nuclear@17: #include <stdio.h>
nuclear@17: #include <string.h>
nuclear@17: #include <inttypes.h>
nuclear@17: #include "vm.h"
nuclear@17: #include <stdio.h>
nuclear@17: #include "intr.h"
nuclear@17: #include "mem.h"
nuclear@17: #include "panic.h"
nuclear@17: 
nuclear@17: 
nuclear@17: #define KMEM_START		0xc0000000
nuclear@17: #define IDMAP_START		0xa0000
nuclear@17: 
nuclear@17: #define ATTR_PGDIR_MASK	0x3f
nuclear@17: #define ATTR_PGTBL_MASK	0x1ff
nuclear@17: #define ADDR_PGENT_MASK	0xfffff000
nuclear@17: 
nuclear@17: #define PAGEFAULT		14
nuclear@17: 
nuclear@22: 
nuclear@22: struct page_range {
nuclear@22: 	int start, end;
nuclear@22: 	struct page_range *next;
nuclear@22: };
nuclear@22: 
nuclear@22: /* defined in vm-asm.S */
nuclear@22: void enable_paging(void);
nuclear@22: void set_pgdir_addr(uint32_t addr);
nuclear@22: uint32_t get_fault_addr(void);
nuclear@22: 
nuclear@22: static void pgfault(int inum, uint32_t err);
nuclear@22: static struct page_range *alloc_node(void);
nuclear@22: static void free_node(struct page_range *node);
nuclear@22: 
nuclear@22: /* page directory */
nuclear@22: static uint32_t *pgdir;
nuclear@22: 
nuclear@22: /* 2 lists of free ranges, for kernel memory and user memory */
nuclear@22: static struct page_range *pglist[2];
nuclear@22: /* list of free page_range structures to be used in the lists */
nuclear@22: static struct page_range *node_pool;
nuclear@22: 
nuclear@22: 
nuclear@17: void init_vm(struct mboot_info *mb)
nuclear@17: {
nuclear@19: 	uint32_t idmap_end;
nuclear@19: 
nuclear@17: 	init_mem(mb);
nuclear@17: 
nuclear@18: 	pgdir = (uint32_t*)alloc_phys_page();
nuclear@17: 	memset(pgdir, 0, sizeof pgdir);
nuclear@17: 
nuclear@17: 	/* map the video memory and kernel code 1-1 */
nuclear@19: 	get_kernel_mem_range(0, &idmap_end);
nuclear@19: 	map_mem_range(IDMAP_START, idmap_end - IDMAP_START, IDMAP_START, 0);
nuclear@17: 
nuclear@17: 	interrupt(PAGEFAULT, pgfault);
nuclear@17: 
nuclear@17: 	set_pgdir_addr((int32_t)pgdir);
nuclear@17: 	enable_paging();
nuclear@17: }
nuclear@17: 
nuclear@17: void map_page(int vpage, int ppage, unsigned int attr)
nuclear@17: {
nuclear@17: 	uint32_t *pgtbl;
nuclear@17: 	int diridx = PAGE_TO_PGTBL(vpage);
nuclear@17: 	int pgidx = PAGE_TO_PGTBL_PG(vpage);
nuclear@17: 
nuclear@17: 	if(!(pgdir[diridx] & PG_PRESENT)) {
nuclear@17: 		uint32_t addr = alloc_phys_page();
nuclear@17: 		pgtbl = (uint32_t*)addr;
nuclear@18: 		memset(pgtbl, 0, PGSIZE);
nuclear@18: 
nuclear@17: 		pgdir[diridx] = addr | (attr & ATTR_PGDIR_MASK) | PG_PRESENT;
nuclear@17: 	} else {
nuclear@17: 		pgtbl = (uint32_t*)(pgdir[diridx] & ADDR_PGENT_MASK);
nuclear@17: 	}
nuclear@17: 
