xref: /linux/drivers/acpi/acpica/exnames.c (revision 95b482a8d31116f3f5c2a5089569393234d06385)
1*95b482a8SLen Brown 
2*95b482a8SLen Brown /******************************************************************************
3*95b482a8SLen Brown  *
4*95b482a8SLen Brown  * Module Name: exnames - interpreter/scanner name load/execute
5*95b482a8SLen Brown  *
6*95b482a8SLen Brown  *****************************************************************************/
7*95b482a8SLen Brown 
8*95b482a8SLen Brown /*
9*95b482a8SLen Brown  * Copyright (C) 2000 - 2008, Intel Corp.
10*95b482a8SLen Brown  * All rights reserved.
11*95b482a8SLen Brown  *
12*95b482a8SLen Brown  * Redistribution and use in source and binary forms, with or without
13*95b482a8SLen Brown  * modification, are permitted provided that the following conditions
14*95b482a8SLen Brown  * are met:
15*95b482a8SLen Brown  * 1. Redistributions of source code must retain the above copyright
16*95b482a8SLen Brown  *    notice, this list of conditions, and the following disclaimer,
17*95b482a8SLen Brown  *    without modification.
18*95b482a8SLen Brown  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19*95b482a8SLen Brown  *    substantially similar to the "NO WARRANTY" disclaimer below
20*95b482a8SLen Brown  *    ("Disclaimer") and any redistribution must be conditioned upon
21*95b482a8SLen Brown  *    including a substantially similar Disclaimer requirement for further
22*95b482a8SLen Brown  *    binary redistribution.
23*95b482a8SLen Brown  * 3. Neither the names of the above-listed copyright holders nor the names
24*95b482a8SLen Brown  *    of any contributors may be used to endorse or promote products derived
25*95b482a8SLen Brown  *    from this software without specific prior written permission.
26*95b482a8SLen Brown  *
27*95b482a8SLen Brown  * Alternatively, this software may be distributed under the terms of the
28*95b482a8SLen Brown  * GNU General Public License ("GPL") version 2 as published by the Free
29*95b482a8SLen Brown  * Software Foundation.
30*95b482a8SLen Brown  *
31*95b482a8SLen Brown  * NO WARRANTY
32*95b482a8SLen Brown  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33*95b482a8SLen Brown  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34*95b482a8SLen Brown  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35*95b482a8SLen Brown  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36*95b482a8SLen Brown  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37*95b482a8SLen Brown  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38*95b482a8SLen Brown  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39*95b482a8SLen Brown  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40*95b482a8SLen Brown  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41*95b482a8SLen Brown  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42*95b482a8SLen Brown  * POSSIBILITY OF SUCH DAMAGES.
43*95b482a8SLen Brown  */
44*95b482a8SLen Brown 
45*95b482a8SLen Brown #include <acpi/acpi.h>
46*95b482a8SLen Brown #include <acpi/accommon.h>
47*95b482a8SLen Brown #include <acpi/acinterp.h>
48*95b482a8SLen Brown #include <acpi/amlcode.h>
49*95b482a8SLen Brown 
50*95b482a8SLen Brown #define _COMPONENT          ACPI_EXECUTER
51*95b482a8SLen Brown ACPI_MODULE_NAME("exnames")
52*95b482a8SLen Brown 
53*95b482a8SLen Brown /* Local prototypes */
54*95b482a8SLen Brown static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs);
55*95b482a8SLen Brown 
56*95b482a8SLen Brown static acpi_status
57*95b482a8SLen Brown acpi_ex_name_segment(u8 ** in_aml_address, char *name_string);
58*95b482a8SLen Brown 
59*95b482a8SLen Brown /*******************************************************************************
60*95b482a8SLen Brown  *
61*95b482a8SLen Brown  * FUNCTION:    acpi_ex_allocate_name_string
62*95b482a8SLen Brown  *
63*95b482a8SLen Brown  * PARAMETERS:  prefix_count        - Count of parent levels. Special cases:
64*95b482a8SLen Brown  *                                    (-1)==root,  0==none
65*95b482a8SLen Brown  *              num_name_segs       - count of 4-character name segments
66*95b482a8SLen Brown  *
67*95b482a8SLen Brown  * RETURN:      A pointer to the allocated string segment.  This segment must
68*95b482a8SLen Brown  *              be deleted by the caller.
