ACPICA 20050617-0624 from Bob Moore <robert.moore@intel.com>

ACPICA 20050617:

Moved the object cache operations into the OS interface
layer (OSL) to allow the host OS to handle these operations
if desired (for example, the Linux OSL will invoke the
slab allocator).  This support is optional; the compile
time define ACPI_USE_LOCAL_CACHE may be used to utilize
the original cache code in the ACPI CA core.  The new OSL
interfaces are shown below.  See utalloc.c for an example
implementation, and acpiosxf.h for the exact interface
definitions.  Thanks to Alexey Starikovskiy.
	acpi_os_create_cache
	acpi_os_delete_cache
	acpi_os_purge_cache
	acpi_os_acquire_object
	acpi_os_release_object

Modified the interfaces to acpi_os_acquire_lock and
acpi_os_release_lock to return and restore a flags
parameter.  This fits better with many OS lock models.
Note: the current execution state (interrupt handler
or not) is no longer passed to these interfaces.  If
necessary, the OSL must determine this state by itself, a
simple and fast operation.  Thanks to Alexey Starikovskiy.

Fixed a problem in the ACPI table handling where a valid
XSDT was assumed present if the revision of the RSDP
was 2 or greater.  According to the ACPI specification,
the XSDT is optional in all cases, and the table manager
therefore now checks for both an RSDP >=2 and a valid
XSDT pointer.  Otherwise, the RSDT pointer is used.
Some ACPI 2.0 compliant BIOSs contain only the RSDT.

Fixed an interpreter problem with the Mid() operator in the
case of an input string where the resulting output string
is of zero length.  It now correctly returns a valid,
null terminated string object instead of a string object
with a null pointer.

Fixed a problem with the control method argument handling
to allow a store to an Arg object that already contains an
object of type Device.  The Device object is now correctly
overwritten.  Previously, an error was returned.

ACPICA 20050624:

Modified the new OSL cache interfaces to use ACPI_CACHE_T
as the type for the host-defined cache object.  This allows
the OSL implementation to define and type this object in
any manner desired, simplifying the OSL implementation.
For example, ACPI_CACHE_T is defined as kmem_cache_t for
Linux, and should be defined in the OS-specific header
file for other operating systems as required.

Changed the interface to AcpiOsAcquireObject to directly
return the requested object as the function return (instead
of ACPI_STATUS.) This change was made for performance
reasons, since this is the purpose of the interface in the
first place.  acpi_os_acquire_object is now similar to the
acpi_os_allocate interface.  Thanks to Alexey Starikovskiy.

Modified the initialization sequence in
acpi_initialize_subsystem to call the OSL interface
acpi_osl_initialize first, before any local initialization.
This change was required because the global initialization
now calls OSL interfaces.

Restructured the code base to split some files because
of size and/or because the code logically belonged in a
separate file.  New files are listed below.

  utilities/utcache.c	/* Local cache interfaces */
  utilities/utmutex.c	/* Local mutex support */
  utilities/utstate.c	/* State object support */
  parser/psloop.c	/* Main AML parse loop */

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 46 insertions, 17 deletions

diff --git a/drivers/acpi/executer/exoparg3.c b/drivers/acpi/executer/exoparg3.c
index 23b068adbf58..197890f443b5 100644
--- a/drivers/acpi/executer/exoparg3.c
+++ b/drivers/acpi/executer/exoparg3.c
@@ -160,7 +160,7 @@ acpi_ex_opcode_3A_1T_1R (
 {
         union acpi_operand_object       **operand = &walk_state->operands[0];
         union acpi_operand_object       *return_desc = NULL;
-        char                            *buffer;
+        char                            *buffer = NULL;
         acpi_status                     status = AE_OK;
         acpi_integer                    index;
         acpi_size                       length;
@@ -193,34 +193,63 @@ acpi_ex_opcode_3A_1T_1R (
                  * If the index is beyond the length of the String/Buffer, or if the
                  * requested length is zero, return a zero-length String/Buffer
                  */
-                if ((index < operand[0]->string.length) &&
-                        (length > 0)) {
-                        /* Truncate request if larger than the actual String/Buffer */
-
-                        if ((index + length) >
-                                operand[0]->string.length) {
-                                length = (acpi_size) operand[0]->string.length -
-                                                 (acpi_size) index;
-                        }
+                if (index >= operand[0]->string.length) {
+                        length = 0;
+                }
+
+                /* Truncate request if larger than the actual String/Buffer */
+
+                else if ((index + length) > operand[0]->string.length) {
+                        length = (acpi_size) operand[0]->string.length -
+                                         (acpi_size) index;
+                }
 
-                        /* Allocate a new buffer for the String/Buffer */
+                /* Strings always have a sub-pointer, not so for buffers */
+
+                switch (ACPI_GET_OBJECT_TYPE (operand[0])) {
+                case ACPI_TYPE_STRING:
+
+                        /* Always allocate a new buffer for the String */
 
                         buffer = ACPI_MEM_CALLOCATE ((acpi_size) length + 1);
                         if (!buffer) {
                                 status = AE_NO_MEMORY;
                                 goto cleanup;
                         }
+                        break;
+
+                case ACPI_TYPE_BUFFER:
+
+                        /* If the requested length is zero, don't allocate a buffer */
+
+                        if (length > 0) {
+                                /* Allocate a new buffer for the Buffer */
+
+                                buffer = ACPI_MEM_CALLOCATE (length);
+                                if (!buffer) {
+                                        status = AE_NO_MEMORY;
+                                        goto cleanup;
+                                }
+                        }
+                        break;
 
+                default:                        /* Should not happen */
+
+                        status = AE_AML_OPERAND_TYPE;
+                        goto cleanup;
+                }
+
+                if (length > 0) {
                         /* Copy the portion requested */
 
                         ACPI_MEMCPY (buffer, operand[0]->string.pointer + index,
                                           length);
+                }
 
-                        /* Set the length of the new String/Buffer */
+                /* Set the length of the new String/Buffer */
 
-                        return_desc->string.pointer = buffer;
-                        return_desc->string.length = (u32) length;
-                }
+                return_desc->string.pointer = buffer;
+                return_desc->string.length = (u32) length;
 
                 /* Mark buffer initialized */
 
@@ -244,13 +273,13 @@ cleanup:
 
         /* Delete return object on error */
 
-        if (ACPI_FAILURE (status)) {
+        if (ACPI_FAILURE (status) || walk_state->result_obj) {
                 acpi_ut_remove_reference (return_desc);
         }
 
         /* Set the return object and exit */
 
-        if (!walk_state->result_obj) {
+        else {
                 walk_state->result_obj = return_desc;
         }
         return_ACPI_STATUS (status);