s390/uaccess: add missing earlyclobber annotations to __clear_user()

commit 89aba4c26fae4e459f755a18912845c348ee48f3 upstream.

Add missing earlyclobber annotation to size, to, and tmp2 operands of the
__clear_user() inline assembly since they are modified or written to before
the last usage of all input operands. This can lead to incorrect register
allocation for the inline assembly.

Fixes: 068043d17fc9 ("[S390] Use alternative user-copy operations for new hardware.")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/all/20230321122514.6da9da5-3-mark.rutland@arm.com/
Cc: stable@vger.kernel.org
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
index 0267405ab7c69fec93f73df3ed35f381b03c7f38..fcfd78f99cb4b7390f450b4cca651679e230bf55 100644 (file)
--- a/arch/s390/lib/uaccess.c
+++ b/arch/s390/lib/uaccess.c
@@ -339,7 +339,7 @@ static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size
                "4: slgr  %0,%0\n"
                "5:\n"
                EX_TABLE(0b,2b) EX_TABLE(3b,5b)
-               : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
+               : "+&a" (size), "+&a" (to), "+a" (tmp1), "=&a" (tmp2)
                : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
        return size;
 }