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

From: Lv Zheng
Date: Wed Mar 09 2016 - 21:54:58 EST


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.

Reported-and-tested-by: Chris Bainbridge <chris.bainbridge@xxxxxxxxx>
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
---
drivers/acpi/acpica/nsinit.c | 2 ++
drivers/acpi/acpica/tbxfload.c | 26 +++++++++++++++++-------
drivers/acpi/acpica/utxfinit.c | 43 ++++++++++------------------------------
3 files changed, 32 insertions(+), 39 deletions(-)

diff --git a/drivers/acpi/acpica/nsinit.c b/drivers/acpi/acpica/nsinit.c
index f029a3d..d4aa8b6 100644
--- a/drivers/acpi/acpica/nsinit.c
+++ b/drivers/acpi/acpica/nsinit.c
@@ -84,6 +84,8 @@ acpi_status acpi_ns_initialize_objects(void)

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,
diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
index 9496b84..3151968 100644
--- a/drivers/acpi/acpica/tbxfload.c
+++ b/drivers/acpi/acpica/tbxfload.c
@@ -81,13 +81,11 @@ acpi_status __init acpi_load_tables(void)
* between acpi_initialize_subsystem() and acpi_load_tables() to use
* their customized default region handlers.
*/
- if (acpi_gbl_group_module_level_code) {
- status = acpi_ev_install_region_handlers();
- if (ACPI_FAILURE(status) && status != AE_ALREADY_EXISTS) {
- ACPI_EXCEPTION((AE_INFO, status,
- "During Region initialization"));
- return_ACPI_STATUS(status);
- }
+ status = acpi_ev_install_region_handlers();
+ if (ACPI_FAILURE(status) && status != AE_ALREADY_EXISTS) {
+ ACPI_EXCEPTION((AE_INFO, status,
+ "During Region initialization"));
+ return_ACPI_STATUS(status);
}

/* Load the namespace from the tables */
@@ -105,6 +103,20 @@ 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_namespace_initialized = TRUE;
return_ACPI_STATUS(status);
}

diff --git a/drivers/acpi/acpica/utxfinit.c b/drivers/acpi/acpica/utxfinit.c
index d70649d..75b5f27 100644
--- a/drivers/acpi/acpica/utxfinit.c
+++ b/drivers/acpi/acpica/utxfinit.c
@@ -154,23 +154,6 @@ acpi_status __init acpi_enable_subsystem(u32 flags)
*/
acpi_gbl_early_initialization = FALSE;

- /*
- * Install the default operation region handlers. These are the
- * handlers that are defined by the ACPI specification to be
- * "always accessible" -- namely, system_memory, system_IO, and
- * PCI_Config. This also means that no _REG methods need to be
- * run for these address spaces. We need to have these handlers
- * installed before any AML code can be executed, especially any
- * module-level code (11/2015).
- */
- if (!acpi_gbl_group_module_level_code) {
- status = acpi_ev_install_region_handlers();
- if (ACPI_FAILURE(status)) {
- ACPI_EXCEPTION((AE_INFO, status,
- "During Region initialization"));
- return_ACPI_STATUS(status);
- }
- }
#if (!ACPI_REDUCED_HARDWARE)

/* Enable ACPI mode */
@@ -284,25 +267,21 @@ acpi_status __init acpi_initialize_objects(u32 flags)
*/
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);
+ }
}
}

- acpi_gbl_namespace_initialized = TRUE;
-
/*
* Initialize all device/region objects in the namespace. This runs
* the device _STA and _INI methods and region _REG methods.
--
1.7.10