Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[linux-2.6] / drivers / acpi / acpica / exstorob.c
1
2 /******************************************************************************
3  *
4  * Module Name: exstorob - AML Interpreter object store support, store to object
5  *
6  *****************************************************************************/
7
8 /*
9  * Copyright (C) 2000 - 2008, Intel Corp.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer,
17  *    without modification.
18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19  *    substantially similar to the "NO WARRANTY" disclaimer below
20  *    ("Disclaimer") and any redistribution must be conditioned upon
21  *    including a substantially similar Disclaimer requirement for further
22  *    binary redistribution.
23  * 3. Neither the names of the above-listed copyright holders nor the names
24  *    of any contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * Alternatively, this software may be distributed under the terms of the
28  * GNU General Public License ("GPL") version 2 as published by the Free
29  * Software Foundation.
30  *
31  * NO WARRANTY
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42  * POSSIBILITY OF SUCH DAMAGES.
43  */
44
45 #include <acpi/acpi.h>
46 #include "accommon.h"
47 #include "acinterp.h"
48
49 #define _COMPONENT          ACPI_EXECUTER
50 ACPI_MODULE_NAME("exstorob")
51
52 /*******************************************************************************
53  *
54  * FUNCTION:    acpi_ex_store_buffer_to_buffer
55  *
56  * PARAMETERS:  source_desc         - Source object to copy
57  *              target_desc         - Destination object of the copy
58  *
59  * RETURN:      Status
60  *
61  * DESCRIPTION: Copy a buffer object to another buffer object.
62  *
63  ******************************************************************************/
64 acpi_status
65 acpi_ex_store_buffer_to_buffer(union acpi_operand_object *source_desc,
66                                union acpi_operand_object *target_desc)
67 {
68         u32 length;
69         u8 *buffer;
70
71         ACPI_FUNCTION_TRACE_PTR(ex_store_buffer_to_buffer, source_desc);
72
73         /* We know that source_desc is a buffer by now */
74
75         buffer = ACPI_CAST_PTR(u8, source_desc->buffer.pointer);
76         length = source_desc->buffer.length;
77
78         /*
79          * If target is a buffer of length zero or is a static buffer,
80          * allocate a new buffer of the proper length
81          */
82         if ((target_desc->buffer.length == 0) ||
83             (target_desc->common.flags & AOPOBJ_STATIC_POINTER)) {
84                 target_desc->buffer.pointer = ACPI_ALLOCATE(length);
85                 if (!target_desc->buffer.pointer) {
86                         return_ACPI_STATUS(AE_NO_MEMORY);
87                 }
88
89                 target_desc->buffer.length = length;
90         }
91
92         /* Copy source buffer to target buffer */
93
94         if (length <= target_desc->buffer.length) {
95
96                 /* Clear existing buffer and copy in the new one */
97
98                 ACPI_MEMSET(target_desc->buffer.pointer, 0,
99                             target_desc->buffer.length);
100                 ACPI_MEMCPY(target_desc->buffer.pointer, buffer, length);
101
102 #ifdef ACPI_OBSOLETE_BEHAVIOR
103                 /*
104                  * NOTE: ACPI versions up to 3.0 specified that the buffer must be
105                  * truncated if the string is smaller than the buffer.  However, "other"
106                  * implementations of ACPI never did this and thus became the defacto
107                  * standard. ACPI 3.0_a changes this behavior such that the buffer
108                  * is no longer truncated.
109                  */
110
111                 /*
112                  * OBSOLETE BEHAVIOR:
113                  * If the original source was a string, we must truncate the buffer,
114                  * according to the ACPI spec.  Integer-to-Buffer and Buffer-to-Buffer
115                  * copy must not truncate the original buffer.
116                  */
117                 if (original_src_type == ACPI_TYPE_STRING) {
118
119                         /* Set the new length of the target */
120
121                         target_desc->buffer.length = length;
122                 }
123 #endif
124         } else {
125                 /* Truncate the source, copy only what will fit */
126
127                 ACPI_MEMCPY(target_desc->buffer.pointer, buffer,
128                             target_desc->buffer.length);
129
130                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
131                                   "Truncating source buffer from %X to %X\n",
132                                   length, target_desc->buffer.length));
133         }
134
135         /* Copy flags */
136
137         target_desc->buffer.flags = source_desc->buffer.flags;
138         target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
139         return_ACPI_STATUS(AE_OK);
140 }
141
142 /*******************************************************************************
143  *
144  * FUNCTION:    acpi_ex_store_string_to_string
145  *
146  * PARAMETERS:  source_desc         - Source object to copy
147  *              target_desc         - Destination object of the copy
148  *
149  * RETURN:      Status
150  *
151  * DESCRIPTION: Copy a String object to another String object
152  *
153  ******************************************************************************/
154
155 acpi_status
156 acpi_ex_store_string_to_string(union acpi_operand_object *source_desc,
157                                union acpi_operand_object *target_desc)
158 {
159         u32 length;
160         u8 *buffer;
161
162         ACPI_FUNCTION_TRACE_PTR(ex_store_string_to_string, source_desc);
163
164         /* We know that source_desc is a string by now */
165
166         buffer = ACPI_CAST_PTR(u8, source_desc->string.pointer);
167         length = source_desc->string.length;
168
169         /*
170          * Replace existing string value if it will fit and the string
171          * pointer is not a static pointer (part of an ACPI table)
172          */
173         if ((length < target_desc->string.length) &&
174             (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
175                 /*
176                  * String will fit in existing non-static buffer.
177                  * Clear old string and copy in the new one
178                  */
179                 ACPI_MEMSET(target_desc->string.pointer, 0,
180                             (acpi_size) target_desc->string.length + 1);
181                 ACPI_MEMCPY(target_desc->string.pointer, buffer, length);
182         } else {
183                 /*
184                  * Free the current buffer, then allocate a new buffer
185                  * large enough to hold the value
186                  */
187                 if (target_desc->string.pointer &&
188                     (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
189
190                         /* Only free if not a pointer into the DSDT */
191
192                         ACPI_FREE(target_desc->string.pointer);
193                 }
194
195                 target_desc->string.pointer = ACPI_ALLOCATE_ZEROED((acpi_size)
196                                                                    length + 1);
197                 if (!target_desc->string.pointer) {
198                         return_ACPI_STATUS(AE_NO_MEMORY);
199                 }
200
201                 target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
202                 ACPI_MEMCPY(target_desc->string.pointer, buffer, length);
203         }
204
205         /* Set the new target length */
206
207         target_desc->string.length = length;
208         return_ACPI_STATUS(AE_OK);
209 }