages);
+    clks_log_hex(CLKS_LOG_INFO, "PMM", "USED_PAGES", pmm_stats.used_pages);
+    clks_log_hex(CLKS_LOG_INFO, "PMM", "DROPPED_PAGES", pmm_stats.dropped_pages);
+
+    clks_heap_init();
+    heap_stats = clks_heap_get_stats();
+
+    clks_log_hex(CLKS_LOG_INFO, "HEAP", "TOTAL_BYTES", heap_stats.total_bytes);
+    clks_log_hex(CLKS_LOG_INFO, "HEAP", "FREE_BYTES", heap_stats.free_bytes);
+
+    heap_probe = clks_kmalloc(128);
+
+    if (heap_probe == CLKS_NULL) {
+        clks_log(CLKS_LOG_ERROR, "HEAP", "KMALLOC SELFTEST FAILED");
+    } else {
+        clks_log(CLKS_LOG_INFO, "HEAP", "KMALLOC SELFTEST OK");
+        clks_kfree(heap_probe);
+    }
+
     clks_log(CLKS_LOG_INFO, "TTY", "VIRTUAL TTY0 READY");
     clks_log(CLKS_LOG_DEBUG, "KERNEL", "IDLE LOOP ENTER");
 

clks/kernel/limine_requests.c

@@ -14,6 +14,13 @@ CLKS_USED static volatile struct limine_framebuffer_request limine_framebuffer_r
         .response = CLKS_NULL,
     };
 
+CLKS_USED static volatile struct limine_memmap_request limine_memmap_request
+    __attribute__((section(".limine_requests"))) = {
+        .id = LIMINE_MEMMAP_REQUEST,
+        .revision = 0,
+        .response = CLKS_NULL,
+    };
+
 CLKS_USED static volatile u64 limine_requests_end[]
     __attribute__((section(".limine_requests_end"))) = LIMINE_REQUESTS_END_MARKER;
 
@@ -34,3 +41,13 @@ const struct limine_framebuffer *clks_boot_get_framebuffer(void) {
 
     return request->response->framebuffers[0];
 }
+
+const struct limine_memmap_response *clks_boot_get_memmap(void) {
+    volatile struct limine_memmap_request *request = &limine_memmap_request;
+
+    if (request->response == CLKS_NULL) {
+        return CLKS_NULL;
+    }
+
+    return request->response;
+}

