367 lines
7.3 KiB
C
367 lines
7.3 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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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/module.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 <kern_util.h>
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#include <asm/futex.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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p4d_t *p4d;
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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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p4d = p4d_offset(pgd, addr);
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if (!p4d_present(*p4d))
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return NULL;
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pud = pud_offset(p4d, 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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struct page *page;
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pte_t *pte;
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int n;
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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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#ifdef CONFIG_64BIT
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pagefault_disable();
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addr = (unsigned long) page_address(page) +
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(addr & ~PAGE_MASK);
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#else
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addr = (unsigned long) kmap_atomic(page) +
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(addr & ~PAGE_MASK);
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#endif
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n = (*op)(addr, len, arg);
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#ifdef CONFIG_64BIT
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pagefault_enable();
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#else
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kunmap_atomic((void *)addr);
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#endif
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return n;
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}
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static long 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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long 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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unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
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}
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EXPORT_SYMBOL(raw_copy_from_user);
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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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unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
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}
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EXPORT_SYMBOL(raw_copy_to_user);
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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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long strncpy_from_user(char *dst, const char __user *src, long count)
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{
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long n;
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char *ptr = dst;
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if (!access_ok(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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EXPORT_SYMBOL(strncpy_from_user);
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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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unsigned long __clear_user(void __user *mem, unsigned long 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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EXPORT_SYMBOL(__clear_user);
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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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long strnlen_user(const char __user *str, long len)
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{
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int count = 0, n;
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if (!access_ok(str, 1))
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return -EFAULT;
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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 0;
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}
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EXPORT_SYMBOL(strnlen_user);
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/**
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* arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
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* argument and comparison of the previous
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* futex value with another constant.
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*
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* @encoded_op: encoded operation to execute
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* @uaddr: pointer to user space address
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*
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* Return:
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* 0 - On success
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* -EFAULT - User access resulted in a page fault
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* -EAGAIN - Atomic operation was unable to complete due to contention
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* -ENOSYS - Operation not supported
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*/
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int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
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{
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int oldval, ret;
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struct page *page;
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unsigned long addr = (unsigned long) uaddr;
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pte_t *pte;
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ret = -EFAULT;
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if (!access_ok(uaddr, sizeof(*uaddr)))
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return -EFAULT;
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preempt_disable();
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pte = maybe_map(addr, 1);
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if (pte == NULL)
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goto out_inuser;
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page = pte_page(*pte);
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#ifdef CONFIG_64BIT
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pagefault_disable();
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addr = (unsigned long) page_address(page) +
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(((unsigned long) addr) & ~PAGE_MASK);
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#else
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addr = (unsigned long) kmap_atomic(page) +
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((unsigned long) addr & ~PAGE_MASK);
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#endif
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uaddr = (u32 *) addr;
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oldval = *uaddr;
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ret = 0;
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switch (op) {
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case FUTEX_OP_SET:
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*uaddr = oparg;
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break;
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case FUTEX_OP_ADD:
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*uaddr += oparg;
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break;
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case FUTEX_OP_OR:
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*uaddr |= oparg;
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break;
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case FUTEX_OP_ANDN:
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*uaddr &= ~oparg;
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break;
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case FUTEX_OP_XOR:
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*uaddr ^= oparg;
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break;
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default:
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ret = -ENOSYS;
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}
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#ifdef CONFIG_64BIT
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pagefault_enable();
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#else
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kunmap_atomic((void *)addr);
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#endif
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out_inuser:
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preempt_enable();
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if (ret == 0)
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*oval = oldval;
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return ret;
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}
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EXPORT_SYMBOL(arch_futex_atomic_op_inuser);
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/**
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* futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
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* uaddr with newval if the current value is
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* oldval.
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* @uval: pointer to store content of @uaddr
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* @uaddr: pointer to user space address
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* @oldval: old value
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* @newval: new value to store to @uaddr
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*
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* Return:
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* 0 - On success
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* -EFAULT - User access resulted in a page fault
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* -EAGAIN - Atomic operation was unable to complete due to contention
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*/
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int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
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u32 oldval, u32 newval)
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{
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struct page *page;
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pte_t *pte;
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int ret = -EFAULT;
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if (!access_ok(uaddr, sizeof(*uaddr)))
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return -EFAULT;
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preempt_disable();
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pte = maybe_map((unsigned long) uaddr, 1);
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if (pte == NULL)
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goto out_inatomic;
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page = pte_page(*pte);
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#ifdef CONFIG_64BIT
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pagefault_disable();
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uaddr = page_address(page) + (((unsigned long) uaddr) & ~PAGE_MASK);
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#else
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uaddr = kmap_atomic(page) + ((unsigned long) uaddr & ~PAGE_MASK);
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#endif
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*uval = *uaddr;
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ret = cmpxchg(uaddr, oldval, newval);
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#ifdef CONFIG_64BIT
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pagefault_enable();
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#else
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kunmap_atomic(uaddr);
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#endif
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ret = 0;
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out_inatomic:
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preempt_enable();
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return ret;
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}
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EXPORT_SYMBOL(futex_atomic_cmpxchg_inatomic);
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