2 * Physical memory allocation
3 * Copyright (c) 2001,2003,2004 David H. Hovemeyer <daveho@cs.umd.edu>
4 * Copyright (c) 2003, Jeffrey K. Hollingsworth <hollings@cs.umd.edu>
7 * This is free software. You are permitted to use,
8 * redistribute, and modify it as specified in the file "COPYING".
11 #include <geekos/defs.h>
12 #include <geekos/ktypes.h>
13 #include <geekos/kassert.h>
14 #include <geekos/bootinfo.h>
15 #include <geekos/gdt.h>
16 #include <geekos/screen.h>
17 #include <geekos/int.h>
18 #include <geekos/malloc.h>
19 #include <geekos/string.h>
20 #include <geekos/mem.h>
22 #include <geekos/serial.h>
23 #include <geekos/debug.h>
26 /* ----------------------------------------------------------------------
28 * ---------------------------------------------------------------------- */
31 * List of Page structures representing each page of physical memory.
33 struct Page* g_pageList;
36 ulong_t g_ramdiskImage;
37 ulong_t s_ramdiskSize;
41 * Number of pages currently available on the freelist.
43 uint_t g_freePageCount = 0;
48 * the disgusting way to get at the memory assigned to a VM
50 extern ulong_t vm_range_start;
51 extern ulong_t vm_range_end;
52 extern ulong_t guest_kernel_start;
53 extern ulong_t guest_kernel_end;
57 /* ----------------------------------------------------------------------
58 * Private data and functions
59 * ---------------------------------------------------------------------- */
64 extern int debugFaults;
65 #define Debug(args...) if (debugFaults) Print(args)
68 * List of pages available for allocation.
70 static struct Page_List s_freeList;
73 * Total number of physical pages.
75 int unsigned s_numPages;
81 * Add a range of pages to the inventory of physical memory.
83 static void Add_Page_Range(ulong_t start, ulong_t end, int flags)
87 PrintBoth("Start: %u (0x%x), End: %u(0x%x) (Type=0x%.4x)\n", (unsigned int)start, start, (unsigned int)end, end, flags);
89 KASSERT(Is_Page_Multiple(start));
90 KASSERT(Is_Page_Multiple(end));
93 //Print("Adding %lu pages\n", (end - start) / PAGE_SIZE);
95 for (addr = start; addr < end; addr += PAGE_SIZE) {
96 // Print("Adding Page at %u\n", (unsigned int)addr);
97 struct Page *page = Get_Page(addr);
101 if (flags == PAGE_AVAIL) {
102 /* Add the page to the freelist */
103 Add_To_Back_Of_Page_List(&s_freeList, page);
105 /* Update free page count */
108 Set_Next_In_Page_List(page, 0);
109 Set_Prev_In_Page_List(page, 0);
113 // Print("%d pages now in freelist\n", g_freePageCount);
117 /* ----------------------------------------------------------------------
119 * ---------------------------------------------------------------------- */
122 * The linker defines this symbol to indicate the end of
123 * the executable image.
128 * Initialize memory management data structures.
129 * Enables the use of Alloc_Page() and Free_Page() functions.
131 void Init_Mem(struct Boot_Info* bootInfo)
133 ulong_t numPages = bootInfo->memSizeKB >> 2;
134 ulong_t endOfMem = numPages * PAGE_SIZE;
135 unsigned numPageListBytes = sizeof(struct Page) * numPages;
136 ulong_t pageListAddr;
145 g_ramdiskImage = bootInfo->ramdisk_image;
146 s_ramdiskSize = bootInfo->ramdisk_size;
152 KASSERT(bootInfo->memSizeKB > 0);
156 * Before we do anything, switch from setup.asm's temporary GDT
157 * to the kernel's permanent GDT.
