ACPI: Enable build of AML interpreter debugger

This patch enables ACPICA debugger files using a configurable
CONFIG_ACPI_DEBUGGER configuration item. Those debugger related code that
was originally masked as ACPI_FUTURE_USAGE now gets unmasked.

Necessary OSL stubs are also added in this patch:
1. acpi_os_readable(): This should be arch specific in Linux, while this
    patch doesn't introduce real implementation and a complex mechanism to
    allow architecture specific acpi_os_readable() to be implemented to
    validate the address. It may be done by future commits.
2. acpi_os_get_line(): This is used to obtain debugger command input. This
    patch only introduces a simple KDB concept example in it and the
    example should be co-working with the code implemented in
    acpi_os_printf(). Since this KDB example won't be compiled unless
    ENABLE_DEBUGGER is defined and it seems Linux has already stopped to
    use ENABLE_DEBUGGER, thus do not expect it can work properly.

This patch also cleans up all other ACPI_FUTURE_USAGE surroundings
accordingly.
1. Since linkage error can be automatically detected, declaration in the
   headers needn't be surrounded by ACPI_FUTURE_USAGE.
   So only the following separate exported fuction bodies are masked by
   this macro (other exported fucntions may have already been masked at
   entire module level via drivers/acpi/acpica/Makefile):
     acpi_install_exception_handler()
     acpi_subsystem_status()
     acpi_get_system_info()
     acpi_get_statistics()
     acpi_install_initialization_handler()
2. Since strip can automatically zap the no-user functions, functions that
   are not marked with ACPI_EXPORT_SYMBOL() needn't get surrounded by
   ACPI_FUTURE_USAGE.
   So the following function which is not used by Linux kernel now won't
   get surrounded by this macro:
     acpi_ps_get_name()

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/acpixf.h

@@ -393,15 +393,11 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status __init acpi_terminate(void))
  */
 ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_enable(void))
 ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_disable(void))
-#ifdef ACPI_FUTURE_USAGE
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status acpi_subsystem_status(void))
-#endif
 
-#ifdef ACPI_FUTURE_USAGE
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			    acpi_get_system_info(struct acpi_buffer
 						 *ret_buffer))
-#endif
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			     acpi_get_statistics(struct acpi_statistics *stats))
 ACPI_EXTERNAL_RETURN_PTR(const char
@@ -625,11 +621,9 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 							       space_id,
 							       acpi_adr_space_handler
 							       handler))
-#ifdef ACPI_FUTURE_USAGE
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			     acpi_install_exception_handler
 			     (acpi_exception_handler handler))
-#endif
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			     acpi_install_interface_handler
 			     (acpi_interface_handler handler))
@@ -750,12 +744,10 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			     acpi_get_current_resources(acpi_handle device,
 							struct acpi_buffer
 							*ret_buffer))
-#ifdef ACPI_FUTURE_USAGE
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			     acpi_get_possible_resources(acpi_handle device,
 							 struct acpi_buffer
 							 *ret_buffer))
-#endif
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			     acpi_get_event_resources(acpi_handle device_handle,
 						      struct acpi_buffer
@@ -844,7 +836,6 @@ ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status
 /*
  * ACPI Timer interfaces
  */
-#ifdef ACPI_FUTURE_USAGE
 ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status
 				acpi_get_timer_resolution(u32 *resolution))
 ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_get_timer(u32 *ticks))
@@ -853,7 +844,6 @@ ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status
 				acpi_get_timer_duration(u32 start_ticks,
 							u32 end_ticks,
 							u32 *time_elapsed))
-#endif				/* ACPI_FUTURE_USAGE */
 
 /*
  * Error/Warning output

include/acpi/platform/aclinux.h

@@ -63,12 +63,16 @@
 
 #define ACPI_USE_SYSTEM_INTTYPES
 
-/* Compile for reduced hardware mode only with this kernel config */
+/* Kernel specific ACPICA configuration */
 
 #ifdef CONFIG_ACPI_REDUCED_HARDWARE_ONLY
 #define ACPI_REDUCED_HARDWARE 1
 #endif
 
+#ifdef CONFIG_ACPI_DEBUGGER
+#define ACPI_DEBUGGER
+#endif
+
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/ctype.h>
@@ -151,7 +155,6 @@
  * OSL interfaces used by utilities
  */
 #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_redirect_output
-#define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_line
 #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_table_by_name
 #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_table_by_index
 #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_table_by_address

include/acpi/platform/aclinuxex.h

@@ -124,6 +124,11 @@ static inline acpi_thread_id acpi_os_get_thread_id(void)
 		lock ? AE_OK : AE_NO_MEMORY; \
 	})
 
+static inline u8 acpi_os_readable(void *pointer, acpi_size length)
+{
+	return TRUE;
+}
+
 /*
  * OSL interfaces added by Linux
  */