sparc: Fix user_addr_max() definition.

We need to use TASK_SIZE because for 64-bit tasks the value
of STACK_TOP actually sits in the middle of the address space
so we'll get false-negatives.

Adjust the TASK_SIZE definition on sparc64 to accomodate this,
in the context in which user_addr_max() is used we have the
test_thread_flag() definition available but not the one for
test_tsk_thread_flag().
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/processor_64.h

@@ -42,7 +42,9 @@
 #define TASK_SIZE_OF(tsk) \
 	(test_tsk_thread_flag(tsk,TIF_32BIT) ? \
 	 (1UL << 32UL) : ((unsigned long)-VPTE_SIZE))
-#define TASK_SIZE	TASK_SIZE_OF(current)
+#define TASK_SIZE \
+	(test_thread_flag(TIF_32BIT) ? \
+	 (1UL << 32UL) : ((unsigned long)-VPTE_SIZE))
 #ifdef __KERNEL__
 
 #define STACK_TOP32	((1UL << 32UL) - PAGE_SIZE)

arch/sparc/include/asm/uaccess.h

@@ -7,7 +7,7 @@
 #endif
 
 #define user_addr_max() \
-	(segment_eq(get_fs(), USER_DS) ? STACK_TOP : ~0UL)
+	(segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL)
 
 extern long strncpy_from_user(char *dest, const char __user *src, long count);