per_cpu: fix DEFINE_PER_CPU_SHARED_ALIGNED for modules

Current module loader lookups ".data.percpu" ELF section to perform
per_cpu relocation.  But DEFINE_PER_CPU_SHARED_ALIGNED() uses another
section (".data.percpu.shared_aligned"), currently only handled in
vmlinux.lds, not by module loader.

To correct this problem, instead of adding logic into module loader, or
using at build time a module.lds file for all arches to group
".data.percpu.shared_aligned" into ".data.percpu", just use ".data.percpu"
for modules.

Alignment requirements are correctly handled by ld and module loader.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/percpu.h

@@ -13,8 +13,14 @@
 	__attribute__((__section__(".data.percpu")))			\
 	PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
 
+#ifdef MODULE
+#define SHARED_ALIGNED_SECTION ".data.percpu"
+#else
+#define SHARED_ALIGNED_SECTION ".data.percpu.shared_aligned"
+#endif
+
 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)			\
-	__attribute__((__section__(".data.percpu.shared_aligned")))	\
+	__attribute__((__section__(SHARED_ALIGNED_SECTION)))		\
 	PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name		\
 	____cacheline_aligned_in_smp
 #else