2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
7 #include <linux/sched.h>
8 #include <linux/slab.h>
9 #include <asm/pgalloc.h>
10 #include <asm/pgtable.h>
11 #include <as-layout.h>
15 extern int __syscall_stub_start;
17 static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
25 pgd = pgd_offset(mm, proc);
26 pud = pud_alloc(mm, pgd, proc);
30 pmd = pmd_alloc(mm, pud, proc);
34 pte = pte_alloc_map(mm, NULL, pmd, proc);
38 *pte = mk_pte(virt_to_page(kernel), __pgprot(_PAGE_PRESENT));
39 *pte = pte_mkread(*pte);
50 int init_new_context(struct task_struct *task, struct mm_struct *mm)
52 struct mm_context *from_mm = NULL;
53 struct mm_context *to_mm = &mm->context;
54 unsigned long stack = 0;
57 stack = get_zeroed_page(GFP_KERNEL);
61 to_mm->id.stack = stack;
62 if (current->mm != NULL && current->mm != &init_mm)
63 from_mm = ¤t->mm->context;
66 to_mm->id.u.pid = copy_context_skas0(stack,
68 else to_mm->id.u.pid = start_userspace(stack);
70 if (to_mm->id.u.pid < 0) {
71 ret = to_mm->id.u.pid;
75 ret = init_new_ldt(to_mm, from_mm);
77 printk(KERN_ERR "init_new_context_skas - init_ldt"
78 " failed, errno = %d\n", ret);
85 if (to_mm->id.stack != 0)
86 free_page(to_mm->id.stack);
91 void uml_setup_stubs(struct mm_struct *mm)
95 ret = init_stub_pte(mm, STUB_CODE,
96 (unsigned long) &__syscall_stub_start);
100 ret = init_stub_pte(mm, STUB_DATA, mm->context.id.stack);
104 mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
105 mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
107 /* dup_mmap already holds mmap_sem */
108 err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
109 VM_READ | VM_MAYREAD | VM_EXEC |
110 VM_MAYEXEC | VM_DONTCOPY | VM_PFNMAP,
111 mm->context.stub_pages);
113 printk(KERN_ERR "install_special_mapping returned %d\n", err);
119 force_sigsegv(SIGSEGV, current);
122 void arch_exit_mmap(struct mm_struct *mm)
126 pte = virt_to_pte(mm, STUB_CODE);
128 pte_clear(mm, STUB_CODE, pte);
130 pte = virt_to_pte(mm, STUB_DATA);
134 pte_clear(mm, STUB_DATA, pte);
137 void destroy_context(struct mm_struct *mm)
139 struct mm_context *mmu = &mm->context;
142 * If init_new_context wasn't called, this will be
143 * zero, resulting in a kill(0), which will result in the
144 * whole UML suddenly dying. Also, cover negative and
145 * 1 cases, since they shouldn't happen either.
147 if (mmu->id.u.pid < 2) {
148 printk(KERN_ERR "corrupt mm_context - pid = %d\n",
152 os_kill_ptraced_process(mmu->id.u.pid, 1);
154 free_page(mmu->id.stack);