[PATCH] Remove most of the special cases for the debug IST stack

Remove most of the special cases for the debug IST stack.  This is a
follow on clean up patch, it requires the bug fix patch that adds
orig_ist.

Signed-off-by: Keith Owens <kaos@ocs.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>

2 files changed, 6 insertions, 36 deletions

diff --git a/arch/x86_64/kernel/setup64.c b/arch/x86_64/kernel/setup64.c
index 491361752c70..9332d2361e08 100644
--- a/arch/x86_64/kernel/setup64.c
+++ b/arch/x86_64/kernel/setup64.c
@@ -237,28 +237,17 @@ void __cpuinit cpu_init (void)
          * set up and load the per-CPU TSS
          */
         for (v = 0; v < N_EXCEPTION_STACKS; v++) {
+                static const unsigned int order[N_EXCEPTION_STACKS] = {
+                        [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
+                        [DEBUG_STACK - 1] = DEBUG_STACK_ORDER
+                };
                 if (cpu) {
-                        static const unsigned int order[N_EXCEPTION_STACKS] = {
-                                [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
-                                [DEBUG_STACK - 1] = DEBUG_STACK_ORDER
-                        };
-
                         estacks = (char *)__get_free_pages(GFP_ATOMIC, order[v]);
                         if (!estacks)
                                 panic("Cannot allocate exception stack %ld %d\n",
                                       v, cpu); 
                 }
-                switch (v + 1) {
-#if DEBUG_STKSZ > EXCEPTION_STKSZ
-                case DEBUG_STACK:
-                        cpu_pda(cpu)->debugstack = (unsigned long)estacks;
-                        estacks += DEBUG_STKSZ;
-                        break;
-#endif
-                default:
-                        estacks += EXCEPTION_STKSZ;
-                        break;
-                }
+                estacks += PAGE_SIZE << order[v];
                 orig_ist->ist[v] = t->ist[v] = (unsigned long)estacks;
         }
 
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 38bc821e457b..fb8486eca1b6 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -162,26 +162,7 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
          * 'stack' is in one of them:
          */
         for (k = 0; k < N_EXCEPTION_STACKS; k++) {
-                unsigned long end;
-
-                /*
-                 * set 'end' to the end of the exception stack.
-                 */
-                switch (k + 1) {
-                /*
-                 * TODO: this block is not needed i think, because
-                 * setup64.c:cpu_init() sets up t->ist[DEBUG_STACK]
-                 * properly too.
-                 */
-#if DEBUG_STKSZ > EXCEPTION_STKSZ
-                case DEBUG_STACK:
-                        end = cpu_pda(cpu)->debugstack + DEBUG_STKSZ;
-                        break;
-#endif
-                default:
-                        end = per_cpu(orig_ist, cpu).ist[k];
-                        break;
-                }
+                unsigned long end = per_cpu(orig_ist, cpu).ist[k];
                 /*
                  * Is 'stack' above this exception frame's end?
                  * If yes then skip to the next frame.