2 files changed, 19 insertions, 10 deletions
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 506ec19a3736..7d10f962aa13 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -3,10 +3,18 @@
 
 #include <linux/compiler.h>
 
+#ifdef CONFIG_GENERIC_BUG
+#define BUGFLAG_WARNING		(1 << 0)
+#define BUGFLAG_TAINT(taint)	(BUGFLAG_WARNING | ((taint) << 8))
+#define BUG_GET_TAINT(bug)	((bug)->flags >> 8)
+#endif
+
+#ifndef __ASSEMBLY__
+#include <linux/kernel.h>
+
 #ifdef CONFIG_BUG
 
 #ifdef CONFIG_GENERIC_BUG
-#ifndef __ASSEMBLY__
 struct bug_entry {
 #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
 	unsigned long	bug_addr;
@@ -23,17 +31,8 @@ struct bug_entry {
 #endif
 	unsigned short	flags;
 };
-#endif		/* __ASSEMBLY__ */
-
-#define BUGFLAG_WARNING		(1 << 0)
-#define BUGFLAG_TAINT(taint)	(BUGFLAG_WARNING | ((taint) << 8))
-#define BUG_GET_TAINT(bug)	((bug)->flags >> 8)
-
 #endif	/* CONFIG_GENERIC_BUG */
 
-#ifndef __ASSEMBLY__
-#include <linux/kernel.h>
-
 /*
  * Don't use BUG() or BUG_ON() unless there's really no way out; one
  * example might be detecting data structure corruption in the middle
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 6f2b45a9b6bc..ff4947b7a976 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -484,6 +484,16 @@ static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 	/*
 	 * The barrier will stabilize the pmdval in a register or on
 	 * the stack so that it will stop changing under the code.
+	 *
+	 * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
+	 * pmd_read_atomic is allowed to return a not atomic pmdval
+	 * (for example pointing to an hugepage that has never been
+	 * mapped in the pmd). The below checks will only care about
+	 * the low part of the pmd with 32bit PAE x86 anyway, with the
+	 * exception of pmd_none(). So the important thing is that if
+	 * the low part of the pmd is found null, the high part will
+	 * be also null or the pmd_none() check below would be
+	 * confused.
 	 */
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	barrier();