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linux/drivers/acpi/acpica/nsload.c
Lv Zheng 74f51b80a0 ACPICA: Namespace: Fix dynamic table loading issues 
ACPICA commit 767ee53354e0c4b7e8e7c57c6dd7bf569f0d52bb

There are issues related to the namespace/interpreter locks, which causes
several ACPI functionalities not specification compliant. The lock issues
were detectec when we were trying to fix the functionalities (please see
Link # [1] for the details).

What's the lock issues? Let's first look into the namespace/interpreter
lock usages inside of the object evaluation and the table loading which are
the key AML interpretion code paths:
Table loading:
acpi_ns_load_table
	L(Namespace)
	acpi_ns_parse_table
		acpi_ns_one_complete_parse(LOAD_PASS1/LOAD_PASS2)
			acpi_ds_load1_begion_op
			acpi_ds_load1_end_op
			acpi_ds_load2_begion_op
			acpi_ds_load2_end_op
	U(Namespace)
Object evaluation:
acpi_ns_evaluate
	L(Interpreter)
	acpi_ps_execute_method
		acpi_ds_exec_begin_op
		acpi_ds_exec_end_op
			U(Interpreter)
			acpi_ns_load_table
				L(Namespace)
				U(Namespace)
			acpi_ev_initialize_region
				L(Namespace)
				U(Namespace)
			address_space.Setup
			address_space.Handler
			acpi_os_wait_semaphore
			acpi_os_acquire_mutex
			acpi_os_sleep
			L(Interpreter)
	U(Interpreter)
	L(Interpreter)
	acpi_ex_resolve_node_to_value
	U(Interpreter)
	acpi_ns_check_return_value
Where:
  1. L(Interpreter) means acquire(MTX_INTERPRETER);
  2. U(Interpreter) means release(MTX_INTERPRETER);
  3. L(Namespace) means acquire(MTX_NAMESPACE);
  4. U(Namespace) means release(MTX_NAMESPACE);

We can see that acpi_ns_exec_module_code() (which invokes acpi_ns_evaluate) is
implemented in a deferred way just in order to avoid to reacquire the
namespace lock. This is in fact the root cause of many other ACPICA issues:
1. We now know for sure that the module code should be executed right in
   place by the Windows AML interpreter. So in the current design, if
   the region initializations/accesses or the table loadings (where the
   namespace surely should be locked again) happening during the table
   loading period, dead lock could happen because ACPICA never unlocks the
   namespace during the AML interpretion.
2. ACPICA interpreter just ensures that all static namespace nodes (named
   objects created during the acpi_load_tables()) are created
   (acpi_ns_lookup()) with the correct lock held, but doesn't ensure that
   the named objects created by the control method are created with the
   same correct lock held. It requires the control methods to be executed
   in a serial way after "loading a table", that's why ACPICA requires
   method auto serialization.

This patch fixes these software design issues by extending interpreter
enter/exit APIs to hold both interpreter/namespace locks to ensure the lock
order correctness, so that we can get these code paths:
Table loading:
acpi_ns_load_table
	E(Interpreter)
		acpi_ns_parse_table
			acpi_ns_one_complete_parse
			acpi_ns_execute_table
				X(Interpreter)
				acpi_ns_load_table
				acpi_ev_initialize_region
				address_space.Setup
				address_space.Handler
				acpi_os_wait_semaphore
				acpi_os_acquire_mutex
				acpi_os_sleep
				E(Interpreter)
	X(Interpreter)
Object evaluation:
acpi_ns_evaluate
	E(Interpreter)
	acpi_ps_execute_method
		X(Interpreter)
		acpi_ns_load_table
		acpi_ev_initialize_region
		address_space.Setup
		address_space.Handler
		acpi_os_wait_semaphore
		acpi_os_acquire_mutex
		acpi_os_sleep
		E(Interpreter)
	X(Interpreter)
Where:
  1. E(Interpreter) means acquire(MTX_INTERPRETER, MTX_NAMESPACE);
  2. X(Interpreter) means release(MTX_NAMESPACE, MTX_INTERPRETER);

After this change, we can see:
1. All namespace nodes creations are locked by the namespace lock.
2. All namespace nodes referencing are locked with the same lock.
3. But we also can notice a defact that, all namespace nodes deletions
   could be affected by this change. As a consequence,
   acpi_ns_delete_namespace_subtree() may delete a static namespace node that
   is still referenced by the interpreter (for example, the parser scopes).
Currently, we needn't worry about the last defact because in ACPICA, table
unloading is not fully functioning, its design strictly relies on the fact
that when the namespace deletion happens, either the AML table or the OSPMs
should have been notified and thus either the AML table or the OSPMs
shouldn't reference deletion-related namespace nodes during the namespace
deletion. And this change still works with the above restrictions applied.
While making this a-step-forward helps us to correct the wrong grammar to
pull many things back to the correct rail. And pulling things back to the
correct rail in return makes it possible for us to support fully
functioning table unloading after doing many cleanups.

