[PATCH] add poison.h and patch primary users

Localize poison values into one header file for better documentation and
easier/quicker debugging and so that the same values won't be used for
multiple purposes.

Use these constants in core arch., mm, driver, and fs code.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Matt Mackall <mpm@selenic.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/mm/init.c

@@ -23,6 +23,7 @@
 #include <linux/init.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
+#include <linux/poison.h>
 #include <linux/bootmem.h>
 #include <linux/slab.h>
 #include <linux/proc_fs.h>
@@ -753,7 +754,7 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 	for (addr = begin; addr < end; addr += PAGE_SIZE) {
 		ClearPageReserved(virt_to_page(addr));
 		init_page_count(virt_to_page(addr));
-		memset((void *)addr, 0xcc, PAGE_SIZE);
+		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 		free_page(addr);
 		totalram_pages++;
 	}

arch/powerpc/mm/init_64.c

@@ -41,6 +41,7 @@
 #include <linux/idr.h>
 #include <linux/nodemask.h>
 #include <linux/module.h>
+#include <linux/poison.h>
 
 #include <asm/pgalloc.h>
 #include <asm/page.h>
@@ -90,7 +91,7 @@ void free_initmem(void)
 
 	addr = (unsigned long)__init_begin;
 	for (; addr < (unsigned long)__init_end; addr += PAGE_SIZE) {
-		memset((void *)addr, 0xcc, PAGE_SIZE);
+		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 		ClearPageReserved(virt_to_page(addr));
 		init_page_count(virt_to_page(addr));
 		free_page(addr);

arch/sparc64/mm/init.c

@@ -18,6 +18,7 @@
 #include <linux/initrd.h>
 #include <linux/swap.h>
 #include <linux/pagemap.h>
+#include <linux/poison.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
 #include <linux/kprobes.h>
@@ -1520,7 +1521,7 @@ void free_initmem(void)
 		page = (addr +
 			((unsigned long) __va(kern_base)) -
 			((unsigned long) KERNBASE));
-		memset((void *)addr, 0xcc, PAGE_SIZE);
+		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 		p = virt_to_page(page);
 
 		ClearPageReserved(p);

arch/x86_64/mm/init.c

@@ -23,6 +23,7 @@
 #include <linux/bootmem.h>
 #include <linux/proc_fs.h>
 #include <linux/pci.h>
+#include <linux/poison.h>
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
 #include <linux/memory_hotplug.h>
@@ -660,7 +661,8 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 	for (addr = begin; addr < end; addr += PAGE_SIZE) {
 		ClearPageReserved(virt_to_page(addr));
 		init_page_count(virt_to_page(addr));
-		memset((void *)(addr & ~(PAGE_SIZE-1)), 0xcc, PAGE_SIZE); 
+		memset((void *)(addr & ~(PAGE_SIZE-1)),
+			POISON_FREE_INITMEM, PAGE_SIZE);
 		free_page(addr);
 		totalram_pages++;
 	}
@@ -668,7 +670,8 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 
 void free_initmem(void)
 {
-	memset(__initdata_begin, 0xba, __initdata_end - __initdata_begin);
+	memset(__initdata_begin, POISON_FREE_INITDATA,
+		__initdata_end - __initdata_begin);
 	free_init_pages("unused kernel memory",
 			(unsigned long)(&__init_begin),
 			(unsigned long)(&__init_end));

drivers/base/dmapool.c

@@ -7,6 +7,7 @@
 #include <linux/dmapool.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/poison.h>
 
 /*
  * Pool allocator ... wraps the dma_alloc_coherent page allocator, so
@@ -35,8 +36,6 @@ struct dma_page {	/* cacheable header for 'allocation' bytes */
 };
 
 #define	POOL_TIMEOUT_JIFFIES	((100 /* msec */ * HZ) / 1000)
-#define	POOL_POISON_FREED	0xa7	/* !inuse */
-#define	POOL_POISON_ALLOCATED	0xa9	/* !initted */
 
 static DECLARE_MUTEX (pools_lock);
 

fs/jbd/journal.c

@@ -34,6 +34,7 @@
 #include <linux/suspend.h>
 #include <linux/pagemap.h>
 #include <linux/kthread.h>
+#include <linux/poison.h>
 #include <linux/proc_fs.h>
 
