percpu: fix DEBUG_PREEMPT per_cpu checking

1e835278 · Hugh Dickins <[email protected]> · 2008-02-23 19:40:17 +00:00

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 <[email protected]>
Reviewed-by: Mike Travis <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: 1e8352784abaedb424e63fa700e93e6c1307785f
Parents: 3a2d5b70

Changes

2 files changed · +3 −1

File	Status	Add	Del	Content
include/asm-generic/percpu.h	modified	+2	−0	View file
include/asm-powerpc/percpu.h	modified	+1	−1	View file

include/asm-generic/percpu.h

View file

diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 4b8d31c..b0e63c6 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -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

include/asm-powerpc/percpu.h

View file

diff --git a/include/asm-powerpc/percpu.h b/include/asm-powerpc/percpu.h
index ccb0523..f879252 100644
--- a/include/asm-powerpc/percpu.h
+++ b/include/asm-powerpc/percpu.h
@@ -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 */