69*95b482a8SLen Brown  *
70*95b482a8SLen Brown  * DESCRIPTION: Allocate a buffer for a name string. Ensure allocated name
71*95b482a8SLen Brown  *              string is long enough, and set up prefix if any.
72*95b482a8SLen Brown  *
73*95b482a8SLen Brown  ******************************************************************************/
74*95b482a8SLen Brown 
75*95b482a8SLen Brown static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs)
76*95b482a8SLen Brown {
77*95b482a8SLen Brown 	char *temp_ptr;
78*95b482a8SLen Brown 	char *name_string;
79*95b482a8SLen Brown 	u32 size_needed;
80*95b482a8SLen Brown 
81*95b482a8SLen Brown 	ACPI_FUNCTION_TRACE(ex_allocate_name_string);
82*95b482a8SLen Brown 
83*95b482a8SLen Brown 	/*
84*95b482a8SLen Brown 	 * Allow room for all \ and ^ prefixes, all segments and a multi_name_prefix.
85*95b482a8SLen Brown 	 * Also, one byte for the null terminator.
86*95b482a8SLen Brown 	 * This may actually be somewhat longer than needed.
87*95b482a8SLen Brown 	 */
88*95b482a8SLen Brown 	if (prefix_count == ACPI_UINT32_MAX) {
89*95b482a8SLen Brown 
90*95b482a8SLen Brown 		/* Special case for root */
91*95b482a8SLen Brown 
92*95b482a8SLen Brown 		size_needed = 1 + (ACPI_NAME_SIZE * num_name_segs) + 2 + 1;
93*95b482a8SLen Brown 	} else {
94*95b482a8SLen Brown 		size_needed =
95*95b482a8SLen Brown 		    prefix_count + (ACPI_NAME_SIZE * num_name_segs) + 2 + 1;
96*95b482a8SLen Brown 	}
97*95b482a8SLen Brown 
98*95b482a8SLen Brown 	/*
99*95b482a8SLen Brown 	 * Allocate a buffer for the name.
100*95b482a8SLen Brown 	 * This buffer must be deleted by the caller!
101*95b482a8SLen Brown 	 */
102*95b482a8SLen Brown 	name_string = ACPI_ALLOCATE(size_needed);
103*95b482a8SLen Brown 	if (!name_string) {
104*95b482a8SLen Brown 		ACPI_ERROR((AE_INFO,
105*95b482a8SLen Brown 			    "Could not allocate size %d", size_needed));
106*95b482a8SLen Brown 		return_PTR(NULL);
107*95b482a8SLen Brown 	}
108*95b482a8SLen Brown 
109*95b482a8SLen Brown 	temp_ptr = name_string;
110*95b482a8SLen Brown 
111*95b482a8SLen Brown 	/* Set up Root or Parent prefixes if needed */
112*95b482a8SLen Brown 
113*95b482a8SLen Brown 	if (prefix_count == ACPI_UINT32_MAX) {
114*95b482a8SLen Brown 		*temp_ptr++ = AML_ROOT_PREFIX;
115*95b482a8SLen Brown 	} else {
116*95b482a8SLen Brown 		while (prefix_count--) {
117*95b482a8SLen Brown 			*temp_ptr++ = AML_PARENT_PREFIX;
118*95b482a8SLen Brown 		}
119*95b482a8SLen Brown 	}
120*95b482a8SLen Brown 
121*95b482a8SLen Brown 	/* Set up Dual or Multi prefixes if needed */
122*95b482a8SLen Brown 
123*95b482a8SLen Brown 	if (num_name_segs > 2) {
124*95b482a8SLen Brown 
125*95b482a8SLen Brown 		/* Set up multi prefixes   */
126*95b482a8SLen Brown 
127*95b482a8SLen Brown 		*temp_ptr++ = AML_MULTI_NAME_PREFIX_OP;
128*95b482a8SLen Brown 		*temp_ptr++ = (char)num_name_segs;
129*95b482a8SLen Brown 	} else if (2 == num_name_segs) {
