[MIPS] Improve unwind_stack()

This patch allows unwind_stack() to return ra for leaf function.
But it tries to detects cases where get_frame_info() wrongly
consider nested function as a leaf one.

It also pass 'unsinged long *sp' instead of 'unsigned long **sp'
as second parameter. The code looks cleaner.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 12 insertions, 12 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 303f00843021..ab77034921c4 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -74,8 +74,9 @@ void (*board_ejtag_handler_setup)(void);
 void (*board_bind_eic_interrupt)(int irq, int regset);
 
 
-static void show_raw_backtrace(unsigned long *sp)
+static void show_raw_backtrace(unsigned long reg29)
 {
+        unsigned long *sp = (unsigned long *)reg29;
         unsigned long addr;
 
         printk("Call Trace:");
@@ -99,30 +100,29 @@ static int __init set_raw_show_trace(char *str)
 }
 __setup("raw_show_trace", set_raw_show_trace);
 
-extern unsigned long unwind_stack(struct task_struct *task,
-                                  unsigned long **sp, unsigned long pc);
+extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+                                  unsigned long pc, unsigned long ra);
+
 static void show_backtrace(struct task_struct *task, struct pt_regs *regs)
 {
-        unsigned long *sp = (long *)regs->regs[29];
+        unsigned long sp = regs->regs[29];
+        unsigned long ra = regs->regs[31];
         unsigned long pc = regs->cp0_epc;
-        int top = 1;
 
         if (raw_show_trace || !__kernel_text_address(pc)) {
                 show_raw_backtrace(sp);
                 return;
         }
         printk("Call Trace:\n");
-        while (__kernel_text_address(pc)) {
+        do {
                 print_ip_sym(pc);
-                pc = unwind_stack(task, &sp, pc);
-                if (top && pc == 0)
-                        pc = regs->regs[31];    /* leaf? */
-                top = 0;
-        }
+                pc = unwind_stack(task, &sp, pc, ra);
+                ra = 0;
+        } while (pc);
         printk("\n");
 }
 #else
-#define show_backtrace(task, r) show_raw_backtrace((long *)(r)->regs[29]);
+#define show_backtrace(task, r) show_raw_backtrace((r)->regs[29]);
 #endif
 
 /*