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SubjectRE: [PATCH v4 3/5] ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by switching to new TermList grammar for table loading
Date
Hi, Rafael

> From: Zheng, Lv
> Subject: [PATCH v4 3/5] ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by
> switching to new TermList grammar for table loading
>
> The MLC (Module Level Code) is an ACPICA terminology describing the
> AML
> code out of any control method, its support is the main contention of the
> interpreter behavior during the table loading.
>
> The original implementation of MLC in ACPICA had several issues:
> 1. Out of any control method, besides of the object creating opcodes, only
> the code blocks wrapped by "If/Else/While" opcodes were supported.
> 2. The supported MLC code blocks were executed after loading the table
> rather than being executed right in place.
>
> ==========================================================
> ==
> The demo of this order issue is as follows:
> Name (OBJ1, 1)
> If (CND1 == 1)
> {
> Name (OBJ2, 2)
> }
> Name (OBJ3, 3)
> The original MLC support created OBJ2 after OBJ3's creation.
>
> ==========================================================
> ==
> Other than these limitations, MLC support in ACPICA looks correct. And
> supporting this should be easy/natural for ACPICA, but enabling of this
> was
> blocked by some ACPICA internal and OSPM specific initialization order
> issues we've fixed recently. The wrong support started from the following
> false bug fixing commit:
> Commit: 80d7951177315f70b5ffd8663985fbf725d07799
> Subject: Add support for module-level executable AML code.
>
> We can confirm Windows interpreter behavior via reverse engineering
> means.
> It can be proven that not only If/Else/While wrapped code blocks, all
> opcodes can be executed at the module level, including operation region
> accesses. And it can be proven that the MLC should be executed right in
> place, not in such a deferred way executed after loading the table.
>
> And the above facts indeed reflect the spec words around ACPI definition
> block tables (DSDT/SSDT/...), the entire table and the Scope object is
> defined by the AML specification in BNF style as:
> AMLCode := DefBlockHeader TermList
> DefScope := ScopeOp PkgLength NameString TermList
> The bodies of the scope opening terms (AMLCode/Scope) are all TermList,
> thus the table loading should be no difference than the control method
> evaluations as the body of the Method is also defined by the AML
> specification as TermList:
> DefMethod := MethodOp PkgLength NameString MethodFlags TermList
> The only difference is: after evaluating control method, created named
> objects may be freed due to no reference, while named objects created by
> the table loading should only be freed after unloading the table.
>
> So this patch follows the spec and the de-facto standard behavior, enables
> the new grammar (TermList) for the table loading.
>
> By doing so, beyond the fixes to the above issues, we can see additional
> differences comparing to the old grammar based table loading:
> 1. Originally, beyond the scope opening terms (AMLCode/Scope),
> If/Else/While wrapped code blocks under the scope creating terms
> (Device/PowerResource/Processor/ThermalZone) are also supported as
> deferred MLC, which violates the spec defined grammar where ObjectList
> is enforced. With MLC support improved as non-deferred, the interpreter
> parses such scope creating terms as TermList rather ObjectList like the
> scope opening terms.
> After probing the Windows behavior and proving that it also parses
> these
> terms as TermList, we submitted an ECR (Engineering Change Request) to
> the ASWG (ACPI Specification Working Group) to clarify this. The ECR is
> titled as "ASL Grammar Clarification for Executable AML Opcodes" and
> has
> been accepted by the ASWG. The new grammar will appear in ACPI
> specification 6.2.
> 2. Originally, Buffer/Package/OperationRegion/CreateXXXField/BankField
> arguments are evaluated in a deferred way after loading the table. With
> MLC support improved, they are also parsed right in place during the
> table loading.
> This is also Windows compliant and the only difference is the removal
> of the debugging messages implemented before
> acpi_ds_execute_arguments(),
> see Link 1 for the details. A previous commit should have ensured that
> acpi_check_address_range() won't regress.
>
> Note that enabling this feature may cause regressions due to long term
> Linux ACPI support on top of the wrong grammar. So this patch also
> prepares
> a global option to be used to roll back to the old grammar during the
> period between a regression is reported and the regression is
> root-cause-fixed. ACPICA BZ 963, fixed by Lv Zheng.
