1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/vm.c	Sat Mar 26 21:39:14 2011 +0200
     1.3 @@ -0,0 +1,147 @@
     1.4 +#include <stdio.h>
     1.5 +#include <string.h>
     1.6 +#include <inttypes.h>
     1.7 +#include "vm.h"
     1.8 +#include <stdio.h>
     1.9 +#include "intr.h"
    1.10 +#include "mem.h"
    1.11 +#include "panic.h"
    1.12 +
    1.13 +
    1.14 +/* defined in vm-asm.S */
    1.15 +void enable_paging(void);
    1.16 +void set_pgdir_addr(uint32_t addr);
    1.17 +uint32_t get_fault_addr(void);
    1.18 +
    1.19 +static void pgfault(int inum, uint32_t err);
    1.20 +
    1.21 +/* page directory */
    1.22 +static uint32_t pgdir[1024];
    1.23 +
    1.24 +#define KMEM_START		0xc0000000
    1.25 +#define IDMAP_START		0xa0000
    1.26 +
    1.27 +#define ATTR_PGDIR_MASK	0x3f
    1.28 +#define ATTR_PGTBL_MASK	0x1ff
    1.29 +#define ADDR_PGENT_MASK	0xfffff000
    1.30 +
    1.31 +#define PAGEFAULT		14
    1.32 +
    1.33 +void init_vm(struct mboot_info *mb)
    1.34 +{
    1.35 +	init_mem(mb);
    1.36 +
    1.37 +	memset(pgdir, 0, sizeof pgdir);
    1.38 +
    1.39 +	/* map the video memory and kernel code 1-1 */
    1.40 +	map_mem_range(IDMAP_START, MAX_BRK - IDMAP_START, IDMAP_START, 0);
    1.41 +
    1.42 +	interrupt(PAGEFAULT, pgfault);
    1.43 +
    1.44 +	set_pgdir_addr((int32_t)pgdir);
    1.45 +	enable_paging();
    1.46 +}
    1.47 +
    1.48 +void map_page(int vpage, int ppage, unsigned int attr)
    1.49 +{
    1.50 +	uint32_t *pgtbl;
    1.51 +	int diridx = PAGE_TO_PGTBL(vpage);
    1.52 +	int pgidx = PAGE_TO_PGTBL_PG(vpage);
    1.53 +
    1.54 +	if(!(pgdir[diridx] & PG_PRESENT)) {
    1.55 +		uint32_t addr = alloc_phys_page();
    1.56 +		pgtbl = (uint32_t*)addr;
    1.57 +		pgdir[diridx] = addr | (attr & ATTR_PGDIR_MASK) | PG_PRESENT;
    1.58 +	} else {
    1.59 +		pgtbl = (uint32_t*)(pgdir[diridx] & ADDR_PGENT_MASK);
    1.60 +	}
    1.61 +
    1.62 +	pgtbl[pgidx] = PAGE_TO_ADDR(ppage) | (attr & ATTR_PGTBL_MASK) | PG_PRESENT;
    1.63 +}
    1.64 +
    1.65 +void unmap_page(int vpage)
    1.66 +{
    1.67 +	uint32_t *pgtbl;
    1.68 +	int diridx = PAGE_TO_PGTBL(vpage);
    1.69 +	int pgidx = PAGE_TO_PGTBL_PG(vpage);
    1.70 +
    1.71 +	if(!(pgdir[diridx] & PG_PRESENT)) {
    1.72 +		goto err;
    1.73 +	}
    1.74 +	pgtbl = (uint32_t*)(pgdir[diridx] & ADDR_PGENT_MASK);
    1.75 +
    1.76 +	if(!(pgtbl[pgidx] & PG_PRESENT)) {
    1.77 +		goto err;
    1.78 +	}
    1.79 +	pgtbl[pgidx] = 0;
    1.80 +
    1.81 +	return;
    1.82 +err:
    1.83 +	printf("unmap_page(%d): page already not mapped\n", vpage);
    1.84 +}
    1.85 +
    1.86 +void map_page_range(int vpg_start, int pgcount, int ppg_start, unsigned int attr)
    1.87 +{
    1.88 +	int i;
    1.89 +
    1.90 +	for(i=0; i<pgcount; i++) {
    1.91 +		map_page(vpg_start + i, ppg_start + i, attr);
    1.92 +	}
    1.93 +}
    1.94 +
    1.95 +void map_mem_range(uint32_t vaddr, size_t sz, uint32_t paddr, unsigned int attr)
    1.96 +{
    1.97 +	int vpg_start, ppg_start, num_pages;
    1.98 +
    1.99 +	if(!sz) return;
   1.100 +
   1.101 +	if(ADDR_TO_PGOFFS(paddr)) {
   1.102 +		panic("map_mem_range called with unaligned physical address: %x\n", paddr);
   1.103 +	}
   1.104 +
   1.105 +	vpg_start = ADDR_TO_PAGE(vaddr);
   1.106 +	ppg_start = ADDR_TO_PAGE(paddr);
   1.107 +	num_pages = ADDR_TO_PAGE(sz) + 1;
   1.108 +
   1.109 +	map_page_range(vpg_start, num_pages, ppg_start, attr);
   1.110 +}
   1.111 +
   1.112 +
   1.113 +/*	if(mb->flags & MB_MMAP) {
   1.114 +		struct mboot_mmap *mem, *mmap_end;
   1.115 +
   1.116 +		mem = mb->mmap;
   1.117 +		mmap_end = (struct mboot_mmap*)((char*)mb->mmap + mb->mmap_len);
   1.118 +
   1.119 +		printf("memory map:\n");
   1.120 +		while(mem < mmap_end) {
   1.121 +			unsigned int end = mem->base_low + mem->length_low;
   1.122 +			char *type = mem->type == MB_MEM_VALID ? "free:" : "hole:";
   1.123 +
   1.124 +			printf("  %s %x - %x (%u bytes)\n", type, mem->base_low, end, mem->length_low);
   1.125 +			mem = (struct mboot_mmap*)((char*)mem + mem->skip + sizeof mem->skip);
   1.126 +		}
   1.127 +	}
   1.128 +
   1.129 +	if(mb->flags & MB_MEM) {
   1.130 +		printf("lower memory: %ukb, upper mem: %ukb\n", mb->mem_lower, mb->mem_upper);
   1.131 +	}
   1.132 +*/
   1.133 +
   1.134 +static void pgfault(int inum, uint32_t err)
   1.135 +{
   1.136 +	printf("~~~~ PAGE FAULT ~~~~\n");
   1.137 +
   1.138 +	printf("fault address: %x\n", get_fault_addr());
   1.139 +
   1.140 +	if(err & PG_PRESENT) {
   1.141 +		if(err & 8) {
   1.142 +			printf("reserved bit set in some paging structure\n");
   1.143 +		} else {
   1.144 +			printf("%s protection violation ", (err & PG_WRITABLE) ? "write" : "read");
   1.145 +			printf("in %s mode\n", err & PG_USER ? "user" : "kernel");
   1.146 +		}
   1.147 +	} else {
   1.148 +		printf("page not present\n");
   1.149 +	}
   1.150 +}