nuclear@17: 	pgtbl[pgidx] = PAGE_TO_ADDR(ppage) | (attr & ATTR_PGTBL_MASK) | PG_PRESENT;
nuclear@17: }
nuclear@17: 
nuclear@17: void unmap_page(int vpage)
nuclear@17: {
nuclear@17: 	uint32_t *pgtbl;
nuclear@17: 	int diridx = PAGE_TO_PGTBL(vpage);
nuclear@17: 	int pgidx = PAGE_TO_PGTBL_PG(vpage);
nuclear@17: 
nuclear@17: 	if(!(pgdir[diridx] & PG_PRESENT)) {
nuclear@17: 		goto err;
nuclear@17: 	}
nuclear@17: 	pgtbl = (uint32_t*)(pgdir[diridx] & ADDR_PGENT_MASK);
nuclear@17: 
nuclear@17: 	if(!(pgtbl[pgidx] & PG_PRESENT)) {
nuclear@17: 		goto err;
nuclear@17: 	}
nuclear@17: 	pgtbl[pgidx] = 0;
nuclear@17: 
nuclear@17: 	return;
nuclear@17: err:
nuclear@17: 	printf("unmap_page(%d): page already not mapped\n", vpage);
nuclear@17: }
nuclear@17: 
nuclear@22: /* if ppg_start is -1, we allocate physical pages to map with alloc_phys_page() */
nuclear@17: void map_page_range(int vpg_start, int pgcount, int ppg_start, unsigned int attr)
nuclear@17: {
nuclear@17: 	int i;
nuclear@17: 
nuclear@17: 	for(i=0; i<pgcount; i++) {
nuclear@22: 		uint32_t paddr = ppg_start == -1 ? alloc_phys_page() : ppg_start + i;
nuclear@22: 
nuclear@22: 		map_page(vpg_start + i, paddr, attr);
nuclear@17: 	}
nuclear@17: }
nuclear@17: 
nuclear@17: void map_mem_range(uint32_t vaddr, size_t sz, uint32_t paddr, unsigned int attr)
nuclear@17: {
nuclear@17: 	int vpg_start, ppg_start, num_pages;
nuclear@17: 
nuclear@17: 	if(!sz) return;
nuclear@17: 
nuclear@17: 	if(ADDR_TO_PGOFFS(paddr)) {
nuclear@17: 		panic("map_mem_range called with unaligned physical address: %x\n", paddr);
nuclear@17: 	}
nuclear@17: 
nuclear@17: 	vpg_start = ADDR_TO_PAGE(vaddr);
nuclear@17: 	ppg_start = ADDR_TO_PAGE(paddr);
nuclear@17: 	num_pages = ADDR_TO_PAGE(sz) + 1;
nuclear@17: 
nuclear@17: 	map_page_range(vpg_start, num_pages, ppg_start, attr);
nuclear@17: }
nuclear@17: 
nuclear@18: uint32_t virt_to_phys(uint32_t vaddr)
nuclear@18: {
nuclear@18: 	uint32_t pgaddr, *pgtbl;
nuclear@18: 	int diridx = ADDR_TO_PGTBL(vaddr);
nuclear@18: 	int pgidx = ADDR_TO_PGTBL_PG(vaddr);
nuclear@18: 
nuclear@18: 	if(!(pgdir[diridx] & PG_PRESENT)) {
nuclear@18: 		panic("virt_to_phys(%x): page table %d not present\n", vaddr, diridx);
nuclear@18: 	}
nuclear@18: 	pgtbl = (uint32_t*)(pgdir[diridx] & PGENT_ADDR_MASK);
nuclear@18: 
nuclear@18: 	if(!(pgtbl[pgidx] & PG_PRESENT)) {
nuclear@18: 		panic("virt_to_phys(%x): page %d not present\n", vaddr, ADDR_TO_PAGE(vaddr));
nuclear@18: 	}
nuclear@18: 	pgaddr = pgtbl[pgidx] & PGENT_ADDR_MASK;
nuclear@18: 
nuclear@18: 	return pgaddr | ADDR_TO_PGOFFS(vaddr);
nuclear@18: }
nuclear@18: 
nuclear@22: /* allocate a contiguous block of virtual memory pages along with
nuclear@22:  * backing physical memory for them, and update the page table.
