![Cesar Eduardo Barros](/assets/img/avatar_default.png)
kunmap_atomic() takes a pointer to within the page, not the struct page. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
254 lines
5 KiB
C
254 lines
5 KiB
C
/*
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* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <linux/err.h>
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#include <linux/highmem.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <asm/current.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include "kern_util.h"
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#include "os.h"
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pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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if (mm == NULL)
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return NULL;
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pgd = pgd_offset(mm, addr);
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if (!pgd_present(*pgd))
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return NULL;
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pud = pud_offset(pgd, addr);
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if (!pud_present(*pud))
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return NULL;
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pmd = pmd_offset(pud, addr);
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if (!pmd_present(*pmd))
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return NULL;
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return pte_offset_kernel(pmd, addr);
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}
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static pte_t *maybe_map(unsigned long virt, int is_write)
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{
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pte_t *pte = virt_to_pte(current->mm, virt);
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int err, dummy_code;
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if ((pte == NULL) || !pte_present(*pte) ||
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(is_write && !pte_write(*pte))) {
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err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
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if (err)
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return NULL;
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pte = virt_to_pte(current->mm, virt);
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}
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if (!pte_present(*pte))
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pte = NULL;
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return pte;
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}
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static int do_op_one_page(unsigned long addr, int len, int is_write,
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int (*op)(unsigned long addr, int len, void *arg), void *arg)
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{
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jmp_buf buf;
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struct page *page;
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pte_t *pte;
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int n, faulted;
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pte = maybe_map(addr, is_write);
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if (pte == NULL)
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return -1;
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page = pte_page(*pte);
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addr = (unsigned long) kmap_atomic(page, KM_UML_USERCOPY) +
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(addr & ~PAGE_MASK);
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current->thread.fault_catcher = &buf;
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faulted = UML_SETJMP(&buf);
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if (faulted == 0)
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n = (*op)(addr, len, arg);
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else
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n = -1;
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current->thread.fault_catcher = NULL;
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kunmap_atomic((void *)addr, KM_UML_USERCOPY);
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return n;
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}
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static int buffer_op(unsigned long addr, int len, int is_write,
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int (*op)(unsigned long, int, void *), void *arg)
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{
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int size, remain, n;
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size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
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remain = len;
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n = do_op_one_page(addr, size, is_write, op, arg);
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if (n != 0) {
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remain = (n < 0 ? remain : 0);
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goto out;
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}
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addr += size;
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remain -= size;
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if (remain == 0)
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goto out;
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while (addr < ((addr + remain) & PAGE_MASK)) {
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n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
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if (n != 0) {
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remain = (n < 0 ? remain : 0);
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goto out;
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}
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addr += PAGE_SIZE;
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remain -= PAGE_SIZE;
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}
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if (remain == 0)
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goto out;
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n = do_op_one_page(addr, remain, is_write, op, arg);
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if (n != 0) {
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remain = (n < 0 ? remain : 0);
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goto out;
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}
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return 0;
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out:
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return remain;
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}
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static int copy_chunk_from_user(unsigned long from, int len, void *arg)
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{
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unsigned long *to_ptr = arg, to = *to_ptr;
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memcpy((void *) to, (void *) from, len);
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*to_ptr += len;
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return 0;
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}
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int copy_from_user(void *to, const void __user *from, int n)
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{
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if (segment_eq(get_fs(), KERNEL_DS)) {
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memcpy(to, (__force void*)from, n);
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return 0;
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}
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return access_ok(VERIFY_READ, from, n) ?
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buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to):
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n;
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}
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static int copy_chunk_to_user(unsigned long to, int len, void *arg)
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{
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unsigned long *from_ptr = arg, from = *from_ptr;
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memcpy((void *) to, (void *) from, len);
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*from_ptr += len;
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return 0;
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}
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int copy_to_user(void __user *to, const void *from, int n)
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{
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if (segment_eq(get_fs(), KERNEL_DS)) {
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memcpy((__force void *) to, from, n);
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return 0;
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}
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return access_ok(VERIFY_WRITE, to, n) ?
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buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) :
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n;
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}
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static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
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{
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char **to_ptr = arg, *to = *to_ptr;
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int n;
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strncpy(to, (void *) from, len);
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n = strnlen(to, len);
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*to_ptr += n;
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if (n < len)
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return 1;
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return 0;
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}
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int strncpy_from_user(char *dst, const char __user *src, int count)
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{
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int n;
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char *ptr = dst;
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if (segment_eq(get_fs(), KERNEL_DS)) {
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strncpy(dst, (__force void *) src, count);
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return strnlen(dst, count);
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}
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if (!access_ok(VERIFY_READ, src, 1))
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return -EFAULT;
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n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
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&ptr);
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if (n != 0)
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return -EFAULT;
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return strnlen(dst, count);
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}
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static int clear_chunk(unsigned long addr, int len, void *unused)
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{
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memset((void *) addr, 0, len);
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return 0;
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}
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int __clear_user(void __user *mem, int len)
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{
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return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
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}
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int clear_user(void __user *mem, int len)
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{
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if (segment_eq(get_fs(), KERNEL_DS)) {
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memset((__force void*)mem, 0, len);
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return 0;
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}
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return access_ok(VERIFY_WRITE, mem, len) ?
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buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len;
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}
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static int strnlen_chunk(unsigned long str, int len, void *arg)
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{
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int *len_ptr = arg, n;
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n = strnlen((void *) str, len);
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*len_ptr += n;
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if (n < len)
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return 1;
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return 0;
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}
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int strnlen_user(const void __user *str, int len)
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{
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int count = 0, n;
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if (segment_eq(get_fs(), KERNEL_DS))
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return strnlen((__force char*)str, len) + 1;
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n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
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if (n == 0)
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return count + 1;
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return -EFAULT;
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}
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