Commit 122b05dd authored by Al Viro's avatar Al Viro
Browse files

amd64: get rid of zeroing 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent d597580d

arch/x86/include/asm/uaccess.h

+12 −0
Original line number Diff line number Diff line
@@ -379,6 +379,18 @@ do { \ 
		     : "=r" (err), ltype(x)				\

		     : "m" (__m(addr)), "i" (errret), "0" (err))



#define __get_user_asm_nozero(x, addr, err, itype, rtype, ltype, errret)	\

	asm volatile("\n"						\

		     "1:	mov"itype" %2,%"rtype"1\n"		\

		     "2:\n"						\

		     ".section .fixup,\"ax\"\n"				\

		     "3:	mov %3,%0\n"				\

		     "	jmp 2b\n"					\

		     ".previous\n"					\

		     _ASM_EXTABLE(1b, 3b)				\

		     : "=r" (err), ltype(x)				\

		     : "m" (__m(addr)), "i" (errret), "0" (err))



/*

 * This doesn't do __uaccess_begin/end - the exception handling

 * around it must do that.

arch/x86/include/asm/uaccess_64.h

+8 −8
Original line number Diff line number Diff line
@@ -59,44 +59,44 @@ int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size) 
	switch (size) {

	case 1:

		__uaccess_begin();

		__get_user_asm(*(u8 *)dst, (u8 __user *)src,

		__get_user_asm_nozero(*(u8 *)dst, (u8 __user *)src,

			      ret, "b", "b", "=q", 1);

		__uaccess_end();

		return ret;

	case 2:

		__uaccess_begin();

		__get_user_asm(*(u16 *)dst, (u16 __user *)src,

		__get_user_asm_nozero(*(u16 *)dst, (u16 __user *)src,

			      ret, "w", "w", "=r", 2);

		__uaccess_end();

		return ret;

	case 4:

		__uaccess_begin();

		__get_user_asm(*(u32 *)dst, (u32 __user *)src,

		__get_user_asm_nozero(*(u32 *)dst, (u32 __user *)src,

			      ret, "l", "k", "=r", 4);

		__uaccess_end();

		return ret;

	case 8:

		__uaccess_begin();

		__get_user_asm(*(u64 *)dst, (u64 __user *)src,

		__get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,

			      ret, "q", "", "=r", 8);

		__uaccess_end();

		return ret;

	case 10:

		__uaccess_begin();

		__get_user_asm(*(u64 *)dst, (u64 __user *)src,

		__get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,

			       ret, "q", "", "=r", 10);

		if (likely(!ret))

			__get_user_asm(*(u16 *)(8 + (char *)dst),

			__get_user_asm_nozero(*(u16 *)(8 + (char *)dst),

				       (u16 __user *)(8 + (char __user *)src),

				       ret, "w", "w", "=r", 2);

		__uaccess_end();

		return ret;

	case 16:

		__uaccess_begin();

		__get_user_asm(*(u64 *)dst, (u64 __user *)src,

		__get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,

			       ret, "q", "", "=r", 16);

		if (likely(!ret))

			__get_user_asm(*(u64 *)(8 + (char *)dst),

			__get_user_asm_nozero(*(u64 *)(8 + (char *)dst),

				       (u64 __user *)(8 + (char __user *)src),

				       ret, "q", "", "=r", 8);

		__uaccess_end();

arch/x86/lib/usercopy.c

+5 −4
Original line number Diff line number Diff line
@@ -76,10 +76,11 @@ EXPORT_SYMBOL(_copy_to_user); 
 */

unsigned long _copy_from_user(void *to, const void __user *from, unsigned n)

{

	unsigned long res = n;

	if (access_ok(VERIFY_READ, from, n))

		n = __copy_from_user(to, from, n);

	else

		memset(to, 0, n);

	return n;

		res = __copy_from_user_inatomic(to, from, n);

	if (unlikely(res))

		memset(to + n - res, 0, res);

	return res;

}

EXPORT_SYMBOL(_copy_from_user);

arch/x86/lib/usercopy_64.c

+0 −4
Original line number Diff line number Diff line
@@ -80,9 +80,5 @@ copy_user_handle_tail(char *to, char *from, unsigned len) 
			break;

	}

	clac();



	/* If the destination is a kernel buffer, we always clear the end */

	if (!__addr_ok(to))

		memset(to, 0, len);

	return len;

}