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-rw-r--r--src/kernel/mm/pmm.cc305
1 files changed, 0 insertions, 305 deletions
diff --git a/src/kernel/mm/pmm.cc b/src/kernel/mm/pmm.cc
deleted file mode 100644
index d3d99ba..0000000
--- a/src/kernel/mm/pmm.cc
+++ /dev/null
@@ -1,305 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Copyright (C) 2026 Richard QIn
- */
-#include "common/types.h"
-#include "kernel/riscv.h"
-#include "kernel/pmm.h"
-#include "kernel/mm.h"
-#include "kernel/fdt.h"
-// #include "kernel/spinlock.h"
-#include "drivers/uart.h"
-#include "lib/string.h"
-
-extern "C" char kernel_end[];
-extern uint64 g_dtb_addr;
-
-// Default memory size 128MB, will be overwritten by FDT
-uint64 g_phys_size = 128 * 1024 * 1024;
-
-namespace PMM
-{
- // Global metadata array pointer
- struct Page *mem_map = nullptr;
- // Total number of physical memory pages
- uint64 total_pages = 0;
- // Free list array (free_area[k] stores the head of the free block list of order=k)
- struct Page *free_area[MAX_ORDER];
- // Protective lock
- Spinlock pmm_lock;
-
- struct Page *pa_to_page(uint64 pa)
- {
- if (pa < KERNBASE || pa >= PHYSTOP)
- return nullptr;
- uint64 pfn = (pa - KERNBASE) >> PGSHIFT;
- if (pfn >= total_pages)
- return nullptr;
- return &mem_map[pfn];
- }
-
- uint64 page_to_pa(struct Page *page)
- {
- uint64 pfn = page - mem_map;
- return KERNBASE + (pfn << PGSHIFT);
- }
-
- void list_add(struct Page *page, int order)
- {
- page->order = order;
- page->flags = 0; // Mark as available
- page->next = free_area[order];
- page->prev = nullptr;
-
- if (free_area[order])
- {
- free_area[order]->prev = page;
- }
- free_area[order] = page;
- }
-
- void list_del(struct Page* page, int order)
- {
- if (page->prev)
- {
- page->prev->next = page->next;
- }
- else
- {
- free_area[order] = page->next;
- }
- if (page->next)
- {
- page->next->prev = page->prev;
- }
- page->next = nullptr;
- page->prev = nullptr;
- }
-
- void init()
- {
- // Use FDT memory size if available
- if (g_devices.mem_size > 0)
- {
- g_phys_size = g_devices.mem_size;
- }
-
- pmm_lock.init("pmm");
-
- uint64 kern_end_pa = PGROUNDUP((uint64)kernel_end);
- total_pages = (PHYSTOP - KERNBASE) / PGSIZE;
-
- Drivers::uart_puts(ANSI_GREEN "[PMM] Total RAM size: ");
- Drivers::uart_put_int(g_phys_size / (1024 * 1024));
- Drivers::uart_puts(" MB\n" ANSI_RESET);
- // Place the mem_map array
- // mem_map is located immediately after kernel_end
- mem_map = (struct Page*)kern_end_pa;
-
- uint64 mem_map_size = total_pages * sizeof(struct Page);
- uint64 free_mem_start = PGROUNDUP(kern_end_pa + mem_map_size);
-
- Drivers::uart_puts(ANSI_GREEN "[PMM] MemMap placed at: " );
- Drivers::print_hex((uint64)mem_map);
- Drivers::uart_puts("\n" ANSI_RESET);
-
- Drivers::uart_puts(ANSI_GREEN "[PMM] Free memory starts at: ");
- Drivers::print_hex(free_mem_start);
- Drivers::uart_puts("\n" ANSI_RESET);
-
- if (free_mem_start >= PHYSTOP)
- {
- Drivers::uart_puts(ANSI_RED "[PMM] Error - Kernel too large, no memory left!\n" ANSI_RESET);
- while (1)
- ;
- }
-
- // Initialize all page states
- for (uint64 i = 0; i < total_pages; i++)
- {
- mem_map[i].flags = PG_reserved;
- mem_map[i].order = 0;
- mem_map[i].refcnt = 0;
- mem_map[i].next = nullptr;
- mem_map[i].prev = nullptr;
- }
-
- for (int i = 0; i < MAX_ORDER; i++)
- {
- free_area[i] = nullptr;
- }
-
- // Release actual free memory to the allocator
- // Range: [free_mem_start, PHYSTOP)
- // Note: need to avoid the page where the DTB is located
- uint64 dtb_pa_start = PGROUNDDOWN(g_dtb_addr);
- uint64 dtb_pa_end = PGROUNDUP(g_dtb_addr + 0x10000);
-
- uint64 p = free_mem_start;
- while (p < PHYSTOP)
- {
- if (p >= dtb_pa_start && p < dtb_pa_end)
- {
- p += PGSIZE;
- continue;
- }
-
- // Mark the page as Used, then call free_pages to release it
- // This allows free_pages to handle the merging logic automatically
- struct Page *page = pa_to_page(p);
- if (page)
- {
- page->flags = PG_used;
- free_pages((void *)p, 0); // Release page by page, let Buddy merge automatically
- }
- p += PGSIZE;
-
-
- }
-
- }
-
- void *alloc_pages(int order)
- {
- if (order < 0 || order >= MAX_ORDER)
- return nullptr;
-
- pmm_lock.acquire();
-
- int current_order = order;
- while (current_order < MAX_ORDER)
- {
- if (free_area[current_order])
- {
- // Find free block
- struct Page *page = free_area[current_order];
- list_del(page, current_order);
-
- // If the block is too large, split it.
- while (current_order > order)
- {
- current_order--;
- // page is the left part (Buddy A)
- // buddy is the right part (Buddy B)
- // Pointer addition: Page* + n is equivalent to address offset n * sizeof(Page)
- // Since mem_map is linearly mapped, mem_map[i + (1<<k)] exactly corresponds to physical address + (1<<k)*PGSIZE
- struct Page *buddy = page + (1 << current_order);
-
- // Add the buddy to a lower-level linked list
- list_add(buddy, current_order);
- }
-
- // Mark as Occupied
- page->flags = PG_used;
- page->order = order; // Record the orders that have been assigned
- page->refcnt = 1;
-
- pmm_lock.release();
- return (void *)page_to_pa(page);
- }
- current_order++;
- }
- pmm_lock.release();
- Drivers::uart_puts("PMM: OOM alloc_pages\n");
- return nullptr;
- }
-
- void free_pages(void *pa, int order)
- {
- if (!pa)
- return;
- struct Page *page = pa_to_page((uint64)pa);
- if (!page)
- return;
- pmm_lock.acquire();
-
- if (!(page->flags & PG_used))
- {
- Drivers::uart_puts("PMM: Double free warning\n");
- pmm_lock.release();
- return;
- }
-
- // Mark as basic status
- page->flags = 0;
- page->refcnt = 0;
-
- // try merge
- uint64 page_idx = page - mem_map;
-
- while (order < MAX_ORDER - 1)
- {
- // calculate Buddy index: index ^ (1 << order)
- uint64 buddy_idx = page_idx ^ (1 << order);
- struct Page *buddy = &mem_map[buddy_idx];
-
- // Check if the Buddy can be merged:
- // 1. Must be within the memory range
- // 2. Must be free (flags == 0)
- // 3. Must be at the current order (to prevent merging already split small blocks)
- if (buddy_idx >= total_pages || (buddy->flags & PG_used) || (buddy->flags & PG_reserved) || buddy->order != order)
- {
- break;
- }
-
- // Can be merged!
- // Remove Buddy from the free list
- list_del(buddy, order);
-
- // Update the current block to the merged block
- // The starting address of the merged block is the smaller one between index and buddy_index
- if (buddy_idx < page_idx)
- {
- page = buddy;
- page_idx = buddy_idx;
- }
-
- order++;
- }
-
- // Insert into the final order linked list
- list_add(page, order);
-
- pmm_lock.release();
- }
-
- void *alloc_page()
- {
- void *p = alloc_pages(0);
- if (p)
- {
- memset(p, 0, PGSIZE);
- }
- return p;
- }
-
- void free_page(void *pa)
- {
- free_pages(pa, 0);
- }
-
- void print_free_lists()
- {
- // Debug print the number of free blocks at each level
- Drivers::uart_puts("PMM Stats: [ ");
- for (int i = 0; i < MAX_ORDER; i++)
- {
- int count = 0;
- struct Page *p = free_area[i];
- while (p)
- {
- count++;
- p = p->next;
- }
- if (count > 0)
- {
- Drivers::uart_puts("Order");
- // Drivers::uart_put_int(i);
- Drivers::uart_puts(":");
- // Drivers::uart_put_int(count);
- Drivers::uart_puts(" ");
- }
- }
- Drivers::uart_puts("]\n");
- }
-} // namespace PMM
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