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Subject[PATCH 02/12] percpu: introduce arch_raw_cpu_ptr()
Date
Currently, archs can override raw_cpu_ptr() directly; however, we
wanna build a layer of indirection in the generic part of percpu so
that we can implement generic features there without affecting archs.

Introduce arch_raw_cpu_ptr() which is used to define raw_cpu_ptr() by
generic percpu code. The two are identical for now. x86 is currently
the only arch which overrides raw_cpu_ptr() and is converted to
define arch_raw_cpu_ptr() instead.

This doesn't introduce any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
arch/x86/include/asm/percpu.h | 2 +-
include/asm-generic/percpu.h | 11 +++++++++--
2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 851bcdc..9bc23f1 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -52,7 +52,7 @@
* Compared to the generic __my_cpu_offset version, the following
* saves one instruction and avoids clobbering a temp register.
*/
-#define raw_cpu_ptr(ptr) \
+#define arch_raw_cpu_ptr(ptr) \
({ \
unsigned long tcp_ptr__; \
__verify_pcpu_ptr(ptr); \
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 63d2b68..a247d80 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -53,9 +53,16 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
#define per_cpu(var, cpu) \
(*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))

-#ifndef raw_cpu_ptr
-#define raw_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
+/*
+ * Arch may define arch_raw_cpu_ptr() to provide more efficient address
+ * translations for raw_cpu_ptr().
+ */
+#ifndef arch_raw_cpu_ptr
+#define arch_raw_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
#endif
+
+#define raw_cpu_ptr(ptr) arch_raw_cpu_ptr(ptr)
+
#ifdef CONFIG_DEBUG_PREEMPT
#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
#else
--
1.9.3


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