529 lines
13 KiB
C
529 lines
13 KiB
C
// vmm.c
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// Author: Josh Holtrop
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// Date: 09/30/03
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// Rewritten from scratch: 12/23/03
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// Modified: 09/12/05
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#include "hos_defines.h"
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#include "kernel.h"
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#include "mm/vmm.h"
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#include "lang/lang.h"
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#include "mm/mm.h"
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int vmm_map_range(void *virt_start, void *virt_end, u32_t phys_start);
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void *vmm_getFreeChunk(u32_t size);
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void vmm_removeHeapEntry(u32_t queue, HeapEntry_t *he);
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int vmm_moreCore(u32_t size);
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int vmm_coalesceEntry(u32_t queue, HeapEntry_t *newHE);
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void vmm_heb_init(HeapEntryBlock_t *heb);
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void vmm_addToQueue(u32_t queue, HeapEntry_t *preceeding, HeapEntry_t *he);
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int vmm_countHeapEntries(HeapEntry_t *he);
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HeapEntry_t *vmm_followChain(HeapEntry_t *he);
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HeapEntry_t *vmm_getUnusedEntry();
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HeapEntry_t *vmm_stripUnusedEntry();
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extern mb_info_t mb_info_block;
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extern mb_module_t mb_modules[MAX_MODULES];
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extern u32_t mm_freepages;
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HeapEntryQueue_t heapEntryQueues[VMM_HE_TYPES]; // linked queues of HeapEntry objects
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HeapEntry_t heapEntryHeadNodes[VMM_HE_TYPES]; // head nodes for linked queues
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HeapEntry_t heapEntryTailNodes[VMM_HE_TYPES]; // tail nodes for linked queues
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HeapEntryBlock_t initialHEB; // block for initial 256 HeapEntry objects
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// This is the initialization procedure for the Virtual Memory Manager
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// It sets up the heap for dynamic memory allocation and virtual page allocation
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void vmm_init()
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{
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int i;
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for (i = 0; i < mb_info_block.mods_count; i++) //page in the kernel modules
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vmm_map_range((void*)mb_modules[i].mod_start, (void*)mb_modules[i].mod_end - 1, mb_modules[i].mod_start - VIRT_OFFSET);
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for (i = 0; i < VMM_HE_TYPES; i++)
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{
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heapEntryQueues[i].count = 0;
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heapEntryQueues[i].head = &heapEntryHeadNodes[i];
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heapEntryHeadNodes[i].next = &heapEntryTailNodes[i];
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heapEntryTailNodes[i].prev = &heapEntryHeadNodes[i];
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}
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vmm_heb_init(&initialHEB);
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vmm_addToQueue(VMM_HE_UNUSED, &heapEntryHeadNodes[VMM_HE_UNUSED], &initialHEB.entry[0]);
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HeapEntry_t *wilderness = vmm_stripUnusedEntry();
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wilderness->base = (void *) HEAP_START;
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wilderness->length = HEAP_LENGTH;
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vmm_addToQueue(VMM_HE_HOLE, &heapEntryHeadNodes[VMM_HE_HOLE], wilderness);
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}
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/* Allocate a physical page and map the virtual address to it, return physical address allocated or NULL */
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int vmm_map(void *virt)
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{
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u32_t dum;
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return vmm_map_addr(virt, &dum);
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}
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int vmm_map_addr(void *virt, u32_t *phys_addr)
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{
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if (mm_freepages < 10)
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return -1;
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return vmm_map1((u32_t)virt, *phys_addr = mm_palloc());
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}
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// This function maps a virtual address to a physical address using the page directory / page table
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int vmm_map1(u32_t virt, u32_t physical)
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{
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virt &= 0xFFFFF000;
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physical &= 0xFFFFF000;
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u32_t pde = virt >> 22;
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u32_t pte = (virt & 0x003FF000) >> 12;
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u32_t *pageTables = (u32_t *)0xFFFFF000; //this is the location of the page directory
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if (!(pageTables[pde] & 0x01)) //the page directory entry is not present, we must allocate a page table
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{
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u32_t newpagetable;
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if (!(newpagetable = mm_palloc()))
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return -1; //out of physical memory
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pageTables[pde] = newpagetable | 0x03;
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invlpg_(0xFFFFF000 + (pde << 2));
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invlpg_(virt); //in case it was cached, so we can fill page table safely
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memsetd((void*)(0xFFC00000 | (pde << 12)), 0, 1024); //zero out new page table
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}
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*(u32_t *)(0xFFC00000 | (pde << 12) | (pte << 2)) = physical | 0x03;
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invlpg_((0xFFC00000 | (pde << 12) | (pte << 2)));
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invlpg_(virt);
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return 0;
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}
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// This function maps a variable number of pages in a row
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int vmm_mapn(u32_t virt, u32_t physical, u32_t n)
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{
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while (n > 0)
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{
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if (vmm_map1(virt, physical))
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return 1; // error mapping page
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virt += 4096;
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physical += 4096;
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n--;
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}
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return 0;
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}
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// This function removes the virtual address's entry in the
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// page directory / page table
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void vmm_unmap1(u32_t virt)
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{
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*(u32_t *)(0xFFC00000 |
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((virt & 0xFFC00000) >> 10) |
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((virt & 0x003FF000) >> 10)) = 0;