>
> Link 1: https://bugzilla.kernel.org/show_bug.cgi?id=112911
> Link 2: https://bugs.acpica.org/show_bug.cgi?id=963
> Tested-by: Chris Bainbridge <chris.bainbridge@gmail.com>
> Signed-off-by: Lv Zheng <lv.zheng@intel.com>
> ---
> drivers/acpi/acpica/acnamesp.h | 3 +
> drivers/acpi/acpica/acparser.h | 2 +
> drivers/acpi/acpica/evrgnini.c | 3 +-
> drivers/acpi/acpica/exconfig.c | 3 +-
> drivers/acpi/acpica/nsload.c | 3 +-
> drivers/acpi/acpica/nsparse.c | 166
> ++++++++++++++++++++++++++++++++--------
> drivers/acpi/acpica/psparse.c | 4 +-
> drivers/acpi/acpica/psxface.c | 71 +++++++++++++++++
> drivers/acpi/acpica/tbxfload.c | 3 +-
> drivers/acpi/acpica/utxfinit.c | 3 +-
> include/acpi/acpixf.h | 6 ++
> 11 files changed, 229 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/acpi/acpica/acnamesp.h
> b/drivers/acpi/acpica/acnamesp.h
> index f33a4ba..829672a 100644
> --- a/drivers/acpi/acpica/acnamesp.h
> +++ b/drivers/acpi/acpica/acnamesp.h
> @@ -130,6 +130,9 @@ acpi_status
> acpi_ns_parse_table(u32 table_index, struct acpi_namespace_node
> *start_node);
>
> acpi_status
> +acpi_ns_execute_table(u32 table_index, struct acpi_namespace_node
> *start_node);
> +
> +acpi_status
> acpi_ns_one_complete_parse(u32 pass_number,
> u32 table_index,
> struct acpi_namespace_node *start_node);
> diff --git a/drivers/acpi/acpica/acparser.h b/drivers/acpi/acpica/acparser.h
> index fc30577..939d411 100644
> --- a/drivers/acpi/acpica/acparser.h
> +++ b/drivers/acpi/acpica/acparser.h
> @@ -78,6 +78,8 @@ extern const u8 acpi_gbl_long_op_index[];
> */
> acpi_status acpi_ps_execute_method(struct acpi_evaluate_info *info);
>
> +acpi_status acpi_ps_execute_table(struct acpi_evaluate_info *info);
> +
> /*
> * psargs - Parse AML opcode arguments
> */
> diff --git a/drivers/acpi/acpica/evrgnini.c b/drivers/acpi/acpica/evrgnini.c
> index b6ea9c0..3843f1f 100644
> --- a/drivers/acpi/acpica/evrgnini.c
> +++ b/drivers/acpi/acpica/evrgnini.c
> @@ -553,7 +553,8 @@ acpi_ev_initialize_region(union
> acpi_operand_object *region_obj,
> *
> * See acpi_ns_exec_module_code
> */
> - if (obj_desc->method.
> + if (!acpi_gbl_parse_table_as_term_list &&
> + obj_desc->method.
> info_flags &
> ACPI_METHOD_MODULE_LEVEL) {
> handler_obj =
> obj_desc-
> >method.dispatch.handler;
> diff --git a/drivers/acpi/acpica/exconfig.c b/drivers/acpi/acpica/exconfig.c
> index 21932d6..75679bc 100644
> --- a/drivers/acpi/acpica/exconfig.c
> +++ b/drivers/acpi/acpica/exconfig.c
> @@ -120,7 +120,8 @@ acpi_ex_add_table(u32 table_index,
> /* Execute any module-level code that was found in the table */
>
> acpi_ex_exit_interpreter();
> - if (acpi_gbl_group_module_level_code) {
> + if (!acpi_gbl_parse_table_as_term_list
> + && acpi_gbl_group_module_level_code) {
> acpi_ns_exec_module_code_list();
> }
> acpi_ex_enter_interpreter();
> diff --git a/drivers/acpi/acpica/nsload.c b/drivers/acpi/acpica/nsload.c
> index b5e2b0a..2daa9a09 100644
> --- a/drivers/acpi/acpica/nsload.c
> +++ b/drivers/acpi/acpica/nsload.c
> @@ -162,7 +162,8 @@ unlock:
> * other ACPI implementations. Optionally, the execution can be
> deferred
> * until later, see acpi_initialize_objects.
