s390: use generic strncpy/strnlen from_user

The s390 variant of strncpy_from_user() is slightly faster than the
generic variant, however convert to the generic variant now to follow
most if not all other architectures.

Converting to the generic variant was already considered a couple of
years ago. See commit f5c8b96 ("s390/uaccess: use sane length for
__strncpy_from_user()").

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Author: hcahca

arch/s390/Kconfig

@@ -130,6 +130,8 @@ config S390
 	select GENERIC_GETTIMEOFDAY
 	select GENERIC_PTDUMP
 	select GENERIC_SMP_IDLE_THREAD
+	select GENERIC_STRNCPY_FROM_USER
+	select GENERIC_STRNLEN_USER
 	select GENERIC_TIME_VSYSCALL
 	select GENERIC_VDSO_TIME_NS
 	select HAVE_ALIGNED_STRUCT_PAGE if SLUB

arch/s390/include/asm/uaccess.h

@@ -233,23 +233,9 @@ raw_copy_in_user(void __user *to, const void __user *from, unsigned long n);
 /*
  * Copy a null terminated string from userspace.
  */
+long __must_check strncpy_from_user(char *dst, const char __user *src, long count);
 
-long __strncpy_from_user(char *dst, const char __user *src, long count);
-
-static inline long __must_check
-strncpy_from_user(char *dst, const char __user *src, long count)
-{
-	might_fault();
-	return __strncpy_from_user(dst, src, count);
-}
-
-unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
-
-static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
-{
-	might_fault();
-	return __strnlen_user(src, n);
-}
+long __must_check strnlen_user(const char __user *src, long count);
 
 /*
  * Zero Userspace

arch/s390/lib/uaccess.c

@@ -338,55 +338,3 @@ unsigned long __clear_user(void __user *to, unsigned long size)
 	return clear_user_xc(to, size);
 }
 EXPORT_SYMBOL(__clear_user);
-
-static inline unsigned long strnlen_user_srst(const char __user *src,
-					      unsigned long size)
-{
-	unsigned long tmp1, tmp2;
-
-	asm volatile(
-		"   lghi  0,0\n"
-		"   la    %2,0(%1)\n"
-		"   la    %3,0(%0,%1)\n"
-		"   slgr  %0,%0\n"
-		"   sacf  256\n"
-		"0: srst  %3,%2\n"
-		"   jo    0b\n"
-		"   la    %0,1(%3)\n"	/* strnlen_user results includes \0 */
-		"   slgr  %0,%1\n"
-		"1: sacf  768\n"
-		EX_TABLE(0b,1b)
-		: "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
-		:
-		: "cc", "memory", "0");
-	return size;
-}
-
-unsigned long __strnlen_user(const char __user *src, unsigned long size)
-{
-	if (unlikely(!size))
-		return 0;
-	return strnlen_user_srst(src, size);
-}
-EXPORT_SYMBOL(__strnlen_user);
-
-long __strncpy_from_user(char *dst, const char __user *src, long size)
-{
-	size_t done, len, offset, len_str;
-
-	if (unlikely(size <= 0))
-		return 0;
-	done = 0;
-	do {
-		offset = (size_t)src & (L1_CACHE_BYTES - 1);
-		len = min(size - done, L1_CACHE_BYTES - offset);
-		if (copy_from_user(dst, src, len))
-			return -EFAULT;
-		len_str = strnlen(dst, len);
-		done += len_str;
-		src += len_str;
-		dst += len_str;
-	} while ((len_str == len) && (done < size));
-	return done;
-}
-EXPORT_SYMBOL(__strncpy_from_user);