parisc,metag: Implement CONFIG_DEBUG_STACK_USAGE option

On parisc and metag the stack grows upwards, so for those we need to
scan the stack downwards in order to calculate how much stack a process
has used.

Tested on a 64bit parisc kernel.

Signed-off-by: Helge Deller <deller@gmx.de>

2 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 34495d2d2d7b..589c4780b077 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2870,10 +2870,18 @@ static inline unsigned long stack_not_used(struct task_struct *p)
         unsigned long *n = end_of_stack(p);
 
         do {    /* Skip over canary */
+# ifdef CONFIG_STACK_GROWSUP
+                n--;
+# else
                 n++;
+# endif
         } while (!*n);
 
+# ifdef CONFIG_STACK_GROWSUP
+        return (unsigned long)end_of_stack(p) - (unsigned long)n;
+# else
         return (unsigned long)n - (unsigned long)end_of_stack(p);
+# endif
 }
 #endif
 extern void set_task_stack_end_magic(struct task_struct *tsk);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 532d4d52d1df..1e9a607534ca 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -558,7 +558,7 @@ config DEBUG_KMEMLEAK_DEFAULT_OFF
 
 config DEBUG_STACK_USAGE
         bool "Stack utilization instrumentation"
-        depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
+        depends on DEBUG_KERNEL && !IA64
         help
           Enables the display of the minimum amount of free stack which each
           task has ever had available in the sysrq-T and sysrq-P debug output.