diff options
Diffstat (limited to 'kernel.soso/vmm.c')
| -rw-r--r-- | kernel.soso/vmm.c | 580 |
1 files changed, 580 insertions, 0 deletions
diff --git a/kernel.soso/vmm.c b/kernel.soso/vmm.c new file mode 100644 index 00000000..43d28110 --- /dev/null +++ b/kernel.soso/vmm.c @@ -0,0 +1,580 @@ +#include "vmm.h" +#include "common.h" +#include "screen.h" +#include "alloc.h" +#include "isr.h" +#include "process.h" +#include "list.h" +#include "debugprint.h" + +uint32 *gKernelPageDirectory = (uint32 *)KERN_PAGE_DIRECTORY; +uint8 gPhysicalPageFrameBitmap[RAM_AS_4M_PAGES / 8]; +uint8 gKernelPageHeapBitmap[RAM_AS_4K_PAGES / 8]; + +static int gTotalPageCount = 0; + +static void handlePageFault(Registers *regs); +static void syncPageDirectoriesKernelMemory(); + +void initializeMemory(uint32 high_mem) +{ + int pg; + unsigned long i; + + registerInterruptHandler(14, handlePageFault); + + gTotalPageCount = (high_mem * 1024) / PAGESIZE_4M; + + for (pg = 0; pg < gTotalPageCount / 8; ++pg) + { + gPhysicalPageFrameBitmap[pg] = 0; + } + + for (pg = gTotalPageCount / 8; pg < RAM_AS_4M_PAGES / 8; ++pg) + { + gPhysicalPageFrameBitmap[pg] = 0xFF; + } + + //Pages reserved for the kernel + for (pg = PAGE_INDEX_4M(0x0); pg < (int)(PAGE_INDEX_4M(RESERVED_AREA)); ++pg) + { + SET_PAGEFRAME_USED(gPhysicalPageFrameBitmap, pg); + } + + //Heap pages reserved + for (pg = 0; pg < RAM_AS_4K_PAGES / 8; ++pg) + { + gKernelPageHeapBitmap[pg] = 0xFF; + } + + for (pg = PAGE_INDEX_4K(KERN_PD_AREA_BEGIN); pg < (int)(PAGE_INDEX_4K(KERN_PD_AREA_END)); ++pg) + { + SET_PAGEHEAP_UNUSED(pg * PAGESIZE_4K); + } + + //Identity map + for (i = 0; i < 4; ++i) + { + gKernelPageDirectory[i] = (i * PAGESIZE_4M | (PG_PRESENT | PG_WRITE | PG_4MB));//add PG_USER for accesing kernel code in user mode + } + + for (i = 4; i < 1024; ++i) + { + gKernelPageDirectory[i] = 0; + } + + //Enable paging + asm(" mov %0, %%eax \n \ + mov %%eax, %%cr3 \n \ + mov %%cr4, %%eax \n \ + or %2, %%eax \n \ + mov %%eax, %%cr4 \n \ + mov %%cr0, %%eax \n \ + or %1, %%eax \n \ + mov %%eax, %%cr0"::"m"(gKernelPageDirectory), "i"(PAGING_FLAG), "i"(PSE_FLAG)); + + initializeKernelHeap(); +} + +char* getPageFrame4M() +{ + int byte, bit; + uint32 page = -1; + + for (byte = 0; byte < RAM_AS_4M_PAGES / 8; byte++) + { + if (gPhysicalPageFrameBitmap[byte] != 0xFF) + { + for (bit = 0; bit < 8; bit++) + { + if (!(gPhysicalPageFrameBitmap[byte] & (1 << bit))) + { + page = 8 * byte + bit; + SET_PAGEFRAME_USED(gPhysicalPageFrameBitmap, page); + Debug_PrintF("DEBUG: got 4M on physical %x\n", page * PAGESIZE_4M); + return (char *) (page * PAGESIZE_4M); + } + } + } + } + + PANIC("Memory is full!"); + return (char *) -1; +} + +void releasePageFrame4M(uint32 p_addr) +{ + Debug_PrintF("DEBUG: released 4M on physical %x\n", p_addr); + + SET_PAGEFRAME_UNUSED(gPhysicalPageFrameBitmap, p_addr); +} + +uint32* getPdFromReservedArea4K() +{ + int byte, bit; + int page = -1; + + //Screen_PrintF("DEBUG: getPdFromReservedArea4K() begin\n"); + + for (byte = 0; byte < RAM_AS_4K_PAGES / 8; byte++) + { + if (gKernelPageHeapBitmap[byte] != 0xFF) + { + for (bit = 0; bit < 8; bit++) + { + if (!(gKernelPageHeapBitmap[byte] & (1 << bit))) + { + page = 8 * byte + bit; + SET_PAGEHEAP_USED(page); + //Screen_PrintF("DEBUG: getPdFromReservedArea4K() found pageIndex:%d\n", page); + return (uint32 *) (page * PAGESIZE_4K); + } + } + } + } + + PANIC("Reserved Page Directory Area is Full!!!"); + return (uint32 *) -1; +} + +void releasePdFromReservedArea4K(uint32 *v_addr) +{ + SET_PAGEHEAP_UNUSED(v_addr); +} + +uint32 *createPd() +{ + int i; + + uint32* pd = getPdFromReservedArea4K(); + + + for (i = 0; i < KERNELMEMORY_PAGE_COUNT; ++i) + { + pd[i] = gKernelPageDirectory[i]; + } + + + for (i = KERNELMEMORY_PAGE_COUNT; i < 1024; ++i) + { + pd[i] = 0; + } + + return pd; +} + +void destroyPd(uint32 *pd) +{ + int startIndex = PAGE_INDEX_4M(USER_OFFSET); + int lastIndex = PAGE_INDEX_4M(USER_OFFSET_END); + + ///we don't touch mmapped areas + + for (int i = startIndex; i < lastIndex; ++i) + { + uint32 p_addr = pd[i] & 0xFFC00000; + + if (p_addr) + { + releasePageFrame4M(p_addr); + } + + pd[i] = 0; + } + + releasePdFromReservedArea4K(pd); +} + +uint32 *copyPd(uint32* pd) +{ + int i; + + uint32* newPd = getPdFromReservedArea4K(); + + + for (i = 0; i < KERNELMEMORY_PAGE_COUNT; ++i) + { + newPd[i] = gKernelPageDirectory[i]; + } + + disablePaging(); + + for (i = KERNELMEMORY_PAGE_COUNT; i < 1024; ++i) + { + newPd[i] = 0; + + if ((pd[i] & PG_PRESENT) == PG_PRESENT) + { + uint32 pagePyhsical = pd[i] & 0xFFC00000; + char* newPagePhysical = getPageFrame4M(); + + memcpy((uint8*)newPagePhysical, (uint8*)pagePyhsical, PAGESIZE_4M); + + uint32 vAddr = (i * 4) << 20; + + //Screen_PrintF("Copied page virtual %x\n", vAddr); + + addPageToPd(newPd, (char*)vAddr, newPagePhysical, PG_USER); + } + } + + enablePaging(); + + return newPd; +} + +//When calling this function: +//If it is intended to alloc kernel memory, v_addr must be < KERN_HEAP_END. +//If it is intended to alloc user memory, v_addr must be > KERN_HEAP_END. +BOOL addPageToPd(uint32* pd, char *v_addr, char *p_addr, int flags) +{ + uint32 *pde = NULL; + + //Screen_PrintF("DEBUG: addPageToPd(): v_addr:%x p_addr:%x flags:%x\n", v_addr, p_addr, flags); + + + int index = (((uint32) v_addr & 0xFFC00000) >> 22); + pde = pd + index; + if ((*pde & PG_PRESENT) == PG_PRESENT) + { + //Already assigned! + Debug_PrintF("ERROR: addPageToPd(): pde:%x is already assigned!!\n", pde); + return FALSE; + } + + //Screen_PrintF("addPageToPd(): index:%d pde:%x\n", index, pde); + + *pde = ((uint32) p_addr) | (PG_PRESENT | PG_4MB | PG_WRITE | flags); + //Screen_PrintF("pde:%x *pde:%x\n", pde, *pde); + + SET_PAGEFRAME_USED(gPhysicalPageFrameBitmap, PAGE_INDEX_4M((uint32)p_addr)); + + asm("invlpg %0"::"m"(v_addr)); + + if (v_addr <= (char*)(KERN_HEAP_END - PAGESIZE_4M)) + { + if (pd == gKernelPageDirectory) + { + syncPageDirectoriesKernelMemory(); + } + else + { + PANIC("Attemped to allocate kernel memory to a page directory which is not the kernel page directory!!!