arm: fix put_user sparse errors

virtio wants to write bitwise types to userspace using put_user.
At the moment this triggers sparse errors, since the value is passed
through an integer.

For example:

	__le32 __user *p;
	__le32 x;
	put_user(x, p);

is safe, but currently triggers a sparse warning.

Fix that up using __force.

Note: this does not suppress any useful sparse checks since caller
assigns x to typeof(*p), which in turn forces all the necessary type
checks.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 4767eb9..74fcde7 100644 (file)
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -413,14 +413,14 @@ do {                                                                      \
 #ifndef __ARMEB__
 #define __put_user_asm_half(x,__pu_addr,err)                   \
 ({                                                             \
-       unsigned long __temp = (unsigned long)(x);              \
+       unsigned long __temp = (__force unsigned long)(x);      \
        __put_user_asm_byte(__temp, __pu_addr, err);            \
        __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err);   \
 })
 #else
 #define __put_user_asm_half(x,__pu_addr,err)                   \
 ({                                                             \
-       unsigned long __temp = (unsigned long)(x);              \
+       unsigned long __temp = (__force unsigned long)(x);      \
        __put_user_asm_byte(__temp >> 8, __pu_addr, err);       \
        __put_user_asm_byte(__temp, __pu_addr + 1, err);        \
 })