s390/dumpstack: implement and use return_address()

[cascardo/linux.git] / arch / s390 / kernel / dumpstack.c

diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
index 1b6081c..69f9908 100644 (file)
--- a/arch/s390/kernel/dumpstack.c
+++ b/arch/s390/kernel/dumpstack.c
@@ -89,6 +89,30 @@ void dump_trace(dump_trace_func_t func, void *data, struct task_struct *task,
 }
 EXPORT_SYMBOL_GPL(dump_trace);
 
+struct return_address_data {
+       unsigned long address;
+       int depth;
+};
+
+static int __return_address(void *data, unsigned long address)
+{
+       struct return_address_data *rd = data;
+
+       if (rd->depth--)
+               return 0;
+       rd->address = address;
+       return 1;
+}
+
+unsigned long return_address(int depth)
+{
+       struct return_address_data rd = { .depth = depth + 2 };
+
+       dump_trace(__return_address, &rd, NULL, current_stack_pointer());
+       return rd.address;
+}
+EXPORT_SYMBOL_GPL(return_address);
+
 static int show_address(void *data, unsigned long address)
 {
        printk("([<%016lx>] %pSR)\n", address, (void *)address);