Merge branch 'linux-next' of git://git.infradead.org/~dedekind/ubi-2.6

1 files changed, 72 insertions, 0 deletions

diff --git a/include/asm-x86/percpu.h b/include/asm-x86/percpu.h
index 736fc3bb8e1e..4e91ee1e37aa 100644
--- a/include/asm-x86/percpu.h
+++ b/include/asm-x86/percpu.h
@@ -22,6 +22,32 @@
 
 DECLARE_PER_CPU(struct x8664_pda, pda);
 
+/*
+ * These are supposed to be implemented as a single instruction which
+ * operates on the per-cpu data base segment.  x86-64 doesn't have
+ * that yet, so this is a fairly inefficient workaround for the
+ * meantime.  The single instruction is atomic with respect to
+ * preemption and interrupts, so we need to explicitly disable
+ * interrupts here to achieve the same effect.  However, because it
+ * can be used from within interrupt-disable/enable, we can't actually
+ * disable interrupts; disabling preemption is enough.
+ */
+#define x86_read_percpu(var)						\
+	({								\
+		typeof(per_cpu_var(var)) __tmp;				\
+		preempt_disable();					\
+		__tmp = __get_cpu_var(var);				\
+		preempt_enable();					\
+		__tmp;							\
+	})
+
+#define x86_write_percpu(var, val)					\
+	do {								\
+		preempt_disable();					\
+		__get_cpu_var(var) = (val);				\
+		preempt_enable();					\
+	} while(0)
+
 #else /* CONFIG_X86_64 */
 
 #ifdef __ASSEMBLY__
@@ -143,4 +169,50 @@ do {							\
 #define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val)
 #endif /* !__ASSEMBLY__ */
 #endif /* !CONFIG_X86_64 */
+
+#ifdef CONFIG_SMP
+
+/*
+ * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
+ * variables that are initialized and accessed before there are per_cpu
+ * areas allocated.
+ */
+
+#define	DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)			\
+	DEFINE_PER_CPU(_type, _name) = _initvalue;			\
+	__typeof__(_type) _name##_early_map[NR_CPUS] __initdata =	\
+				{ [0 ... NR_CPUS-1] = _initvalue };	\
+	__typeof__(_type) *_name##_early_ptr = _name##_early_map
+
+#define EXPORT_EARLY_PER_CPU_SYMBOL(_name)			\
+	EXPORT_PER_CPU_SYMBOL(_name)
+
+#define DECLARE_EARLY_PER_CPU(_type, _name)			\
+	DECLARE_PER_CPU(_type, _name);				\
+	extern __typeof__(_type) *_name##_early_ptr;		\
+	extern __typeof__(_type)  _name##_early_map[]
+
+#define	early_per_cpu_ptr(_name) (_name##_early_ptr)
+#define	early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
+#define	early_per_cpu(_name, _cpu) 				\
+	(early_per_cpu_ptr(_name) ?				\
+		early_per_cpu_ptr(_name)[_cpu] :		\
+		per_cpu(_name, _cpu))
+
+#else	/* !CONFIG_SMP */
+#define	DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)		\
+	DEFINE_PER_CPU(_type, _name) = _initvalue
+
+#define EXPORT_EARLY_PER_CPU_SYMBOL(_name)			\
+	EXPORT_PER_CPU_SYMBOL(_name)
+
+#define DECLARE_EARLY_PER_CPU(_type, _name)			\
+	DECLARE_PER_CPU(_type, _name)
+
+#define	early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
+#define	early_per_cpu_ptr(_name) NULL
+/* no early_per_cpu_map() */
+
+#endif	/* !CONFIG_SMP */
+
 #endif /* _ASM_X86_PERCPU_H_ */