162 PrintBoth("Total Memory Size: %u MBytes\n", bootInfo->memSizeKB/1024);
163 PrintBoth("Page List (at 0x%x) Size: %u bytes\n", &s_freeList, numPageListBytes);
167 * bios area (1 page reserved)
168 * kernel_thread_obj (1 page)
169 * kernel_stack (1 page)
172 * ISA_HOLE_START - ISA_HOLE_END: hardware
174 * start - end: kernel
175 * VM Guest (variable pages)
177 * Page List (variable pages)
178 * Available Memory for VMM (4096 pages)
179 * Ramdisk //Zheng 08/03/2008
180 * VM Memory (everything else)
183 //kernEnd = Round_Up_To_Page((ulong_t)&end);
184 kernEnd = (ulong_t)&end;
186 PrintBoth("Kernel End=%lx\n", kernEnd);
189 /* ************************************************************************************** */
190 /* If we have dynamic loading of the guest kernel, we should put the relocation code here */
191 /* ************************************************************************************** */
193 kernEnd = Round_Up_To_Page(kernEnd);
195 heapEnd = Round_Up_To_Page(heapAddr + KERNEL_HEAP_SIZE);
196 pageListAddr = heapEnd;
197 pageListEnd = Round_Up_To_Page(pageListAddr + numPageListBytes);
198 /* Global variables */
199 // These must be set before we can call Add_Page_Range..
200 g_pageList = (struct Page*) pageListAddr;
201 s_numPages = numPages;
203 vmmMemEnd = Round_Up_To_Page(pageListEnd + VMM_AVAIL_MEM_SIZE);
208 * copy the ramdisk to this area
211 initrdAddr = vmmMemEnd;
212 initrdEnd = Round_Up_To_Page(initrdAddr + s_ramdiskSize);
213 PrintBoth("mem.c(%d) Move ramdisk(%dB) from %x to %x", __LINE__, s_ramdiskSize, g_ramdiskImage, initrdAddr);
214 memcpy((ulong_t *)initrdAddr, (ulong_t *)g_ramdiskImage, s_ramdiskSize);
215 PrintBoth(" done\n");
216 PrintBoth("mem.c(%d) Set 0 to unused bytes in the last ramdisk page from %x to %x", __LINE__, initrdAddr+s_ramdiskSize, initrdEnd);
217 memset((ulong_t *)initrdAddr+s_ramdiskSize, 0, initrdEnd-(initrdAddr+s_ramdiskSize));
218 PrintBoth(" done\n");
222 vm_range_start = initrdEnd;
223 vm_range_end = endOfMem;
227 * the disgusting way to get at the memory assigned to a VM
230 vm_range_start = vmmMemEnd;
231 vm_range_end = endOfMem;
235 Add_Page_Range(0, PAGE_SIZE, PAGE_UNUSED); // BIOS area
236 Add_Page_Range(PAGE_SIZE, PAGE_SIZE * 3, PAGE_ALLOCATED); // Intial kernel thread obj + stack
237 Add_Page_Range(PAGE_SIZE * 3, ISA_HOLE_START, PAGE_AVAIL); // Available space
238 Add_Page_Range(ISA_HOLE_START, ISA_HOLE_END, PAGE_HW); // Hardware ROMs
239 Add_Page_Range(KERNEL_START_ADDR, kernEnd, PAGE_KERN); // VMM Kernel
240 // Add_Page_Range(guest_kernel_start, guestEnd, PAGE_VM); // Guest kernel location
241 Add_Page_Range(heapAddr, heapEnd, PAGE_HEAP); // Heap
242 Add_Page_Range(pageListAddr, pageListEnd, PAGE_KERN); // Page List
243 Add_Page_Range(pageListEnd, vmmMemEnd, PAGE_AVAIL); // Available VMM memory
249 Add_Page_Range(vmmMemEnd, initrdEnd, PAGE_ALLOCATED); //Ramdisk memory area
