x86/dumpstack: Add get_stack_pointer() and get_frame_pointer()

The various functions involved in dumping the stack all do similar
things with regard to getting the stack pointer and the frame pointer
based on the regs and task arguments.  Create helper functions to
do that instead.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f448914885a35f333fe04da1b97a6c2cc1f80974.1472057064.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index f0ddf855957e..6d6f46837eea 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -170,15 +170,14 @@ show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 void show_stack(struct task_struct *task, unsigned long *sp)
 {
         unsigned long bp = 0;
-        unsigned long stack;
 
         /*
          * Stack frames below this one aren't interesting.  Don't show them
          * if we're printing for %current.
          */
         if (!sp && (!task || task == current)) {
-                sp = &stack;
-                bp = stack_frame(current, NULL);
+                sp = get_stack_pointer(current, NULL);
+                bp = (unsigned long)get_frame_pointer(current, NULL);
         }
 
         show_stack_log_lvl(task, NULL, sp, bp, "");