--- /dev/null
+/*
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/err.h>
+#include <linux/highmem.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <asm/current.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <kern_util.h>
+#include <os.h>
+
+pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+
+ if (mm == NULL)
+ return NULL;
+
+ pgd = pgd_offset(mm, addr);
+ if (!pgd_present(*pgd))
+ return NULL;
+
+ pud = pud_offset(pgd, addr);
+ if (!pud_present(*pud))
+ return NULL;
+
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ return NULL;
+
+ return pte_offset_kernel(pmd, addr);
+}
+
+static pte_t *maybe_map(unsigned long virt, int is_write)
+{
+ pte_t *pte = virt_to_pte(current->mm, virt);
+ int err, dummy_code;
+
+ if ((pte == NULL) || !pte_present(*pte) ||
+ (is_write && !pte_write(*pte))) {
+ err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
+ if (err)
+ return NULL;
+ pte = virt_to_pte(current->mm, virt);
+ }
+ if (!pte_present(*pte))
+ pte = NULL;
+
+ return pte;
+}
+
+static int do_op_one_page(unsigned long addr, int len, int is_write,
+ int (*op)(unsigned long addr, int len, void *arg), void *arg)
+{
+ jmp_buf buf;
+ struct page *page;
+ pte_t *pte;
+ int n, faulted;
+
+ pte = maybe_map(addr, is_write);
+ if (pte == NULL)
+ return -1;
+
+ page = pte_page(*pte);
+ addr = (unsigned long) kmap_atomic(page) +
+ (addr & ~PAGE_MASK);
+
+ current->thread.fault_catcher = &buf;
+
+ faulted = UML_SETJMP(&buf);
+ if (faulted == 0)
+ n = (*op)(addr, len, arg);
+ else
+ n = -1;
+
+ current->thread.fault_catcher = NULL;
+
+ kunmap_atomic((void *)addr);
+
+ return n;
+}
+
+static int buffer_op(unsigned long addr, int len, int is_write,
+ int (*op)(unsigned long, int, void *), void *arg)
+{
+ int size, remain, n;
+
+ size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
+ remain = len;
+
+ n = do_op_one_page(addr, size, is_write, op, arg);
+ if (n != 0) {
+ remain = (n < 0 ? remain : 0);
+ goto out;
+ }
+
+ addr += size;
+ remain -= size;
+ if (remain == 0)
+ goto out;
+
+ while (addr < ((addr + remain) & PAGE_MASK)) {
+ n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
+ if (n != 0) {
+ remain = (n < 0 ? remain : 0);
+ goto out;
+ }
+
+ addr += PAGE_SIZE;
+ remain -= PAGE_SIZE;
+ }
+ if (remain == 0)
+ goto out;
+
+ n = do_op_one_page(addr, remain, is_write, op, arg);
+ if (n != 0) {
+ remain = (n < 0 ? remain : 0);
+ goto out;
+ }
+
+ return 0;
+ out:
+ return remain;
+}
+
+static int copy_chunk_from_user(unsigned long from, int len, void *arg)
+{
+ unsigned long *to_ptr = arg, to = *to_ptr;
+
+ memcpy((void *) to, (void *) from, len);
+ *to_ptr += len;
+ return 0;
+}
+
+int copy_from_user(void *to, const void __user *from, int n)
+{
+ if (segment_eq(get_fs(), KERNEL_DS)) {
+ memcpy(to, (__force void*)from, n);
+ return 0;
+ }
+
+ return access_ok(VERIFY_READ, from, n) ?
+ buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to):
+ n;
+}
+EXPORT_SYMBOL(copy_from_user);
+
+static int copy_chunk_to_user(unsigned long to, int len, void *arg)
+{
+ unsigned long *from_ptr = arg, from = *from_ptr;
+
+ memcpy((void *) to, (void *) from, len);
+ *from_ptr += len;
+ return 0;
+}
+
+int copy_to_user(void __user *to, const void *from, int n)
+{
+ if (segment_eq(get_fs(), KERNEL_DS)) {
+ memcpy((__force void *) to, from, n);
+ return 0;
+ }
+
+ return access_ok(VERIFY_WRITE, to, n) ?
+ buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) :
+ n;
+}
+EXPORT_SYMBOL(copy_to_user);
+
+static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
+{
+ char **to_ptr = arg, *to = *to_ptr;
+ int n;
+
+ strncpy(to, (void *) from, len);
+ n = strnlen(to, len);
+ *to_ptr += n;
+
+ if (n < len)
+ return 1;
+ return 0;
+}
+
+int strncpy_from_user(char *dst, const char __user *src, int count)
+{
+ int n;
+ char *ptr = dst;
+
+ if (segment_eq(get_fs(), KERNEL_DS)) {
+ strncpy(dst, (__force void *) src, count);
+ return strnlen(dst, count);
+ }
+
+ if (!access_ok(VERIFY_READ, src, 1))
+ return -EFAULT;
+
+ n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
+ &ptr);
+ if (n != 0)
+ return -EFAULT;
+ return strnlen(dst, count);
+}
+EXPORT_SYMBOL(strncpy_from_user);
+
+static int clear_chunk(unsigned long addr, int len, void *unused)
+{
+ memset((void *) addr, 0, len);
+ return 0;
+}
+
+int __clear_user(void __user *mem, int len)
+{
+ return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
+}
+
+int clear_user(void __user *mem, int len)
+{
+ if (segment_eq(get_fs(), KERNEL_DS)) {
+ memset((__force void*)mem, 0, len);
+ return 0;
+ }
+
+ return access_ok(VERIFY_WRITE, mem, len) ?
+ buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len;
+}
+EXPORT_SYMBOL(clear_user);
+
+static int strnlen_chunk(unsigned long str, int len, void *arg)
+{
+ int *len_ptr = arg, n;
+
+ n = strnlen((void *) str, len);
+ *len_ptr += n;
+
+ if (n < len)
+ return 1;
+ return 0;
+}
+
+int strnlen_user(const void __user *str, int len)
+{
+ int count = 0, n;
+
+ if (segment_eq(get_fs(), KERNEL_DS))
+ return strnlen((__force char*)str, len) + 1;
+
+ n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
+ if (n == 0)
+ return count + 1;
+ return 0;
+}
+EXPORT_SYMBOL(strnlen_user);
Code Review / kvmfornfv.git / blobdiff