> */
> - if (!acpi_gbl_group_module_level_code) {
> + if (!acpi_gbl_parse_table_as_term_list
> + && !acpi_gbl_group_module_level_code) {
> acpi_ns_exec_module_code_list();
> }
>
> diff --git a/drivers/acpi/acpica/nsparse.c b/drivers/acpi/acpica/nsparse.c
> index 1783cd7..f475889 100644
> --- a/drivers/acpi/acpica/nsparse.c
> +++ b/drivers/acpi/acpica/nsparse.c
> @@ -54,6 +54,98 @@ ACPI_MODULE_NAME("nsparse")
>
>
> /*********************************************************
> **********************
> *
> + * FUNCTION: ns_execute_table
> + *
> + * PARAMETERS: table_desc - An ACPI table descriptor for table to
> parse
> + * start_node - Where to enter the table into the namespace
> + *
> + * RETURN: Status
> + *
> + * DESCRIPTION: Load ACPI/AML table by executing the entire table as a
> + * term_list.
> + *
> +
> **********************************************************
> ********************/
> +acpi_status
> +acpi_ns_execute_table(u32 table_index, struct acpi_namespace_node
> *start_node)
> +{
> + acpi_status status;
> + struct acpi_table_header *table;
> + acpi_owner_id owner_id;
> + struct acpi_evaluate_info *info = NULL;
> + u32 aml_length;
> + u8 *aml_start;
> + union acpi_operand_object *method_obj = NULL;
> +
> + ACPI_FUNCTION_TRACE(ns_execute_table);
> +
> + status = acpi_get_table_by_index(table_index, &table);
> + if (ACPI_FAILURE(status)) {
> + return_ACPI_STATUS(status);
> + }
> +
> + /* Table must consist of at least a complete header */
> +
> + if (table->length < sizeof(struct acpi_table_header)) {
> + return_ACPI_STATUS(AE_BAD_HEADER);
> + }
> +
> + aml_start = (u8 *)table + sizeof(struct acpi_table_header);
> + aml_length = table->length - sizeof(struct acpi_table_header);
> +
> + status = acpi_tb_get_owner_id(table_index, &owner_id);
> + if (ACPI_FAILURE(status)) {
> + return_ACPI_STATUS(status);
> + }
> +
> + /* Create, initialize, and link a new temporary method object */
> +
> + method_obj =
> acpi_ut_create_internal_object(ACPI_TYPE_METHOD);
> + if (!method_obj) {
> + return_ACPI_STATUS(AE_NO_MEMORY);
> + }
> +
> + /* Allocate the evaluation information block */
> +
> + info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
> + if (!info) {
> + status = AE_NO_MEMORY;
> + goto cleanup;
> + }
> +
> + ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
> + "Create table code block: %p\n", method_obj));
> +
> + method_obj->method.aml_start = aml_start;
> + method_obj->method.aml_length = aml_length;
> + method_obj->method.owner_id = owner_id;
> + method_obj->method.info_flags |=
> ACPI_METHOD_MODULE_LEVEL;
> +
> + info->pass_number = ACPI_IMODE_EXECUTE;
> + info->node = start_node;
> + info->obj_desc = method_obj;
> + info->node_flags = info->node->flags;
> + info->full_pathname = acpi_ns_get_normalized_pathname(info-
> >node, TRUE);
> + if (!info->full_pathname) {
> + status = AE_NO_MEMORY;
> + goto cleanup;
> + }
> +
> + (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
> + status = acpi_ps_execute_table(info);
> + (void)acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
[Lv Zheng]
I got a report that we have lock order issue in the previous bug fix:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2f38b1b1
And I'll send a quick fix for that later today.

After investigation, we found that ACPICA namespace lock design actually requires a big change in order to support this grammar change.
This means that this patch still need to be improved.
And the above 3 lines are currently known to be not compliant to the current ACPICA namespace lock design.

So please drop this series, and I'll re-send this series after improving the ACPICA namespace lock design.

Sorry for the issues.

Thanks and best regards
-Lv


> +
> +cleanup:
> + if (info) {
> + ACPI_FREE(info->full_pathname);
> + info->full_pathname = NULL;
> + }
> + ACPI_FREE(info);
> + acpi_ut_remove_reference(method_obj);
> + return_ACPI_STATUS(status);
> +}
> +
> +/********************************************************
> ***********************
> + *
> * FUNCTION: ns_one_complete_parse
> *
> * PARAMETERS: pass_number - 1 or 2
> @@ -64,6 +156,7 @@ ACPI_MODULE_NAME("nsparse")
> * DESCRIPTION: Perform one complete parse of an ACPI/AML table.
