MIPS: Add new unwind_stack variant

The unwind_stack_by_address variant supports unwinding based
on any kernel code address.
This symbol is also exported so it can be called from modules.

Signed-off-by: Daniel Kalmar <kalmard@homejinni.com>
Signed-off-by: Gergely Kis <gergely@homejinni.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index d2112d3cf115..c28fbe6107bc 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -373,18 +373,18 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 
 
 #ifdef CONFIG_KALLSYMS
-/* used by show_backtrace() */
-unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
-                           unsigned long pc, unsigned long *ra)
+/* generic stack unwinding function */
+unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
+                                              unsigned long *sp,
+                                              unsigned long pc,
+                                              unsigned long *ra)
 {
-        unsigned long stack_page;
         struct mips_frame_info info;
         unsigned long size, ofs;
         int leaf;
         extern void ret_from_irq(void);
         extern void ret_from_exception(void);
 
-        stack_page = (unsigned long)task_stack_page(task);
         if (!stack_page)
                 return 0;
 
@@ -443,6 +443,15 @@ unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
         *ra = 0;
         return __kernel_text_address(pc) ? pc : 0;
 }
+EXPORT_SYMBOL(unwind_stack_by_address);
+
+/* used by show_backtrace() */
+unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+                           unsigned long pc, unsigned long *ra)
+{
+        unsigned long stack_page = (unsigned long)task_stack_page(task);
+        return unwind_stack_by_address(stack_page, sp, pc, ra);
+}
 #endif
 
 /*