 #include <asm/uaccess.h>
@@ -1675,7 +1676,7 @@ static void journal_free_journal_head(struct journal_head *jh)
 {
 #ifdef CONFIG_JBD_DEBUG
 	atomic_dec(&nr_journal_heads);
-	memset(jh, 0x5b, sizeof(*jh));
+	memset(jh, JBD_POISON_FREE, sizeof(*jh));
 #endif
 	kmem_cache_free(journal_head_cache, jh);
 }

include/linux/list.h

@@ -4,17 +4,10 @@
 #ifdef __KERNEL__
 
 #include <linux/stddef.h>
+#include <linux/poison.h>
 #include <linux/prefetch.h>
 #include <asm/system.h>
 
-/*
- * These are non-NULL pointers that will result in page faults
- * under normal circumstances, used to verify that nobody uses
- * non-initialized list entries.
- */
-#define LIST_POISON1  ((void *) 0x00100100)
-#define LIST_POISON2  ((void *) 0x00200200)
-
 /*
  * Simple doubly linked list implementation.
  *

include/linux/poison.h

@@ -0,0 +1,45 @@
+#ifndef _LINUX_POISON_H
+#define _LINUX_POISON_H
+
+/********** include/linux/list.h **********/
+/*
+ * These are non-NULL pointers that will result in page faults
+ * under normal circumstances, used to verify that nobody uses
+ * non-initialized list entries.
+ */
+#define LIST_POISON1  ((void *) 0x00100100)
+#define LIST_POISON2  ((void *) 0x00200200)
+
+/********** mm/slab.c **********/
+/*
+ * Magic nums for obj red zoning.
+ * Placed in the first word before and the first word after an obj.
+ */
+#define	RED_INACTIVE	0x5A2CF071UL	/* when obj is inactive */
+#define	RED_ACTIVE	0x170FC2A5UL	/* when obj is active */
+
+/* ...and for poisoning */
+#define	POISON_INUSE	0x5a	/* for use-uninitialised poisoning */
+#define POISON_FREE	0x6b	/* for use-after-free poisoning */
+#define	POISON_END	0xa5	/* end-byte of poisoning */
+
+/********** arch/$ARCH/mm/init.c **********/
+#define POISON_FREE_INITMEM	0xcc
+
+/********** arch/x86_64/mm/init.c **********/
+#define	POISON_FREE_INITDATA	0xba
+
+/********** arch/ia64/hp/common/sba_iommu.c **********/
+/*
+ * arch/ia64/hp/common/sba_iommu.c uses a 16-byte poison string with a
+ * value of "SBAIOMMU POISON\0" for spill-over poisoning.
+ */
+
+/********** fs/jbd/journal.c **********/
+#define JBD_POISON_FREE	0x5b
+
+/********** drivers/base/dmapool.c **********/
+#define	POOL_POISON_FREED	0xa7	/* !inuse */
+#define	POOL_POISON_ALLOCATED	0xa9	/* !initted */
+
+#endif

mm/slab.c

@@ -89,6 +89,7 @@
 #include	<linux/config.h>
 #include	<linux/slab.h>
 #include	<linux/mm.h>
+#include	<linux/poison.h>
 #include	<linux/swap.h>
 #include	<linux/cache.h>
 #include	<linux/interrupt.h>
@@ -492,17 +493,6 @@ struct kmem_cache {
 #endif
 
 #if DEBUG
-/*
- * Magic nums for obj red zoning.
- * Placed in the first word before and the first word after an obj.
- */
-#define	RED_INACTIVE	0x5A2CF071UL	/* when obj is inactive */
-#define	RED_ACTIVE	0x170FC2A5UL	/* when obj is active */
-
-/* ...and for poisoning */
-#define	POISON_INUSE	0x5a	/* for use-uninitialised poisoning */
-#define POISON_FREE	0x6b	/* for use-after-free poisoning */
-#define	POISON_END	0xa5	/* end-byte of poisoning */
 
 /*
  * memory layout of objects: