mm/migrate: mark unmap_and_move() "noinline" to avoid ICE in gcc 4.7.3

With gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-12ubuntu1) :

    mm/migrate.c: In function `migrate_pages':
    mm/migrate.c:1148:1: internal compiler error: in push_minipool_fix, at config/arm/arm.c:13500
    Please submit a full bug report,
    with preprocessed source if appropriate.
    See <file:///usr/share/doc/gcc-4.7/README.Bugs> for instructions.
    Preprocessed source stored into /tmp/ccPoM1tr.out file, please attach this to your bugreport.
    make[1]: *** [mm/migrate.o] Error 1
    make: *** [mm/migrate.o] Error 2

Mark unmap_and_move() (which is used in a single place only) "noinline"
to work around this compiler bug.

[akpm@linux-foundation.org: make it conditional on gcc-4.7.3 and arm]
[khilman@kernel.org: fine-tune compiler versions]
[akpm@linux-foundation.org: fix comment]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reported-by: Kevin Hilman <khilman@kernel.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/migrate.c

@@ -900,13 +900,24 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
 	return rc;
 }
 
+/*
+ * gcc 4.7 and 4.8 on arm get an ICEs when inlining unmap_and_move().  Work
+ * around it.
+ */
+#if (GCC_VERSION >= 40700 && GCC_VERSION < 40900) && defined(CONFIG_ARM)
+#define ICE_noinline noinline
+#else
+#define ICE_noinline
+#endif
+
 /*
  * Obtain the lock on page, remove all ptes and migrate the page
  * to the newly allocated page in newpage.
  */
-static int unmap_and_move(new_page_t get_new_page, free_page_t put_new_page,
-			unsigned long private, struct page *page, int force,
-			enum migrate_mode mode)
+static ICE_noinline int unmap_and_move(new_page_t get_new_page,
+				   free_page_t put_new_page,
+				   unsigned long private, struct page *page,
+				   int force, enum migrate_mode mode)
 {
 	int rc = 0;
 	int *result = NULL;