130*95b482a8SLen Brown 
131*95b482a8SLen Brown 		/* Set up dual prefixes */
132*95b482a8SLen Brown 
133*95b482a8SLen Brown 		*temp_ptr++ = AML_DUAL_NAME_PREFIX;
134*95b482a8SLen Brown 	}
135*95b482a8SLen Brown 
136*95b482a8SLen Brown 	/*
137*95b482a8SLen Brown 	 * Terminate string following prefixes. acpi_ex_name_segment() will
138*95b482a8SLen Brown 	 * append the segment(s)
139*95b482a8SLen Brown 	 */
140*95b482a8SLen Brown 	*temp_ptr = 0;
141*95b482a8SLen Brown 
142*95b482a8SLen Brown 	return_PTR(name_string);
143*95b482a8SLen Brown }
144*95b482a8SLen Brown 
145*95b482a8SLen Brown /*******************************************************************************
146*95b482a8SLen Brown  *
147*95b482a8SLen Brown  * FUNCTION:    acpi_ex_name_segment
148*95b482a8SLen Brown  *
149*95b482a8SLen Brown  * PARAMETERS:  in_aml_address  - Pointer to the name in the AML code
150*95b482a8SLen Brown  *              name_string     - Where to return the name. The name is appended
151*95b482a8SLen Brown  *                                to any existing string to form a namepath
152*95b482a8SLen Brown  *
153*95b482a8SLen Brown  * RETURN:      Status
154*95b482a8SLen Brown  *
155*95b482a8SLen Brown  * DESCRIPTION: Extract an ACPI name (4 bytes) from the AML byte stream
156*95b482a8SLen Brown  *
157*95b482a8SLen Brown  ******************************************************************************/
158*95b482a8SLen Brown 
159*95b482a8SLen Brown static acpi_status acpi_ex_name_segment(u8 ** in_aml_address, char *name_string)
160*95b482a8SLen Brown {
161*95b482a8SLen Brown 	char *aml_address = (void *)*in_aml_address;
162*95b482a8SLen Brown 	acpi_status status = AE_OK;
163*95b482a8SLen Brown 	u32 index;
164*95b482a8SLen Brown 	char char_buf[5];
165*95b482a8SLen Brown 
166*95b482a8SLen Brown 	ACPI_FUNCTION_TRACE(ex_name_segment);
167*95b482a8SLen Brown 
168*95b482a8SLen Brown 	/*
169*95b482a8SLen Brown 	 * If first character is a digit, then we know that we aren't looking at a
170*95b482a8SLen Brown 	 * valid name segment
171*95b482a8SLen Brown 	 */
172*95b482a8SLen Brown 	char_buf[0] = *aml_address;
173*95b482a8SLen Brown 
174*95b482a8SLen Brown 	if ('0' <= char_buf[0] && char_buf[0] <= '9') {
175*95b482a8SLen Brown 		ACPI_ERROR((AE_INFO, "Invalid leading digit: %c", char_buf[0]));
176*95b482a8SLen Brown 		return_ACPI_STATUS(AE_CTRL_PENDING);
177*95b482a8SLen Brown 	}
178*95b482a8SLen Brown 
179*95b482a8SLen Brown 	ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "Bytes from stream:\n"));
180*95b482a8SLen Brown 
181*95b482a8SLen Brown 	for (index = 0; (index < ACPI_NAME_SIZE)
182*95b482a8SLen Brown 	     && (acpi_ut_valid_acpi_char(*aml_address, 0)); index++) {
183*95b482a8SLen Brown 		char_buf[index] = *aml_address++;
184*95b482a8SLen Brown 		ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "%c\n", char_buf[index]));
185*95b482a8SLen Brown 	}
186*95b482a8SLen Brown 
187*95b482a8SLen Brown 	/* Valid name segment  */
188*95b482a8SLen Brown 
189*95b482a8SLen Brown 	if (index == 4) {
190*95b482a8SLen Brown 
191*95b482a8SLen Brown 		/* Found 4 valid characters */
192*95b482a8SLen Brown 
193*95b482a8SLen Brown 		char_buf[4] = '\0';
194*95b482a8SLen Brown 
195*95b482a8SLen Brown 		if (name_string) {
196*95b482a8SLen Brown 			ACPI_STRCAT(name_string, char_buf);
197*95b482a8SLen Brown 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
198*95b482a8SLen Brown 					  "Appended to - %s\n", name_string));
199*95b482a8SLen Brown 		} else {
200*95b482a8SLen Brown 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
201*95b482a8SLen Brown 					  "No Name string - %s\n", char_buf));
202*95b482a8SLen Brown 		}
203*95b482a8SLen Brown 	} else if (index == 0) {
204*95b482a8SLen Brown 		/*
205*95b482a8SLen Brown 		 * First character was not a valid name character,
206*95b482a8SLen Brown 		 * so we are looking at something other than a name.
207*95b482a8SLen Brown 		 */
208*95b482a8SLen Brown 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
209*95b482a8SLen Brown 				  "Leading character is not alpha: %02Xh (not a name)\n",
210*95b482a8SLen Brown 				  char_buf[0]));
211*95b482a8SLen Brown 		status = AE_CTRL_PENDING;
212*95b482a8SLen Brown 	} else {
213*95b482a8SLen Brown 		/*
214*95b482a8SLen Brown 		 * Segment started with one or more valid characters, but fewer than
215*95b482a8SLen Brown 		 * the required 4
216*95b482a8SLen Brown 		 */
217*95b482a8SLen Brown 		status = AE_AML_BAD_NAME;
218*95b482a8SLen Brown 		ACPI_ERROR((AE_INFO,
219*95b482a8SLen Brown 			    "Bad character %02x in name, at %p",
220*95b482a8SLen Brown 			    *aml_address, aml_address));
221*95b482a8SLen Brown 	}
222*95b482a8SLen Brown 
223*95b482a8SLen Brown 	*in_aml_address = ACPI_CAST_PTR(u8, aml_address);
224*95b482a8SLen Brown 	return_ACPI_STATUS(status);
225*95b482a8SLen Brown }
226*95b482a8SLen Brown 
227*95b482a8SLen Brown /*******************************************************************************
228*95b482a8SLen Brown  *
229*95b482a8SLen Brown  * FUNCTION:    acpi_ex_get_name_string
230*95b482a8SLen Brown  *
231*95b482a8SLen Brown  * PARAMETERS:  data_type           - Object type to be associated with this
232*95b482a8SLen Brown  *                                    name
233*95b482a8SLen Brown  *              in_aml_address      - Pointer to the namestring in the AML code
234*95b482a8SLen Brown  *              out_name_string     - Where the namestring is returned
235*95b482a8SLen Brown  *              out_name_length     - Length of the returned string
236*95b482a8SLen Brown  *
237*95b482a8SLen Brown  * RETURN:      Status, namestring and length
238*95b482a8SLen Brown  *
239*95b482a8SLen Brown  * DESCRIPTION: Extract a full namepath from the AML byte stream,
240*95b482a8SLen Brown  *              including any prefixes.
241*95b482a8SLen Brown  *
242*95b482a8SLen Brown  ******************************************************************************/
243*95b482a8SLen Brown 
244*95b482a8SLen Brown acpi_status
245*95b482a8SLen Brown acpi_ex_get_name_string(acpi_object_type data_type,
246*95b482a8SLen Brown 			u8 * in_aml_address,
247*95b482a8SLen Brown 			char **out_name_string, u32 * out_name_length)
248*95b482a8SLen Brown {
249*95b482a8SLen Brown 	acpi_status status = AE_OK;
250*95b482a8SLen Brown 	u8 *aml_address = in_aml_address;
251*95b482a8SLen Brown 	char *name_string = NULL;
252*95b482a8SLen Brown 	u32 num_segments;
253*95b482a8SLen Brown 	u32 prefix_count = 0;
254*95b482a8SLen Brown 	u8 has_prefix = FALSE;
255*95b482a8SLen Brown 
256*95b482a8SLen Brown 	ACPI_FUNCTION_TRACE_PTR(ex_get_name_string, aml_address);
257*95b482a8SLen Brown 
258*95b482a8SLen Brown 	if (ACPI_TYPE_LOCAL_REGION_FIELD == data_type ||
259*95b482a8SLen Brown 	    ACPI_TYPE_LOCAL_BANK_FIELD == data_type ||
260*95b482a8SLen Brown 	    ACPI_TYPE_LOCAL_INDEX_FIELD == data_type) {
261*95b482a8SLen Brown 
262*95b482a8SLen Brown 		/* Disallow prefixes for types associated with field_unit names */
263*95b482a8SLen Brown 
264*95b482a8SLen Brown 		name_string = acpi_ex_allocate_name_string(0, 1);
265*95b482a8SLen Brown 		if (!name_string) {
266*95b482a8SLen Brown 			status = AE_NO_MEMORY;
267*95b482a8SLen Brown 		} else {
268*95b482a8SLen Brown 			status =
269*95b482a8SLen Brown 			    acpi_ex_name_segment(&aml_address, name_string);
270*95b482a8SLen Brown 		}
271*95b482a8SLen Brown 	} else {
272*95b482a8SLen Brown 		/*
273*95b482a8SLen Brown 		 * data_type is not a field name.
274*95b482a8SLen Brown 		 * Examine first character of name for root or parent prefix operators
275*95b482a8SLen Brown 		 */
276*95b482a8SLen Brown 		switch (*aml_address) {
277*95b482a8SLen Brown 		case AML_ROOT_PREFIX:
278*95b482a8SLen Brown 
279*95b482a8SLen Brown 			ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
280*95b482a8SLen Brown 					  "RootPrefix(\\) at %p\n",
281*95b482a8SLen Brown 					  aml_address));
282*95b482a8SLen Brown 
283*95b482a8SLen Brown 			/*
284*95b482a8SLen Brown 			 * Remember that we have a root_prefix --
285*95b482a8SLen Brown 			 * see comment in acpi_ex_allocate_name_string()
286*95b482a8SLen Brown 			 */
287*95b482a8SLen Brown 			aml_address++;
288*95b482a8SLen Brown 			prefix_count = ACPI_UINT32_MAX;
289*95b482a8SLen Brown 			has_prefix = TRUE;
290*95b482a8SLen Brown 			break;
291*95b482a8SLen Brown 
292*95b482a8SLen Brown 		case AML_PARENT_PREFIX:
293*95b482a8SLen Brown 
294*95b482a8SLen Brown 			/* Increment past possibly multiple parent prefixes */
295*95b482a8SLen Brown 
296*95b482a8SLen Brown 			do {
297*95b482a8SLen Brown 				ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
298*95b482a8SLen Brown 						  "ParentPrefix (^) at %p\n",
299*95b482a8SLen Brown 						  aml_address));
300*95b482a8SLen Brown 
301*95b482a8SLen Brown 				aml_address++;
302*95b482a8SLen Brown 				prefix_count++;
303*95b482a8SLen Brown 
304*95b482a8SLen Brown 			} while (*aml_address == AML_PARENT_PREFIX);
