1 files changed, 61 insertions, 36 deletions

diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index d85172e9ed45..4b8d31cda1a0 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -3,54 +3,79 @@
 #include <linux/compiler.h>
 #include <linux/threads.h>
 
-#define __GENERIC_PER_CPU
+/*
+ * Determine the real variable name from the name visible in the
+ * kernel sources.
+ */
+#define per_cpu_var(var) per_cpu__##var
+
 #ifdef CONFIG_SMP
 
+/*
+ * per_cpu_offset() is the offset that has to be added to a
+ * percpu variable to get to the instance for a certain processor.
+ *
+ * Most arches use the __per_cpu_offset array for those offsets but
+ * some arches have their own ways of determining the offset (x86_64, s390).
+ */
+#ifndef __per_cpu_offset
 extern unsigned long __per_cpu_offset[NR_CPUS];
 
 #define per_cpu_offset(x) (__per_cpu_offset[x])
+#endif
 
-/* Separate out the type, so (int[3], foo) works. */
-#define DEFINE_PER_CPU(type, name) \
-    __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
-
-#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)               \
-    __attribute__((__section__(".data.percpu.shared_aligned"))) \
-    __typeof__(type) per_cpu__##name                            \
-    ____cacheline_aligned_in_smp
-
-/* var is in discarded region: offset to particular copy we want */
-#define per_cpu(var, cpu) (*({                          \
-        extern int simple_identifier_##var(void);       \
-        RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]); }))
-#define __get_cpu_var(var) per_cpu(var, smp_processor_id())
-#define __raw_get_cpu_var(var) per_cpu(var, raw_smp_processor_id())
-
-/* A macro to avoid #include hell... */
-#define percpu_modcopy(pcpudst, src, size)                      \
-do {                                                            \
-        unsigned int __i;                                       \
-        for_each_possible_cpu(__i)                              \
-                memcpy((pcpudst)+__per_cpu_offset[__i],         \
-                       (src), (size));                          \
-} while (0)
-#else /* ! SMP */
+/*
+ * Determine the offset for the currently active processor.
+ * An arch may define __my_cpu_offset to provide a more effective
+ * means of obtaining the offset to the per cpu variables of the
+ * current processor.
+ */
+#ifndef __my_cpu_offset
+#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
+#define my_cpu_offset per_cpu_offset(smp_processor_id())
+#else
+#define my_cpu_offset __my_cpu_offset
+#endif
+
+/*
+ * Add a offset to a pointer but keep the pointer as is.
+ *
+ * Only S390 provides its own means of moving the pointer.
+ */
+#ifndef SHIFT_PERCPU_PTR
+#define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset))
+#endif
 
-#define DEFINE_PER_CPU(type, name) \
-    __typeof__(type) per_cpu__##name
+/*
+ * A percpu variable may point to a discarded regions. The following are
+ * established ways to produce a usable pointer from the percpu variable
+ * offset.
+ */
+#define per_cpu(var, cpu) \
+        (*SHIFT_PERCPU_PTR(&per_cpu_var(var), per_cpu_offset(cpu)))
+#define __get_cpu_var(var) \
+        (*SHIFT_PERCPU_PTR(&per_cpu_var(var), my_cpu_offset))
+#define __raw_get_cpu_var(var) \
+        (*SHIFT_PERCPU_PTR(&per_cpu_var(var), __my_cpu_offset))
 
-#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)       \
-    DEFINE_PER_CPU(type, name)
 
-#define per_cpu(var, cpu)                       (*((void)(cpu), &per_cpu__##var))
-#define __get_cpu_var(var)                      per_cpu__##var
-#define __raw_get_cpu_var(var)                  per_cpu__##var
+#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
+extern void setup_per_cpu_areas(void);
+#endif
+
+#else /* ! SMP */
+
+#define per_cpu(var, cpu)                       (*((void)(cpu), &per_cpu_var(var)))
+#define __get_cpu_var(var)                      per_cpu_var(var)
+#define __raw_get_cpu_var(var)                  per_cpu_var(var)
 
 #endif  /* SMP */
 
-#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name
+#ifndef PER_CPU_ATTRIBUTES
+#define PER_CPU_ATTRIBUTES
+#endif
 
-#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
-#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
+#define DECLARE_PER_CPU(type, name) extern PER_CPU_ATTRIBUTES \
+                                        __typeof__(type) per_cpu_var(name)
 
 #endif /* _ASM_GENERIC_PERCPU_H_ */