nuclear@17: #include <stdio.h>
nuclear@19: #include <string.h>
nuclear@17: #include "mem.h"
nuclear@17: #include "panic.h"
nuclear@17: #include "vm.h"
nuclear@17: 
nuclear@19: #define FREE		0
nuclear@19: #define USED		1
nuclear@19: 
nuclear@19: #define BM_IDX(pg)	((pg) / 32)
nuclear@19: #define BM_BIT(pg)	((pg) & 0x1f)
nuclear@19: 
nuclear@19: #define IS_FREE(pg) ((bitmap[BM_IDX(pg)] & (1 << BM_BIT(pg))) == 0)
nuclear@19: 
nuclear@19: static void mark_page(int pg, int free);
nuclear@19: static void add_memory(uint32_t start, size_t size);
nuclear@19: 
nuclear@17: /* end of kernel image */
nuclear@17: extern int _end;
nuclear@17: 
nuclear@19: static uint32_t *bitmap;
nuclear@19: static int bmsize, last_alloc_idx;
nuclear@17: 
nuclear@17: void init_mem(struct mboot_info *mb)
nuclear@17: {
nuclear@19: 	int i, num_pages, max_pg = 0;
nuclear@19: 	uint32_t used_end;
nuclear@19: 
nuclear@19: 	num_pages = 0;
nuclear@19: 	last_alloc_idx = 0;
nuclear@19: 
nuclear@19: 	bitmap = (uint32_t*)&_end;
nuclear@19: 
nuclear@19: 	/* start by marking all posible pages as used */
nuclear@19: 	memset(bitmap, 0xff, 1024 * 1024 / 8);
nuclear@19: 
nuclear@19: 	/* build the memory map */
nuclear@19: 	if(mb->flags & MB_MMAP) {
nuclear@19: 		struct mboot_mmap *mem, *mmap_end;
nuclear@19: 
nuclear@19: 		mem = mb->mmap;
nuclear@19: 		mmap_end = (struct mboot_mmap*)((char*)mb->mmap + mb->mmap_len);
nuclear@19: 
nuclear@19: 		printf("memory map:\n");
nuclear@19: 		while(mem < mmap_end) {
nuclear@19: 			char *type;
nuclear@19: 			unsigned int end = mem->base_low + mem->length_low;
nuclear@19: 
nuclear@19: 			if(mem->type == MB_MEM_VALID) {
nuclear@19: 				type = "free:";
nuclear@19: 				add_memory(mem->base_low, mem->length_low);
nuclear@19: 
nuclear@19: 				num_pages = ADDR_TO_PAGE(mem->base_low + mem->length_low);
nuclear@19: 				if(max_pg < num_pages) {
nuclear@19: 					max_pg = num_pages;
nuclear@19: 				}
nuclear@19: 			} else {
nuclear@19: 				type = "hole:";
nuclear@19: 			}
nuclear@19: 
nuclear@19: 			printf("  %s %x - %x (%u bytes)\n", type, mem->base_low, end, mem->length_low);
nuclear@19: 			mem = (struct mboot_mmap*)((char*)mem + mem->skip + sizeof mem->skip);
nuclear@19: 		}
nuclear@19: 	} else if(mb->flags & MB_MEM) {
nuclear@19: 		add_memory(0, mb->mem_lower);
nuclear@19: 		add_memory(0x100000, mb->mem_upper * 1024);
nuclear@19: 		max_pg = mb->mem_upper / 4;
nuclear@19: 
nuclear@19: 		printf("lower memory: %ukb, upper mem: %ukb\n", mb->mem_lower, mb->mem_upper);
nuclear@19: 	} else {
nuclear@19: 		panic("didn't get any memory info from the boot loader, I give up\n");
nuclear@19: 	}
nuclear@19: 
nuclear@19: 	bmsize = max_pg / 8;	/* size of the bitmap in bytes */
nuclear@19: 
nuclear@19: 	/* mark all the used pages as ... well ... used */
nuclear@19: 	used_end = ((uint32_t)bitmap + bmsize - 1);
nuclear@19: 
nuclear@19: 	printf("marking pages up to %x ", used_end);
nuclear@19: 	used_end = ADDR_TO_PAGE(used_end);
nuclear@19: 	printf("(page: %d) inclusive as used\n", used_end);
nuclear@19: 
nuclear@19: 	for(i=0; i<=used_end; i++) {
nuclear@19: 		mark_page(i, USED);
nuclear@19: 	}
nuclear@19: 
nuclear@19: 	/*for(i=0; i<bmsize / 4; i++) {
nuclear@19: 		printf("%3d [%x]\n", i, bitmap[i]);
nuclear@19: 		asm("hlt");
nuclear@19: 	}
nuclear@19: 	putchar('\n');*/
nuclear@17: }
nuclear@17: 
nuclear@17: uint32_t alloc_phys_page(void)
nuclear@17: {
nuclear@19: 	int i, idx, max;
nuclear@17: 
nuclear@19: 	idx = last_alloc_idx;
nuclear@19: 	max = bmsize / 4;
nuclear@19: 
nuclear@19: 	while(idx <= max) {
nuclear@19: 		/* if at least one bit is 0 then we have at least
nuclear@19: 		 * one free page. find it and allocate it.
