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linux/drivers/acpi/acpica/extrace.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: extrace - Support for interpreter execution tracing
*
*****************************************************************************/
/*
* 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 "acinterp.h"
#define _COMPONENT ACPI_EXECUTER
ACPI_MODULE_NAME("extrace")
static union acpi_operand_object *acpi_gbl_trace_method_object = NULL;
/* Local prototypes */
#ifdef ACPI_DEBUG_OUTPUT
static const char *acpi_ex_get_trace_event_name(acpi_trace_event_type type);
#endif
/*******************************************************************************
*
* FUNCTION: acpi_ex_interpreter_trace_enabled
*
* PARAMETERS: name - Whether method name should be matched,
* this should be checked before starting
* the tracer
*
* RETURN: TRUE if interpreter trace is enabled.
*
* DESCRIPTION: Check whether interpreter trace is enabled
*
******************************************************************************/
static u8 acpi_ex_interpreter_trace_enabled(char *name)
{
/* Check if tracing is enabled */
if (!(acpi_gbl_trace_flags & ACPI_TRACE_ENABLED)) {
return (FALSE);
}
/*
* Check if tracing is filtered:
*
* 1. If the tracer is started, acpi_gbl_trace_method_object should have
* been filled by the trace starter
* 2. If the tracer is not started, acpi_gbl_trace_method_name should be
* matched if it is specified
* 3. If the tracer is oneshot style, acpi_gbl_trace_method_name should
* not be cleared by the trace stopper during the first match
*/
if (acpi_gbl_trace_method_object) {
return (TRUE);
}
if (name &&
(acpi_gbl_trace_method_name &&
strcmp(acpi_gbl_trace_method_name, name))) {
return (FALSE);
}
if ((acpi_gbl_trace_flags & ACPI_TRACE_ONESHOT) &&
!acpi_gbl_trace_method_name) {
return (FALSE);
}
return (TRUE);
}
/*******************************************************************************
*
* FUNCTION: acpi_ex_get_trace_event_name
*
* PARAMETERS: type - Trace event type
*
* RETURN: Trace event name.
*
* DESCRIPTION: Used to obtain the full trace event name.
*
******************************************************************************/
#ifdef ACPI_DEBUG_OUTPUT
static const char *acpi_ex_get_trace_event_name(acpi_trace_event_type type)
{
switch (type) {
case ACPI_TRACE_AML_METHOD:
return "Method";
case ACPI_TRACE_AML_OPCODE:
return "Opcode";
case ACPI_TRACE_AML_REGION:
return "Region";
default:
return "";
}
}
#endif
/*******************************************************************************
*
* FUNCTION: acpi_ex_trace_point
*
* PARAMETERS: type - Trace event type
* begin - TRUE if before execution
* aml - Executed AML address
* pathname - Object path
*
* RETURN: None
*
* DESCRIPTION: Internal interpreter execution trace.
*
******************************************************************************/
void
acpi_ex_trace_point(acpi_trace_event_type type,
u8 begin, u8 *aml, char *pathname)
{
ACPI_FUNCTION_NAME(ex_trace_point);
if (pathname) {
ACPI_DEBUG_PRINT((ACPI_DB_TRACE_POINT,
"%s %s [0x%p:%s] execution.\n",
acpi_ex_get_trace_event_name(type),
begin ? "Begin" : "End", aml, pathname));
} else {
ACPI_DEBUG_PRINT((ACPI_DB_TRACE_POINT,
"%s %s [0x%p] execution.\n",
acpi_ex_get_trace_event_name(type),
begin ? "Begin" : "End", aml));
}
}
/*******************************************************************************
*
* FUNCTION: acpi_ex_start_trace_method
*
* PARAMETERS: method_node - Node of the method
* obj_desc - The method object
* walk_state - current state, NULL if not yet executing
* a method.
*
* RETURN: None
*
* DESCRIPTION: Start control method execution trace
*
******************************************************************************/
void
acpi_ex_start_trace_method(struct acpi_namespace_node *method_node,
union acpi_operand_object *obj_desc,
struct acpi_walk_state *walk_state)
{
char *pathname = NULL;
u8 enabled = FALSE;
ACPI_FUNCTION_NAME(ex_start_trace_method);
if (method_node) {
pathname = acpi_ns_get_normalized_pathname(method_node, TRUE);
}
enabled = acpi_ex_interpreter_trace_enabled(pathname);
if (enabled && !acpi_gbl_trace_method_object) {
acpi_gbl_trace_method_object = obj_desc;
acpi_gbl_original_dbg_level = acpi_dbg_level;
acpi_gbl_original_dbg_layer = acpi_dbg_layer;
acpi_dbg_level = ACPI_TRACE_LEVEL_ALL;
acpi_dbg_layer = ACPI_TRACE_LAYER_ALL;
if (acpi_gbl_trace_dbg_level) {
acpi_dbg_level = acpi_gbl_trace_dbg_level;
}
if (acpi_gbl_trace_dbg_layer) {
acpi_dbg_layer = acpi_gbl_trace_dbg_layer;
}
}
if (enabled) {
ACPI_TRACE_POINT(ACPI_TRACE_AML_METHOD, TRUE,
obj_desc ? obj_desc->method.aml_start : NULL,
pathname);
}
if (pathname) {
ACPI_FREE(pathname);
}
}
/*******************************************************************************
*
* FUNCTION: acpi_ex_stop_trace_method
*
* PARAMETERS: method_node - Node of the method
* obj_desc - The method object
* walk_state - current state, NULL if not yet executing
* a method.
*
* RETURN: None
*
* DESCRIPTION: Stop control method execution trace
*
******************************************************************************/
void
acpi_ex_stop_trace_method(struct acpi_namespace_node *method_node,
union acpi_operand_object *obj_desc,
struct acpi_walk_state *walk_state)
{
char *pathname = NULL;
u8 enabled;
ACPI_FUNCTION_NAME(ex_stop_trace_method);
if (method_node) {
pathname = acpi_ns_get_normalized_pathname(method_node, TRUE);
}
enabled = acpi_ex_interpreter_trace_enabled(NULL);
if (enabled) {
ACPI_TRACE_POINT(ACPI_TRACE_AML_METHOD, FALSE,
obj_desc ? obj_desc->method.aml_start : NULL,
pathname);
}
/* Check whether the tracer should be stopped */
if (acpi_gbl_trace_method_object == obj_desc) {
/* Disable further tracing if type is one-shot */
if (acpi_gbl_trace_flags & ACPI_TRACE_ONESHOT) {
acpi_gbl_trace_method_name = NULL;
}
acpi_dbg_level = acpi_gbl_original_dbg_level;
acpi_dbg_layer = acpi_gbl_original_dbg_layer;
acpi_gbl_trace_method_object = NULL;
}
if (pathname) {
ACPI_FREE(pathname);
}
}
/*******************************************************************************
*
* FUNCTION: acpi_ex_start_trace_opcode
*
* PARAMETERS: op - The parser opcode object
* walk_state - current state, NULL if not yet executing
* a method.
*
* RETURN: None
*
* DESCRIPTION: Start opcode execution trace
*
******************************************************************************/
void
acpi_ex_start_trace_opcode(union acpi_parse_object *op,
struct acpi_walk_state *walk_state)
{
ACPI_FUNCTION_NAME(ex_start_trace_opcode);
if (acpi_ex_interpreter_trace_enabled(NULL) &&
(acpi_gbl_trace_flags & ACPI_TRACE_OPCODE)) {
ACPI_TRACE_POINT(ACPI_TRACE_AML_OPCODE, TRUE,
op->common.aml, op->common.aml_op_name);
}
}
/*******************************************************************************
*
* FUNCTION: acpi_ex_stop_trace_opcode
*
* PARAMETERS: op - The parser opcode object
* walk_state - current state, NULL if not yet executing
* a method.
*
* RETURN: None
*
* DESCRIPTION: Stop opcode execution trace
*
******************************************************************************/
void
acpi_ex_stop_trace_opcode(union acpi_parse_object *op,
struct acpi_walk_state *walk_state)
{
ACPI_FUNCTION_NAME(ex_stop_trace_opcode);
if (acpi_ex_interpreter_trace_enabled(NULL) &&
(acpi_gbl_trace_flags & ACPI_TRACE_OPCODE)) {
ACPI_TRACE_POINT(ACPI_TRACE_AML_OPCODE, FALSE,
op->common.aml, op->common.aml_op_name);
}
}
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