1 files changed, 402 insertions, 26 deletions

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 8e4ead6435fb..cf5efbcf716c 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -34,8 +34,6 @@
 
 #ifdef CONFIG_SMP
 
-#ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA
-
 /* minimum unit size, also is the maximum supported allocation size */
 #define PCPU_MIN_UNIT_SIZE              PFN_ALIGN(64 << 10)
 
@@ -130,28 +128,6 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
 #define per_cpu_ptr(ptr, cpu)   SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
 
 extern void *__alloc_reserved_percpu(size_t size, size_t align);
-
-#else /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
-
-struct percpu_data {
-        void *ptrs[1];
-};
-
-/* pointer disguising messes up the kmemleak objects tracking */
-#ifndef CONFIG_DEBUG_KMEMLEAK
-#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
-#else
-#define __percpu_disguise(pdata) (struct percpu_data *)(pdata)
-#endif
-
-#define per_cpu_ptr(ptr, cpu)                                           \
-({                                                                      \
-        struct percpu_data *__p = __percpu_disguise(ptr);               \
-        (__typeof__(ptr))__p->ptrs[(cpu)];                              \
-})
-
-#endif /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
-
 extern void *__alloc_percpu(size_t size, size_t align);
 extern void free_percpu(void *__pdata);
 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
@@ -194,8 +170,8 @@ static inline void *pcpu_lpage_remapped(void *kaddr)
 
 #endif /* CONFIG_SMP */
 
-#define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type), \
-                                                       __alignof__(type))
+#define alloc_percpu(type)      \
+        (typeof(type) *)__alloc_percpu(sizeof(type), __alignof__(type))
 
 /*
  * Optional methods for optimized non-lvalue per-cpu variable access.
@@ -249,4 +225,404 @@ do {									\
 # define percpu_xor(var, val)           __percpu_generic_to_op(var, (val), ^=)
 #endif
 
+/*
+ * Branching function to split up a function into a set of functions that
+ * are called for different scalar sizes of the objects handled.
+ */
+
+extern void __bad_size_call_parameter(void);
+
+#define __pcpu_size_call_return(stem, variable)                         \
+({      typeof(variable) pscr_ret__;                                    \
+        switch(sizeof(variable)) {                                      \
+        case 1: pscr_ret__ = stem##1(variable);break;                   \
+        case 2: pscr_ret__ = stem##2(variable);break;                   \
+        case 4: pscr_ret__ = stem##4(variable);break;                   \
+        case 8: pscr_ret__ = stem##8(variable);break;                   \
+        default:                                                        \
+                __bad_size_call_parameter();break;                      \
+        }                                                               \
+        pscr_ret__;                                                     \
+})
+
+#define __pcpu_size_call(stem, variable, ...)                           \
+do {                                                                    \
+        switch(sizeof(variable)) {                                      \
+                case 1: stem##1(variable, __VA_ARGS__);break;           \
+                case 2: stem##2(variable, __VA_ARGS__);break;           \
+                case 4: stem##4(variable, __VA_ARGS__);break;           \
+                case 8: stem##8(variable, __VA_ARGS__);break;           \
+                default:                                                \
+                        __bad_size_call_parameter();break;              \
+        }                                                               \
+} while (0)
+
+/*
+ * Optimized manipulation for memory allocated through the per cpu
+ * allocator or for addresses of per cpu variables (can be determined
+ * using per_cpu_var(xx).
+ *
+ * These operation guarantee exclusivity of access for other operations
+ * on the *same* processor. The assumption is that per cpu data is only
+ * accessed by a single processor instance (the current one).
+ *
+ * The first group is used for accesses that must be done in a
+ * preemption safe way since we know that the context is not preempt
+ * safe. Interrupts may occur. If the interrupt modifies the variable
+ * too then RMW actions will not be reliable.
+ *
+ * The arch code can provide optimized functions in two ways:
+ *
+ * 1. Override the function completely. F.e. define this_cpu_add().
+ *    The arch must then ensure that the various scalar format passed
+ *    are handled correctly.
+ *
+ * 2. Provide functions for certain scalar sizes. F.e. provide
+ *    this_cpu_add_2() to provide per cpu atomic operations for 2 byte
+ *    sized RMW actions. If arch code does not provide operations for
+ *    a scalar size then the fallback in the generic code will be
+ *    used.
+ */
+
+#define _this_cpu_generic_read(pcp)                                     \
+({      typeof(pcp) ret__;                                              \
+        preempt_disable();                                              \
+        ret__ = *this_cpu_ptr(&(pcp));                                  \
+        preempt_enable();                                               \
+        ret__;                                                          \
+})
+
+#ifndef this_cpu_read
+# ifndef this_cpu_read_1
+#  define this_cpu_read_1(pcp)  _this_cpu_generic_read(pcp)
+# endif
+# ifndef this_cpu_read_2
+#  define this_cpu_read_2(pcp)  _this_cpu_generic_read(pcp)
+# endif
+# ifndef this_cpu_read_4
+#  define this_cpu_read_4(pcp)  _this_cpu_generic_read(pcp)
+# endif
+# ifndef this_cpu_read_8
+#  define this_cpu_read_8(pcp)  _this_cpu_generic_read(pcp)
+# endif
+# define this_cpu_read(pcp)     __pcpu_size_call_return(this_cpu_read_, (pcp))
+#endif
+
+#define _this_cpu_generic_to_op(pcp, val, op)                           \
+do {                                                                    \
+        preempt_disable();                                              \
+        *__this_cpu_ptr(&pcp) op val;                                   \
+        preempt_enable();                                               \
+} while (0)
+
+#ifndef this_cpu_write
+# ifndef this_cpu_write_1
+#  define this_cpu_write_1(pcp, val)    _this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# ifndef this_cpu_write_2
+#  define this_cpu_write_2(pcp, val)    _this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# ifndef this_cpu_write_4
+#  define this_cpu_write_4(pcp, val)    _this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# ifndef this_cpu_write_8
+#  define this_cpu_write_8(pcp, val)    _this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# define this_cpu_write(pcp, val)       __pcpu_size_call(this_cpu_write_, (pcp), (val))
+#endif
+
+#ifndef this_cpu_add
+# ifndef this_cpu_add_1
+#  define this_cpu_add_1(pcp, val)      _this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef this_cpu_add_2
+#  define this_cpu_add_2(pcp, val)      _this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef this_cpu_add_4
+#  define this_cpu_add_4(pcp, val)      _this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef this_cpu_add_8
+#  define this_cpu_add_8(pcp, val)      _this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# define this_cpu_add(pcp, val)         __pcpu_size_call(this_cpu_add_, (pcp), (val))
+#endif
+
+#ifndef this_cpu_sub
+# define this_cpu_sub(pcp, val)         this_cpu_add((pcp), -(val))
+#endif
+
+#ifndef this_cpu_inc
+# define this_cpu_inc(pcp)              this_cpu_add((pcp), 1)
+#endif
+
+#ifndef this_cpu_dec
+# define this_cpu_dec(pcp)              this_cpu_sub((pcp), 1)
+#endif
+
+#ifndef this_cpu_and
+# ifndef this_cpu_and_1
+#  define this_cpu_and_1(pcp, val)      _this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef this_cpu_and_2
+#  define this_cpu_and_2(pcp, val)      _this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef this_cpu_and_4
+#  define this_cpu_and_4(pcp, val)      _this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef this_cpu_and_8
+#  define this_cpu_and_8(pcp, val)      _this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# define this_cpu_and(pcp, val)         __pcpu_size_call(this_cpu_and_, (pcp), (val))
+#endif
+
+#ifndef this_cpu_or
+# ifndef this_cpu_or_1
+#  define this_cpu_or_1(pcp, val)       _this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef this_cpu_or_2
+#  define this_cpu_or_2(pcp, val)       _this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef this_cpu_or_4
+#  define this_cpu_or_4(pcp, val)       _this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef this_cpu_or_8
+#  define this_cpu_or_8(pcp, val)       _this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# define this_cpu_or(pcp, val)          __pcpu_size_call(this_cpu_or_, (pcp), (val))
+#endif
+
+#ifndef this_cpu_xor
+# ifndef this_cpu_xor_1
+#  define this_cpu_xor_1(pcp, val)      _this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef this_cpu_xor_2
+#  define this_cpu_xor_2(pcp, val)      _this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef this_cpu_xor_4
+#  define this_cpu_xor_4(pcp, val)      _this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef this_cpu_xor_8
+#  define this_cpu_xor_8(pcp, val)      _this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# define this_cpu_xor(pcp, val)         __pcpu_size_call(this_cpu_or_, (pcp), (val))
+#endif
+
+/*
+ * Generic percpu operations that do not require preemption handling.
+ * Either we do not care about races or the caller has the
+ * responsibility of handling preemptions issues. Arch code can still
+ * override these instructions since the arch per cpu code may be more
+ * efficient and may actually get race freeness for free (that is the
+ * case for x86 for example).
+ *
+ * If there is no other protection through preempt disable and/or
+ * disabling interupts then one of these RMW operations can show unexpected
+ * behavior because the execution thread was rescheduled on another processor
+ * or an interrupt occurred and the same percpu variable was modified from
+ * the interrupt context.
+ */
+#ifndef __this_cpu_read
+# ifndef __this_cpu_read_1
+#  define __this_cpu_read_1(pcp)        (*__this_cpu_ptr(&(pcp)))
+# endif
+# ifndef __this_cpu_read_2
+#  define __this_cpu_read_2(pcp)        (*__this_cpu_ptr(&(pcp)))
+# endif
+# ifndef __this_cpu_read_4
+#  define __this_cpu_read_4(pcp)        (*__this_cpu_ptr(&(pcp)))
+# endif
+# ifndef __this_cpu_read_8
+#  define __this_cpu_read_8(pcp)        (*__this_cpu_ptr(&(pcp)))
+# endif
+# define __this_cpu_read(pcp)   __pcpu_size_call_return(__this_cpu_read_, (pcp))
+#endif
+
+#define __this_cpu_generic_to_op(pcp, val, op)                          \
+do {                                                                    \
+        *__this_cpu_ptr(&(pcp)) op val;                                 \
+} while (0)
+
+#ifndef __this_cpu_write
+# ifndef __this_cpu_write_1
+#  define __this_cpu_write_1(pcp, val)  __this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# ifndef __this_cpu_write_2
+#  define __this_cpu_write_2(pcp, val)  __this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# ifndef __this_cpu_write_4
+#  define __this_cpu_write_4(pcp, val)  __this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# ifndef __this_cpu_write_8
+#  define __this_cpu_write_8(pcp, val)  __this_cpu_generic_to_op((pcp), (val), =)
+# endif
+# define __this_cpu_write(pcp, val)     __pcpu_size_call(__this_cpu_write_, (pcp), (val))
+#endif
+
+#ifndef __this_cpu_add
+# ifndef __this_cpu_add_1
+#  define __this_cpu_add_1(pcp, val)    __this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef __this_cpu_add_2
+#  define __this_cpu_add_2(pcp, val)    __this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef __this_cpu_add_4
+#  define __this_cpu_add_4(pcp, val)    __this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef __this_cpu_add_8
+#  define __this_cpu_add_8(pcp, val)    __this_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# define __this_cpu_add(pcp, val)       __pcpu_size_call(__this_cpu_add_, (pcp), (val))
+#endif
+
+#ifndef __this_cpu_sub
+# define __this_cpu_sub(pcp, val)       __this_cpu_add((pcp), -(val))
+#endif
+
+#ifndef __this_cpu_inc
+# define __this_cpu_inc(pcp)            __this_cpu_add((pcp), 1)
+#endif
+
+#ifndef __this_cpu_dec
+# define __this_cpu_dec(pcp)            __this_cpu_sub((pcp), 1)
+#endif
+
+#ifndef __this_cpu_and
+# ifndef __this_cpu_and_1
+#  define __this_cpu_and_1(pcp, val)    __this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef __this_cpu_and_2
+#  define __this_cpu_and_2(pcp, val)    __this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef __this_cpu_and_4
+#  define __this_cpu_and_4(pcp, val)    __this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef __this_cpu_and_8
+#  define __this_cpu_and_8(pcp, val)    __this_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# define __this_cpu_and(pcp, val)       __pcpu_size_call(__this_cpu_and_, (pcp), (val))
+#endif
+
+#ifndef __this_cpu_or
+# ifndef __this_cpu_or_1
+#  define __this_cpu_or_1(pcp, val)     __this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef __this_cpu_or_2
+#  define __this_cpu_or_2(pcp, val)     __this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef __this_cpu_or_4
+#  define __this_cpu_or_4(pcp, val)     __this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef __this_cpu_or_8
+#  define __this_cpu_or_8(pcp, val)     __this_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# define __this_cpu_or(pcp, val)        __pcpu_size_call(__this_cpu_or_, (pcp), (val))
+#endif
+
+#ifndef __this_cpu_xor
+# ifndef __this_cpu_xor_1
+#  define __this_cpu_xor_1(pcp, val)    __this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef __this_cpu_xor_2
+#  define __this_cpu_xor_2(pcp, val)    __this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef __this_cpu_xor_4
+#  define __this_cpu_xor_4(pcp, val)    __this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef __this_cpu_xor_8
+#  define __this_cpu_xor_8(pcp, val)    __this_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# define __this_cpu_xor(pcp, val)       __pcpu_size_call(__this_cpu_xor_, (pcp), (val))
+#endif
+
+/*
+ * IRQ safe versions of the per cpu RMW operations. Note that these operations
+ * are *not* safe against modification of the same variable from another
+ * processors (which one gets when using regular atomic operations)
+ . They are guaranteed to be atomic vs. local interrupts and
+ * preemption only.
+ */
+#define irqsafe_cpu_generic_to_op(pcp, val, op)                         \
+do {                                                                    \
+        unsigned long flags;                                            \
+        local_irq_save(flags);                                          \
+        *__this_cpu_ptr(&(pcp)) op val;                                 \
+        local_irq_restore(flags);                                       \
+} while (0)
+
+#ifndef irqsafe_cpu_add
+# ifndef irqsafe_cpu_add_1
+#  define irqsafe_cpu_add_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef irqsafe_cpu_add_2
+#  define irqsafe_cpu_add_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef irqsafe_cpu_add_4
+#  define irqsafe_cpu_add_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# ifndef irqsafe_cpu_add_8
+#  define irqsafe_cpu_add_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
+# endif
+# define irqsafe_cpu_add(pcp, val) __pcpu_size_call(irqsafe_cpu_add_, (pcp), (val))
+#endif
+
+#ifndef irqsafe_cpu_sub
+# define irqsafe_cpu_sub(pcp, val)      irqsafe_cpu_add((pcp), -(val))
+#endif
+
+#ifndef irqsafe_cpu_inc
+# define irqsafe_cpu_inc(pcp)   irqsafe_cpu_add((pcp), 1)
+#endif
+
+#ifndef irqsafe_cpu_dec
+# define irqsafe_cpu_dec(pcp)   irqsafe_cpu_sub((pcp), 1)
+#endif
+
+#ifndef irqsafe_cpu_and
+# ifndef irqsafe_cpu_and_1
+#  define irqsafe_cpu_and_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef irqsafe_cpu_and_2
+#  define irqsafe_cpu_and_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef irqsafe_cpu_and_4
+#  define irqsafe_cpu_and_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# ifndef irqsafe_cpu_and_8
+#  define irqsafe_cpu_and_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
+# endif
+# define irqsafe_cpu_and(pcp, val) __pcpu_size_call(irqsafe_cpu_and_, (val))
+#endif
+
+#ifndef irqsafe_cpu_or
+# ifndef irqsafe_cpu_or_1
+#  define irqsafe_cpu_or_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef irqsafe_cpu_or_2
+#  define irqsafe_cpu_or_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef irqsafe_cpu_or_4
+#  define irqsafe_cpu_or_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# ifndef irqsafe_cpu_or_8
+#  define irqsafe_cpu_or_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
+# endif
+# define irqsafe_cpu_or(pcp, val) __pcpu_size_call(irqsafe_cpu_or_, (val))
+#endif
+
+#ifndef irqsafe_cpu_xor
+# ifndef irqsafe_cpu_xor_1
+#  define irqsafe_cpu_xor_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef irqsafe_cpu_xor_2
+#  define irqsafe_cpu_xor_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef irqsafe_cpu_xor_4
+#  define irqsafe_cpu_xor_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# ifndef irqsafe_cpu_xor_8
+#  define irqsafe_cpu_xor_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
+# endif
+# define irqsafe_cpu_xor(pcp, val) __pcpu_size_call(irqsafe_cpu_xor_, (val))
+#endif
+
 #endif /* __LINUX_PERCPU_H */