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ACPICA: Add a lock to the internal object reference count mechanism

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Certain external interfaces need to update object references
without holding the interpreter or namespace mutex objects. To
prevent race conditions, add a spinlock around the increment
and decrement of the reference counts for internal ACPI
objects. Reported by Andriy Gapon (avg@FreeBSD.org).

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Andriy Gapon <avg@FreeBSD.org>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Bob Moore 2013-04-12 00:25:41 +00:00 committed by Rafael J. Wysocki
parent 475df486f5
commit 58892c962a
3 changed files with 57 additions and 35 deletions
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1
drivers/acpi/acpica/acglobal.h
View file

@ -224,6 +224,7 @@ ACPI_EXTERN u8 acpi_gbl_global_lock_pending;
*/
ACPI_EXTERN acpi_spinlock acpi_gbl_gpe_lock; /* For GPE data structs and registers */
ACPI_EXTERN acpi_spinlock acpi_gbl_hardware_lock; /* For ACPI H/W except GPE registers */
ACPI_EXTERN acpi_spinlock acpi_gbl_reference_count_lock;
/* Mutex for _OSI support */

82
drivers/acpi/acpica/utdelete.c
View file

@ -359,19 +359,20 @@ void acpi_ut_delete_internal_object_list(union acpi_operand_object **obj_list)
* FUNCTION: acpi_ut_update_ref_count
*
* PARAMETERS: object - Object whose ref count is to be updated
* action - What to do
* action - What to do (REF_INCREMENT or REF_DECREMENT)
*
* RETURN: New ref count
* RETURN: None. Sets new reference count within the object
*
* DESCRIPTION: Modify the ref count and return it.
* DESCRIPTION: Modify the reference count for an internal acpi object
*
******************************************************************************/
static void
acpi_ut_update_ref_count(union acpi_operand_object *object, u32 action)
{
u16 count;
u16 new_count;
u16 original_count;
u16 new_count = 0;
acpi_cpu_flags lock_flags;
ACPI_FUNCTION_NAME(ut_update_ref_count);
@ -379,46 +380,58 @@ acpi_ut_update_ref_count(union acpi_operand_object *object, u32 action)
return;
}
count = object->common.reference_count;
new_count = count;
/*
* Perform the reference count action (increment, decrement, force delete)
* Always get the reference count lock. Note: Interpreter and/or
* Namespace is not always locked when this function is called.
*/
lock_flags = acpi_os_acquire_lock(acpi_gbl_reference_count_lock);
original_count = object->common.reference_count;
/* Perform the reference count action (increment, decrement) */
switch (action) {
case REF_INCREMENT:
new_count++;
new_count = original_count + 1;
object->common.reference_count = new_count;
acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
/* The current reference count should never be zero here */
if (!original_count) {
ACPI_WARNING((AE_INFO,
"Obj %p, Reference Count was zero before increment\n",
object));
}
ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
"Obj %p Refs=%X, [Incremented]\n",
object, new_count));
"Obj %p Type %.2X Refs %.2X [Incremented]\n",
object, object->common.type, new_count));
break;
case REF_DECREMENT:
if (count < 1) {
ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
"Obj %p Refs=%X, can't decrement! (Set to 0)\n",
object, new_count));
/* The current reference count must be non-zero */
new_count = 0;
} else {
new_count--;
ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
"Obj %p Refs=%X, [Decremented]\n",
object, new_count));
if (original_count) {
new_count = original_count - 1;
object->common.reference_count = new_count;
}
if (object->common.type == ACPI_TYPE_METHOD) {
ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
"Method Obj %p Refs=%X, [Decremented]\n",
object, new_count));
acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
if (!original_count) {
ACPI_WARNING((AE_INFO,
"Obj %p, Reference Count is already zero, cannot decrement\n",
object));
}
object->common.reference_count = new_count;
ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
"Obj %p Type %.2X Refs %.2X [Decremented]\n",
object, object->common.type, new_count));
/* Actually delete the object on a reference count of zero */
if (new_count == 0) {
acpi_ut_delete_internal_obj(object);
}
@ -426,18 +439,20 @@ acpi_ut_update_ref_count(union acpi_operand_object *object, u32 action)
default:
ACPI_ERROR((AE_INFO, "Unknown action (0x%X)", action));
break;
acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
ACPI_ERROR((AE_INFO, "Unknown Reference Count action (0x%X)",
action));
return;
}
/*
* Sanity check the reference count, for debug purposes only.
* (A deleted object will have a huge reference count)
*/
if (count > ACPI_MAX_REFERENCE_COUNT) {
if (new_count > ACPI_MAX_REFERENCE_COUNT) {
ACPI_WARNING((AE_INFO,
"Large Reference Count (0x%X) in object %p",
count, object));
"Large Reference Count (0x%X) in object %p, Type=0x%.2X",
new_count, object, object->common.type));
}
}
@ -702,7 +717,6 @@ void acpi_ut_remove_reference(union acpi_operand_object *object)
/*
* Allow a NULL pointer to be passed in, just ignore it. This saves
* each caller from having to check. Also, ignore NS nodes.
*
*/
if (!object ||
(ACPI_GET_DESCRIPTOR_TYPE(object) == ACPI_DESC_TYPE_NAMED)) {

9
drivers/acpi/acpica/utmutex.c
View file

@ -81,7 +81,7 @@ acpi_status acpi_ut_mutex_initialize(void)
}
}
/* Create the spinlocks for use at interrupt level */
/* Create the spinlocks for use at interrupt level or for speed */
status = acpi_os_create_lock (&acpi_gbl_gpe_lock);
if (ACPI_FAILURE (status)) {
@ -93,7 +93,13 @@ acpi_status acpi_ut_mutex_initialize(void)
return_ACPI_STATUS (status);
}
status = acpi_os_create_lock(&acpi_gbl_reference_count_lock);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
}
/* Mutex for _OSI support */
status = acpi_os_create_mutex(&acpi_gbl_osi_mutex);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
@ -136,6 +142,7 @@ void acpi_ut_mutex_terminate(void)
acpi_os_delete_lock(acpi_gbl_gpe_lock);
acpi_os_delete_lock(acpi_gbl_hardware_lock);
acpi_os_delete_lock(acpi_gbl_reference_count_lock);
/* Delete the reader/writer lock */