2 files changed, 23 insertions, 6 deletions

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index c7376bf80b06..8ca18e26d7e3 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -16,15 +16,27 @@
  * While the GPIO programming interface defines valid GPIO numbers
  * to be in the range 0..MAX_INT, this library restricts them to the
  * smaller range 0..ARCH_NR_GPIOS-1.
+ *
+ * ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of
+ * builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is
+ * actually an estimate of a board-specific value.
  */
 
 #ifndef ARCH_NR_GPIOS
 #define ARCH_NR_GPIOS           256
 #endif
 
+/*
+ * "valid" GPIO numbers are nonnegative and may be passed to
+ * setup routines like gpio_request().  only some valid numbers
+ * can successfully be requested and used.
+ *
+ * Invalid GPIO numbers are useful for indicating no-such-GPIO in
+ * platform data and other tables.
+ */
+
 static inline int gpio_is_valid(int number)
 {
-        /* only some non-negative numbers are valid */
         return ((unsigned)number) < ARCH_NR_GPIOS;
 }
 
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index b5043a9890d8..08923b684768 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -70,11 +70,16 @@ extern void setup_per_cpu_areas(void);
 
 #else /* ! SMP */
 
-#define per_cpu(var, cpu)                       (*((void)(cpu), &(var)))
-#define __get_cpu_var(var)                      (var)
-#define __raw_get_cpu_var(var)                  (var)
-#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
-#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
+#define VERIFY_PERCPU_PTR(__p) ({                       \
+        __verify_pcpu_ptr((__p));                       \
+        (typeof(*(__p)) __kernel __force *)(__p);       \
+})
+
+#define per_cpu(var, cpu)       (*((void)(cpu), VERIFY_PERCPU_PTR(&(var))))
+#define __get_cpu_var(var)      (*VERIFY_PERCPU_PTR(&(var)))
+#define __raw_get_cpu_var(var)  (*VERIFY_PERCPU_PTR(&(var)))
+#define this_cpu_ptr(ptr)       per_cpu_ptr(ptr, 0)
+#define __this_cpu_ptr(ptr)     this_cpu_ptr(ptr)
 
 #endif  /* SMP */