uint32_t brk(uint32_t addr) {
/* change the value of break address. this increases
* or decreases data segment size.
*/
uint32_t first_page, last_page, i;
/* receive umem structure of current process: */
umem_t *umem = &(curproc->umem);
/* check limits: */
if (addr >= umem->heap_end || addr < umem->heap_start)
/* no memory :( */
return umem->brk_addr; /* just return current break. */
/* compare addr with current break: */
if (addr > umem->brk_addr) {
/* move forward (map) */
first_page = (umem->brk_addr+PAGE_SIZE-1) & PAGE_BASE_MASK;
last_page = (addr-1) & PAGE_BASE_MASK;
for (i = first_page; i <= last_page; i+=PAGE_SIZE)
arch_vmpage_map(umem, i, 1 /* user mode */);
} else if (addr < umem->brk_addr) {
/* move backwards (umap) */
first_page = (addr+PAGE_SIZE-1) & PAGE_BASE_MASK;
last_page = (umem->brk_addr-1) & PAGE_BASE_MASK;
for (i = first_page; i <= last_page; i+=PAGE_SIZE)
arch_vmpage_unmap(umem, i);
}
/* set & return the new break: */
return umem->brk_addr = addr;
}
void *kmalloc(uint32_t size) {
/* local vars */
linknode *ptr;
uint32_t base, i;
/* Get free hole: */
base = get_hole(log2(nextpow2(size)));
/* Allocate physical pages: */
for (i = base & 0xFFFFF000; i < base+size; i+=PAGE_SIZE)
arch_vmpage_map(NULL, i, 0);
/* Store info about this allocated space... */
ptr = (linknode *) get_hole(log2(16));
arch_vmpage_map(NULL, (uint32_t) ptr, 0);
linkedlist_add(&usedlist, ptr);
ptr->datum[0] = base;
ptr->datum[1] = size;
return (void *) base;
}
void kmem_init() {
/* initialize free lists: */
/* ----------------------- */
uint32_t i;
for (i = 0; i < 32; i++)
linkedlist_init(&freelist[i]);
linkedlist_init(&usedlist);
arch_vmpage_map(NULL, KERNEL_MEMORY_BASE, 0);
linkedlist_add(&freelist[U], (linknode *)((uint32_t) KERNEL_MEMORY_BASE));
kmem_initialized = 1;
}
int32_t umem_copy(umem_t *src, umem_t *dest) {
/* used by fork() to copy src into dest. */
uint32_t i, j;
uint8_t *buf1, *buf2;
buf1 = (uint8_t *) kmalloc(PAGE_SIZE);
if (buf1 == NULL)
return ENOMEM;
buf2 = (uint8_t *) kmalloc(PAGE_SIZE);
if (buf2 == NULL) {
kfree(buf1);
return ENOMEM;
}
/* copy umem; */
for (i=USER_MEMORY_BASE; i<KERNEL_MEMORY_BASE; i+=PAGE_DIR_SIZE) {
if (!arch_vmdir_isMapped(src, i))
continue;
for (j = i; j < i + PAGE_DIR_SIZE; j+=PAGE_SIZE) {
if (!arch_vmpage_isMapped(src, j))
continue;
arch_vmpage_map(dest, (int32_t) j, 1 /* user mode */);
arch_vmpage_copy(src, j, dest, j, buf1, buf2);
}
}
/* free the buffers: */
kfree(buf1);
kfree(buf2);
/* copy heap parameters: */
dest->heap_start = src->heap_start;
dest->brk_addr = src->brk_addr;
dest->heap_end = src->heap_end;
/* done: */
return ESUCCESS;
}
uint32_t get_hole(uint32_t i) {
if (i > U) return NULL;
if (i < L) i = L;
if (freelist[i].count) {
linknode *ptr = freelist[i] .first;
/* Remove first element from the free list. */
linkedlist_remove(&freelist[i], ptr, NULL);
if (i > 11) arch_vmpage_unmap(NULL, ptr);
return (uint32_t) ptr;
} else {
uint32_t ret = get_hole(i+1);
if (ret == NULL)
return ret;
/* Split ret to two (2^i) chunks, one is free, the other returned. */
arch_vmpage_map(NULL, ret + pow2(i), 0);
linkedlist_add(&freelist[i], (linknode *) (ret + pow2(i)));
/* printk("ret: %x %dBytes\n", ret, pow2(i)); */
return ret;
}
}
uint32_t mmap(uint32_t base, uint32_t size, uint32_t type,
uint32_t flags, uint32_t fd, uint64_t off) {
int32_t pages;
uint32_t addr;
umem_t *umem = &(curproc->umem); /* current process umem image. */
/*printk("mmap called: %x, size: %x\n", base, size);*/
/* make sure fd is valid if a file is to be used */
if (type & MMAP_TYPE_FILE) {
if (fd < 0 || fd >= FD_MAX || curproc->file[fd] == NULL)
return 0;
}
if (!base) {
/* allocate space */
base = umem->heap_end - size;
}
size += base & (~PAGE_BASE_MASK); /* rectify "size". */
base = base & PAGE_BASE_MASK;
pages = (size+PAGE_SIZE-1)/PAGE_SIZE; /* pages to be allocated. */
size = pages*PAGE_SIZE; /* actual size. */
/*printk(" - %x, size: %x\n", base, size); */
/* make sure the system is initialized. */
if (curproc == NULL)
return 0; /* system is not initialized. */
/* check whether the given range is valid or not. */
for (addr = base; addr < base + size; addr+=PAGE_SIZE) {
if (addr<USER_MEMORY_BASE || addr>=KERNEL_MEMORY_BASE) {
return 0; /* invalid */
}
}
/* update heap end: */
if (base < umem->heap_end)
umem->heap_end = base;
/* now allocate. */
for (addr = base; addr < base + size; addr+=PAGE_SIZE) {
arch_vmpage_map(umem, (int32_t) addr, 1 /* user mode */);
/* mapping a file? */
if (type & MMAP_TYPE_FILE) {
/* read file information */
file_t *file = curproc->file[fd];
inode_t *inode = file->inode;
file_mem_t *region = inode->sma.first;
/* shared? */
if (flags & MMAP_FLAGS_SHARED) {
/* search for the wanted region */
while (region != NULL) {
if (region->pos == off) {
/* found */
region->ref++;
break;
}
region = region->next;
}
/* region found or not? */
if (!region) {
/* region not found, create it */
region = kmalloc(sizeof(file_mem_t));
if (!region)
return 0;
if (file_reopen(file, &(region->file)))
return 0;
region->pos = off;
region->paddr = 0;
region->ref = 1;
/* add to the inode */
linkedlist_add(&(inode->sma), region);
}
} else {
/* not shared, allocate a new one */
region = kmalloc(sizeof(file_mem_t));
if (!region)
return 0;
if (file_reopen(file, &(region->file)))
return 0;
region->pos = off;
region->paddr = 0;
region->ref = 1;
}
/* attach the virtual page to the mapping */
arch_vmpage_attach_file(umem, (int32_t) addr, region);
/* update offset */
off += PAGE_SIZE;
}
}
/* return the base address. */
return base;
}