From dc4aace160165bd15400a79f9f5ab97405278f48 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 20 Jun 2016 10:35:20 +0200 Subject: s390/uaccess: fix __put_get_user_asm define The __put_get_user_asm defines an inline assmembly which makes use of the asm register construct. The parameters passed to that define may also contain function calls. It is a gcc restriction that between register asm statements and the use of any such annotated variables function calls may clobber the register / variable contents. Or in other words: gcc would generate broken code. This can be achieved e.g. with the following code: get_user(x, func() ? a : b); where the call of func would clobber register zero which is used by the __put_get_user_asm define. To avoid this add two static inline functions which don't have these side effects. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/uaccess.h | 61 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 59 insertions(+), 2 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h index 2ea7f3208cd2..9b49cf1daa8f 100644 --- a/arch/s390/include/asm/uaccess.h +++ b/arch/s390/include/asm/uaccess.h @@ -151,8 +151,65 @@ unsigned long __must_check __copy_to_user(void __user *to, const void *from, __rc; \ }) -#define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL) -#define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL) +static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size) +{ + unsigned long spec = 0x810000UL; + int rc; + + switch (size) { + case 1: + rc = __put_get_user_asm((unsigned char __user *)ptr, + (unsigned char *)x, + size, spec); + break; + case 2: + rc = __put_get_user_asm((unsigned short __user *)ptr, + (unsigned short *)x, + size, spec); + break; + case 4: + rc = __put_get_user_asm((unsigned int __user *)ptr, + (unsigned int *)x, + size, spec); + break; + case 8: + rc = __put_get_user_asm((unsigned long __user *)ptr, + (unsigned long *)x, + size, spec); + break; + }; + return rc; +} + +static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size) +{ + unsigned long spec = 0x81UL; + int rc; + + switch (size) { + case 1: + rc = __put_get_user_asm((unsigned char *)x, + (unsigned char __user *)ptr, + size, spec); + break; + case 2: + rc = __put_get_user_asm((unsigned short *)x, + (unsigned short __user *)ptr, + size, spec); + break; + case 4: + rc = __put_get_user_asm((unsigned int *)x, + (unsigned int __user *)ptr, + size, spec); + break; + case 8: + rc = __put_get_user_asm((unsigned long *)x, + (unsigned long __user *)ptr, + size, spec); + break; + }; + return rc; +} #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */ -- cgit v1.2.3