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invlpg_(virt);
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}
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// This function removes multiple pages' entries
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void vmm_unmapn(u32_t virt, u32_t n)
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{
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while (n > 0)
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{
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vmm_unmap1(virt);
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virt += 4096;
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n--;
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}
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}
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// This function maps an entire address range into memory
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int vmm_map_range(void *virt_start, void *virt_end, u32_t phys_start)
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{
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if (virt_end < virt_start)
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return -1; // invalid region
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while (virt_start < virt_end)
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{
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if (vmm_map1((u32_t)virt_start, phys_start))
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return -2; // out of memory
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virt_start += 4096;
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phys_start += 4096;
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}
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return 0;
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}
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// kernel virtual memory allocator
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void *kmalloc(u32_t size)
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{
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k_enter_critical();
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if (size % VMM_MALLOC_GRANULARITY)
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size = size + VMM_MALLOC_GRANULARITY -
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(size % VMM_MALLOC_GRANULARITY);
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/* added 09/12/05 by josh - fixed bug returning size 0 segments
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multiple times */
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if (size < VMM_MALLOC_GRANULARITY)
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size = VMM_MALLOC_GRANULARITY;
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void *attempt = vmm_getFreeChunk(size);
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if (attempt)
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{
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k_leave_critical();
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return attempt;
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}
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if (vmm_moreCore(size))
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{
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k_leave_critical();
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return NULL; //we could not get any more heap memory
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}
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attempt = vmm_getFreeChunk(size);
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k_leave_critical();
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return attempt;
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}
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// kernel virtual memory de-allocator
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int kfree(void *addr)
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{
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k_enter_critical();
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HeapEntry_t *he = heapEntryQueues[VMM_HE_USED].head->next;
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while (he->next)
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{
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if (he->base == addr)
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{
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vmm_removeHeapEntry(VMM_HE_USED, he);
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if (vmm_coalesceEntry(VMM_HE_FREE, he))
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vmm_addToQueue(VMM_HE_FREE, heapEntryQueues[VMM_HE_FREE].head, he);
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else
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vmm_addToQueue(VMM_HE_UNUSED, heapEntryQueues[VMM_HE_UNUSED].head, he);
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break;
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}
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he = (HeapEntry_t *)he->next;
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}
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k_leave_critical();
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return 0;
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}
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// This function allocates a virtual page and maps it to a physical page
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void *vmm_palloc()
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{
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u32_t dum;
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return vmm_palloc_addr(&dum);
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}
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void *vmm_palloc_addr(u32_t *phys_addr)
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{
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k_enter_critical();
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HeapEntry_t *he = heapEntryQueues[VMM_HE_HOLE].head->next;
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HeapEntry_t *wilderness = he;
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while (he->next)
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{
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if (he->length == 4096)
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{
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vmm_removeHeapEntry(VMM_HE_HOLE, he);
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vmm_addToQueue(VMM_HE_USED, &heapEntryHeadNodes[VMM_HE_USED], he);
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if (vmm_map_addr(he->base, phys_addr))
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he->base = NULL;
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k_leave_critical();
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return he->base;
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}
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if (he->length > wilderness->length)
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wilderness = he;
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he = (HeapEntry_t *)he->next;
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}
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if (wilderness->length < 0x00010000) //leave 16 pages free
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{
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k_leave_critical();
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return NULL;
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}
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wilderness->length -= 4096; //strip 4k from the top
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he = vmm_getUnusedEntry();
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he->base = wilderness->base + wilderness->length;
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he->length = 4096;
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vmm_addToQueue(VMM_HE_USED, &heapEntryHeadNodes[VMM_HE_USED], he);
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if (vmm_map_addr(he->base, phys_addr))
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he->base = NULL;
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k_leave_critical();
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return he->base;
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}
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// This function frees a previously-allocated virtual page
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int vmm_pfree(void *addr)
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{
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u32_t pbase = *(u32_t *)(0xFFC00000 |
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(((u32_t)addr & 0xFFC00000) >> 10) |
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(((u32_t)addr & 0x003FF000) >> 10));