While this patch is generated, all namespace locks are examined to ensure
that they can meet either of the following pattens:
1. L(Namespace)
   U(Namespace)
2. E(Interpreter)
   X(Interpreter)
3. E(Interpreter)
   X(Interpreter)
   L(Namespace)
   U(Namespace)
   E(Interpreter)
   X(Interpreter)
We ensure this by adding X(Interpreter)/E(Interpreter) or removing
U(Namespace)/L(Namespace) for those currently are executed in the following
order:
   E(Interpreter)
   L(Namespace)
   U(Namespace)
   X(Interpreter)
And adding E(Interpreter)/X(Interpreter) for those currently are executed
in the following order:
   X(Interpreter)
   E(Interpreter)

Originally, the interpreter lock is held for the execution AML opcodes, the
namespace lock is held for the named object creation AML opcodes. Since
they are actually same in MS interpreter (can all be executed during the
table loading), we can combine the 2 locks and tune the locking code better
in this way. Lv Zheng.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=153541 # [1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=121701 # [1]
Link: https://bugs.acpica.org/show_bug.cgi?id=1323
Link: https://github.com/acpica/acpica/commit/767ee533
Reported-and-tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reported-and-tested-by: Greg White <gwhite@kupulau.com>
Reported-and-tested-by: Dutch Guy <lucht_piloot@gmx.net>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-09-10 02:43:02 +02:00

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/******************************************************************************
*
* Module Name: nsload - namespace loading/expanding/contracting procedures
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2016, Intel Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#include <acpi/acpi.h>
#include "accommon.h"
#include "acnamesp.h"
#include "acdispat.h"
#include "actables.h"
#include "acinterp.h"
#define _COMPONENT ACPI_NAMESPACE
ACPI_MODULE_NAME("nsload")
/* Local prototypes */
#ifdef ACPI_FUTURE_IMPLEMENTATION
acpi_status acpi_ns_unload_namespace(acpi_handle handle);
static acpi_status acpi_ns_delete_subtree(acpi_handle start_handle);
#endif
#ifndef ACPI_NO_METHOD_EXECUTION
/*******************************************************************************
*
* FUNCTION: acpi_ns_load_table
*
* PARAMETERS: table_index - Index for table to be loaded
* node - Owning NS node
*
* RETURN: Status
*
* DESCRIPTION: Load one ACPI table into the namespace
*
******************************************************************************/
acpi_status
acpi_ns_load_table(u32 table_index, struct acpi_namespace_node *node)
{
acpi_status status;
ACPI_FUNCTION_TRACE(ns_load_table);
/* If table already loaded into namespace, just return */
if (acpi_tb_is_table_loaded(table_index)) {
status = AE_ALREADY_EXISTS;
goto unlock;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"**** Loading table into namespace ****\n"));
status = acpi_tb_allocate_owner_id(table_index);
if (ACPI_FAILURE(status)) {
goto unlock;
}
/*
* Parse the table and load the namespace with all named
* objects found within. Control methods are NOT parsed
* at this time. In fact, the control methods cannot be
* parsed until the entire namespace is loaded, because
* if a control method makes a forward reference (call)
* to another control method, we can't continue parsing
* because we don't know how many arguments to parse next!
*/
status = acpi_ns_parse_table(table_index, node);
if (ACPI_SUCCESS(status)) {
acpi_tb_set_table_loaded_flag(table_index, TRUE);
} else {
/*
* On error, delete any namespace objects created by this table.
* We cannot initialize these objects, so delete them. There are
* a couple of expecially bad cases:
* AE_ALREADY_EXISTS - namespace collision.
* AE_NOT_FOUND - the target of a Scope operator does not
* exist. This target of Scope must already exist in the
* namespace, as per the ACPI specification.
*/
acpi_ns_delete_namespace_by_owner(acpi_gbl_root_table_list.
tables[table_index].owner_id);
acpi_tb_release_owner_id(table_index);
return_ACPI_STATUS(status);
}
unlock:
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
}
/*
* Now we can parse the control methods. We always parse
* them here for a sanity check, and if configured for
* just-in-time parsing, we delete the control method
* parse trees.
*/
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"**** Begin Table Object Initialization\n"));
status = acpi_ds_initialize_objects(table_index, node);
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"**** Completed Table Object Initialization\n"));
/*
* Execute any module-level code that was detected during the table load
* phase. Although illegal since ACPI 2.0, there are many machines that
* contain this type of code. Each block of detected executable AML code
* outside of any control method is wrapped with a temporary control
* method object and placed on a global list. The methods on this list
* are executed below.
*
* This case executes the module-level code for each table immediately
* after the table has been loaded. This provides compatibility with
* other ACPI implementations. Optionally, the execution can be deferred
* until later, see acpi_initialize_objects.
*/
if (!acpi_gbl_parse_table_as_term_list
&& !acpi_gbl_group_module_level_code) {
acpi_ns_exec_module_code_list();
}
return_ACPI_STATUS(status);
}
#ifdef ACPI_OBSOLETE_FUNCTIONS
/*******************************************************************************
*
* FUNCTION: acpi_load_namespace
*
* PARAMETERS: None
*
* RETURN: Status
*
* DESCRIPTION: Load the name space from what ever is pointed to by DSDT.
* (DSDT points to either the BIOS or a buffer.)
*
******************************************************************************/
acpi_status acpi_ns_load_namespace(void)
{
acpi_status status;
ACPI_FUNCTION_TRACE(acpi_load_name_space);
/* There must be at least a DSDT installed */
if (acpi_gbl_DSDT == NULL) {
ACPI_ERROR((AE_INFO, "DSDT is not in memory"));
return_ACPI_STATUS(AE_NO_ACPI_TABLES);
}
/*
* Load the namespace. The DSDT is required,
* but the SSDT and PSDT tables are optional.
*/
status = acpi_ns_load_table_by_type(ACPI_TABLE_ID_DSDT);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
}
/* Ignore exceptions from these */
(void)acpi_ns_load_table_by_type(ACPI_TABLE_ID_SSDT);
(void)acpi_ns_load_table_by_type(ACPI_TABLE_ID_PSDT);
ACPI_DEBUG_PRINT_RAW((ACPI_DB_INIT,
"ACPI Namespace successfully loaded at root %p\n",
acpi_gbl_root_node));
return_ACPI_STATUS(status);
}
#endif
#ifdef ACPI_FUTURE_IMPLEMENTATION
/*******************************************************************************
*
* FUNCTION: acpi_ns_delete_subtree
*
* PARAMETERS: start_handle - Handle in namespace where search begins
*
* RETURNS Status
*
* DESCRIPTION: Walks the namespace starting at the given handle and deletes
* all objects, entries, and scopes in the entire subtree.
*
* Namespace/Interpreter should be locked or the subsystem should
* be in shutdown before this routine is called.
*
******************************************************************************/
static acpi_status acpi_ns_delete_subtree(acpi_handle start_handle)
{
acpi_status status;
acpi_handle child_handle;
acpi_handle parent_handle;
acpi_handle next_child_handle;
acpi_handle dummy;
u32 level;
ACPI_FUNCTION_TRACE(ns_delete_subtree);
parent_handle = start_handle;
child_handle = NULL;
level = 1;
/*
* Traverse the tree of objects until we bubble back up
* to where we started.
*/
while (level > 0) {
/* Attempt to get the next object in this scope */
status = acpi_get_next_object(ACPI_TYPE_ANY, parent_handle,
child_handle, &next_child_handle);
child_handle = next_child_handle;
/* Did we get a new object? */
if (ACPI_SUCCESS(status)) {
/* Check if this object has any children */
if (ACPI_SUCCESS
(acpi_get_next_object
(ACPI_TYPE_ANY, child_handle, NULL, &dummy))) {
/*
* There is at least one child of this object,
* visit the object
*/
level++;
parent_handle = child_handle;
child_handle = NULL;
}
} else {
/*
* No more children in this object, go back up to
* the object's parent
*/
level--;
/* Delete all children now */
acpi_ns_delete_children(child_handle);
child_handle = parent_handle;
status = acpi_get_parent(parent_handle, &parent_handle);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
}
}
}
/* Now delete the starting object, and we are done */
acpi_ns_remove_node(child_handle);
return_ACPI_STATUS(AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_ns_unload_name_space
*
* PARAMETERS: handle - Root of namespace subtree to be deleted
*
* RETURN: Status
*
* DESCRIPTION: Shrinks the namespace, typically in response to an undocking
* event. Deletes an entire subtree starting from (and
* including) the given handle.
*
******************************************************************************/
acpi_status acpi_ns_unload_namespace(acpi_handle handle)
{
acpi_status status;
ACPI_FUNCTION_TRACE(ns_unload_name_space);
/* Parameter validation */
if (!acpi_gbl_root_node) {
return_ACPI_STATUS(AE_NO_NAMESPACE);
}
if (!handle) {
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
/* This function does the real work */
status = acpi_ns_delete_subtree(handle);
return_ACPI_STATUS(status);
}
#endif
#endif
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