Merge tag 'arc-4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

[cascardo/linux.git] / arch / x86 / kernel / unwind_guess.c

diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c
index b5a834c..2d721e5 100644 (file)
--- a/arch/x86/kernel/unwind_guess.c
+++ b/arch/x86/kernel/unwind_guess.c
@@ -5,6 +5,16 @@
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
 
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+       if (unwind_done(state))
+               return 0;
+
+       return ftrace_graph_ret_addr(state->task, &state->graph_idx,
+                                    *state->sp, state->sp);
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
 bool unwind_next_frame(struct unwind_state *state)
 {
        struct stack_info *info = &state->stack_info;
@@ -37,7 +47,14 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
        get_stack_info(first_frame, state->task, &state->stack_info,
                       &state->stack_mask);
 
-       if (!__kernel_text_address(*first_frame))
+       /*
+        * The caller can provide the address of the first frame directly
+        * (first_frame) or indirectly (regs->sp) to indicate which stack frame
+        * to start unwinding at.  Skip ahead until we reach it.
+        */
+       if (!unwind_done(state) &&
+           (!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
+           !__kernel_text_address(*first_frame)))
                unwind_next_frame(state);
 }
 EXPORT_SYMBOL_GPL(__unwind_start);