xref: /freebsd/sys/contrib/dev/acpica/components/utilities/utcksum.c (revision 9a4bc5208fad4d69360dbbe769e28a37419c4e21)
1*9a4bc520SJung-uk Kim /******************************************************************************
2*9a4bc520SJung-uk Kim  *
3*9a4bc520SJung-uk Kim  * Module Name: utcksum - Support generating table checksums
4*9a4bc520SJung-uk Kim  *
5*9a4bc520SJung-uk Kim  *****************************************************************************/
6*9a4bc520SJung-uk Kim 
7*9a4bc520SJung-uk Kim /******************************************************************************
8*9a4bc520SJung-uk Kim  *
9*9a4bc520SJung-uk Kim  * 1. Copyright Notice
10*9a4bc520SJung-uk Kim  *
11*9a4bc520SJung-uk Kim  * Some or all of this work - Copyright (c) 1999 - 2022, Intel Corp.
12*9a4bc520SJung-uk Kim  * All rights reserved.
13*9a4bc520SJung-uk Kim  *
14*9a4bc520SJung-uk Kim  * 2. License
15*9a4bc520SJung-uk Kim  *
16*9a4bc520SJung-uk Kim  * 2.1. This is your license from Intel Corp. under its intellectual property
17*9a4bc520SJung-uk Kim  * rights. You may have additional license terms from the party that provided
18*9a4bc520SJung-uk Kim  * you this software, covering your right to use that party's intellectual
19*9a4bc520SJung-uk Kim  * property rights.
20*9a4bc520SJung-uk Kim  *
21*9a4bc520SJung-uk Kim  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
22*9a4bc520SJung-uk Kim  * copy of the source code appearing in this file ("Covered Code") an
23*9a4bc520SJung-uk Kim  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
24*9a4bc520SJung-uk Kim  * base code distributed originally by Intel ("Original Intel Code") to copy,
25*9a4bc520SJung-uk Kim  * make derivatives, distribute, use and display any portion of the Covered
26*9a4bc520SJung-uk Kim  * Code in any form, with the right to sublicense such rights; and
27*9a4bc520SJung-uk Kim  *
28*9a4bc520SJung-uk Kim  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
29*9a4bc520SJung-uk Kim  * license (with the right to sublicense), under only those claims of Intel
30*9a4bc520SJung-uk Kim  * patents that are infringed by the Original Intel Code, to make, use, sell,
31*9a4bc520SJung-uk Kim  * offer to sell, and import the Covered Code and derivative works thereof
32*9a4bc520SJung-uk Kim  * solely to the minimum extent necessary to exercise the above copyright
33*9a4bc520SJung-uk Kim  * license, and in no event shall the patent license extend to any additions
34*9a4bc520SJung-uk Kim  * to or modifications of the Original Intel Code. No other license or right
35*9a4bc520SJung-uk Kim  * is granted directly or by implication, estoppel or otherwise;
36*9a4bc520SJung-uk Kim  *
37*9a4bc520SJung-uk Kim  * The above copyright and patent license is granted only if the following
38*9a4bc520SJung-uk Kim  * conditions are met:
39*9a4bc520SJung-uk Kim  *
40*9a4bc520SJung-uk Kim  * 3. Conditions
41*9a4bc520SJung-uk Kim  *
42*9a4bc520SJung-uk Kim  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
43*9a4bc520SJung-uk Kim  * Redistribution of source code of any substantial portion of the Covered
44*9a4bc520SJung-uk Kim  * Code or modification with rights to further distribute source must include
45*9a4bc520SJung-uk Kim  * the above Copyright Notice, the above License, this list of Conditions,
46*9a4bc520SJung-uk Kim  * and the following Disclaimer and Export Compliance provision. In addition,
47*9a4bc520SJung-uk Kim  * Licensee must cause all Covered Code to which Licensee contributes to
48*9a4bc520SJung-uk Kim  * contain a file documenting the changes Licensee made to create that Covered
49*9a4bc520SJung-uk Kim  * Code and the date of any change. Licensee must include in that file the
50*9a4bc520SJung-uk Kim  * documentation of any changes made by any predecessor Licensee. Licensee
51*9a4bc520SJung-uk Kim  * must include a prominent statement that the modification is derived,
52*9a4bc520SJung-uk Kim  * directly or indirectly, from Original Intel Code.
