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Subject[PATCH 3/3] riscv: fix __user annotation for __copy_user()
Date
__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@gmail.com>
---
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
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