x86, percpu: Fix DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED()

DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED() put percpu variables in
.page_aligned section without adding any alignment restrictions.
Currently, this doesn't cause any problem because all users of the
macros have explicit page alignment and page-sized but it's much safer
to enforce page alignment from the macros.  After all, it's what they
claim to do.

Add __aligned(PAGE_SIZE) to DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED() and
drop explicit alignment from it users.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index 68438e18fff4..afd5f8b7061f 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -69,11 +69,13 @@
 /*
  * Declaration/definition used for per-CPU variables that must be page aligned.
  */
-#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name)                                \
-        DECLARE_PER_CPU_SECTION(type, name, ".page_aligned")
+#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name)                        \
+        DECLARE_PER_CPU_SECTION(type, name, ".page_aligned")            \
+        __aligned(PAGE_SIZE)
 
 #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name)                         \
-        DEFINE_PER_CPU_SECTION(type, name, ".page_aligned")
+        DEFINE_PER_CPU_SECTION(type, name, ".page_aligned")             \
+        __aligned(PAGE_SIZE)
 
 /*
  * Intermodule exports for per-CPU variables.