1 files changed, 36 insertions, 14 deletions

diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
index a36799e85693..d58eac1a8288 100644
--- a/arch/parisc/kernel/unwind.c
+++ b/arch/parisc/kernel/unwind.c
@@ -13,6 +13,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/kallsyms.h>
+#include <linux/sort.h>
 
 #include <asm/uaccess.h>
 #include <asm/assembly.h>
@@ -115,24 +116,18 @@ unwind_table_init(struct unwind_table *table, const char *name,
         }
 }
 
+static int cmp_unwind_table_entry(const void *a, const void *b)
+{
+        return ((const struct unwind_table_entry *)a)->region_start
+             - ((const struct unwind_table_entry *)b)->region_start;
+}
+
 static void
 unwind_table_sort(struct unwind_table_entry *start,
                   struct unwind_table_entry *finish)
 {
-        struct unwind_table_entry el, *p, *q;
-
-        for (p = start + 1; p < finish; ++p) {
-                if (p[0].region_start < p[-1].region_start) {
-                        el = *p;
-                        q = p;
-                        do {
-                                q[0] = q[-1];
-                                --q;
-                        } while (q > start && 
-                                 el.region_start < q[-1].region_start);
-                        *q = el;
-                }
-        }
+        sort(start, finish - start, sizeof(struct unwind_table_entry),
+             cmp_unwind_table_entry, NULL);
 }
 
 struct unwind_table *
@@ -417,3 +412,30 @@ int unwind_to_user(struct unwind_frame_info *info)
 
         return ret;
 }
+
+unsigned long return_address(unsigned int level)
+{
+        struct unwind_frame_info info;
+        struct pt_regs r;
+        unsigned long sp;
+
+        /* initialize unwind info */
+        asm volatile ("copy %%r30, %0" : "=r"(sp));
+        memset(&r, 0, sizeof(struct pt_regs));
+        r.iaoq[0] = (unsigned long) current_text_addr();
+        r.gr[2] = (unsigned long) __builtin_return_address(0);
+        r.gr[30] = sp;
+        unwind_frame_init(&info, current, &r);
+
+        /* unwind stack */
+        ++level;
+        do {
+                if (unwind_once(&info) < 0 || info.ip == 0)
+                        return 0;
+                if (!__kernel_text_address(info.ip)) {
+                        return 0;
+                }
+        } while (info.ip && level--);
+
+        return info.ip;
+}