Commit e93a1cb8 authored by Heiko Carstens's avatar Heiko Carstens Committed by Arnd Bergmann
Browse files

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 f5c8b960 ("s390/uaccess: use sane length for
__strncpy_from_user()").

Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent b26b1816

arch/s390/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -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

+2 −16
Original line number Diff line number Diff line
@@ -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

+0 −52
Original line number Diff line number Diff line
@@ -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);