summaryrefslogtreecommitdiffstats
path: root/arch/m32r/include/asm/uaccess.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/m32r/include/asm/uaccess.h')
-rw-r--r--arch/m32r/include/asm/uaccess.h693
1 files changed, 693 insertions, 0 deletions
diff --git a/arch/m32r/include/asm/uaccess.h b/arch/m32r/include/asm/uaccess.h
new file mode 100644
index 000000000000..1c7047bea200
--- /dev/null
+++ b/arch/m32r/include/asm/uaccess.h
@@ -0,0 +1,693 @@
+#ifndef _ASM_M32R_UACCESS_H
+#define _ASM_M32R_UACCESS_H
+
+/*
+ * linux/include/asm-m32r/uaccess.h
+ *
+ * M32R version.
+ * Copyright (C) 2004, 2006 Hirokazu Takata <takata at linux-m32r.org>
+ */
+
+/*
+ * User space memory access functions
+ */
+#include <linux/errno.h>
+#include <linux/thread_info.h>
+#include <asm/page.h>
+#include <asm/setup.h>
+
+#define VERIFY_READ 0
+#define VERIFY_WRITE 1
+
+/*
+ * The fs value determines whether argument validity checking should be
+ * performed or not. If get_fs() == USER_DS, checking is performed, with
+ * get_fs() == KERNEL_DS, checking is bypassed.
+ *
+ * For historical reasons, these macros are grossly misnamed.
+ */
+
+#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
+
+#ifdef CONFIG_MMU
+
+#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
+#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
+#define get_ds() (KERNEL_DS)
+#define get_fs() (current_thread_info()->addr_limit)
+#define set_fs(x) (current_thread_info()->addr_limit = (x))
+
+#else /* not CONFIG_MMU */
+
+#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
+#define USER_DS MAKE_MM_SEG(0xFFFFFFFF)
+#define get_ds() (KERNEL_DS)
+
+static inline mm_segment_t get_fs(void)
+{
+ return USER_DS;
+}
+
+static inline void set_fs(mm_segment_t s)
+{
+}
+
+#endif /* not CONFIG_MMU */
+
+#define segment_eq(a,b) ((a).seg == (b).seg)
+
+#define __addr_ok(addr) \
+ ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
+
+/*
+ * Test whether a block of memory is a valid user space address.
+ * Returns 0 if the range is valid, nonzero otherwise.
+ *
+ * This is equivalent to the following test:
+ * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
+ *
+ * This needs 33-bit arithmetic. We have a carry...
+ */
+#define __range_ok(addr,size) ({ \
+ unsigned long flag, roksum; \
+ __chk_user_ptr(addr); \
+ asm ( \
+ " cmpu %1, %1 ; clear cbit\n" \
+ " addx %1, %3 ; set cbit if overflow\n" \
+ " subx %0, %0\n" \
+ " cmpu %4, %1\n" \
+ " subx %0, %5\n" \
+ : "=&r" (flag), "=r" (roksum) \
+ : "1" (addr), "r" ((int)(size)), \
+ "r" (current_thread_info()->addr_limit.seg), "r" (0) \
+ : "cbit" ); \
+ flag; })
+
+/**
+ * access_ok: - Checks if a user space pointer is valid
+ * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
+ * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
+ * to write to a block, it is always safe to read from it.
+ * @addr: User space pointer to start of block to check
+ * @size: Size of block to check
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Checks if a pointer to a block of memory in user space is valid.
+ *
+ * Returns true (nonzero) if the memory block may be valid, false (zero)
+ * if it is definitely invalid.
+ *
+ * Note that, depending on architecture, this function probably just
+ * checks that the pointer is in the user space range - after calling
+ * this function, memory access functions may still return -EFAULT.
+ */
+#ifdef CONFIG_MMU
+#define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0))
+#else
+static inline int access_ok(int type, const void *addr, unsigned long size)
+{
+ unsigned long val = (unsigned long)addr;
+
+ return ((val >= memory_start) && ((val + size) < memory_end));
+}
+#endif /* CONFIG_MMU */
+
+/*
+ * The exception table consists of pairs of addresses: the first is the
+ * address of an instruction that is allowed to fault, and the second is
+ * the address at which the program should continue. No registers are
+ * modified, so it is entirely up to the continuation code to figure out
+ * what to do.
+ *
+ * All the routines below use bits of fixup code that are out of line
+ * with the main instruction path. This means when everything is well,
+ * we don't even have to jump over them. Further, they do not intrude
+ * on our cache or tlb entries.
+ */
+
+struct exception_table_entry
+{
+ unsigned long insn, fixup;
+};
+
+extern int fixup_exception(struct pt_regs *regs);
+
+/*
+ * These are the main single-value transfer routines. They automatically
+ * use the right size if we just have the right pointer type.
+ *
+ * This gets kind of ugly. We want to return _two_ values in "get_user()"
+ * and yet we don't want to do any pointers, because that is too much
+ * of a performance impact. Thus we have a few rather ugly macros here,
+ * and hide all the uglyness from the user.
+ *
+ * The "__xxx" versions of the user access functions are versions that
+ * do not verify the address space, that must have been done previously
+ * with a separate "access_ok()" call (this is used when we do multiple
+ * accesses to the same area of user memory).
+ */
+
+/* Careful: we have to cast the result to the type of the pointer for sign
+ reasons */
+/**
+ * get_user: - Get a simple variable from user space.
+ * @x: Variable to store result.
+ * @ptr: Source address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple variable from user space to kernel
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and the result of
+ * dereferencing @ptr must be assignable to @x without a cast.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ * On error, the variable @x is set to zero.
+ */
+#define get_user(x,ptr) \
+ __get_user_check((x),(ptr),sizeof(*(ptr)))
+
+/**
+ * put_user: - Write a simple value into user space.
+ * @x: Value to copy to user space.
+ * @ptr: Destination address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple value from kernel space to user
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and @x must be assignable
+ * to the result of dereferencing @ptr.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ */
+#define put_user(x,ptr) \
+ __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
+
+/**
+ * __get_user: - Get a simple variable from user space, with less checking.
+ * @x: Variable to store result.
+ * @ptr: Source address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple variable from user space to kernel
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and the result of
+ * dereferencing @ptr must be assignable to @x without a cast.
+ *
+ * Caller must check the pointer with access_ok() before calling this
+ * function.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ * On error, the variable @x is set to zero.
+ */
+#define __get_user(x,ptr) \
+ __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
+
+#define __get_user_nocheck(x,ptr,size) \
+({ \
+ long __gu_err = 0; \
+ unsigned long __gu_val; \
+ might_sleep(); \
+ __get_user_size(__gu_val,(ptr),(size),__gu_err); \
+ (x) = (__typeof__(*(ptr)))__gu_val; \
+ __gu_err; \
+})
+
+#define __get_user_check(x,ptr,size) \
+({ \
+ long __gu_err = -EFAULT; \
+ unsigned long __gu_val = 0; \
+ const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
+ might_sleep(); \
+ if (access_ok(VERIFY_READ,__gu_addr,size)) \
+ __get_user_size(__gu_val,__gu_addr,(size),__gu_err); \
+ (x) = (__typeof__(*(ptr)))__gu_val; \
+ __gu_err; \
+})
+
+extern long __get_user_bad(void);
+
+#define __get_user_size(x,ptr,size,retval) \
+do { \
+ retval = 0; \
+ __chk_user_ptr(ptr); \
+ switch (size) { \
+ case 1: __get_user_asm(x,ptr,retval,"ub"); break; \
+ case 2: __get_user_asm(x,ptr,retval,"uh"); break; \
+ case 4: __get_user_asm(x,ptr,retval,""); break; \
+ default: (x) = __get_user_bad(); \
+ } \
+} while (0)
+
+#define __get_user_asm(x, addr, err, itype) \
+ __asm__ __volatile__( \
+ " .fillinsn\n" \
+ "1: ld"itype" %1,@%2\n" \
+ " .fillinsn\n" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ " .balign 4\n" \
+ "3: ldi %0,%3\n" \
+ " seth r14,#high(2b)\n" \
+ " or3 r14,r14,#low(2b)\n" \
+ " jmp r14\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .balign 4\n" \
+ " .long 1b,3b\n" \
+ ".previous" \
+ : "=&r" (err), "=&r" (x) \
+ : "r" (addr), "i" (-EFAULT), "0" (err) \
+ : "r14", "memory")
+
+/**
+ * __put_user: - Write a simple value into user space, with less checking.
+ * @x: Value to copy to user space.
+ * @ptr: Destination address, in user space.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * This macro copies a single simple value from kernel space to user
+ * space. It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and @x must be assignable
+ * to the result of dereferencing @ptr.
+ *
+ * Caller must check the pointer with access_ok() before calling this
+ * function.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ */
+#define __put_user(x,ptr) \
+ __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
+
+
+#define __put_user_nocheck(x,ptr,size) \
+({ \
+ long __pu_err; \
+ might_sleep(); \
+ __put_user_size((x),(ptr),(size),__pu_err); \
+ __pu_err; \
+})
+
+
+#define __put_user_check(x,ptr,size) \
+({ \
+ long __pu_err = -EFAULT; \
+ __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
+ might_sleep(); \
+ if (access_ok(VERIFY_WRITE,__pu_addr,size)) \
+ __put_user_size((x),__pu_addr,(size),__pu_err); \
+ __pu_err; \
+})
+
+#if defined(__LITTLE_ENDIAN__)
+#define __put_user_u64(x, addr, err) \
+ __asm__ __volatile__( \
+ " .fillinsn\n" \
+ "1: st %L1,@%2\n" \
+ " .fillinsn\n" \
+ "2: st %H1,@(4,%2)\n" \
+ " .fillinsn\n" \
+ "3:\n" \
+ ".section .fixup,\"ax\"\n" \
+ " .balign 4\n" \
+ "4: ldi %0,%3\n" \
+ " seth r14,#high(3b)\n" \
+ " or3 r14,r14,#low(3b)\n" \
+ " jmp r14\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .balign 4\n" \
+ " .long 1b,4b\n" \
+ " .long 2b,4b\n" \
+ ".previous" \
+ : "=&r" (err) \
+ : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err) \
+ : "r14", "memory")
+
+#elif defined(__BIG_ENDIAN__)
+#define __put_user_u64(x, addr, err) \
+ __asm__ __volatile__( \
+ " .fillinsn\n" \
+ "1: st %H1,@%2\n" \
+ " .fillinsn\n" \
+ "2: st %L1,@(4,%2)\n" \
+ " .fillinsn\n" \
+ "3:\n" \
+ ".section .fixup,\"ax\"\n" \
+ " .balign 4\n" \
+ "4: ldi %0,%3\n" \
+ " seth r14,#high(3b)\n" \
+ " or3 r14,r14,#low(3b)\n" \
+ " jmp r14\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .balign 4\n" \
+ " .long 1b,4b\n" \
+ " .long 2b,4b\n" \
+ ".previous" \
+ : "=&r" (err) \
+ : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err) \
+ : "r14", "memory")
+#else
+#error no endian defined
+#endif
+
+extern void __put_user_bad(void);
+
+#define __put_user_size(x,ptr,size,retval) \
+do { \
+ retval = 0; \
+ __chk_user_ptr(ptr); \
+ switch (size) { \
+ case 1: __put_user_asm(x,ptr,retval,"b"); break; \
+ case 2: __put_user_asm(x,ptr,retval,"h"); break; \
+ case 4: __put_user_asm(x,ptr,retval,""); break; \
+ case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\
+ default: __put_user_bad(); \
+ } \
+} while (0)
+
+struct __large_struct { unsigned long buf[100]; };
+#define __m(x) (*(struct __large_struct *)(x))
+
+/*
+ * Tell gcc we read from memory instead of writing: this is because
+ * we do not write to any memory gcc knows about, so there are no
+ * aliasing issues.
+ */
+#define __put_user_asm(x, addr, err, itype) \
+ __asm__ __volatile__( \
+ " .fillinsn\n" \
+ "1: st"itype" %1,@%2\n" \
+ " .fillinsn\n" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ " .balign 4\n" \
+ "3: ldi %0,%3\n" \
+ " seth r14,#high(2b)\n" \
+ " or3 r14,r14,#low(2b)\n" \
+ " jmp r14\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .balign 4\n" \
+ " .long 1b,3b\n" \
+ ".previous" \
+ : "=&r" (err) \
+ : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err) \
+ : "r14", "memory")
+
+/*
+ * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
+ * we return the initial request size (1, 2 or 4), as copy_*_user should do.
+ * If a store crosses a page boundary and gets a fault, the m32r will not write
+ * anything, so this is accurate.
+ */
+
+/*
+ * Copy To/From Userspace
+ */
+
+/* Generic arbitrary sized copy. */
+/* Return the number of bytes NOT copied. */
+#define __copy_user(to,from,size) \
+do { \
+ unsigned long __dst, __src, __c; \
+ __asm__ __volatile__ ( \
+ " mv r14, %0\n" \
+ " or r14, %1\n" \
+ " beq %0, %1, 9f\n" \
+ " beqz %2, 9f\n" \
+ " and3 r14, r14, #3\n" \
+ " bnez r14, 2f\n" \
+ " and3 %2, %2, #3\n" \
+ " beqz %3, 2f\n" \
+ " addi %0, #-4 ; word_copy \n" \
+ " .fillinsn\n" \
+ "0: ld r14, @%1+\n" \
+ " addi %3, #-1\n" \
+ " .fillinsn\n" \
+ "1: st r14, @+%0\n" \
+ " bnez %3, 0b\n" \
+ " beqz %2, 9f\n" \
+ " addi %0, #4\n" \
+ " .fillinsn\n" \
+ "2: ldb r14, @%1 ; byte_copy \n" \
+ " .fillinsn\n" \
+ "3: stb r14, @%0\n" \
+ " addi %1, #1\n" \
+ " addi %2, #-1\n" \
+ " addi %0, #1\n" \
+ " bnez %2, 2b\n" \
+ " .fillinsn\n" \
+ "9:\n" \
+ ".section .fixup,\"ax\"\n" \
+ " .balign 4\n" \
+ "5: addi %3, #1\n" \
+ " addi %1, #-4\n" \
+ " .fillinsn\n" \
+ "6: slli %3, #2\n" \
+ " add %2, %3\n" \
+ " addi %0, #4\n" \
+ " .fillinsn\n" \
+ "7: seth r14, #high(9b)\n" \
+ " or3 r14, r14, #low(9b)\n" \
+ " jmp r14\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .balign 4\n" \
+ " .long 0b,6b\n" \
+ " .long 1b,5b\n" \
+ " .long 2b,9b\n" \
+ " .long 3b,9b\n" \
+ ".previous\n" \
+ : "=&r" (__dst), "=&r" (__src), "=&r" (size), \
+ "=&r" (__c) \
+ : "0" (to), "1" (from), "2" (size), "3" (size / 4) \
+ : "r14", "memory"); \
+} while (0)
+
+#define __copy_user_zeroing(to,from,size) \
+do { \
+ unsigned long __dst, __src, __c; \
+ __asm__ __volatile__ ( \
+ " mv r14, %0\n" \
+ " or r14, %1\n" \
+ " beq %0, %1, 9f\n" \
+ " beqz %2, 9f\n" \
+ " and3 r14, r14, #3\n" \
+ " bnez r14, 2f\n" \
+ " and3 %2, %2, #3\n" \
+ " beqz %3, 2f\n" \
+ " addi %0, #-4 ; word_copy \n" \
+ " .fillinsn\n" \
+ "0: ld r14, @%1+\n" \
+ " addi %3, #-1\n" \
+ " .fillinsn\n" \
+ "1: st r14, @+%0\n" \
+ " bnez %3, 0b\n" \
+ " beqz %2, 9f\n" \
+ " addi %0, #4\n" \
+ " .fillinsn\n" \
+ "2: ldb r14, @%1 ; byte_copy \n" \
+ " .fillinsn\n" \
+ "3: stb r14, @%0\n" \
+ " addi %1, #1\n" \
+ " addi %2, #-1\n" \
+ " addi %0, #1\n" \
+ " bnez %2, 2b\n" \
+ " .fillinsn\n" \
+ "9:\n" \
+ ".section .fixup,\"ax\"\n" \
+ " .balign 4\n" \
+ "5: addi %3, #1\n" \
+ " addi %1, #-4\n" \
+ " .fillinsn\n" \
+ "6: slli %3, #2\n" \
+ " add %2, %3\n" \
+ " addi %0, #4\n" \
+ " .fillinsn\n" \
+ "7: ldi r14, #0 ; store zero \n" \
+ " .fillinsn\n" \
+ "8: addi %2, #-1\n" \
+ " stb r14, @%0 ; ACE? \n" \
+ " addi %0, #1\n" \
+ " bnez %2, 8b\n" \
+ " seth r14, #high(9b)\n" \
+ " or3 r14, r14, #low(9b)\n" \
+ " jmp r14\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .balign 4\n" \
+ " .long 0b,6b\n" \
+ " .long 1b,5b\n" \
+ " .long 2b,7b\n" \
+ " .long 3b,7b\n" \
+ ".previous\n" \
+ : "=&r" (__dst), "=&r" (__src), "=&r" (size), \
+ "=&r" (__c) \
+ : "0" (to), "1" (from), "2" (size), "3" (size / 4) \
+ : "r14", "memory"); \
+} while (0)
+
+
+/* We let the __ versions of copy_from/to_user inline, because they're often
+ * used in fast paths and have only a small space overhead.
+ */
+static inline unsigned long __generic_copy_from_user_nocheck(void *to,
+ const void __user *from, unsigned long n)
+{
+ __copy_user_zeroing(to,from,n);
+ return n;
+}
+
+static inline unsigned long __generic_copy_to_user_nocheck(void __user *to,
+ const void *from, unsigned long n)
+{
+ __copy_user(to,from,n);
+ return n;
+}
+
+unsigned long __generic_copy_to_user(void __user *, const void *, unsigned long);
+unsigned long __generic_copy_from_user(void *, const void __user *, unsigned long);
+
+/**
+ * __copy_to_user: - Copy a block of data into user space, with less checking.
+ * @to: Destination address, in user space.
+ * @from: Source address, in kernel space.
+ * @n: Number of bytes to copy.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Copy data from kernel space to user space. Caller must check
+ * the specified block with access_ok() before calling this function.
+ *
+ * Returns number of bytes that could not be copied.
+ * On success, this will be zero.
+ */
+#define __copy_to_user(to,from,n) \
+ __generic_copy_to_user_nocheck((to),(from),(n))
+
+#define __copy_to_user_inatomic __copy_to_user
+#define __copy_from_user_inatomic __copy_from_user
+
+/**
+ * copy_to_user: - Copy a block of data into user space.
+ * @to: Destination address, in user space.
+ * @from: Source address, in kernel space.
+ * @n: Number of bytes to copy.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Copy data from kernel space to user space.
+ *
+ * Returns number of bytes that could not be copied.
+ * On success, this will be zero.
+ */
+#define copy_to_user(to,from,n) \
+({ \
+ might_sleep(); \
+ __generic_copy_to_user((to),(from),(n)); \
+})
+
+/**
+ * __copy_from_user: - Copy a block of data from user space, with less checking. * @to: Destination address, in kernel space.
+ * @from: Source address, in user space.
+ * @n: Number of bytes to copy.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Copy data from user space to kernel space. Caller must check
+ * the specified block with access_ok() before calling this function.
+ *
+ * Returns number of bytes that could not be copied.
+ * On success, this will be zero.
+ *
+ * If some data could not be copied, this function will pad the copied
+ * data to the requested size using zero bytes.
+ */
+#define __copy_from_user(to,from,n) \
+ __generic_copy_from_user_nocheck((to),(from),(n))
+
+/**
+ * copy_from_user: - Copy a block of data from user space.
+ * @to: Destination address, in kernel space.
+ * @from: Source address, in user space.
+ * @n: Number of bytes to copy.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Copy data from user space to kernel space.
+ *
+ * Returns number of bytes that could not be copied.
+ * On success, this will be zero.
+ *
+ * If some data could not be copied, this function will pad the copied
+ * data to the requested size using zero bytes.
+ */
+#define copy_from_user(to,from,n) \
+({ \
+ might_sleep(); \
+ __generic_copy_from_user((to),(from),(n)); \
+})
+
+long __must_check strncpy_from_user(char *dst, const char __user *src,
+ long count);
+long __must_check __strncpy_from_user(char *dst,
+ const char __user *src, long count);
+
+/**
+ * __clear_user: - Zero a block of memory in user space, with less checking.
+ * @to: Destination address, in user space.
+ * @n: Number of bytes to zero.
+ *
+ * Zero a block of memory in user space. Caller must check
+ * the specified block with access_ok() before calling this function.
+ *
+ * Returns number of bytes that could not be cleared.
+ * On success, this will be zero.
+ */
+unsigned long __clear_user(void __user *mem, unsigned long len);
+
+/**
+ * clear_user: - Zero a block of memory in user space.
+ * @to: Destination address, in user space.
+ * @n: Number of bytes to zero.
+ *
+ * Zero a block of memory in user space. Caller must check
+ * the specified block with access_ok() before calling this function.
+ *
+ * Returns number of bytes that could not be cleared.
+ * On success, this will be zero.
+ */
+unsigned long clear_user(void __user *mem, unsigned long len);
+
+/**
+ * strlen_user: - Get the size of a string in user space.
+ * @str: The string to measure.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Get the size of a NUL-terminated string in user space.
+ *
+ * Returns the size of the string INCLUDING the terminating NUL.
+ * On exception, returns 0.
+ *
+ * If there is a limit on the length of a valid string, you may wish to
+ * consider using strnlen_user() instead.
+ */
+#define strlen_user(str) strnlen_user(str, ~0UL >> 1)
+long strnlen_user(const char __user *str, long n);
+
+#endif /* _ASM_M32R_UACCESS_H */