Andrew,

This patch is a follow up to thread initiated by Gianni Tedesco
in http://marc.info/?l=linux-kernel&m=121059431214889&w=2
(oprofile BUG() in current kernel.)

Thank you

[PATCH] 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: Eric Dumazet <dada1@cosmosbay.com>
---
 include/linux/percpu.h |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index d746a2a..0bb9e91 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -13,8 +13,14 @@
 	__attribute__((__section__(".data.percpu")))			\
 	PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
 
+#ifdef CONFIG_MODULES
+#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

原文链接: http://lkml.org/lkml/2008/5/13/228
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