Merge commit 'origin/master' into for-linus/xen/master

* commit 'origin/master': (4825 commits)
  Fix build errors due to CONFIG_BRANCH_TRACER=y
  parport: Use the PCI IRQ if offered
  tty: jsm cleanups
  Adjust path to gpio headers
  KGDB_SERIAL_CONSOLE check for module
  Change KCONFIG name
  tty: Blackin CTS/RTS
  Change hardware flow control from poll to interrupt driven
  Add support for the MAX3100 SPI UART.
  lanana: assign a device name and numbering for MAX3100
  serqt: initial clean up pass for tty side
  tty: Use the generic RS485 ioctl on CRIS
  tty: Correct inline types for tty_driver_kref_get()
  splice: fix deadlock in splicing to file
  nilfs2: support nanosecond timestamp
  nilfs2: introduce secondary super block
  nilfs2: simplify handling of active state of segments
  nilfs2: mark minor flag for checkpoint created by internal operation
  nilfs2: clean up sketch file
  nilfs2: super block operations fix endian bug
  ...

Conflicts:
	arch/x86/include/asm/thread_info.h
	arch/x86/lguest/boot.c
	drivers/xen/manage.c

1 files changed, 129 insertions, 0 deletions

diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c
new file mode 100644
index 00000000000..a1e3324de2b
--- /dev/null
+++ b/mm/debug-pagealloc.c
@@ -0,0 +1,129 @@
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/page-debug-flags.h>
+#include <linux/poison.h>
+
+static inline void set_page_poison(struct page *page)
+{
+	__set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
+}
+
+static inline void clear_page_poison(struct page *page)
+{
+	__clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
+}
+
+static inline bool page_poison(struct page *page)
+{
+	return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
+}
+
+static void poison_highpage(struct page *page)
+{
+	/*
+	 * Page poisoning for highmem pages is not implemented.
+	 *
+	 * This can be called from interrupt contexts.
+	 * So we need to create a new kmap_atomic slot for this
+	 * application and it will need interrupt protection.
+	 */
+}
+
+static void poison_page(struct page *page)
+{
+	void *addr;
+
+	if (PageHighMem(page)) {
+		poison_highpage(page);
+		return;
+	}
+	set_page_poison(page);
+	addr = page_address(page);
+	memset(addr, PAGE_POISON, PAGE_SIZE);
+}
+
+static void poison_pages(struct page *page, int n)
+{
+	int i;
+
+	for (i = 0; i < n; i++)
+		poison_page(page + i);
+}
+
+static bool single_bit_flip(unsigned char a, unsigned char b)
+{
+	unsigned char error = a ^ b;
+
+	return error && !(error & (error - 1));
+}
+
+static void check_poison_mem(unsigned char *mem, size_t bytes)
+{
+	unsigned char *start;
+	unsigned char *end;
+
+	for (start = mem; start < mem + bytes; start++) {
+		if (*start != PAGE_POISON)
+			break;
+	}
+	if (start == mem + bytes)
+		return;
+
+	for (end = mem + bytes - 1; end > start; end--) {
+		if (*end != PAGE_POISON)
+			break;
+	}
+
+	if (!printk_ratelimit())
+		return;
+	else if (start == end && single_bit_flip(*start, PAGE_POISON))
+		printk(KERN_ERR "pagealloc: single bit error\n");
+	else
+		printk(KERN_ERR "pagealloc: memory corruption\n");
+
+	print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
+			end - start + 1, 1);
+	dump_stack();
+}
+
+static void unpoison_highpage(struct page *page)
+{
+	/*
+	 * See comment in poison_highpage().
+	 * Highmem pages should not be poisoned for now
+	 */
+	BUG_ON(page_poison(page));
+}
+
+static void unpoison_page(struct page *page)
+{
+	if (PageHighMem(page)) {
+		unpoison_highpage(page);
+		return;
+	}
+	if (page_poison(page)) {
+		void *addr = page_address(page);
+
+		check_poison_mem(addr, PAGE_SIZE);
+		clear_page_poison(page);
+	}
+}
+
+static void unpoison_pages(struct page *page, int n)
+{
+	int i;
+
+	for (i = 0; i < n; i++)
+		unpoison_page(page + i);
+}
+
+void kernel_map_pages(struct page *page, int numpages, int enable)
+{
+	if (!debug_pagealloc_enabled)
+		return;
+
+	if (enable)
+		unpoison_pages(page, numpages);
+	else
+		poison_pages(page, numpages);
+}