[PATCH 3/3] riscv: fix __user annotation for __copy_user()
From: Luc Van Oostenryck
Date: Fri Jun 01 2018 - 11:22:08 EST
__copy_user() is a function, written in assembly, used to copy
memory between kernel & user space. As such its to & from args
may both take a user pointer or a kernel pointer.
However the prototype for this function declare these two args
as 'void __user *', which is no more & no less correct than
declaring them as 'void *'. In fact theer is no possible correct
annotation for such a function.
The problem is worked around here by declaring these args as
unsigned long and casting them to the right type in each of
two callers raw_copy_{to,from}_user() as some kind of cast would
be needed anyway.
Note: another solution, maybe cleaner but slightly more complex,
would be to declare two version of __copy_user,
either in the asm file or via an alias, each having already
the correct typing for raw_copy_{to,from}_user().
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
arch/riscv/include/asm/uaccess.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index 14b0b22fb..c7a6a4a4a 100644
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -392,19 +392,19 @@ do { \
})
-extern unsigned long __must_check __copy_user(void __user *to,
- const void __user *from, unsigned long n);
+extern unsigned long __must_check __copy_user(unsigned long to,
+ const unsigned long from, unsigned long n);
static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
- return __copy_user(to, from, n);
+ return __copy_user((unsigned long)to, (unsigned long)from, n);
}
static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
- return __copy_user(to, from, n);
+ return __copy_user((unsigned long)to, (unsigned long)from, n);
}
extern long strncpy_from_user(char *dest, const char __user *src, long count);
--
2.17.1