2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
7 #include <linux/highmem.h>
9 #include <linux/module.h>
10 #include <linux/sched.h>
11 #include <asm/current.h>
13 #include <asm/pgtable.h>
14 #include <kern_util.h>
17 pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
26 pgd = pgd_offset(mm, addr);
27 if (!pgd_present(*pgd))
30 pud = pud_offset(pgd, addr);
31 if (!pud_present(*pud))
34 pmd = pmd_offset(pud, addr);
35 if (!pmd_present(*pmd))
38 return pte_offset_kernel(pmd, addr);
41 static pte_t *maybe_map(unsigned long virt, int is_write)
43 pte_t *pte = virt_to_pte(current->mm, virt);
46 if ((pte == NULL) || !pte_present(*pte) ||
47 (is_write && !pte_write(*pte))) {
48 err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
51 pte = virt_to_pte(current->mm, virt);
53 if (!pte_present(*pte))
59 static int do_op_one_page(unsigned long addr, int len, int is_write,
60 int (*op)(unsigned long addr, int len, void *arg), void *arg)
67 pte = maybe_map(addr, is_write);
71 page = pte_page(*pte);
72 addr = (unsigned long) kmap_atomic(page) +
75 current->thread.fault_catcher = &buf;
77 faulted = UML_SETJMP(&buf);
79 n = (*op)(addr, len, arg);
83 current->thread.fault_catcher = NULL;
85 kunmap_atomic((void *)addr);
90 static long buffer_op(unsigned long addr, int len, int is_write,
91 int (*op)(unsigned long, int, void *), void *arg)
95 size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
98 n = do_op_one_page(addr, size, is_write, op, arg);
100 remain = (n < 0 ? remain : 0);
109 while (addr < ((addr + remain) & PAGE_MASK)) {
110 n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
112 remain = (n < 0 ? remain : 0);
122 n = do_op_one_page(addr, remain, is_write, op, arg);
124 remain = (n < 0 ? remain : 0);
133 static int copy_chunk_from_user(unsigned long from, int len, void *arg)
135 unsigned long *to_ptr = arg, to = *to_ptr;
137 memcpy((void *) to, (void *) from, len);
142 long __copy_from_user(void *to, const void __user *from, unsigned long n)
144 if (segment_eq(get_fs(), KERNEL_DS)) {
145 memcpy(to, (__force void*)from, n);
149 return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
151 EXPORT_SYMBOL(__copy_from_user);
153 static int copy_chunk_to_user(unsigned long to, int len, void *arg)
155 unsigned long *from_ptr = arg, from = *from_ptr;
157 memcpy((void *) to, (void *) from, len);
162 long __copy_to_user(void __user *to, const void *from, unsigned long n)
164 if (segment_eq(get_fs(), KERNEL_DS)) {
165 memcpy((__force void *) to, from, n);
169 return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
171 EXPORT_SYMBOL(__copy_to_user);
173 static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
175 char **to_ptr = arg, *to = *to_ptr;
178 strncpy(to, (void *) from, len);
179 n = strnlen(to, len);
187 long __strncpy_from_user(char *dst, const char __user *src, long count)
192 if (segment_eq(get_fs(), KERNEL_DS)) {
193 strncpy(dst, (__force void *) src, count);
194 return strnlen(dst, count);
197 n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
201 return strnlen(dst, count);
203 EXPORT_SYMBOL(__strncpy_from_user);
205 static int clear_chunk(unsigned long addr, int len, void *unused)
207 memset((void *) addr, 0, len);
211 unsigned long __clear_user(void __user *mem, unsigned long len)
213 if (segment_eq(get_fs(), KERNEL_DS)) {
214 memset((__force void*)mem, 0, len);
218 return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
220 EXPORT_SYMBOL(__clear_user);
222 static int strnlen_chunk(unsigned long str, int len, void *arg)
224 int *len_ptr = arg, n;
226 n = strnlen((void *) str, len);
234 long __strnlen_user(const void __user *str, long len)
238 if (segment_eq(get_fs(), KERNEL_DS))
239 return strnlen((__force char*)str, len) + 1;
241 n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
246 EXPORT_SYMBOL(__strnlen_user);