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if (vmm_unmapp(addr))
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return -1;
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mm_pfree(pbase);
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return 0;
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}
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int vmm_unmapp(void *addr)
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{
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if (!addr)
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return -2;
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k_enter_critical();
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HeapEntry_t *he = heapEntryQueues[VMM_HE_USED].head->next;
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while (he->next)
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{
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if (he->base == addr) //found the page to free
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{
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vmm_removeHeapEntry(VMM_HE_USED, he);
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vmm_unmap1((u32_t)he->base);
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vmm_addToQueue(VMM_HE_HOLE, &heapEntryHeadNodes[VMM_HE_HOLE], he);
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k_leave_critical();
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return 0;
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}
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he = he->next;
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}
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k_leave_critical();
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return -1; // page not found
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}
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// This function allocates and zeros memory for the given number of objects,
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// given the size of each object
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void *kcalloc(u32_t number, u32_t size)
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{
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void *mem = kmalloc(number * size);
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if (!mem)
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return NULL; //could not get memory
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memset(mem, 0, number * size);
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return mem;
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}
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// This function re-allocates memory already allocated, preserving the old contents
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// (as long as newSize is greater than oldSize)
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void *krealloc(void *orig, unsigned int newSize)
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{
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void *newMem;
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if ((newMem = kmalloc(newSize)))
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{
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HeapEntry_t *he = heapEntryQueues[VMM_HE_USED].head->next;
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while (he->next)
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{
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if (he->base == orig)
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{
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memcpy(newMem, orig, (he->length < newSize ? he->length : newSize));
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kfree(orig);
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return newMem;
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}
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he = (HeapEntry_t *)he->next;
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}
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kfree(newMem);
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return NULL; // base address not found
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}
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else
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return NULL; // could not get mem for new chunk
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}
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// This function returns the base address of a free chunk of virtual memory - called from kmalloc()
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void *vmm_getFreeChunk(u32_t size)
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{
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HeapEntry_t *he = heapEntryQueues[VMM_HE_FREE].head->next;
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HeapEntry_t *good = NULL;
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while (he->next) // he is not the tail node
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{
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if (he->length == size)
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{
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vmm_removeHeapEntry(VMM_HE_FREE, he);
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vmm_addToQueue(VMM_HE_USED, heapEntryQueues[VMM_HE_USED].head, he);
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return he->base;
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}
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if (good)
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{
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if ((he->length > size) && (he->length < good->length))
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good = he;
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}
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else
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{
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if (he->length > size)
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good = he;
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}
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he = (HeapEntry_t *)he->next;
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}
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if (!good)
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return NULL;
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HeapEntry_t *newHE = vmm_getUnusedEntry();
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newHE->base = good->base;
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newHE->length = size;
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newHE->next = NULL;
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newHE->prev = NULL;
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good->base += size;
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good->length -= size;
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vmm_addToQueue(VMM_HE_USED, heapEntryQueues[VMM_HE_USED].head, newHE);
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return newHE->base;
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}
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// This function retrieves more core memory for the virtual memory allocator to allocate
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int vmm_moreCore(u32_t size)
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{
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int pages = (size >> 12) + 2;
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size = pages << 12;
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if ((mm_freepages - 5) < pages)
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return -1; // out of physical memory
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HeapEntry_t *he = heapEntryQueues[VMM_HE_HOLE].head->next;
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HeapEntry_t *wilderness = he;
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while (he->next)
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{
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if (he->length > wilderness->length)
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wilderness = he;
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he = (HeapEntry_t *)he->next;
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}
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if (wilderness->length <= size)
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return -2; // out of virtual memory
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int i;
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void *virt = wilderness->base;
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for (i = 0; i < pages; i++)
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{
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vmm_map(virt);
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virt += 4096;
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}
