2 * arch/s390/lib/uaccess_pt.c
4 * User access functions based on page table walks.
6 * Copyright IBM Corp. 2006
7 * Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
10 #include <linux/errno.h>
12 #include <asm/uaccess.h>
13 #include <asm/futex.h>
15 static inline int __handle_fault(struct mm_struct *mm, unsigned long address,
18 struct vm_area_struct *vma;
21 down_read(&mm->mmap_sem);
22 vma = find_vma(mm, address);
25 if (unlikely(vma->vm_start > address)) {
26 if (!(vma->vm_flags & VM_GROWSDOWN))
28 if (expand_stack(vma, address))
33 /* page not present, check vm flags */
34 if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
37 if (!(vma->vm_flags & VM_WRITE))
42 switch (handle_mm_fault(mm, vma, address, write_access)) {
58 up_read(&mm->mmap_sem);
62 up_read(&mm->mmap_sem);
63 if (is_init(current)) {
65 down_read(&mm->mmap_sem);
68 printk("VM: killing process %s\n", current->comm);
72 up_read(&mm->mmap_sem);
73 current->thread.prot_addr = address;
74 current->thread.trap_no = 0x11;
75 force_sig(SIGBUS, current);
79 static inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
80 size_t n, int write_user)
82 struct mm_struct *mm = current->mm;
83 unsigned long offset, pfn, done, size;
91 spin_lock(&mm->page_table_lock);
93 pgd = pgd_offset(mm, uaddr);
94 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
97 pmd = pmd_offset(pgd, uaddr);
98 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
101 pte = pte_offset_map(pmd, uaddr);
102 if (!pte || !pte_present(*pte) ||
103 (write_user && !pte_write(*pte)))
110 offset = uaddr & (PAGE_SIZE - 1);
111 size = min(n - done, PAGE_SIZE - offset);
113 to = (void *)((pfn << PAGE_SHIFT) + offset);
116 from = (void *)((pfn << PAGE_SHIFT) + offset);
119 memcpy(to, from, size);
124 spin_unlock(&mm->page_table_lock);
127 spin_unlock(&mm->page_table_lock);
128 if (__handle_fault(mm, uaddr, write_user))
133 size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
137 if (segment_eq(get_fs(), KERNEL_DS)) {
138 memcpy(to, (void __kernel __force *) from, n);
141 rc = __user_copy_pt((unsigned long) from, to, n, 0);
143 memset(to + n - rc, 0, rc);
147 size_t copy_to_user_pt(size_t n, void __user *to, const void *from)
149 if (segment_eq(get_fs(), KERNEL_DS)) {
150 memcpy((void __kernel __force *) to, from, n);
153 return __user_copy_pt((unsigned long) to, (void *) from, n, 1);