> *
>
> **********************************************************
> ********************/
> +
> acpi_status
> acpi_ns_one_complete_parse(u32 pass_number,
> u32 table_index,
> @@ -173,38 +266,47 @@ acpi_ns_parse_table(u32 table_index, struct
> acpi_namespace_node *start_node)
>
> acpi_ex_enter_interpreter();
>
> - /*
> - * AML Parse, pass 1
> - *
> - * In this pass, we load most of the namespace. Control methods
> - * are not parsed until later. A parse tree is not created. Instead,
> - * each Parser Op subtree is deleted when it is finished. This saves
> - * a great deal of memory, and allows a small cache of parse
> objects
> - * to service the entire parse. The second pass of the parse then
> - * performs another complete parse of the AML.
> - */
> - ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "**** Start pass 1\n"));
> -
> - status = acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS1,
> - table_index, start_node);
> - if (ACPI_FAILURE(status)) {
> - goto error_exit;
> - }
> -
> - /*
> - * AML Parse, pass 2
> - *
> - * In this pass, we resolve forward references and other things
> - * that could not be completed during the first pass.
> - * Another complete parse of the AML is performed, but the
> - * overhead of this is compensated for by the fact that the
> - * parse objects are all cached.
> - */
> - ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "**** Start pass 2\n"));
> - status = acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS2,
> - table_index, start_node);
> - if (ACPI_FAILURE(status)) {
> - goto error_exit;
> + if (acpi_gbl_parse_table_as_term_list) {
> + ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "**** Start load
> pass\n"));
> +
> + status = acpi_ns_execute_table(table_index, start_node);
> + if (ACPI_FAILURE(status)) {
> + goto error_exit;
> + }
> + } else {
> + /*
> + * AML Parse, pass 1
> + *
> + * In this pass, we load most of the namespace. Control
> methods
> + * are not parsed until later. A parse tree is not created.
> + * Instead, each Parser Op subtree is deleted when it is
> finished.
> + * This saves a great deal of memory, and allows a small
> cache of
> + * parse objects to service the entire parse. The second
> pass of
> + * the parse then performs another complete parse of the
> AML.
> + */
> + ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "**** Start pass
> 1\n"));
> +
> + status =
> acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS1,
> + table_index, start_node);
> + if (ACPI_FAILURE(status)) {
> + goto error_exit;
> + }
> +
> + /*
> + * AML Parse, pass 2
> + *
> + * In this pass, we resolve forward references and other
> things
> + * that could not be completed during the first pass.
> + * Another complete parse of the AML is performed, but
> the
> + * overhead of this is compensated for by the fact that the
> + * parse objects are all cached.
> + */
> + ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "**** Start pass
> 2\n"));
> + status =
> acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS2,
> + table_index, start_node);
> + if (ACPI_FAILURE(status)) {
> + goto error_exit;
> + }
> }
>
> error_exit:
> diff --git a/drivers/acpi/acpica/psparse.c b/drivers/acpi/acpica/psparse.c
> index 0a23897..3aa9162 100644
> --- a/drivers/acpi/acpica/psparse.c
> +++ b/drivers/acpi/acpica/psparse.c
> @@ -571,7 +571,9 @@ acpi_status acpi_ps_parse_aml(struct
> acpi_walk_state *walk_state)
> * cleanup to do
> */
> if (((walk_state->parse_flags & ACPI_PARSE_MODE_MASK)
> ==
> - ACPI_PARSE_EXECUTE) || (ACPI_FAILURE(status))) {
> + ACPI_PARSE_EXECUTE &&
> + !(walk_state->parse_flags &
> ACPI_PARSE_MODULE_LEVEL)) ||
> + (ACPI_FAILURE(status))) {
> acpi_ds_terminate_control_method(walk_state->
> method_desc,
> walk_state);
> diff --git a/drivers/acpi/acpica/psxface.c b/drivers/acpi/acpica/psxface.c
> index cf30cd82..fccc0e5 100644
> --- a/drivers/acpi/acpica/psxface.c
> +++ b/drivers/acpi/acpica/psxface.c
> @@ -252,6 +252,77 @@ cleanup:
>
>