\n"); + } + } + else + { + if (pd == gKernelPageDirectory) + { + //No panic here. Because we allow kernel to map anywhere! + } + } + + return TRUE; +} + +BOOL removePageFromPd(uint32* pd, char *v_addr, BOOL releasePageFrame) +{ + int index = (((uint32) v_addr & 0xFFC00000) >> 22); + uint32* pde = pd + index; + if ((*pde & PG_PRESENT) == PG_PRESENT) + { + uint32 p_addr = *pde & 0xFFC00000; + + if (releasePageFrame) + { + releasePageFrame4M(p_addr); + } + + *pde = 0; + + asm("invlpg %0"::"m"(v_addr)); + + if (v_addr <= (char*)(KERN_HEAP_END - PAGESIZE_4M)) + { + if (pd == gKernelPageDirectory) + { + syncPageDirectoriesKernelMemory(); + } + } + + return TRUE; + } + + return FALSE; +} + +static void syncPageDirectoriesKernelMemory() +{ + //get page directory list + //it can be easier to traverse proccesses(and access its pd) here + for (int byte = 0; byte < RAM_AS_4M_PAGES / 8; byte++) + { + if (gKernelPageHeapBitmap[byte] != 0xFF) + { + for (int bit = 0; bit < 8; bit++) + { + if ((gKernelPageHeapBitmap[byte] & (1 << bit))) + { + int page = 8 * byte + bit; + + uint32* pd = (uint32*)(page * PAGESIZE_4K); + + for (int i = 0; i < KERNELMEMORY_PAGE_COUNT; ++i) + { + pd[i] = gKernelPageDirectory[i]; + } + } + } + } + } +} + +uint32 getTotalPageCount() +{ + return gTotalPageCount; +} + +uint32 getUsedPageCount() +{ + int count = 0; + for (int i = 0; i < gTotalPageCount; ++i) + { + if(IS_PAGEFRAME_USED(gPhysicalPageFrameBitmap, i)) + { + ++count; + } + } + + return count; +} + +uint32 getFreePageCount() +{ + return gTotalPageCount - getUsedPageCount(); +} + +static void printPageFaultInfo(uint32 faultingAddress, Registers *regs) +{ + int present = regs->errorCode & 0x1; + int rw = regs->errorCode & 0x2; + int us = regs->errorCode & 0x4; + int reserved = regs->errorCode & 0x8; + int id = regs->errorCode & 0x10; + + printkf("Page fault!!! When trying to %s %x - IP:%x\n", rw ? "write to" : "read from", faultingAddress, regs->eip); + printkf("The page was %s\n", present ? "present" : "not present"); + + if (reserved) + { + printkf("Reserved bit was set\n"); + } + + if (id) + { + printkf("Caused by an instruction fetch\n"); + } + + printkf("CPU was in %s\n", us ? "user-mode" : "supervisor mode"); +} + +static void handlePageFault(Registers *regs) +{ + // A page fault has occurred. + + // The faulting address is stored in the CR2 register. + uint32 faultingAddress; + asm volatile("mov %%cr2, %0" : "=r" (faultingAddress)); + + //Debug_PrintF("page_fault()\n"); + //Debug_PrintF("stack of handler is %x\n", &faultingAddress); + + Thread* faultingThread = getCurrentThread(); + if (NULL != faultingThread) + { + Thread* mainThread = getMainKernelThread(); + + if (mainThread == faultingThread) + { + printPageFaultInfo(faultingAddress, regs); + + PANIC("Page fault in Kernel main thread!!!"); + } + else + { + printPageFaultInfo(faultingAddress, regs); + + Debug_PrintF("Faulting thread is %d\n", faultingThread->threadId); + + if (faultingThread->userMode) + { + Debug_PrintF("Destroying process %d\n", faultingThread->owner->pid); + + destroyProcess(faultingThread->owner); + } + else + { + Debug_PrintF("Destroying kernel