53*9a4bc520SJung-uk Kim  *
54*9a4bc520SJung-uk Kim  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
55*9a4bc520SJung-uk Kim  * Redistribution of source code of any substantial portion of the Covered
56*9a4bc520SJung-uk Kim  * Code or modification without rights to further distribute source must
57*9a4bc520SJung-uk Kim  * include the following Disclaimer and Export Compliance provision in the
58*9a4bc520SJung-uk Kim  * documentation and/or other materials provided with distribution. In
59*9a4bc520SJung-uk Kim  * addition, Licensee may not authorize further sublicense of source of any
60*9a4bc520SJung-uk Kim  * portion of the Covered Code, and must include terms to the effect that the
61*9a4bc520SJung-uk Kim  * license from Licensee to its licensee is limited to the intellectual
62*9a4bc520SJung-uk Kim  * property embodied in the software Licensee provides to its licensee, and
63*9a4bc520SJung-uk Kim  * not to intellectual property embodied in modifications its licensee may
64*9a4bc520SJung-uk Kim  * make.
65*9a4bc520SJung-uk Kim  *
66*9a4bc520SJung-uk Kim  * 3.3. Redistribution of Executable. Redistribution in executable form of any
67*9a4bc520SJung-uk Kim  * substantial portion of the Covered Code or modification must reproduce the
68*9a4bc520SJung-uk Kim  * above Copyright Notice, and the following Disclaimer and Export Compliance
69*9a4bc520SJung-uk Kim  * provision in the documentation and/or other materials provided with the
70*9a4bc520SJung-uk Kim  * distribution.
71*9a4bc520SJung-uk Kim  *
72*9a4bc520SJung-uk Kim  * 3.4. Intel retains all right, title, and interest in and to the Original
73*9a4bc520SJung-uk Kim  * Intel Code.
74*9a4bc520SJung-uk Kim  *
75*9a4bc520SJung-uk Kim  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
76*9a4bc520SJung-uk Kim  * Intel shall be used in advertising or otherwise to promote the sale, use or
77*9a4bc520SJung-uk Kim  * other dealings in products derived from or relating to the Covered Code
78*9a4bc520SJung-uk Kim  * without prior written authorization from Intel.
79*9a4bc520SJung-uk Kim  *
80*9a4bc520SJung-uk Kim  * 4. Disclaimer and Export Compliance
81*9a4bc520SJung-uk Kim  *
82*9a4bc520SJung-uk Kim  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
83*9a4bc520SJung-uk Kim  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
84*9a4bc520SJung-uk Kim  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
85*9a4bc520SJung-uk Kim  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
86*9a4bc520SJung-uk Kim  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
87*9a4bc520SJung-uk Kim  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
88*9a4bc520SJung-uk Kim  * PARTICULAR PURPOSE.
89*9a4bc520SJung-uk Kim  *
90*9a4bc520SJung-uk Kim  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
91*9a4bc520SJung-uk Kim  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
92*9a4bc520SJung-uk Kim  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
93*9a4bc520SJung-uk Kim  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
94*9a4bc520SJung-uk Kim  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
95*9a4bc520SJung-uk Kim  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
96*9a4bc520SJung-uk Kim  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
97*9a4bc520SJung-uk Kim  * LIMITED REMEDY.
