/*===========================================================================*
* pt_new *
*===========================================================================*/
PUBLIC int pt_new(pt_t *pt)
{
/* Allocate a pagetable root. On i386, allocate a page-aligned page directory
* and set them to 0 (indicating no page tables are allocated). Lookup
* its physical address as we'll need that in the future. Verify it's
* page-aligned.
*/
int i;
/* Don't ever re-allocate/re-move a certain process slot's
* page directory once it's been created. This is a fraction
* faster, but also avoids having to invalidate the page
* mappings from in-kernel page tables pointing to
* the page directories (the page_directories data).
*/
if(!pt->pt_dir &&
!(pt->pt_dir = vm_allocpage(&pt->pt_dir_phys, VMP_PAGEDIR))) {
return ENOMEM;
}
for(i = 0; i < I386_VM_DIR_ENTRIES; i++) {
pt->pt_dir[i] = 0; /* invalid entry (I386_VM_PRESENT bit = 0) */
pt->pt_pt[i] = NULL;
}
/* Where to start looking for free virtual address space? */
pt->pt_virtop = 0;
/* Map in kernel. */
if(pt_mapkernel(pt) != OK)
panic("pt_new: pt_mapkernel failed");
return OK;
}
/*===========================================================================*
* pt_writemap *
*===========================================================================*/
int pt_writemap(struct vmproc * vmp,
pt_t *pt,
vir_bytes v,
phys_bytes physaddr,
size_t bytes,
u32_t flags,
u32_t writemapflags)
{
/* Write mapping into page table. Allocate a new page table if necessary. */
/* Page directory and table entries for this virtual address. */
int p, pages;
int verify = 0;
int ret = OK;
#ifdef CONFIG_SMP
int vminhibit_clear = 0;
/* FIXME
* don't do it everytime, stop the process only on the first change and
* resume the execution on the last change. Do in a wrapper of this
* function
*/
if (vmp && vmp->vm_endpoint != NONE && vmp->vm_endpoint != VM_PROC_NR &&
!(vmp->vm_flags & VMF_EXITING)) {
sys_vmctl(vmp->vm_endpoint, VMCTL_VMINHIBIT_SET, 0);
vminhibit_clear = 1;
}
#endif
if(writemapflags & WMF_VERIFY)
verify = 1;
assert(!(bytes % VM_PAGE_SIZE));
assert(!(flags & ~(PTF_ALLFLAGS)));
pages = bytes / VM_PAGE_SIZE;
/* MAP_NONE means to clear the mapping. It doesn't matter
* what's actually written into the PTE if PRESENT
* isn't on, so we can just write MAP_NONE into it.
*/
assert(physaddr == MAP_NONE || (flags & ARCH_VM_PTE_PRESENT));
assert(physaddr != MAP_NONE || !flags);
/* First make sure all the necessary page tables are allocated,
* before we start writing in any of them, because it's a pain
* to undo our work properly.
*/
ret = pt_ptalloc_in_range(pt, v, v + VM_PAGE_SIZE*pages, flags, verify);
if(ret != OK) {
printf("VM: writemap: pt_ptalloc_in_range failed\n");
goto resume_exit;
}
/* Now write in them. */
for(p = 0; p < pages; p++) {
u32_t entry;
int pde = ARCH_VM_PDE(v);
int pte = ARCH_VM_PTE(v);
assert(!(v % VM_PAGE_SIZE));
assert(pte >= 0 && pte < ARCH_VM_PT_ENTRIES);
assert(pde >= 0 && pde < ARCH_VM_DIR_ENTRIES);
/* Page table has to be there. */
assert(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT);
/* We do not expect it to be a bigpage. */
assert(!(pt->pt_dir[pde] & ARCH_VM_BIGPAGE));
/* Make sure page directory entry for this page table
* is marked present and page table entry is available.
*/
assert(pt->pt_pt[pde]);
#if SANITYCHECKS
/* We don't expect to overwrite a page. */
if(!(writemapflags & (WMF_OVERWRITE|WMF_VERIFY)))
assert(!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT));
#endif
if(writemapflags & (WMF_WRITEFLAGSONLY|WMF_FREE)) {
#if defined(__i386__)
physaddr = pt->pt_pt[pde][pte] & ARCH_VM_ADDR_MASK;
#elif defined(__arm__)
physaddr = pt->pt_pt[pde][pte] & ARM_VM_PTE_MASK;
#endif
}
if(writemapflags & WMF_FREE) {
free_mem(ABS2CLICK(physaddr), 1);
}
/* Entry we will write. */
#if defined(__i386__)
entry = (physaddr & ARCH_VM_ADDR_MASK) | flags;
#elif defined(__arm__)
entry = (physaddr & ARM_VM_PTE_MASK) | flags;
#endif
if(verify) {
u32_t maskedentry;
maskedentry = pt->pt_pt[pde][pte];
#if defined(__i386__)
maskedentry &= ~(I386_VM_ACC|I386_VM_DIRTY);
#endif
/* Verify pagetable entry. */
#if defined(__i386__)
if(entry & ARCH_VM_PTE_RW) {
/* If we expect a writable page, allow a readonly page. */
maskedentry |= ARCH_VM_PTE_RW;
}
#elif defined(__arm__)
if(!(entry & ARCH_VM_PTE_RO)) {
/* If we expect a writable page, allow a readonly page. */
maskedentry &= ~ARCH_VM_PTE_RO;
}
maskedentry &= ~(ARM_VM_PTE_WB|ARM_VM_PTE_WT);
#endif
if(maskedentry != entry) {
printf("pt_writemap: mismatch: ");
#if defined(__i386__)
if((entry & ARCH_VM_ADDR_MASK) !=
(maskedentry & ARCH_VM_ADDR_MASK)) {
#elif defined(__arm__)
if((entry & ARM_VM_PTE_MASK) !=
(maskedentry & ARM_VM_PTE_MASK)) {
#endif
printf("pt_writemap: physaddr mismatch (0x%lx, 0x%lx); ",
(long)entry, (long)maskedentry);
} else printf("phys ok; ");
printf(" flags: found %s; ",
ptestr(pt->pt_pt[pde][pte]));
printf(" masked %s; ",
ptestr(maskedentry));
printf(" expected %s\n", ptestr(entry));
printf("found 0x%x, wanted 0x%x\n",
pt->pt_pt[pde][pte], entry);
ret = EFAULT;
goto resume_exit;
}
} else {
/* Write pagetable entry. */
pt->pt_pt[pde][pte] = entry;
}
physaddr += VM_PAGE_SIZE;
v += VM_PAGE_SIZE;
}
resume_exit:
#ifdef CONFIG_SMP
if (vminhibit_clear) {
assert(vmp && vmp->vm_endpoint != NONE && vmp->vm_endpoint != VM_PROC_NR &&
!(vmp->vm_flags & VMF_EXITING));
sys_vmctl(vmp->vm_endpoint, VMCTL_VMINHIBIT_CLEAR, 0);
}
#endif
return ret;
}
/*===========================================================================*
* pt_checkrange *
*===========================================================================*/
int pt_checkrange(pt_t *pt, vir_bytes v, size_t bytes,
int write)
{
int p, pages;
assert(!(bytes % VM_PAGE_SIZE));
pages = bytes / VM_PAGE_SIZE;
for(p = 0; p < pages; p++) {
int pde = ARCH_VM_PDE(v);
int pte = ARCH_VM_PTE(v);
assert(!(v % VM_PAGE_SIZE));
assert(pte >= 0 && pte < ARCH_VM_PT_ENTRIES);
assert(pde >= 0 && pde < ARCH_VM_DIR_ENTRIES);
/* Page table has to be there. */
if(!(pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT))
return EFAULT;
/* Make sure page directory entry for this page table
* is marked present and page table entry is available.
*/
assert((pt->pt_dir[pde] & ARCH_VM_PDE_PRESENT) && pt->pt_pt[pde]);
if(!(pt->pt_pt[pde][pte] & ARCH_VM_PTE_PRESENT)) {
return EFAULT;
}
#if defined(__i386__)
if(write && !(pt->pt_pt[pde][pte] & ARCH_VM_PTE_RW)) {
#elif defined(__arm__)
if(write && (pt->pt_pt[pde][pte] & ARCH_VM_PTE_RO)) {
#endif
return EFAULT;
}
v += VM_PAGE_SIZE;
}
return OK;
}
/*===========================================================================*
* pt_new *
*===========================================================================*/
int pt_new(pt_t *pt)
{
/* Allocate a pagetable root. Allocate a page-aligned page directory
* and set them to 0 (indicating no page tables are allocated). Lookup
* its physical address as we'll need that in the future. Verify it's
* page-aligned.
