staging: android: binder: Add copy_flat_binder_object()

This patch adds copy_flat_binder_object macro() that will help
dereference struct flat_binder_object on 64bit systems where the
structure differs between 32bit and 64bit userspace.

This patch is a temporary patch that will be extended with 32bit compat
handling.

Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>

diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c
index 6dd58a2283618137300acfd27496a571f33b8c62..16ce8f4e5ed2140b0787ad8176f66a850172aaef 100644 (file)
--- a/drivers/staging/android/binder.c
+++ b/drivers/staging/android/binder.c
@@ -145,6 +145,11 @@ module_param_call(stop_on_user_error, binder_set_stop_on_user_error,
 #define deref_helper(ptr)          (*(typeof(size_t *))ptr)
 #define size_helper(x)             sizeof(x)
 
+static inline struct flat_binder_object *copy_flat_binder_object(void __user *ptr)
+{
+       return (struct flat_binder_object *)ptr;
+}
+
 enum binder_stat_types {
        BINDER_STAT_PROC,
        BINDER_STAT_THREAD,
@@ -1258,7 +1263,7 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
                         debug_id, deref_helper(offp), buffer->data_size);
                        continue;
                }
-               fp = (struct flat_binder_object *)(buffer->data + deref_helper(offp));
+               fp = copy_flat_binder_object(buffer->data + deref_helper(offp));
                switch (fp->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {
@@ -1512,7 +1517,7 @@ static void binder_transaction(struct binder_proc *proc,
                        return_error = BR_FAILED_REPLY;
                        goto err_bad_offset;
                }
-               fp = (struct flat_binder_object *)(t->buffer->data + deref_helper(offp));
+               fp = copy_flat_binder_object(t->buffer->data + deref_helper(offp));
                switch (fp->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {