void uml_setup_stubs(struct mm_struct *mm)
{
int err, ret;
if (!skas_needs_stub)
return;
ret = init_stub_pte(mm, STUB_CODE,
(unsigned long) &__syscall_stub_start);
if (ret)
goto out;
ret = init_stub_pte(mm, STUB_DATA, mm->context.id.stack);
if (ret)
goto out;
mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
/* dup_mmap already holds mmap_sem */
err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
VM_READ | VM_MAYREAD | VM_EXEC |
VM_MAYEXEC | VM_DONTCOPY,
mm->context.stub_pages);
if (err) {
printk(KERN_ERR "install_special_mapping returned %d\n", err);
goto out;
}
return;
out:
force_sigsegv(SIGSEGV, current);
}
int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
{
struct mmu_context_skas *from_mm = NULL;
struct mmu_context_skas *to_mm = &mm->context.skas;
unsigned long stack = 0;
int ret = -ENOMEM;
if(skas_needs_stub){
stack = get_zeroed_page(GFP_KERNEL);
if(stack == 0)
goto out;
/* This zeros the entry that pgd_alloc didn't, needed since
* we are about to reinitialize it, and want mm.nr_ptes to
* be accurate.
*/
mm->pgd[USER_PTRS_PER_PGD] = __pgd(0);
ret = init_stub_pte(mm, CONFIG_STUB_CODE,
(unsigned long) &__syscall_stub_start);
if(ret)
goto out_free;
ret = init_stub_pte(mm, CONFIG_STUB_DATA, stack);
if(ret)
goto out_free;
mm->nr_ptes--;
}
to_mm->id.stack = stack;
if(current->mm != NULL && current->mm != &init_mm)
from_mm = ¤t->mm->context.skas;
if(proc_mm){
ret = new_mm(stack);
if(ret < 0){
printk("init_new_context_skas - new_mm failed, "
"errno = %d\n", ret);
goto out_free;
}
to_mm->id.u.mm_fd = ret;
}
else {
if(from_mm)
to_mm->id.u.pid = copy_context_skas0(stack,
from_mm->id.u.pid);
else to_mm->id.u.pid = start_userspace(stack);
}
ret = init_new_ldt(to_mm, from_mm);
if(ret < 0){
printk("init_new_context_skas - init_ldt"
" failed, errno = %d\n", ret);
goto out_free;
}
return 0;
out_free:
if(to_mm->id.stack != 0)
free_page(to_mm->id.stack);
out:
return ret;
}