nuclear@19: 		 */
nuclear@19: 		if(bitmap[idx] != 0xffffffff) {
nuclear@19: 			for(i=0; i<32; i++) {
nuclear@19: 				int pg = idx * 32 + i;
nuclear@19: 
nuclear@19: 				if(IS_FREE(pg)) {
nuclear@19: 					mark_page(pg, USED);
nuclear@19: 
nuclear@19: 					last_alloc_idx = idx;
nuclear@19: 
nuclear@19: 					printf("alloc_phys_page() -> %x (page: %d)\n", PAGE_TO_ADDR(pg), pg);
nuclear@19: 					return PAGE_TO_ADDR(pg);
nuclear@19: 				}
nuclear@19: 			}
nuclear@19: 			panic("can't happen: alloc_phys_page (mem.c)\n");
nuclear@19: 		}
nuclear@19: 		idx++;
nuclear@17: 	}
nuclear@17: 
nuclear@19: 	panic("alloc_phys_page(): out of memory\n");
nuclear@19: 	return 0;
nuclear@19: }
nuclear@19: 
nuclear@19: void free_phys_page(uint32_t addr)
nuclear@19: {
nuclear@19: 	int pg = ADDR_TO_PAGE(addr);
nuclear@19: 	int bmidx = BM_IDX(pg);
nuclear@19: 
nuclear@19: 	if(!IS_FREE(pg)) {
nuclear@19: 		panic("free_phys_page(%d): I thought that was already free!\n", pg);
nuclear@17: 	}
nuclear@17: 
nuclear@19: 	mark_page(pg, FREE);
nuclear@19: 	if(bmidx < last_alloc_idx) {
nuclear@19: 		last_alloc_idx = bmidx;
nuclear@19: 	}
nuclear@19: }
nuclear@17: 
nuclear@19: void get_kernel_mem_range(uint32_t *start, uint32_t *end)
nuclear@19: {
nuclear@19: 	if(start) {
nuclear@19: 		*start = 0x100000;
nuclear@19: 	}
nuclear@19: 	if(end) {
nuclear@19: 		uint32_t e = (uint32_t)bitmap + bmsize;
nuclear@19: 
nuclear@19: 		if(e & PGOFFS_MASK) {
nuclear@19: 			*end = (e + 4096) & PGOFFS_MASK;
nuclear@19: 		} else {
nuclear@19: 			*end = e;
nuclear@19: 		}
nuclear@19: 	}
nuclear@17: }
nuclear@19: 
nuclear@19: static void add_memory(uint32_t start, size_t sz)
nuclear@19: {
nuclear@19: 	int i, szpg, pg;
nuclear@19: 
nuclear@19: 	szpg = ADDR_TO_PAGE(sz);
nuclear@19: 	pg = ADDR_TO_PAGE(start);
nuclear@19: 
nuclear@19: 	for(i=0; i<szpg; i++) {
nuclear@19: 		mark_page(pg++, FREE);
nuclear@19: 	}
nuclear@19: }
nuclear@19: 
nuclear@19: static void mark_page(int pg, int used)
nuclear@19: {
nuclear@19: 	int idx = BM_IDX(pg);
nuclear@19: 	int bit = BM_BIT(pg);
nuclear@19: 
nuclear@19: 	if(used) {
nuclear@19: 		bitmap[idx] |= 1 << bit;
nuclear@19: 	} else {
nuclear@19: 		bitmap[idx] &= ~(1 << bit);
nuclear@19: 	}
nuclear@19: }
nuclear@19: