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percpu: fix DEBUG_PREEMPT per_cpu checking

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2.6.25-rc1 percpu changes broke CONFIG_DEBUG_PREEMPT's per_cpu checking
on several architectures.  On s390, sparc64 and x86 it's been weakened to
not checking at all; whereas on powerpc64 it's become too strict, issuing
warnings from __raw_get_cpu_var in io_schedule and init_timer for example.

Fix this by weakening powerpc's __my_cpu_offset to use the non-checking
local_paca instead of get_paca (which itself contains such a check);
and strengthening the generic my_cpu_offset to go the old slow way via
smp_processor_id when CONFIG_DEBUG_PREEMPT (debug_smp_processor_id is
where all the knowledge of what's correct when lives).

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Reviewed-by: Mike Travis <travis@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins 2008-02-23 19:40:17 +00:00 committed by Linus Torvalds
parent 3a2d5b7001
commit 1e8352784a
2 changed files with 3 additions and 1 deletions
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2
include/asm-generic/percpu.h
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@ -32,6 +32,8 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
*/
#ifndef __my_cpu_offset
#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
#endif
#ifdef CONFIG_DEBUG_PREEMPT
#define my_cpu_offset per_cpu_offset(smp_processor_id())
#else
#define my_cpu_offset __my_cpu_offset

2
include/asm-powerpc/percpu.h
View File

@ -13,7 +13,7 @@
#include <asm/paca.h>
#define __per_cpu_offset(cpu) (paca[cpu].data_offset)
#define __my_cpu_offset get_paca()->data_offset
#define __my_cpu_offset local_paca->data_offset
#define per_cpu_offset(x) (__per_cpu_offset(x))
#endif /* CONFIG_SMP */