clks/kernel/pmm.c

@@ -0,0 +1,105 @@
+#include <clks/pmm.h>
+#include <clks/string.h>
+#include <clks/types.h>
+
+#define CLKS_PMM_MAX_TRACKED_PAGES 262144ULL
+#define CLKS_PMM_MIN_USABLE_ADDR   0x100000ULL
+
+static u64 clks_pmm_free_stack[CLKS_PMM_MAX_TRACKED_PAGES];
+static u64 clks_pmm_free_top = 0;
+static u64 clks_pmm_managed_pages = 0;
+static u64 clks_pmm_dropped_pages = 0;
+
+static u64 clks_align_up_u64(u64 value, u64 alignment) {
+    return (value + alignment - 1ULL) & ~(alignment - 1ULL);
+}
+
+static u64 clks_align_down_u64(u64 value, u64 alignment) {
+    return value & ~(alignment - 1ULL);
+}
+
+void clks_pmm_init(const struct limine_memmap_response *memmap) {
+    u64 i;
+
+    clks_pmm_free_top = 0;
+    clks_pmm_managed_pages = 0;
+    clks_pmm_dropped_pages = 0;
+    clks_memset(clks_pmm_free_stack, 0, sizeof(clks_pmm_free_stack));
+
+    if (memmap == CLKS_NULL) {
+        return;
+    }
+
+    for (i = 0; i < memmap->entry_count; i++) {
+        const struct limine_memmap_entry *entry = memmap->entries[i];
+        u64 start;
+        u64 end;
+        u64 addr;
+
+        if (entry == CLKS_NULL) {
+            continue;
+        }
+
+        if (entry->type != LIMINE_MEMMAP_USABLE) {
+            continue;
+        }
+
+        start = clks_align_up_u64(entry->base, CLKS_PAGE_SIZE);
+        end = clks_align_down_u64(entry->base + entry->length, CLKS_PAGE_SIZE);
+
+        if (end <= start) {
+            continue;
+        }
+
+        for (addr = start; addr < end; addr += CLKS_PAGE_SIZE) {
+            if (addr < CLKS_PMM_MIN_USABLE_ADDR) {
+                continue;
+            }
+
+            if (clks_pmm_free_top < CLKS_PMM_MAX_TRACKED_PAGES) {
+                clks_pmm_free_stack[clks_pmm_free_top] = addr;
+                clks_pmm_free_top++;
+                clks_pmm_managed_pages++;
+            } else {
+                clks_pmm_dropped_pages++;
+            }
+        }
+    }
+}
+
+u64 clks_pmm_alloc_page(void) {
+    if (clks_pmm_free_top == 0) {
+        return 0ULL;
+    }
+
+    clks_pmm_free_top--;
+    return clks_pmm_free_stack[clks_pmm_free_top];
+}
+
+void clks_pmm_free_page(u64 phys_addr) {
+    if (phys_addr == 0ULL) {
+        return;
+    }
+
+    if ((phys_addr & (CLKS_PAGE_SIZE - 1ULL)) != 0ULL) {
+        return;
+    }
+
+    if (clks_pmm_free_top >= CLKS_PMM_MAX_TRACKED_PAGES) {
+        return;
+    }
+
+    clks_pmm_free_stack[clks_pmm_free_top] = phys_addr;
+    clks_pmm_free_top++;
+}
+
+struct clks_pmm_stats clks_pmm_get_stats(void) {
+    struct clks_pmm_stats stats;
+
+    stats.managed_pages = clks_pmm_managed_pages;
+    stats.free_pages = clks_pmm_free_top;
+    stats.used_pages = clks_pmm_managed_pages - clks_pmm_free_top;
+    stats.dropped_pages = clks_pmm_dropped_pages;
+
+    return stats;
+}

docs/stage2.md

@@ -0,0 +1,35 @@
+# CLeonOS Stage2
+
+## Stage Goal
+- Introduce foundational memory management for CLKS.
+- Initialize physical memory manager (PMM) from Limine memmap.
+- Add kernel heap allocator (`clks_kmalloc`/`clks_kfree`) without external libc.
+- Emit memory statistics via kernel log during boot.
+
+## Acceptance Criteria
+- Kernel receives valid Limine memmap response.
+- PMM initializes and prints managed/free/used/dropped page counts.
+- Heap initializes and prints total/free bytes.
+- `clks_kmalloc` self-test allocates and frees successfully.
+- Kernel still reaches idle loop without panic.
+
+## Build Targets
+- `make setup`
+- `make iso`
+- `make run`
+- `make debug`
+
+## QEMU Command
+- `qemu-system-x86_64 -M q35 -m 1024M -cdrom build/CLeonOS-x86_64.iso -serial stdio`
+
+## Common Bugs and Debugging
+- `NO LIMINE MEMMAP RESPONSE`:
+  - Check Limine protocol entry in `configs/limine.conf` and ensure `protocol: limine` is used.
+- PMM managed pages are 0:
+  - Validate `LIMINE_MEMMAP_REQUEST` ID and section placement in `limine_requests.c`.
+- Heap self-test failed:
+  - Inspect `heap.c` block split/merge logic and verify allocator init was called.
+- Limine panic about ELF segment permissions:
+  - Ensure linker sections are page-aligned and segment permissions do not share pages.
+- Limine artifacts missing during ISO packaging:
+  - Verify `make setup` completed and `limine/bin/*` files exist.