250 // Add_Page_Range(vmmMemEnd, endOfMem, PAGE_VM); // Memory allocated to the VM
251 // Until we get a more intelligent memory allocator
252 Add_Page_Range(initrdEnd, endOfMem, PAGE_AVAIL); // Memory allocated to the VM
254 Add_Page_Range(vmmMemEnd, endOfMem, PAGE_AVAIL); // Memory allocated to the VM
257 /* Initialize the kernel heap */
258 Init_Heap(heapAddr, KERNEL_HEAP_SIZE);
260 PrintBoth("%uKB memory detected, %u pages in freelist, %d bytes in kernel heap\n",
261 bootInfo->memSizeKB, g_freePageCount, KERNEL_HEAP_SIZE);
263 PrintBoth("Memory Layout:\n");
264 PrintBoth("%x to %x - BIOS AREA\n", 0, PAGE_SIZE - 1);
265 PrintBoth("%x to %x - KERNEL_THREAD_OBJ\n", PAGE_SIZE, PAGE_SIZE * 2 - 1);
266 PrintBoth("%x to %x - KERNEL_STACK\n", PAGE_SIZE * 2, PAGE_SIZE * 3 - 1);
267 PrintBoth("%lx to %x - FREE\n", PAGE_SIZE * 3, ISA_HOLE_START - 1);
268 PrintBoth("%x to %x - ISA_HOLE\n", ISA_HOLE_START, ISA_HOLE_END - 1);
269 PrintBoth("%x to %x - KERNEL CODE + VM_KERNEL\n", KERNEL_START_ADDR, kernEnd - 1);
270 // PrintBoth("%x to %x - VM_KERNEL\n", kernEnd, guestEnd - 1);
271 PrintBoth("%x to %x - KERNEL HEAP\n", heapAddr, heapEnd - 1);
272 PrintBoth("%lx to %lx - PAGE LIST\n", pageListAddr, pageListEnd - 1);
273 PrintBoth("%lx to %x - FREE\n", pageListEnd, vmmMemEnd - 1);
279 PrintBoth("%lx to %x - RAMDISK\n", vmmMemEnd, initrdEnd - 1);
281 PrintBoth("%lx to %x - GUEST_MEMORY (also free)\n", initrdEnd, endOfMem - 1);
283 PrintBoth("%lx to %x - GUEST_MEMORY (also free)\n", vmmMemEnd, endOfMem - 1);
288 * Initialize the .bss section of the kernel executable image.
292 extern char BSS_START, BSS_END;
294 /* Fill .bss with zeroes */
295 memset(&BSS_START, '\0', &BSS_END - &BSS_START);
296 // screen is not inited yet - PAD
297 // PrintBoth("BSS Inited, BSS_START=%x, BSS_END=%x\n",BSS_START,BSS_END);
301 * Allocate a page of physical memory.
303 void* Alloc_Page(void)
308 bool iflag = Begin_Int_Atomic();
310 /* See if we have a free page */
311 if (!Is_Page_List_Empty(&s_freeList)) {
312 /* Remove the first page on the freelist. */
313 page = Get_Front_Of_Page_List(&s_freeList);
314 KASSERT((page->flags & PAGE_ALLOCATED) == 0);
315 Remove_From_Front_Of_Page_List(&s_freeList);
317 /* Mark page as having been allocated. */
318 page->flags |= PAGE_ALLOCATED;
320 result = (void*) Get_Page_Address(page);
323 End_Int_Atomic(iflag);
329 * Free a page of physical memory.
331 void Free_Page(void* pageAddr)
333 ulong_t addr = (ulong_t) pageAddr;
337 iflag = Begin_Int_Atomic();
339 KASSERT(Is_Page_Multiple(addr));
341 /* Get the Page object for this page */
342 page = Get_Page(addr);
343 KASSERT((page->flags & PAGE_ALLOCATED) != 0);
345 /* Clear the allocation bit */
346 page->flags &= ~(PAGE_ALLOCATED);
348 /* Put the page back on the freelist */
349 Add_To_Back_Of_Page_List(&s_freeList, page);
352 End_Int_Atomic(iflag);