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366 lines
7.3 KiB
366 lines
7.3 KiB
// 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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