nuclear@22:  */
nuclear@22: int pgalloc(int num, int area)
nuclear@22: {
nuclear@22: 	int ret = -1;
nuclear@22: 	struct page_range *node, *prev, dummy;
nuclear@22: 
nuclear@22: 	dummy.next = pglist[area];
nuclear@22: 	node = pglist[area];
nuclear@22: 	prev = &dummy;
nuclear@22: 
nuclear@22: 	while(node) {
nuclear@22: 		if(node->end - node->start >= num) {
nuclear@22: 			ret = node->start;
nuclear@22: 			node->start += num;
nuclear@22: 
nuclear@22: 			if(node->start == node->end) {
nuclear@22: 				prev->next = node->next;
nuclear@22: 				node->next = 0;
nuclear@22: 
nuclear@22: 				if(node == pglist[area]) {
nuclear@22: 					pglist[area] = 0;
nuclear@22: 				}
nuclear@22: 				free_node(node);
nuclear@22: 			}
nuclear@22: 			break;
nuclear@22: 		}
nuclear@22: 
nuclear@22: 		prev = node;
nuclear@22: 		node = node->next;
nuclear@22: 	}
nuclear@22: 
nuclear@22: 	if(ret >= 0) {
nuclear@22: 		/* allocate physical storage and map them */
nuclear@22: 		map_page_range(ret, num, -1, 0);
nuclear@22: 	}
nuclear@22: 
nuclear@22: 	return ret;
nuclear@22: }
nuclear@22: 
nuclear@22: void pgfree(int start, int num)
nuclear@22: {
nuclear@22: 	/* TODO */
nuclear@22: }
nuclear@22: 
nuclear@17: static void pgfault(int inum, uint32_t err)
nuclear@17: {
nuclear@17: 	printf("~~~~ PAGE FAULT ~~~~\n");
nuclear@17: 
nuclear@17: 	printf("fault address: %x\n", get_fault_addr());
nuclear@17: 
nuclear@17: 	if(err & PG_PRESENT) {
nuclear@17: 		if(err & 8) {
nuclear@17: 			printf("reserved bit set in some paging structure\n");
nuclear@17: 		} else {
nuclear@17: 			printf("%s protection violation ", (err & PG_WRITABLE) ? "write" : "read");
nuclear@17: 			printf("in %s mode\n", err & PG_USER ? "user" : "kernel");
nuclear@17: 		}
nuclear@17: 	} else {
nuclear@17: 		printf("page not present\n");
nuclear@17: 	}
nuclear@19: 
nuclear@19: 	panic("unhandled page fault\n");
nuclear@17: }
nuclear@22: 
nuclear@22: /* --- page range list node management --- */
nuclear@22: static struct page_range *alloc_node(void)
nuclear@22: {
nuclear@22: 	struct page_range *node;
nuclear@22: 	uint32_t paddr;
nuclear@22: 
nuclear@22: 	if(node_pool) {
nuclear@22: 		node = node_pool;
nuclear@22: 		node_pool = node_pool->next;
nuclear@22: 		return node;
nuclear@22: 	}
nuclear@22: 
nuclear@22: 	/* no node structures in the pool, we need to allocate and map
nuclear@22: 	 * a page, split it up into node structures, add them in the pool
nuclear@22: 	 * and allocate one of them.
nuclear@22: 	 */
nuclear@22: 	if(!(paddr = alloc_phys_page())) {
nuclear@22: 		panic("ran out of physical memory while allocating VM range structures\n");
nuclear@22: 	}
nuclear@22: 
nuclear@22: 	/* TODO cont. */
nuclear@22: 	return 0;
nuclear@22: }
nuclear@22: 
nuclear@22: static void free_node(struct page_range *node)
nuclear@22: {
nuclear@22: 	node->next = node_pool;
nuclear@22: 	node_pool = node;
nuclear@22: }