98*9a4bc520SJung-uk Kim  *
99*9a4bc520SJung-uk Kim  * 4.3. Licensee shall not export, either directly or indirectly, any of this
100*9a4bc520SJung-uk Kim  * software or system incorporating such software without first obtaining any
101*9a4bc520SJung-uk Kim  * required license or other approval from the U. S. Department of Commerce or
102*9a4bc520SJung-uk Kim  * any other agency or department of the United States Government. In the
103*9a4bc520SJung-uk Kim  * event Licensee exports any such software from the United States or
104*9a4bc520SJung-uk Kim  * re-exports any such software from a foreign destination, Licensee shall
105*9a4bc520SJung-uk Kim  * ensure that the distribution and export/re-export of the software is in
106*9a4bc520SJung-uk Kim  * compliance with all laws, regulations, orders, or other restrictions of the
107*9a4bc520SJung-uk Kim  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
108*9a4bc520SJung-uk Kim  * any of its subsidiaries will export/re-export any technical data, process,
109*9a4bc520SJung-uk Kim  * software, or service, directly or indirectly, to any country for which the
110*9a4bc520SJung-uk Kim  * United States government or any agency thereof requires an export license,
111*9a4bc520SJung-uk Kim  * other governmental approval, or letter of assurance, without first obtaining
112*9a4bc520SJung-uk Kim  * such license, approval or letter.
113*9a4bc520SJung-uk Kim  *
114*9a4bc520SJung-uk Kim  *****************************************************************************
115*9a4bc520SJung-uk Kim  *
116*9a4bc520SJung-uk Kim  * Alternatively, you may choose to be licensed under the terms of the
117*9a4bc520SJung-uk Kim  * following license:
118*9a4bc520SJung-uk Kim  *
119*9a4bc520SJung-uk Kim  * Redistribution and use in source and binary forms, with or without
120*9a4bc520SJung-uk Kim  * modification, are permitted provided that the following conditions
121*9a4bc520SJung-uk Kim  * are met:
122*9a4bc520SJung-uk Kim  * 1. Redistributions of source code must retain the above copyright
123*9a4bc520SJung-uk Kim  *    notice, this list of conditions, and the following disclaimer,
124*9a4bc520SJung-uk Kim  *    without modification.
125*9a4bc520SJung-uk Kim  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
126*9a4bc520SJung-uk Kim  *    substantially similar to the "NO WARRANTY" disclaimer below
127*9a4bc520SJung-uk Kim  *    ("Disclaimer") and any redistribution must be conditioned upon
128*9a4bc520SJung-uk Kim  *    including a substantially similar Disclaimer requirement for further
129*9a4bc520SJung-uk Kim  *    binary redistribution.
130*9a4bc520SJung-uk Kim  * 3. Neither the names of the above-listed copyright holders nor the names
131*9a4bc520SJung-uk Kim  *    of any contributors may be used to endorse or promote products derived
132*9a4bc520SJung-uk Kim  *    from this software without specific prior written permission.
133*9a4bc520SJung-uk Kim  *
134*9a4bc520SJung-uk Kim  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
135*9a4bc520SJung-uk Kim  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
136*9a4bc520SJung-uk Kim  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
137*9a4bc520SJung-uk Kim  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
138*9a4bc520SJung-uk Kim  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
139*9a4bc520SJung-uk Kim  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
140*9a4bc520SJung-uk Kim  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
141*9a4bc520SJung-uk Kim  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
142*9a4bc520SJung-uk Kim  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
143*9a4bc520SJung-uk Kim  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
144*9a4bc520SJung-uk Kim  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
145*9a4bc520SJung-uk Kim  *
146*9a4bc520SJung-uk Kim  * Alternatively, you may choose to be licensed under the terms of the
147*9a4bc520SJung-uk Kim  * GNU General Public License ("GPL") version 2 as published by the Free
148*9a4bc520SJung-uk Kim  * Software Foundation.
