[PATCH 4.5 107/200] ACPICA / Interpreter: Fix a regression triggered because of wrong Linux ECDT support

Greg Kroah-Hartman
2016-05-03T01:14:08Z

From: Lv Zheng <lv.zheng@intel.com>

commit 5508df89756f8378024828e185724a9bd2348985 upstream.

It is reported that the following commit triggers regressions:
Linux commit: efaed9be998b5ae0afb7458e057e5f4402b43fa0
ACPICA commit: 31178590dde82368fdb0f6b0e466b6c0add96c57
Subject: ACPICA: Events: Enhance acpi_ev_execute_reg_method() to
ensure no _REG evaluations can happen during OS early boot
stages

This is because that the ECDT support is not corrected in Linux, and Linux
requires to execute _REG for ECDT (though this sounds so wrong), we need to
ensure acpi_gbl_namespace_initialized is set before ECDT probing in order
for _REG to be executed. Since we have to move
"acpi_gbl_namespace_initialized = TRUE" to the initialization step
happening before ECDT probing, acpi_load_tables() is the best candidate for
now. Thus this patch fixes the regression by doing so.

But if the ECDT support is fixed, Linux will not execute _REG for ECDT, and
ECDT probing will happen before acpi_load_tables(). At that time, we still
want to ensure acpi_gbl_namespace_initialized is set after executing
acpi_ns_initialize_objects() (under the condition of
acpi_gbl_group_module_level_code = FALSE), this patch also moves
acpi_ns_initialize_objects() to acpi_load_tables() accordingly.

Since acpi_ns_initialize_objects() doesn't seem to be skippable, this
patch also removes ACPI_NO_OBJECT_INIT for the one invoked in
acpi_load_tables(). And since the default region handlers should always be
installed before loading the tables, this patch also removes useless
acpi_gbl_group_module_level_code check accordingly. Reported by Chris
Bainbridge, Fixed by Lv Zheng.

Fixes: efaed9be998b (ACPICA: Events: Enhance acpi_ev_execute_reg_method() to ensure no _REG evaluations can happen during OS early boot stages)
Reported-and-tested-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/acpi/acpica/nsinit.c | 2 ++
drivers/acpi/acpica/tbxfload.c | 14 ++++++++++++++
drivers/acpi/acpica/utxfinit.c | 25 +++++++++++--------------
3 files changed, 27 insertions(+), 14 deletions(-)

--- a/drivers/acpi/acpica/nsinit.c
+++ b/drivers/acpi/acpica/nsinit.c
@@ -83,6 +83,8 @@ acpi_status acpi_ns_initialize_objects(v

ACPI_FUNCTION_TRACE(ns_initialize_objects);

+ ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
+ "[Init] Completing Initialization of ACPI Objects\n"));
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
"**** Starting initialization of namespace objects ****\n"));
ACPI_DEBUG_PRINT_RAW((ACPI_DB_INIT,
--- a/drivers/acpi/acpica/tbxfload.c
+++ b/drivers/acpi/acpica/tbxfload.c
@@ -83,6 +83,20 @@ acpi_status __init acpi_load_tables(void
"While loading namespace from ACPI tables"));
}

+ if (!acpi_gbl_group_module_level_code) {
+ /*
+ * Initialize the objects that remain uninitialized. This
+ * runs the executable AML that may be part of the
+ * declaration of these objects:
+ * operation_regions, buffer_fields, Buffers, and Packages.
+ */
+ status = acpi_ns_initialize_objects();
+ if (ACPI_FAILURE(status)) {
+ return_ACPI_STATUS(status);
+ }
+ }
+
+ acpi_gbl_reg_methods_enabled = TRUE;
return_ACPI_STATUS(status);
}

--- a/drivers/acpi/acpica/utxfinit.c
+++ b/drivers/acpi/acpica/utxfinit.c
@@ -267,7 +267,6 @@ acpi_status __init acpi_initialize_objec
* initialized, even if they contain executable AML (see the call to
* acpi_ns_initialize_objects below).
*/
- acpi_gbl_reg_methods_enabled = TRUE;
if (!(flags & ACPI_NO_ADDRESS_SPACE_INIT)) {
ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
"[Init] Executing _REG OpRegion methods\n"));
@@ -299,20 +298,18 @@ acpi_status __init acpi_initialize_objec
*/
if (acpi_gbl_group_module_level_code) {
acpi_ns_exec_module_code_list();
- }

- /*
- * Initialize the objects that remain uninitialized. This runs the
- * executable AML that may be part of the declaration of these objects:
- * operation_regions, buffer_fields, Buffers, and Packages.
- */
- if (!(flags & ACPI_NO_OBJECT_INIT)) {
- ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
- "[Init] Completing Initialization of ACPI Objects\n"));
-
- status = acpi_ns_initialize_objects();
- if (ACPI_FAILURE(status)) {
- return_ACPI_STATUS(status);
+ /*
+ * Initialize the objects that remain uninitialized. This
+ * runs the executable AML that may be part of the
+ * declaration of these objects:
+ * operation_regions, buffer_fields, Buffers, and Packages.
+ */
+ if (!(flags & ACPI_NO_OBJECT_INIT)) {
+ status = acpi_ns_initialize_objects();
+ if (ACPI_FAILURE(status)) {
+ return_ACPI_STATUS(status);
+ }
}
}