ACPICA: Re-implement interpreters' "serialized mode"

Enhanced the implementation of the interpreters'
serialized mode (boot with "acpi_serialize" to set
acpi_glb_all_methods_serialized flag.)
When this mode is specified, instead of creating a serialization
semaphore per control method, the interpreter lock is
simply no longer released before a blocking operation
during control method execution. This effectively makes
the AML Interpreter single-threaded. The overhead of a
semaphore per-method is eliminated.

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 6 insertions, 15 deletions

diff --git a/drivers/acpi/events/evregion.c b/drivers/acpi/events/evregion.c
index 21caae04fe85..ef459716931e 100644
--- a/drivers/acpi/events/evregion.c
+++ b/drivers/acpi/events/evregion.c
@@ -291,7 +291,6 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
                                u32 bit_width, acpi_integer * value)
 {
         acpi_status status;
-        acpi_status status2;
         acpi_adr_space_handler handler;
         acpi_adr_space_setup region_setup;
         union acpi_operand_object *handler_desc;
@@ -345,7 +344,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
                  * setup will potentially execute control methods
                  * (e.g., _REG method for this region)
                  */
-                acpi_ex_exit_interpreter();
+                acpi_ex_relinquish_interpreter();
 
                 status = region_setup(region_obj, ACPI_REGION_ACTIVATE,
                                       handler_desc->address_space.context,
@@ -353,10 +352,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
 
                 /* Re-enter the interpreter */
 
-                status2 = acpi_ex_enter_interpreter();
-                if (ACPI_FAILURE(status2)) {
-                        return_ACPI_STATUS(status2);
-                }
+                acpi_ex_reacquire_interpreter();
 
                 /* Check for failure of the Region Setup */
 
@@ -409,7 +405,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
                  * exit the interpreter because the handler *might* block -- we don't
                  * know what it will do, so we can't hold the lock on the intepreter.
                  */
-                acpi_ex_exit_interpreter();
+                acpi_ex_relinquish_interpreter();
         }
 
         /* Call the handler */
@@ -430,10 +426,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
                  * We just returned from a non-default handler, we must re-enter the
                  * interpreter
                  */
-                status2 = acpi_ex_enter_interpreter();
-                if (ACPI_FAILURE(status2)) {
-                        return_ACPI_STATUS(status2);
-                }
+                acpi_ex_reacquire_interpreter();
         }
 
         return_ACPI_STATUS(status);
diff --git a/drivers/acpi/events/evxface.c b/drivers/acpi/events/evxface.c
index 923fd2b46955..a2af48ed88cd 100644
--- a/drivers/acpi/events/evxface.c
+++ b/drivers/acpi/events/evxface.c
@@ -768,11 +768,9 @@ acpi_status acpi_acquire_global_lock(u16 timeout, u32 * handle)
                 return (AE_BAD_PARAMETER);
         }
 
-        status = acpi_ex_enter_interpreter();
-        if (ACPI_FAILURE(status)) {
-                return (status);
-        }
+        /* Must lock interpreter to prevent race conditions */
 
+        acpi_ex_enter_interpreter();
         status = acpi_ev_acquire_global_lock(timeout);
         acpi_ex_exit_interpreter();