Merge branch 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 irq updates from Ingo Molnar:
 "Here are the main changes in this tree:

   - Introduce x86-64 IRQ/exception/debug stack guard pages to detect
     stack overflows immediately and deterministically.

   - Clean up over a decade worth of cruft accumulated.

  The outcome of this should be more clear-cut faults/crashes when any
  of the low level x86 CPU stacks overflow, instead of silent memory
  corruption and sporadic failures much later on"

* 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  x86/irq: Fix outdated comments
  x86/irq/64: Remove stack overflow debug code
  x86/irq/64: Remap the IRQ stack with guard pages
  x86/irq/64: Split the IRQ stack into its own pages
  x86/irq/64: Init hardirq_stack_ptr during CPU hotplug
  x86/irq/32: Handle irq stack allocation failure proper
  x86/irq/32: Invoke irq_ctx_init() from init_IRQ()
  x86/irq/64: Rename irq_stack_ptr to hardirq_stack_ptr
  x86/irq/32: Rename hard/softirq_stack to hard/softirq_stack_ptr
  x86/irq/32: Make irq stack a character array
  x86/irq/32: Define IRQ_STACK_SIZE
  x86/dumpstack/64: Speedup in_exception_stack()
  x86/exceptions: Split debug IST stack
  x86/exceptions: Enable IST guard pages
  x86/exceptions: Disconnect IST index and stack order
  x86/cpu: Remove orig_ist array
  x86/cpu: Prepare TSS.IST setup for guard pages
  x86/dumpstack/64: Use cpu_entry_area instead of orig_ist
  x86/irq/64: Use cpu entry area instead of orig_ist
  x86/traps: Use cpu_entry_area instead of orig_ist
  ...

1 files changed, 6 insertions, 42 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 9142ee992493..284ab737faee 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1467,53 +1467,17 @@ static bool is_debug_pagealloc_cache(struct kmem_cache *cachep)
 }
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
-static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
-			    unsigned long caller)
-{
-	int size = cachep->object_size;
-
-	addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
-
-	if (size < 5 * sizeof(unsigned long))
-		return;
-
-	*addr++ = 0x12345678;
-	*addr++ = caller;
-	*addr++ = smp_processor_id();
-	size -= 3 * sizeof(unsigned long);
-	{
-		unsigned long *sptr = &caller;
-		unsigned long svalue;
-
-		while (!kstack_end(sptr)) {
-			svalue = *sptr++;
-			if (kernel_text_address(svalue)) {
-				*addr++ = svalue;
-				size -= sizeof(unsigned long);
-				if (size <= sizeof(unsigned long))
-					break;
-			}
-		}
-
-	}
-	*addr++ = 0x87654321;
-}
-
-static void slab_kernel_map(struct kmem_cache *cachep, void *objp,
-				int map, unsigned long caller)
+static void slab_kernel_map(struct kmem_cache *cachep, void *objp, int map)
 {
 	if (!is_debug_pagealloc_cache(cachep))
 		return;
 
-	if (caller)
-		store_stackinfo(cachep, objp, caller);
-
 	kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map);
 }
 
 #else
 static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp,
-				int map, unsigned long caller) {}
+				int map) {}
 
 #endif
 
@@ -1661,7 +1625,7 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep,
 
 		if (cachep->flags & SLAB_POISON) {
 			check_poison_obj(cachep, objp);
-			slab_kernel_map(cachep, objp, 1, 0);
+			slab_kernel_map(cachep, objp, 1);
 		}
 		if (cachep->flags & SLAB_RED_ZONE) {
 			if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
@@ -2433,7 +2397,7 @@ static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page)
 		/* need to poison the objs? */
 		if (cachep->flags & SLAB_POISON) {
 			poison_obj(cachep, objp, POISON_FREE);
-			slab_kernel_map(cachep, objp, 0, 0);
+			slab_kernel_map(cachep, objp, 0);
 		}
 	}
 #endif
@@ -2812,7 +2776,7 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 
 	if (cachep->flags & SLAB_POISON) {
 		poison_obj(cachep, objp, POISON_FREE);
-		slab_kernel_map(cachep, objp, 0, caller);
+		slab_kernel_map(cachep, objp, 0);
 	}
 	return objp;
 }
@@ -3076,7 +3040,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 		return objp;
 	if (cachep->flags & SLAB_POISON) {
 		check_poison_obj(cachep, objp);
-		slab_kernel_map(cachep, objp, 1, 0);
+		slab_kernel_map(cachep, objp, 1);
 		poison_obj(cachep, objp, POISON_INUSE);
 	}
 	if (cachep->flags & SLAB_STORE_USER)