s390: stack address vs thread_info

Avoid using the address of a process' thread_info structure as the
kernel stack address. This will break as soon as the thread_info
structure will be removed from the stack, and in addition it makes the
code a bit more understandable.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/kprobes.h

@@ -43,9 +43,9 @@ typedef u16 kprobe_opcode_t;
 #define MAX_INSN_SIZE		0x0003
 #define MAX_STACK_SIZE		64
 #define MIN_STACK_SIZE(ADDR) (((MAX_STACK_SIZE) < \
-	(((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR))) \
+	(((unsigned long)task_stack_page(current)) + THREAD_SIZE - (ADDR))) \
 	? (MAX_STACK_SIZE) \
-	: (((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR)))
+	: (((unsigned long)task_stack_page(current)) + THREAD_SIZE - (ADDR)))
 
 #define kretprobe_blacklist_size 0
 

arch/s390/kernel/dumpstack.c

@@ -78,14 +78,10 @@ void dump_trace(dump_trace_func_t func, void *data, struct task_struct *task,
 	sp = __dump_trace(func, data, sp,
 			  S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
 			  S390_lowcore.async_stack + frame_size);
-	if (task)
-		__dump_trace(func, data, sp,
-			     (unsigned long)task_stack_page(task),
-			     (unsigned long)task_stack_page(task) + THREAD_SIZE);
-	else
-		__dump_trace(func, data, sp,
-			     S390_lowcore.thread_info,
-			     S390_lowcore.thread_info + THREAD_SIZE);
+	task = task ?: current;
+	__dump_trace(func, data, sp,
+		     (unsigned long)task_stack_page(task),
+		     (unsigned long)task_stack_page(task) + THREAD_SIZE);
 }
 EXPORT_SYMBOL_GPL(dump_trace);