> /*********************************************************
> **********************
> *
> + * FUNCTION: acpi_ps_execute_table
> + *
> + * PARAMETERS: info - Method info block, contains:
> + * node - Node to where the is entered into the
> + * namespace
> + * obj_desc - Pseudo method object describing the AML
> + * code of the entire table
> + * pass_number - Parse or execute pass
> + *
> + * RETURN: Status
> + *
> + * DESCRIPTION: Execute a table
> + *
> +
> **********************************************************
> ********************/
> +
> +acpi_status acpi_ps_execute_table(struct acpi_evaluate_info *info)
> +{
> + acpi_status status;
> + union acpi_parse_object *op = NULL;
> + struct acpi_walk_state *walk_state = NULL;
> +
> + ACPI_FUNCTION_TRACE(ps_execute_table);
> +
> + /* Create and init a Root Node */
> +
> + op = acpi_ps_create_scope_op(info->obj_desc-
> >method.aml_start);
> + if (!op) {
> + status = AE_NO_MEMORY;
> + goto cleanup;
> + }
> +
> + /* Create and initialize a new walk state */
> +
> + walk_state =
> + acpi_ds_create_walk_state(info->obj_desc->method.owner_id,
> NULL,
> + NULL, NULL);
> + if (!walk_state) {
> + status = AE_NO_MEMORY;
> + goto cleanup;
> + }
> +
> + status = acpi_ds_init_aml_walk(walk_state, op, info->node,
> + info->obj_desc->method.aml_start,
> + info->obj_desc->method.aml_length,
> info,
> + info->pass_number);
> + if (ACPI_FAILURE(status)) {
> + goto cleanup;
> + }
> +
> + if (info->obj_desc->method.info_flags &
> ACPI_METHOD_MODULE_LEVEL) {
> + walk_state->parse_flags |= ACPI_PARSE_MODULE_LEVEL;
> + }
> +
> + /*
> + * Parse the AML, walk_state will be deleted by parse_aml
> + */
> + status = acpi_ps_parse_aml(walk_state);
> + walk_state = NULL;
> +
> +cleanup:
> + if (op) {
> + acpi_ps_delete_parse_tree(op);
> + }
> + if (walk_state) {
> + acpi_ds_delete_walk_state(walk_state);
> + }
> + return_ACPI_STATUS(status);
> +}
> +
> +/********************************************************
> ***********************
> + *
> * FUNCTION: acpi_ps_update_parameter_list
> *
> * PARAMETERS: info - See struct acpi_evaluate_info
> diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
> index ac71abc..2b9e87f 100644
> --- a/drivers/acpi/acpica/tbxfload.c
> +++ b/drivers/acpi/acpica/tbxfload.c
> @@ -103,7 +103,8 @@ acpi_status __init acpi_load_tables(void)
> "While loading namespace from ACPI
> tables"));
> }
>
> - if (!acpi_gbl_group_module_level_code) {
> + if (acpi_gbl_parse_table_as_term_list
> + || !acpi_gbl_group_module_level_code) {
> /*
> * Initialize the objects that remain uninitialized. This
> * runs the executable AML that may be part of the
> diff --git a/drivers/acpi/acpica/utxfinit.c b/drivers/acpi/acpica/utxfinit.c
> index 75b5f27..e41424a 100644
> --- a/drivers/acpi/acpica/utxfinit.c
> +++ b/drivers/acpi/acpica/utxfinit.c
> @@ -265,7 +265,8 @@ acpi_status __init acpi_initialize_objects(u32 flags)
> * all of the tables have been loaded. It is a legacy option and is
> * not compatible with other ACPI implementations. See
> acpi_ns_load_table.
> */
> - if (acpi_gbl_group_module_level_code) {
> + if (!acpi_gbl_parse_table_as_term_list
> + && acpi_gbl_group_module_level_code) {
> acpi_ns_exec_module_code_list();
>
> /*
> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
> index 4e4c214..22b0397 100644
> --- a/include/acpi/acpixf.h
> +++ b/include/acpi/acpixf.h
> @@ -195,6 +195,12 @@ ACPI_INIT_GLOBAL(u8,
> acpi_gbl_do_not_use_xsdt, FALSE);
> ACPI_INIT_GLOBAL(u8, acpi_gbl_group_module_level_code, FALSE);
>
> /*
> + * Optionally support module level code by parsing the entire table as
> + * a term_list. Default is FALSE, do not execute entire table.
> + */
> +ACPI_INIT_GLOBAL(u8, acpi_gbl_parse_table_as_term_list, FALSE);
> +
> +/*
> * Optionally use 32-bit FADT addresses if and when there is a conflict
> * (address mismatch) between the 32-bit and 64-bit versions of the
> * address. Although ACPICA adheres to the ACPI specification which
> --
> 1.7.10

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