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Pull linus#master to merge PER_CPU_DEF_ATTRIBUTES and alpha build fix
changes. As alpha in percpu tree uses 'weak' attribute instead of
inline assembly, there's no need for __used attribute.
Conflicts:
arch/alpha/include/asm/percpu.h
arch/mn10300/kernel/vmlinux.lds.S
include/linux/percpu-defs.h
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alpha percpu access requires custom SHIFT_PERCPU_PTR() definition for
modules to work around addressing range limitation. This is done via
generating inline assembly using C preprocessing which forces the
assembler to generate external reference. This happens behind the
compiler's back and makes the compiler think that static percpu variables
in modules are unused.
This used to be worked around by using __unused attribute for percpu
variables which prevent the compiler from omitting the variable; however,
recent declare/definition attribute unification change broke this as
__used can't be used for declaration. Also, in the process,
PER_CPU_ATTRIBUTES definition in alpha percpu.h got broken.
This patch adds PER_CPU_DEF_ATTRIBUTES which is only used for definitions
and make alpha use it to add __used for percpu variables in modules. This
also fixes the PER_CPU_ATTRIBUTES double definition bug.
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: maximilian attems <max@stro.at>
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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__weak is necessary only for definition and might even not work in
declaration. Drop it from declaration.
This change was suggested by Ivan Kokshaysky.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
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Some archs (alpha and s390) need to use weak definitions for percpu
variables in modules so that the compiler generates external
references for them.
This patch implements weak percpu definitions which arch can enable by
defining ARCH_NEEDS_WEAK_PER_CPU in arch percpu header file. This
weak definition adds the following two restrictions on percpu variable
definitions.
1. percpu symbols must be unique whether static or not
2. percpu variables can't be defined inside a function
To ensure that these restrictions are observed in generic code, config
option DEBUG_FORCE_WEAK_PER_CPU enables weak percpu definitions for
all cases.
This patch is inspired by Ivan Kokshaysky's alpha percpu patch.
[ Impact: stricter rules for percpu variables, one more debug config option ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Howells <dhowells@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
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Collect the DECLARE/DEFINE declarations together in linux/percpu-defs.h so
that they're in one place, and give them descriptive comments, particularly
the SHARED_ALIGNED variant.
It would be nice to collect these in linux/percpu.h, but that's not possible
without sorting out the severe #include recursion between the x86 arch headers
and the general headers (and possibly other arches too).
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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