On 09.08.2019 15:42, Andrew Cooper wrote:
On 09/08/2019 13:32, Jan Beulich wrote:
Insert explicit alignment such that the result is safe even with objects
shorter than a page in length. The POINTER_ALIGN for __bss_end is to
cover
the lack of SMP_CACHE_BYTES alignment, as the loops which zero the BSS
use
pointer-sized stores on all architectures.
...
v4:
* Drop stray trailing ALIGN(). Make DEFINE_PER_CPU_PAGE_ALIGNED() verify
the alignment rather than specifying it.
My feelings about the stray-ness of ALIGN() notwithstanding, the commit
message now wrong and needs correcting.
Oh, indeed, and not just for this aspect.
--- a/xen/include/xen/percpu.h
+++ b/xen/include/xen/percpu.h
@@ -9,9 +9,17 @@
* The _##name concatenation is being used here to prevent 'name'
from getting
* macro expanded, while still allowing a per-architecture symbol
name prefix.
*/
-#define DEFINE_PER_CPU(type, name) __DEFINE_PER_CPU(type, _##name, )
+#define DEFINE_PER_CPU(type, name) \
+ __DEFINE_PER_CPU(__section(".bss.percpu"), type, _ ## name)
+
+#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
+ typedef char name ## _chk_t[BUILD_BUG_ON_ZERO(__alignof(type) & \
+ (PAGE_SIZE - 1))]; \
+ __DEFINE_PER_CPU(__section(".bss.percpu.page_aligned"), \
+ type, _ ## name)
I think this would be easier to read as:
#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
typedef char name ## _chk_t[ \
BUILD_BUG_ON_ZERO(__alignof(type) & (PAGE_SIZE - 1))]; \
__DEFINE_PER_CPU(__section(".bss.percpu.page_aligned"), \
type, _ ## name)
By not breaking important bit of logic across a newline.
Will do.
Preferably with this changed, but definitely with the commit message
fixed, Acked-by: Andrew Cooper <andrew.coop...@citrix.com>
Thanks, Jan
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
