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 if (skas_needs_stub) {
58 stack = get_zeroed_page(GFP_KERNEL);
63 to_mm->id.stack = stack;
64 if (current->mm != NULL && current->mm != &init_mm)
65 from_mm = ¤t->mm->context;
70 printk(KERN_ERR "init_new_context_skas - "
71 "new_mm failed, errno = %d\n", ret);
74 to_mm->id.u.mm_fd = ret;
78 to_mm->id.u.pid = copy_context_skas0(stack,
80 else to_mm->id.u.pid = start_userspace(stack);
82 if (to_mm->id.u.pid < 0) {
83 ret = to_mm->id.u.pid;
88 ret = init_new_ldt(to_mm, from_mm);
90 printk(KERN_ERR "init_new_context_skas - init_ldt"
91 " failed, errno = %d\n", ret);
98 if (to_mm->id.stack != 0)
99 free_page(to_mm->id.stack);
104 void uml_setup_stubs(struct mm_struct *mm)
109 if (!skas_needs_stub)
112 ret = init_stub_pte(mm, STUB_CODE,
113 (unsigned long) &__syscall_stub_start);
117 ret = init_stub_pte(mm, STUB_DATA, mm->context.id.stack);
121 mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
122 mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
124 /* dup_mmap already holds mmap_sem */
125 err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
126 VM_READ | VM_MAYREAD | VM_EXEC |
127 VM_MAYEXEC | VM_DONTCOPY,
128 mm->context.stub_pages);
130 printk(KERN_ERR "install_special_mapping returned %d\n", err);
136 force_sigsegv(SIGSEGV, current);
139 void arch_exit_mmap(struct mm_struct *mm)
143 pte = virt_to_pte(mm, STUB_CODE);
145 pte_clear(mm, STUB_CODE, pte);
147 pte = virt_to_pte(mm, STUB_DATA);
151 pte_clear(mm, STUB_DATA, pte);
154 void destroy_context(struct mm_struct *mm)
156 struct mm_context *mmu = &mm->context;
159 os_close_file(mmu->id.u.mm_fd);
162 * If init_new_context wasn't called, this will be
163 * zero, resulting in a kill(0), which will result in the
164 * whole UML suddenly dying. Also, cover negative and
165 * 1 cases, since they shouldn't happen either.
167 if (mmu->id.u.pid < 2) {
168 printk(KERN_ERR "corrupt mm_context - pid = %d\n",
172 os_kill_ptraced_process(mmu->id.u.pid, 1);
176 free_page(mmu->id.stack);