149*9a4bc520SJung-uk Kim  *
150*9a4bc520SJung-uk Kim  *****************************************************************************/
151*9a4bc520SJung-uk Kim 
152*9a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/acpi.h>
153*9a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/accommon.h>
154*9a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/acdisasm.h>
155*9a4bc520SJung-uk Kim #include <contrib/dev/acpica/include/acutils.h>
156*9a4bc520SJung-uk Kim 
157*9a4bc520SJung-uk Kim 
158*9a4bc520SJung-uk Kim /* This module used for application-level code only */
159*9a4bc520SJung-uk Kim 
160*9a4bc520SJung-uk Kim #define _COMPONENT          ACPI_CA_DISASSEMBLER
161*9a4bc520SJung-uk Kim         ACPI_MODULE_NAME    ("utcksum")
162*9a4bc520SJung-uk Kim 
163*9a4bc520SJung-uk Kim 
164*9a4bc520SJung-uk Kim /*******************************************************************************
165*9a4bc520SJung-uk Kim  *
166*9a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtVerifyChecksum
167*9a4bc520SJung-uk Kim  *
168*9a4bc520SJung-uk Kim  * PARAMETERS:  Table               - ACPI table to verify
169*9a4bc520SJung-uk Kim  *              Length              - Length of entire table
170*9a4bc520SJung-uk Kim  *
171*9a4bc520SJung-uk Kim  * RETURN:      Status
172*9a4bc520SJung-uk Kim  *
173*9a4bc520SJung-uk Kim  * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
174*9a4bc520SJung-uk Kim  *              exception on bad checksum.
175*9a4bc520SJung-uk Kim  *              Note: We don't have to check for a CDAT here, since CDAT is
176*9a4bc520SJung-uk Kim  *              not in the RSDT/XSDT, and the CDAT table is never installed
177*9a4bc520SJung-uk Kim  *              via ACPICA.
178*9a4bc520SJung-uk Kim  *
179*9a4bc520SJung-uk Kim  ******************************************************************************/
180*9a4bc520SJung-uk Kim 
181*9a4bc520SJung-uk Kim ACPI_STATUS
182*9a4bc520SJung-uk Kim AcpiUtVerifyChecksum (
183*9a4bc520SJung-uk Kim     ACPI_TABLE_HEADER       *Table,
184*9a4bc520SJung-uk Kim     UINT32                  Length)
185*9a4bc520SJung-uk Kim {
186*9a4bc520SJung-uk Kim     UINT8                   Checksum;
187*9a4bc520SJung-uk Kim 
188*9a4bc520SJung-uk Kim 
189*9a4bc520SJung-uk Kim     /*
190*9a4bc520SJung-uk Kim      * FACS/S3PT:
191*9a4bc520SJung-uk Kim      * They are the odd tables, have no standard ACPI header and no checksum
192*9a4bc520SJung-uk Kim      */
193*9a4bc520SJung-uk Kim     if (ACPI_COMPARE_NAMESEG (Table->Signature, ACPI_SIG_S3PT) ||
194*9a4bc520SJung-uk Kim         ACPI_COMPARE_NAMESEG (Table->Signature, ACPI_SIG_FACS))
195*9a4bc520SJung-uk Kim     {
196*9a4bc520SJung-uk Kim         return (AE_OK);
197*9a4bc520SJung-uk Kim     }
198*9a4bc520SJung-uk Kim 
199*9a4bc520SJung-uk Kim     /* Compute the checksum on the table */
200*9a4bc520SJung-uk Kim 
201*9a4bc520SJung-uk Kim     Length = Table->Length;
202*9a4bc520SJung-uk Kim     Checksum = AcpiUtGenerateChecksum (ACPI_CAST_PTR (UINT8, Table), Length, Table->Checksum);
203*9a4bc520SJung-uk Kim 
204*9a4bc520SJung-uk Kim     /* Computed checksum matches table? */
205*9a4bc520SJung-uk Kim 
206*9a4bc520SJung-uk Kim     if (Checksum != Table->Checksum)
207*9a4bc520SJung-uk Kim     {
208*9a4bc520SJung-uk Kim         ACPI_BIOS_WARNING ((AE_INFO,
209*9a4bc520SJung-uk Kim             "Incorrect checksum in table [%4.4s] - 0x%2.2X, "
210*9a4bc520SJung-uk Kim             "should be 0x%2.2X",
211*9a4bc520SJung-uk Kim             Table->Signature, Table->Checksum,
212*9a4bc520SJung-uk Kim             Table->Checksum - Checksum));
213*9a4bc520SJung-uk Kim 
214*9a4bc520SJung-uk Kim #if (ACPI_CHECKSUM_ABORT)
215*9a4bc520SJung-uk Kim         return (AE_BAD_CHECKSUM);
216*9a4bc520SJung-uk Kim #endif
217*9a4bc520SJung-uk Kim     }
218*9a4bc520SJung-uk Kim 
219*9a4bc520SJung-uk Kim     return (AE_OK);
220*9a4bc520SJung-uk Kim }
221*9a4bc520SJung-uk Kim 
222*9a4bc520SJung-uk Kim 
223*9a4bc520SJung-uk Kim /*******************************************************************************
224*9a4bc520SJung-uk Kim  *
225*9a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtVerifyCdatChecksum
226*9a4bc520SJung-uk Kim  *
227*9a4bc520SJung-uk Kim  * PARAMETERS:  Table               - CDAT ACPI table to verify
228*9a4bc520SJung-uk Kim  *              Length              - Length of entire table
229*9a4bc520SJung-uk Kim  *
230*9a4bc520SJung-uk Kim  * RETURN:      Status
231*9a4bc520SJung-uk Kim  *
232*9a4bc520SJung-uk Kim  * DESCRIPTION: Verifies that the CDAT table checksums to zero. Optionally
233*9a4bc520SJung-uk Kim  *              returns an exception on bad checksum.
234*9a4bc520SJung-uk Kim  *
235*9a4bc520SJung-uk Kim  ******************************************************************************/
236*9a4bc520SJung-uk Kim 
237*9a4bc520SJung-uk Kim ACPI_STATUS
238*9a4bc520SJung-uk Kim AcpiUtVerifyCdatChecksum (
239*9a4bc520SJung-uk Kim     ACPI_TABLE_CDAT         *CdatTable,
240*9a4bc520SJung-uk Kim     UINT32                  Length)
241*9a4bc520SJung-uk Kim {
242*9a4bc520SJung-uk Kim     UINT8                   Checksum;
243*9a4bc520SJung-uk Kim 
244*9a4bc520SJung-uk Kim 
245*9a4bc520SJung-uk Kim     /* Compute the checksum on the table */
246*9a4bc520SJung-uk Kim 
247*9a4bc520SJung-uk Kim     Checksum = AcpiUtGenerateChecksum (ACPI_CAST_PTR (UINT8, CdatTable),
248*9a4bc520SJung-uk Kim                     CdatTable->Length, CdatTable->Checksum);
249*9a4bc520SJung-uk Kim 
250*9a4bc520SJung-uk Kim     /* Computed checksum matches table? */
251*9a4bc520SJung-uk Kim 
252*9a4bc520SJung-uk Kim     if (Checksum != CdatTable->Checksum)
253*9a4bc520SJung-uk Kim     {
254*9a4bc520SJung-uk Kim         ACPI_BIOS_WARNING ((AE_INFO,
255*9a4bc520SJung-uk Kim             "Incorrect checksum in table [%4.4s] - 0x%2.2X, "
256*9a4bc520SJung-uk Kim             "should be 0x%2.2X",
257*9a4bc520SJung-uk Kim             AcpiGbl_CDAT, CdatTable->Checksum, Checksum));
258*9a4bc520SJung-uk Kim 
259*9a4bc520SJung-uk Kim #if (ACPI_CHECKSUM_ABORT)
260*9a4bc520SJung-uk Kim         return (AE_BAD_CHECKSUM);
261*9a4bc520SJung-uk Kim #endif
262*9a4bc520SJung-uk Kim     }
263*9a4bc520SJung-uk Kim 
264*9a4bc520SJung-uk Kim     CdatTable->Checksum = Checksum;
265*9a4bc520SJung-uk Kim     return (AE_OK);
266*9a4bc520SJung-uk Kim }
267*9a4bc520SJung-uk Kim 
268*9a4bc520SJung-uk Kim 
269*9a4bc520SJung-uk Kim /*******************************************************************************
270*9a4bc520SJung-uk Kim  *
271*9a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtGenerateChecksum
272*9a4bc520SJung-uk Kim  *
273*9a4bc520SJung-uk Kim  * PARAMETERS:  Table               - Pointer to table to be checksummed
274*9a4bc520SJung-uk Kim  *              Length              - Length of the table
275*9a4bc520SJung-uk Kim  *              OriginalChecksum    - Value of the checksum field
276*9a4bc520SJung-uk Kim  *
277*9a4bc520SJung-uk Kim  * RETURN:      8 bit checksum of buffer
278*9a4bc520SJung-uk Kim  *
279*9a4bc520SJung-uk Kim  * DESCRIPTION: Computes an 8 bit checksum of the table.
280*9a4bc520SJung-uk Kim  *
281*9a4bc520SJung-uk Kim  ******************************************************************************/
282*9a4bc520SJung-uk Kim 
283*9a4bc520SJung-uk Kim UINT8
284*9a4bc520SJung-uk Kim AcpiUtGenerateChecksum (
285*9a4bc520SJung-uk Kim     void                    *Table,
286*9a4bc520SJung-uk Kim     UINT32                  Length,
287*9a4bc520SJung-uk Kim     UINT8                   OriginalChecksum)
288*9a4bc520SJung-uk Kim {
289*9a4bc520SJung-uk Kim     UINT8                   Checksum;
290*9a4bc520SJung-uk Kim 
291*9a4bc520SJung-uk Kim 
292*9a4bc520SJung-uk Kim     /* Sum the entire table as-is */
293*9a4bc520SJung-uk Kim 
294*9a4bc520SJung-uk Kim     Checksum = AcpiUtChecksum ((UINT8 *) Table, Length);
295*9a4bc520SJung-uk Kim 
296*9a4bc520SJung-uk Kim     /* Subtract off the existing checksum value in the table */
297*9a4bc520SJung-uk Kim 
298*9a4bc520SJung-uk Kim     Checksum = (UINT8) (Checksum - OriginalChecksum);
299*9a4bc520SJung-uk Kim 
300*9a4bc520SJung-uk Kim     /* Compute and return the final checksum */
301*9a4bc520SJung-uk Kim 
302*9a4bc520SJung-uk Kim     Checksum = (UINT8) (0 - Checksum);
303*9a4bc520SJung-uk Kim     return (Checksum);
304*9a4bc520SJung-uk Kim }
305*9a4bc520SJung-uk Kim 
306*9a4bc520SJung-uk Kim 
307*9a4bc520SJung-uk Kim /*******************************************************************************
308*9a4bc520SJung-uk Kim  *
309*9a4bc520SJung-uk Kim  * FUNCTION:    AcpiUtChecksum
310*9a4bc520SJung-uk Kim  *
311*9a4bc520SJung-uk Kim  * PARAMETERS:  Buffer          - Pointer to memory region to be checked
312*9a4bc520SJung-uk Kim  *              Length          - Length of this memory region
313*9a4bc520SJung-uk Kim  *
314*9a4bc520SJung-uk Kim  * RETURN:      Checksum (UINT8)
315*9a4bc520SJung-uk Kim  *
316*9a4bc520SJung-uk Kim  * DESCRIPTION: Calculates circular checksum of memory region.
317*9a4bc520SJung-uk Kim  *
318*9a4bc520SJung-uk Kim  ******************************************************************************/
319*9a4bc520SJung-uk Kim 
320*9a4bc520SJung-uk Kim UINT8
321*9a4bc520SJung-uk Kim AcpiUtChecksum (
322*9a4bc520SJung-uk Kim     UINT8                   *Buffer,
323*9a4bc520SJung-uk Kim     UINT32                  Length)
324*9a4bc520SJung-uk Kim {
325*9a4bc520SJung-uk Kim     UINT8                   Sum = 0;
326*9a4bc520SJung-uk Kim     UINT8                   *End = Buffer + Length;
327*9a4bc520SJung-uk Kim 
328*9a4bc520SJung-uk Kim 
329*9a4bc520SJung-uk Kim     while (Buffer < End)
330*9a4bc520SJung-uk Kim     {
331*9a4bc520SJung-uk Kim         Sum = (UINT8) (Sum + *(Buffer++));
332*9a4bc520SJung-uk Kim     }
333*9a4bc520SJung-uk Kim 
334*9a4bc520SJung-uk Kim     return (Sum);
335*9a4bc520SJung-uk Kim }
336