thread %d\n", faultingThread->threadId); + + destroyThread(faultingThread); + } + + waitForSchedule(); + } + } + else + { + printPageFaultInfo(faultingAddress, regs); + + PANIC("Page fault!!!"); + } +} + +void initializeProcessMmap(Process* process) +{ + int page = 0; + + for (page = 0; page < RAM_AS_4M_PAGES / 8; ++page) + { + process->mmappedVirtualMemory[page] = 0xFF; + } + + //Virtual pages reserved for mmap + for (page = PAGE_INDEX_4M(USER_OFFSET_MMAP); page < (int)(PAGE_INDEX_4M(USER_OFFSET_MMAP_END)); ++page) + { +//? printkf("reserving for mmap: %x\n", page*PAGESIZE_4M); + SET_PAGEFRAME_UNUSED(process->mmappedVirtualMemory, page * PAGESIZE_4M); + } +} + +//this functions uses either pAddress or pAddressList +//both of them must not be null! +void* mapMemory(Process* process, uint32 nBytes, uint32 pAddress, List* pAddressList) +{ + if (nBytes == 0) + { + return NULL; + } + + int pageIndex = 0; + + int neededPages = (nBytes / PAGESIZE_4M) + 1; + + if (pAddressList) + { + if (List_GetCount(pAddressList) < neededPages) + { + return NULL; + } + } + else if (0 == pAddress) + { + return NULL; + } + + int foundAdjacent = 0; + + uint32 vMem = 0; + + for (pageIndex = PAGE_INDEX_4M(USER_OFFSET_MMAP); pageIndex < (int)(PAGE_INDEX_4M(USER_OFFSET_MMAP_END)); ++pageIndex) + { + if (IS_PAGEFRAME_USED(process->mmappedVirtualMemory, pageIndex)) + { + foundAdjacent = 0; + vMem = 0; + } + else + { + if (0 == foundAdjacent) + { + vMem = pageIndex * PAGESIZE_4M; + } + ++foundAdjacent; + } + + if (foundAdjacent == neededPages) + { + break; + } + } + + //Debug_PrintF("mapMemory: needed:%d foundAdjacent:%d vMem:%x\n", neededPages, foundAdjacent, vMem); + + if (foundAdjacent == neededPages) + { + uint32 p = 0; + ListNode* pListNode = NULL; + if (pAddressList) + { + pListNode = List_GetFirstNode(pAddressList); + p = (uint32)(uint32*)pListNode->data; + } + else + { + p = pAddress; + } + p = p & 0xFFC00000; + uint32 v = vMem; + for (int i = 0; i < neededPages; ++i) + { + addPageToPd(process->pd, (char*)v, (char*)p, PG_USER); + + SET_PAGEFRAME_USED(process->mmappedVirtualMemory, PAGE_INDEX_4M(v)); + + v += PAGESIZE_4M; + + if (pAddressList) + { + pListNode = pListNode->next; + p = (uint32)(uint32*)pListNode->data; + p = p & 0xFFC00000; + } + else + { + p += PAGESIZE_4M; + } + } + + return (void*)vMem; + } + + return NULL; +} + +BOOL unmapMemory(Process* process, uint32 nBytes, uint32 vAddress) +{ + if (nBytes == 0) + { + return FALSE; + } + + if (vAddress < USER_OFFSET_MMAP) + { + return FALSE; + } + + int pageIndex = 0; + + int neededPages = (nBytes / PAGESIZE_4M) + 1; + + int startIndex = PAGE_INDEX_4M(vAddress); + int endIndex = startIndex + neededPages; + + BOOL result = FALSE; + + for (pageIndex = startIndex; pageIndex < endIndex; ++pageIndex) + { + if (IS_PAGEFRAME_USED(process->mmappedVirtualMemory, pageIndex)) + { + char* vAddr = (char*)(pageIndex * PAGESIZE_4M); + + removePageFromPd(process->pd, vAddr, FALSE); + + SET_PAGEFRAME_UNUSED(process->mmappedVirtualMemory, vAddr); + + result = TRUE; + } + } + + return result; +} |