[patch 5/6] cleanups to help using per-cpu variables from asm

Jeremy Fitzhardinge
2007-03-31T04:55:04Z

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This patch does a few small cleanups:
- use PER_CPU_NAME to generate the names of per-cpu variables
- use lea to add the per_cpu offset in PER_CPU(), because it doesn't
affect condition flags
- add PER_CPU_VAR which allows direct access to pre-cpu variables
with the %fs: prefix on SMP.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>

---
include/asm-i386/percpu.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

===================================================================
--- a/include/asm-i386/percpu.h
+++ b/include/asm-i386/percpu.h
@@ -16,12 +16,14 @@
* PER_CPU(cpu_gdt_descr, %ebx)
*/
#ifdef CONFIG_SMP
+#define PER_CPU(var, reg) \
+ movl %fs:per_cpu__##this_cpu_off, reg; \
+ lea per_cpu__##var(reg), reg
+#define PER_CPU_VAR(var) %fs:per_cpu__##var
+#else /* ! SMP */
#define PER_CPU(var, reg) \
- movl %fs:per_cpu__this_cpu_off, reg; \
- addl $per_cpu__##var, reg
-#else /* ! SMP */
-#define PER_CPU(var, reg) \
- movl $per_cpu__##var, reg;
+ movl $per_cpu__##var, reg
+#define PER_CPU_VAR(var) per_cpu__##var
#endif /* SMP */

#else /* ...!ASSEMBLY */

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