x86/dumpstack: Make stack name tags more comprehensible

NMI stack dumps are bracketed by the following tags:

  <NMI>
  ...
  <EOE>

The ending tag is kind of confusing if you don't already know what "EOE"
means (end of exception).  The same ending tag is also used to mark the
end of all other exceptions' stacks.  For example:

  <#DF>
  ...
  <EOE>

And similarly, "EOI" is used as the ending tag for interrupts:

  <IRQ>
  ...
  <EOI>

Change the tags to be more comprehensible by making them symmetrical and
more XML-esque:

  <NMI>
  ...
  </NMI>

  <#DF>
  ...
  </#DF>

  <IRQ>
  ...
  </IRQ>

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/180196e3754572540b595bc56b947d43658979a7.1479491159.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 8 insertions, 14 deletions

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index ab0f8b90b51b..fac189efcc34 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -28,23 +28,17 @@ static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
 	[DEBUG_STACK - 1]			= DEBUG_STKSZ
 };
 
-void stack_type_str(enum stack_type type, const char **begin, const char **end)
+const char *stack_type_name(enum stack_type type)
 {
 	BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
 
-	switch (type) {
-	case STACK_TYPE_IRQ:
-		*begin = "IRQ";
-		*end   = "EOI";
-		break;
-	case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
-		*begin = exception_stack_names[type - STACK_TYPE_EXCEPTION];
-		*end   = "EOE";
-		break;
-	default:
-		*begin = NULL;
-		*end   = NULL;
-	}
+	if (type == STACK_TYPE_IRQ)
+		return "IRQ";
+
+	if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
+		return exception_stack_names[type - STACK_TYPE_EXCEPTION];
+
+	return NULL;
 }
 
 static bool in_exception_stack(unsigned long *stack, struct stack_info *info)