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HeapEntry_t *newHE = vmm_getUnusedEntry();
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newHE->base = wilderness->base;
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newHE->length = size;
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newHE->next = 0;
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newHE->prev = 0;
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wilderness->base += size;
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wilderness->length -= size;
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if (vmm_coalesceEntry(VMM_HE_FREE, newHE)) // returns 0 on success (coalesced into previous entry)
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vmm_addToQueue(VMM_HE_FREE, heapEntryQueues[VMM_HE_FREE].head, newHE);
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else
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vmm_addToQueue(VMM_HE_UNUSED, heapEntryQueues[VMM_HE_UNUSED].head, newHE);
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return 0;
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}
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// This function coalesces to heap entries into one
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int vmm_coalesceEntry(u32_t queue, HeapEntry_t *newHE)
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{
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HeapEntry_t *existing = heapEntryQueues[queue].head->next;
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while (existing->next)
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{
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if ((existing->base + existing->length) == newHE->base)
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{
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existing->length += newHE->length;
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return 0;
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}
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else if ((newHE->base + newHE->length) == existing->base)
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{
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existing->base = newHE->base;
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existing->length += newHE->length;
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return 0;
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}
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existing = (HeapEntry_t *)existing->next;
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}
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return -1; // an entry to coalesce with was not found
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}
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// This function removes a heap entry from a queue
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void vmm_removeHeapEntry(u32_t queue, HeapEntry_t *he)
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{
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((HeapEntry_t *)he->prev)->next = he->next;
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((HeapEntry_t *)he->next)->prev = he->prev;
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heapEntryQueues[queue].count--;
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he->next = NULL;
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he->prev = NULL;
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}
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// This function initialzes a Heap Entry Block to entries linked together
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void vmm_heb_init(HeapEntryBlock_t *heb)
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{
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int a;
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for (a = 0; a < 255; a++)
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{
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heb->entry[a].next = &heb->entry[a+1];
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heb->entry[a+1].prev = &heb->entry[a];
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}
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heb->entry[0].prev = NULL;
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heb->entry[255].next = NULL;
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}
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// This function adds a HeapEntry structure to the queue following 'preceeding' the queue
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// fails if add to tail (add one element before tail node)
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void vmm_addToQueue(u32_t queue, HeapEntry_t *preceeding, HeapEntry_t *he)
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{
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heapEntryQueues[queue].count += vmm_countHeapEntries(he);
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HeapEntry_t *last = vmm_followChain(he);
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last->next = preceeding->next;
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he->prev = preceeding;
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((HeapEntry_t *)last->next)->prev = last;
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preceeding->next = he;
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}
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// This function returns how many HeapEntry objects are in a queue starting/including from the object given
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int vmm_countHeapEntries(HeapEntry_t *he)
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{
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int count = 0;
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while (he)
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{
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count++;
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he = (HeapEntry_t *)he->next;
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}
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return count;
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}
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// This function follows a chain of HeapEntry objects and returns a pointer to the last one
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HeapEntry_t *vmm_followChain(HeapEntry_t *he)
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{
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while (he->next)
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he = (HeapEntry_t *)he->next;
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return he;
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}
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// This function breaks an unused chunk from its queue and returns a pointer to it
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// 09/10/05 nasty bug fixed by josh, wasn't adding unused entries when we ran out of them
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HeapEntry_t *vmm_getUnusedEntry()
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{
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if (heapEntryQueues[VMM_HE_UNUSED].count < 5)
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{
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HeapEntry_t *he = heapEntryQueues[VMM_HE_HOLE].head->next;
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HeapEntry_t *wilderness = he;
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while (he)
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{
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if ((he->length) > (wilderness->length))
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wilderness = he;
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he = (HeapEntry_t *)he->next;
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}
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if (wilderness->length < 10000)
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{
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k_check(-1, "Kernel panic: out of virtual memory\n");
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}
|
|
wilderness->length -= 4096; //strip 4k from the top
|
|
HeapEntryBlock_t *newHEB = wilderness->base + wilderness->length;
|
|
vmm_map(newHEB);
|
|
vmm_heb_init(newHEB);
|
|
vmm_addToQueue(VMM_HE_UNUSED, heapEntryTailNodes[VMM_HE_UNUSED].prev, &newHEB->entry[0]);
|
|
}
|
|
return vmm_stripUnusedEntry();
|
|
}
|
|
|
|
|
|
// Return pointer to an unused HeapEntry object, ASSUMES THERE IS ONE PRESENT IN QUEUE
|
|
HeapEntry_t *vmm_stripUnusedEntry()
|
|
{
|
|
HeapEntry_t *he = heapEntryQueues[VMM_HE_UNUSED].head->next;
|
|
heapEntryQueues[VMM_HE_UNUSED].head->next = he->next;
|
|
if (! he->next)
|
|
k_check(1, "kernel panic: he->next is NULL\n");
|
|
((HeapEntry_t *)he->next)->prev = he->prev;
|
|
heapEntryQueues[VMM_HE_UNUSED].count--;
|
|
he->next = 0;
|
|
he->prev = 0;
|
|
return he;
|
|
}
|
|
|
|
|
|
|
|
|
|
|
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|