PUBLIC void vm_init(struct proc *newptproc)
{
if(vm_running)
minix_panic("vm_init: vm_running", NO_NUM);
vm_set_cr3(newptproc);
level0(vm_enable_paging);
vm_running = 1;
}
PUBLIC void vm_set_cr3(struct proc *newptproc)
{
int u = 0;
if(!intr_disabled()) { lock; u = 1; }
vm_cr3= newptproc->p_seg.p_cr3;
if(vm_cr3) {
level0(set_cr3);
ptproc = newptproc;
}
if(u) { unlock; }
}
PUBLIC void vm_init(void)
{
int o;
phys_bytes p, pt_size;
phys_bytes vm_dir_base, vm_pt_base, phys_mem;
u32_t entry;
unsigned pages;
struct proc* rp;
struct proc *sys = proc_addr(SYSTEM);
static int init_done = 0;
if (!vm_size)
minix_panic("i386_vm_init: no space for page tables", NO_NUM);
if(init_done)
return;
/* Align page directory */
o= (vm_base % I386_PAGE_SIZE);
if (o != 0)
o= I386_PAGE_SIZE-o;
vm_dir_base= vm_base+o;
/* Page tables start after the page directory */
vm_pt_base= vm_dir_base+I386_PAGE_SIZE;
pt_size= (vm_base+vm_size)-vm_pt_base;
pt_size -= (pt_size % I386_PAGE_SIZE);
/* Compute the number of pages based on vm_mem_high */
pages= (vm_mem_high-1)/I386_PAGE_SIZE + 1;
if (pages * I386_VM_PT_ENT_SIZE > pt_size)
minix_panic("i386_vm_init: page table too small", NO_NUM);
for (p= 0; p*I386_VM_PT_ENT_SIZE < pt_size; p++)
{
phys_mem= p*I386_PAGE_SIZE;
entry= phys_mem | I386_VM_USER | I386_VM_WRITE |
I386_VM_PRESENT;
if (phys_mem >= vm_mem_high)
entry= 0;
#if VM_KERN_NOPAGEZERO
if (phys_mem == (sys->p_memmap[T].mem_phys << CLICK_SHIFT) ||
phys_mem == (sys->p_memmap[D].mem_phys << CLICK_SHIFT)) {
entry = 0;
}
#endif
phys_put32(vm_pt_base + p*I386_VM_PT_ENT_SIZE, entry);
}
for (p= 0; p < I386_VM_DIR_ENTRIES; p++)
{
phys_mem= vm_pt_base + p*I386_PAGE_SIZE;
entry= phys_mem | I386_VM_USER | I386_VM_WRITE |
I386_VM_PRESENT;
if (phys_mem >= vm_pt_base + pt_size)
entry= 0;
phys_put32(vm_dir_base + p*I386_VM_PT_ENT_SIZE, entry);
}
/* Set this cr3 in all currently running processes for
* future context switches.
*/
for (rp=BEG_PROC_ADDR; rp<END_PROC_ADDR; rp++) {
u32_t mycr3;
if(isemptyp(rp)) continue;
rp->p_seg.p_cr3 = vm_dir_base;
}
kernel_cr3 = vm_dir_base;
/* Set this cr3 now (not active until paging enabled). */
vm_set_cr3(vm_dir_base);
/* Actually enable paging (activating cr3 load above). */
level0(vm_enable_paging);
/* Don't do this init in the future. */
init_done = 1;
vm_running = 1;
}