2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
7 #include "linux/sched.h"
8 #include "asm/pgalloc.h"
9 #include "asm/pgtable.h"
10 #include "as-layout.h"
14 extern int __syscall_stub_start;
16 static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
24 pgd = pgd_offset(mm, proc);
25 pud = pud_alloc(mm, pgd, proc);
29 pmd = pmd_alloc(mm, pud, proc);
33 pte = pte_alloc_map(mm, pmd, proc);
37 *pte = mk_pte(virt_to_page(kernel), __pgprot(_PAGE_PRESENT));
38 *pte = pte_mkread(*pte);
49 int init_new_context(struct task_struct *task, struct mm_struct *mm)
51 struct mm_context *from_mm = NULL;
52 struct mm_context *to_mm = &mm->context;
53 unsigned long stack = 0;
56 if (skas_needs_stub) {
57 stack = get_zeroed_page(GFP_KERNEL);
62 to_mm->id.stack = stack;
63 if (current->mm != NULL && current->mm != &init_mm)
64 from_mm = ¤t->mm->context;
69 printk(KERN_ERR "init_new_context_skas - "
70 "new_mm failed, errno = %d\n", ret);
73 to_mm->id.u.mm_fd = ret;
77 to_mm->id.u.pid = copy_context_skas0(stack,
79 else to_mm->id.u.pid = start_userspace(stack);
81 if (to_mm->id.u.pid < 0) {
82 ret = to_mm->id.u.pid;
87 ret = init_new_ldt(to_mm, from_mm);
89 printk(KERN_ERR "init_new_context_skas - init_ldt"
90 " failed, errno = %d\n", ret);
97 if (to_mm->id.stack != 0)
98 free_page(to_mm->id.stack);
103 void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
108 if (!skas_needs_stub)
111 ret = init_stub_pte(mm, STUB_CODE,
112 (unsigned long) &__syscall_stub_start);
116 ret = init_stub_pte(mm, STUB_DATA, mm->context.id.stack);
120 pages = kmalloc(2 * sizeof(struct page *), GFP_KERNEL);
122 printk(KERN_ERR "arch_dup_mmap failed to allocate 2 page "
127 pages[0] = virt_to_page(&__syscall_stub_start);
128 pages[1] = virt_to_page(mm->context.id.stack);
130 /* dup_mmap already holds mmap_sem */
131 err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
132 VM_READ | VM_MAYREAD | VM_EXEC |
133 VM_MAYEXEC | VM_DONTCOPY, pages);
135 printk(KERN_ERR "install_special_mapping returned %d\n", err);
143 force_sigsegv(SIGSEGV, current);
146 void arch_exit_mmap(struct mm_struct *mm)
150 pte = virt_to_pte(mm, STUB_CODE);
152 pte_clear(mm, STUB_CODE, pte);
154 pte = virt_to_pte(mm, STUB_DATA);
158 pte_clear(mm, STUB_DATA, pte);
161 void destroy_context(struct mm_struct *mm)
163 struct mm_context *mmu = &mm->context;
166 os_close_file(mmu->id.u.mm_fd);
169 * If init_new_context wasn't called, this will be
170 * zero, resulting in a kill(0), which will result in the
171 * whole UML suddenly dying. Also, cover negative and
172 * 1 cases, since they shouldn't happen either.
174 if (mmu->id.u.pid < 2) {
175 printk(KERN_ERR "corrupt mm_context - pid = %d\n",
179 os_kill_ptraced_process(mmu->id.u.pid, 1);
183 free_page(mmu->id.stack);