*/
int i, r;
/* Don't ever re-allocate/re-move a certain process slot's
* page directory once it's been created. This is a fraction
* faster, but also avoids having to invalidate the page
* mappings from in-kernel page tables pointing to
* the page directories (the page_directories data).
*/
if(!pt->pt_dir &&
!(pt->pt_dir = vm_allocpages((phys_bytes *)&pt->pt_dir_phys,
VMP_PAGEDIR, ARCH_PAGEDIR_SIZE/VM_PAGE_SIZE))) {
return ENOMEM;
}
assert(!((u32_t)pt->pt_dir_phys % ARCH_PAGEDIR_SIZE));
for(i = 0; i < ARCH_VM_DIR_ENTRIES; i++) {
pt->pt_dir[i] = 0; /* invalid entry (PRESENT bit = 0) */
pt->pt_pt[i] = NULL;
}
/* Where to start looking for free virtual address space? */
pt->pt_virtop = 0;
/* Map in kernel. */
if((r=pt_mapkernel(pt)) != OK)
return r;
return OK;
}
/*===========================================================================*
* pt_init *
*===========================================================================*/
PUBLIC void pt_init(phys_bytes usedlimit)
{
/* By default, the kernel gives us a data segment with pre-allocated
* memory that then can't grow. We want to be able to allocate memory
* dynamically, however. So here we copy the part of the page table
* that's ours, so we get a private page table. Then we increase the
* hardware segment size so we can allocate memory above our stack.
*/
pt_t *newpt;
int s, r;
vir_bytes v;
phys_bytes lo, hi;
vir_bytes extra_clicks;
u32_t moveup = 0;
int global_bit_ok = 0;
int free_pde;
int p;
struct vm_ep_data ep_data;
vir_bytes sparepages_mem;
phys_bytes sparepages_ph;
vir_bytes ptr;
/* Shorthand. */
newpt = &vmprocess->vm_pt;
/* Get ourselves spare pages. */
ptr = (vir_bytes) static_sparepages;
ptr += I386_PAGE_SIZE - (ptr % I386_PAGE_SIZE);
if(!(sparepages_mem = ptr))
panic("pt_init: aalloc for spare failed");
if((r=sys_umap(SELF, VM_D, (vir_bytes) sparepages_mem,
I386_PAGE_SIZE*SPAREPAGES, &sparepages_ph)) != OK)
panic("pt_init: sys_umap failed: %d", r);
missing_spares = 0;
assert(STATIC_SPAREPAGES < SPAREPAGES);
for(s = 0; s < SPAREPAGES; s++) {
if(s >= STATIC_SPAREPAGES) {
sparepages[s].page = NULL;
missing_spares++;
continue;
}
sparepages[s].page = (void *) (sparepages_mem + s*I386_PAGE_SIZE);
sparepages[s].phys = sparepages_ph + s*I386_PAGE_SIZE;
}
/* global bit and 4MB pages available? */
global_bit_ok = _cpufeature(_CPUF_I386_PGE);
bigpage_ok = _cpufeature(_CPUF_I386_PSE);
/* Set bit for PTE's and PDE's if available. */
if(global_bit_ok)
global_bit = I386_VM_GLOBAL;
/* The kernel and boot time processes need an identity mapping.
* We use full PDE's for this without separate page tables.
* Figure out which pde we can start using for other purposes.
*/
id_map_high_pde = usedlimit / I386_BIG_PAGE_SIZE;
/* We have to make mappings up till here. */
free_pde = id_map_high_pde+1;
/* Initial (current) range of our virtual address space. */
lo = CLICK2ABS(vmprocess->vm_arch.vm_seg[T].mem_phys);
hi = CLICK2ABS(vmprocess->vm_arch.vm_seg[S].mem_phys +
vmprocess->vm_arch.vm_seg[S].mem_len);
assert(!(lo % I386_PAGE_SIZE));
assert(!(hi % I386_PAGE_SIZE));
if(lo < VM_PROCSTART) {
moveup = VM_PROCSTART - lo;
assert(!(VM_PROCSTART % I386_PAGE_SIZE));
assert(!(lo % I386_PAGE_SIZE));
assert(!(moveup % I386_PAGE_SIZE));
}
/* Make new page table for ourselves, partly copied
* from the current one.
*/
if(pt_new(newpt) != OK)
panic("pt_init: pt_new failed");
/* Set up mappings for VM process. */
for(v = lo; v < hi; v += I386_PAGE_SIZE) {
phys_bytes addr;
u32_t flags;
/* We have to write the new position in the PT,
* so we can move our segments.
*/
if(pt_writemap(vmprocess, newpt, v+moveup, v, I386_PAGE_SIZE,
I386_VM_PRESENT|I386_VM_WRITE|I386_VM_USER, 0) != OK)
panic("pt_init: pt_writemap failed");
}
/* Move segments up too. */
vmprocess->vm_arch.vm_seg[T].mem_phys += ABS2CLICK(moveup);
vmprocess->vm_arch.vm_seg[D].mem_phys += ABS2CLICK(moveup);
vmprocess->vm_arch.vm_seg[S].mem_phys += ABS2CLICK(moveup);
/* Allocate us a page table in which to remember page directory
* pointers.
*/
if(!(page_directories = vm_allocpage(&page_directories_phys,
VMP_PAGETABLE)))
panic("no virt addr for vm mappings");
memset(page_directories, 0, I386_PAGE_SIZE);
/* Increase our hardware data segment to create virtual address
* space above our stack. We want to increase it to VM_DATATOP,
* like regular processes have.
*/
extra_clicks = ABS2CLICK(VM_DATATOP - hi);
vmprocess->vm_arch.vm_seg[S].mem_len += extra_clicks;
/* We pretend to the kernel we have a huge stack segment to
* increase our data segment.
*/
vmprocess->vm_arch.vm_data_top =
(vmprocess->vm_arch.vm_seg[S].mem_vir +
vmprocess->vm_arch.vm_seg[S].mem_len) << CLICK_SHIFT;
/* Where our free virtual address space starts.
* This is only a hint to the VM system.
*/
newpt->pt_virtop = 0;
/* Let other functions know VM now has a private page table. */
vmprocess->vm_flags |= VMF_HASPT;
/* Now reserve another pde for kernel's own mappings. */
{
int kernmap_pde;
phys_bytes addr, len;
int flags, index = 0;
u32_t offset = 0;
kernmap_pde = free_pde++;
offset = kernmap_pde * I386_BIG_PAGE_SIZE;
while(sys_vmctl_get_mapping(index, &addr, &len,
&flags) == OK) {
vir_bytes vir;
if(index >= MAX_KERNMAPPINGS)
panic("VM: too many kernel mappings: %d", index);
kern_mappings[index].phys_addr = addr;
kern_mappings[index].len = len;
kern_mappings[index].flags = flags;
kern_mappings[index].lin_addr = offset;
kern_mappings[index].flags =
I386_VM_PRESENT | I386_VM_USER | I386_VM_WRITE |
global_bit;
if(flags & VMMF_UNCACHED)
kern_mappings[index].flags |= PTF_NOCACHE;
if(addr % I386_PAGE_SIZE)
panic("VM: addr unaligned: %d", addr);
if(len % I386_PAGE_SIZE)
panic("VM: len unaligned: %d", len);
vir = arch_map2vir(&vmproc[VMP_SYSTEM], offset);
if(sys_vmctl_reply_mapping(index, vir) != OK)
panic("VM: reply failed");
offset += len;
index++;
kernmappings++;
}
}
/* Find a PDE below processes available for mapping in the
* page directories (readonly).
*/
pagedir_pde = free_pde++;
pagedir_pde_val = (page_directories_phys & I386_VM_ADDR_MASK) |
I386_VM_PRESENT | I386_VM_USER | I386_VM_WRITE;
/* Tell kernel about free pde's. */
while(free_pde*I386_BIG_PAGE_SIZE < VM_PROCSTART) {
if((r=sys_vmctl(SELF, VMCTL_I386_FREEPDE, free_pde++)) != OK) {
panic("VMCTL_I386_FREEPDE failed: %d", r);
}
}
/* first pde in use by process. */
proc_pde = free_pde;
/* Give our process the new, copied, private page table. */
pt_mapkernel(newpt); /* didn't know about vm_dir pages earlier */
pt_bind(newpt, vmprocess);
/* new segment limit for the kernel after paging is enabled */
ep_data.data_seg_limit = free_pde*I386_BIG_PAGE_SIZE;
/* the memory map which must be installed after paging is enabled */
ep_data.mem_map = vmprocess->vm_arch.vm_seg;
/* Now actually enable paging. */
if(sys_vmctl_enable_paging(&ep_data) != OK)
panic("pt_init: enable paging failed");
/* Back to reality - this is where the stack actually is. */
vmprocess->vm_arch.vm_seg[S].mem_len -= extra_clicks;
/* Pretend VM stack top is the same as any regular process, not to
* have discrepancies with new VM instances later on.
*/
vmprocess->vm_stacktop = VM_STACKTOP;
/* All OK. */
return;
}
/*===========================================================================*
* pt_init_mem *
*===========================================================================*/
PUBLIC void pt_init_mem()
{
/* Architecture-specific memory initialization. Make sure all the pages
* shared with the kernel and VM's page tables are mapped above the stack,
* so that we can easily transfer existing mappings for new VM instances.
*/
u32_t new_page_directories_phys, *new_page_directories;
u32_t new_pt_dir_phys, *new_pt_dir;
u32_t new_pt_phys, *new_pt;
pt_t *vmpt;
int i;
vmpt = &vmprocess->vm_pt;
/* We should be running this when VM has been assigned a page
* table and memory initialization has already been performed.
*/
assert(vmprocess->vm_flags & VMF_HASPT);
assert(meminit_done);
/* Throw away static spare pages. */
vm_checkspares();
for(i = 0; i < SPAREPAGES; i++) {
if(sparepages[i].page && (vir_bytes) sparepages[i].page
< vmprocess->vm_stacktop) {
sparepages[i].page = NULL;
missing_spares++;
}
}
vm_checkspares();
/* Rellocate page for page directories pointers. */
if(!(new_page_directories = vm_allocpage(&new_page_directories_phys,
VMP_PAGETABLE)))
panic("unable to reallocated page for page dir ptrs");
assert((vir_bytes) new_page_directories >= vmprocess->vm_stacktop);
memcpy(new_page_directories, page_directories, I386_PAGE_SIZE);
page_directories = new_page_directories;
pagedir_pde_val = (new_page_directories_phys & I386_VM_ADDR_MASK) |
(pagedir_pde_val & ~I386_VM_ADDR_MASK);
/* Remap in kernel. */
pt_mapkernel(vmpt);
/* Reallocate VM's page directory. */
if((vir_bytes) vmpt->pt_dir < vmprocess->vm_stacktop) {
if(!(new_pt_dir= vm_allocpage(&new_pt_dir_phys, VMP_PAGEDIR))) {
panic("unable to reallocate VM's page directory");
}
assert((vir_bytes) new_pt_dir >= vmprocess->vm_stacktop);
memcpy(new_pt_dir, vmpt->pt_dir, I386_PAGE_SIZE);
vmpt->pt_dir = new_pt_dir;
vmpt->pt_dir_phys = new_pt_dir_phys;
pt_bind(vmpt, vmprocess);
}
/* Reallocate VM's page tables. */
for(i = proc_pde; i < I386_VM_DIR_ENTRIES; i++) {
if(!(vmpt->pt_dir[i] & I386_VM_PRESENT)) {
continue;
}
assert(vmpt->pt_pt[i]);
if((vir_bytes) vmpt->pt_pt[i] >= vmprocess->vm_stacktop) {
continue;
}
vm_checkspares();
if(!(new_pt = vm_allocpage(&new_pt_phys, VMP_PAGETABLE)))
panic("unable to reallocate VM's page table");
assert((vir_bytes) new_pt >= vmprocess->vm_stacktop);
memcpy(new_pt, vmpt->pt_pt[i], I386_PAGE_SIZE);
vmpt->pt_pt[i] = new_pt;
vmpt->pt_dir[i] = (new_pt_phys & I386_VM_ADDR_MASK) |
(vmpt->pt_dir[i] & ~I386_VM_ADDR_MASK);
}
}
