s390/uaccess: fix possible register corruption in strnlen_user_srst()
The whole point of the out-of-line strnlen_user_srst() function was to
avoid corruption of register 0 due to register asm assignment.
However 'somebody' :) forgot to remove the update_primary_asce() function
call, which may clobber register 0 contents.
So let's remove that call and also move the size check to the calling
function.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
index 23f866b..7416efe 100644
--- a/arch/s390/lib/uaccess.c
+++ b/arch/s390/lib/uaccess.c
@@ -338,9 +338,6 @@
register unsigned long reg0 asm("0") = 0;
unsigned long tmp1, tmp2;
- if (unlikely(!size))
- return 0;
- update_primary_asce(current);
asm volatile(
" la %2,0(%1)\n"
" la %3,0(%0,%1)\n"
@@ -359,6 +356,8 @@
unsigned long __strnlen_user(const char __user *src, unsigned long size)
{
+ if (unlikely(!size))
+ return 0;
update_primary_asce(current);
return strnlen_user_srst(src, size);
}