x86: use the new generic strnlen_user() function

This throws away the old x86-specific functions in favor of the generic
optimized version.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/Kconfig

@@ -94,6 +94,7 @@ config X86
 	select GENERIC_TIME_VSYSCALL if X86_64
 	select KTIME_SCALAR if X86_32
 	select GENERIC_STRNCPY_FROM_USER
+	select GENERIC_STRNLEN_USER
 
 config INSTRUCTION_DECODER
 	def_bool (KPROBES || PERF_EVENTS || UPROBES)

arch/x86/include/asm/uaccess.h

@@ -566,6 +566,9 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
 extern __must_check long
 strncpy_from_user(char *dst, const char __user *src, long count);
 
+extern __must_check long strlen_user(const char __user *str);
+extern __must_check long strnlen_user(const char __user *str, long n);
+
 /*
  * movsl can be slow when source and dest are not both 8-byte aligned
  */

arch/x86/include/asm/uaccess_32.h

@@ -213,23 +213,6 @@ static inline unsigned long __must_check copy_from_user(void *to,
 	return n;
 }
 
-/**
- * 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, LONG_MAX)
-
-long strnlen_user(const char __user *str, long n);
 unsigned long __must_check clear_user(void __user *mem, unsigned long len);
 unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
 

arch/x86/include/asm/uaccess_64.h

@@ -208,9 +208,6 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 	}
 }
 
-__must_check long strnlen_user(const char __user *str, long n);
-__must_check long __strnlen_user(const char __user *str, long n);
-__must_check long strlen_user(const char __user *str);
 __must_check unsigned long clear_user(void __user *mem, unsigned long len);
 __must_check unsigned long __clear_user(void __user *mem, unsigned long len);
 

arch/x86/lib/usercopy_32.c

@@ -95,47 +95,6 @@ __clear_user(void __user *to, unsigned long n)
 }
 EXPORT_SYMBOL(__clear_user);
 
-/**
- * strnlen_user: - Get the size of a string in user space.
- * @s: The string to measure.
- * @n: The maximum valid length
- *
- * 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 the string is too long, returns a value greater than @n.
- */
-long strnlen_user(const char __user *s, long n)
-{
-	unsigned long mask = -__addr_ok(s);
-	unsigned long res, tmp;
-
-	might_fault();
-
-	__asm__ __volatile__(
-		"	testl %0, %0\n"
-		"	jz 3f\n"
-		"	andl %0,%%ecx\n"
-		"0:	repne; scasb\n"
-		"	setne %%al\n"
-		"	subl %%ecx,%0\n"
-		"	addl %0,%%eax\n"
-		"1:\n"
-		".section .fixup,\"ax\"\n"
-		"2:	xorl %%eax,%%eax\n"
-		"	jmp 1b\n"
-		"3:	movb $1,%%al\n"
-		"	jmp 1b\n"
-		".previous\n"
-		_ASM_EXTABLE(0b,2b)
-		:"=&r" (n), "=&D" (s), "=&a" (res), "=&c" (tmp)
-		:"0" (n), "1" (s), "2" (0), "3" (mask)
-		:"cc");
-	return res & mask;
-}
-EXPORT_SYMBOL(strnlen_user);
-
 #ifdef CONFIG_X86_INTEL_USERCOPY
 static unsigned long
 __copy_user_intel(void __user *to, const void *from, unsigned long size)

arch/x86/lib/usercopy_64.c

@@ -52,54 +52,6 @@ unsigned long clear_user(void __user *to, unsigned long n)
 }
 EXPORT_SYMBOL(clear_user);
 
-/*
- * Return the size of a string (including the ending 0)
- *
- * Return 0 on exception, a value greater than N if too long
- */
-
-long __strnlen_user(const char __user *s, long n)
-{
-	long res = 0;
-	char c;
-
-	while (1) {
-		if (res>n)
-			return n+1;
-		if (__get_user(c, s))
-			return 0;
-		if (!c)
-			return res+1;
-		res++;
-		s++;
-	}
-}
-EXPORT_SYMBOL(__strnlen_user);
-
-long strnlen_user(const char __user *s, long n)
-{
-	if (!access_ok(VERIFY_READ, s, 1))
-		return 0;
-	return __strnlen_user(s, n);
-}
-EXPORT_SYMBOL(strnlen_user);
-
-long strlen_user(const char __user *s)
-{
-	long res = 0;
-	char c;
-
-	for (;;) {
-		if (get_user(c, s))
-			return 0;
-		if (!c)
-			return res+1;
-		res++;
-		s++;
-	}
-}
-EXPORT_SYMBOL(strlen_user);
-
 unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
 {
 	if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {