x86/percpu: Move some percpu accessors around to reduce ifdeffery

Move some percpu accessors around, mainly to reduce ifdeffery
and improve readabilty by following dependencies between
accessors.

No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240520080951.121049-2-ubizjak@gmail.com

arch/x86/include/asm/percpu.h

@@ -445,17 +445,6 @@ do {									\
 #define this_cpu_try_cmpxchg128(pcp, ovalp, nval)	percpu_try_cmpxchg128_op(16, volatile, pcp, ovalp, nval)
 #endif
 
-/*
- * this_cpu_read() makes gcc load the percpu variable every time it is
- * accessed while this_cpu_read_stable() allows the value to be cached.
- * this_cpu_read_stable() is more efficient and can be used if its value
- * is guaranteed to be valid across cpus.  The current users include
- * pcpu_hot.current_task and pcpu_hot.top_of_stack, both of which are
- * actually per-thread variables implemented as per-CPU variables and
- * thus stable for the duration of the respective task.
- */
-#define this_cpu_read_stable(pcp)	__pcpu_size_call_return(this_cpu_read_stable_, pcp)
-
 #define raw_cpu_read_1(pcp)		__raw_cpu_read(1, , pcp)
 #define raw_cpu_read_2(pcp)		__raw_cpu_read(2, , pcp)
 #define raw_cpu_read_4(pcp)		__raw_cpu_read(4, , pcp)
@@ -470,16 +459,6 @@ do {									\
 #define this_cpu_write_2(pcp, val)	__raw_cpu_write(2, volatile, pcp, val)
 #define this_cpu_write_4(pcp, val)	__raw_cpu_write(4, volatile, pcp, val)
 
-#ifdef CONFIG_X86_64
-#define raw_cpu_read_8(pcp)		__raw_cpu_read(8, , pcp)
-#define raw_cpu_write_8(pcp, val)	__raw_cpu_write(8, , pcp, val)
-
-#define this_cpu_read_8(pcp)		__raw_cpu_read(8, volatile, pcp)
-#define this_cpu_write_8(pcp, val)	__raw_cpu_write(8, volatile, pcp, val)
-#endif
-
-#define this_cpu_read_const(pcp)	__raw_cpu_read_const(pcp)
-
 #define this_cpu_read_stable_1(pcp)	__raw_cpu_read_stable(1, pcp)
 #define this_cpu_read_stable_2(pcp)	__raw_cpu_read_stable(2, pcp)
 #define this_cpu_read_stable_4(pcp)	__raw_cpu_read_stable(4, pcp)
@@ -535,6 +514,12 @@ do {									\
  * 32 bit must fall back to generic operations.
  */
 #ifdef CONFIG_X86_64
+#define raw_cpu_read_8(pcp)		__raw_cpu_read(8, , pcp)
+#define raw_cpu_write_8(pcp, val)	__raw_cpu_write(8, , pcp, val)
+
+#define this_cpu_read_8(pcp)		__raw_cpu_read(8, volatile, pcp)
+#define this_cpu_write_8(pcp, val)	__raw_cpu_write(8, volatile, pcp, val)
+
 #define this_cpu_read_stable_8(pcp)	__raw_cpu_read_stable(8, pcp)
 
 #define raw_cpu_add_8(pcp, val)			percpu_add_op(8, , (pcp), val)
@@ -561,6 +546,19 @@ do {									\
 #define raw_cpu_read_long(pcp)		raw_cpu_read_4(pcp)
 #endif
 
+#define this_cpu_read_const(pcp)	__raw_cpu_read_const(pcp)
+
+/*
+ * this_cpu_read() makes gcc load the percpu variable every time it is
+ * accessed while this_cpu_read_stable() allows the value to be cached.
+ * this_cpu_read_stable() is more efficient and can be used if its value
+ * is guaranteed to be valid across cpus.  The current users include
+ * pcpu_hot.current_task and pcpu_hot.top_of_stack, both of which are
+ * actually per-thread variables implemented as per-CPU variables and
+ * thus stable for the duration of the respective task.
+ */
+#define this_cpu_read_stable(pcp)	__pcpu_size_call_return(this_cpu_read_stable_, pcp)
+
 #define x86_this_cpu_constant_test_bit(_nr, _var)			\
 ({									\
 	unsigned long __percpu *addr__ =				\