305*95b482a8SLen Brown 
306*95b482a8SLen Brown 			has_prefix = TRUE;
307*95b482a8SLen Brown 			break;
308*95b482a8SLen Brown 
309*95b482a8SLen Brown 		default:
310*95b482a8SLen Brown 
311*95b482a8SLen Brown 			/* Not a prefix character */
312*95b482a8SLen Brown 
313*95b482a8SLen Brown 			break;
314*95b482a8SLen Brown 		}
315*95b482a8SLen Brown 
316*95b482a8SLen Brown 		/* Examine first character of name for name segment prefix operator */
317*95b482a8SLen Brown 
318*95b482a8SLen Brown 		switch (*aml_address) {
319*95b482a8SLen Brown 		case AML_DUAL_NAME_PREFIX:
320*95b482a8SLen Brown 
321*95b482a8SLen Brown 			ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
322*95b482a8SLen Brown 					  "DualNamePrefix at %p\n",
323*95b482a8SLen Brown 					  aml_address));
324*95b482a8SLen Brown 
325*95b482a8SLen Brown 			aml_address++;
326*95b482a8SLen Brown 			name_string =
327*95b482a8SLen Brown 			    acpi_ex_allocate_name_string(prefix_count, 2);
328*95b482a8SLen Brown 			if (!name_string) {
329*95b482a8SLen Brown 				status = AE_NO_MEMORY;
330*95b482a8SLen Brown 				break;
331*95b482a8SLen Brown 			}
332*95b482a8SLen Brown 
333*95b482a8SLen Brown 			/* Indicate that we processed a prefix */
334*95b482a8SLen Brown 
335*95b482a8SLen Brown 			has_prefix = TRUE;
336*95b482a8SLen Brown 
337*95b482a8SLen Brown 			status =
338*95b482a8SLen Brown 			    acpi_ex_name_segment(&aml_address, name_string);
339*95b482a8SLen Brown 			if (ACPI_SUCCESS(status)) {
340*95b482a8SLen Brown 				status =
341*95b482a8SLen Brown 				    acpi_ex_name_segment(&aml_address,
342*95b482a8SLen Brown 							 name_string);
343*95b482a8SLen Brown 			}
344*95b482a8SLen Brown 			break;
345*95b482a8SLen Brown 
346*95b482a8SLen Brown 		case AML_MULTI_NAME_PREFIX_OP:
347*95b482a8SLen Brown 
348*95b482a8SLen Brown 			ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
349*95b482a8SLen Brown 					  "MultiNamePrefix at %p\n",
350*95b482a8SLen Brown 					  aml_address));
351*95b482a8SLen Brown 
352*95b482a8SLen Brown 			/* Fetch count of segments remaining in name path */
353*95b482a8SLen Brown 
354*95b482a8SLen Brown 			aml_address++;
355*95b482a8SLen Brown 			num_segments = *aml_address;
356*95b482a8SLen Brown 
357*95b482a8SLen Brown 			name_string =
358*95b482a8SLen Brown 			    acpi_ex_allocate_name_string(prefix_count,
359*95b482a8SLen Brown 							 num_segments);
360*95b482a8SLen Brown 			if (!name_string) {
361*95b482a8SLen Brown 				status = AE_NO_MEMORY;
362*95b482a8SLen Brown 				break;
363*95b482a8SLen Brown 			}
364*95b482a8SLen Brown 
365*95b482a8SLen Brown 			/* Indicate that we processed a prefix */
366*95b482a8SLen Brown 
367*95b482a8SLen Brown 			aml_address++;
368*95b482a8SLen Brown 			has_prefix = TRUE;
369*95b482a8SLen Brown 
370*95b482a8SLen Brown 			while (num_segments &&
371*95b482a8SLen Brown 			       (status =
372*95b482a8SLen Brown 				acpi_ex_name_segment(&aml_address,
373*95b482a8SLen Brown 						     name_string)) == AE_OK) {
374*95b482a8SLen Brown 				num_segments--;
375*95b482a8SLen Brown 			}
376*95b482a8SLen Brown 
377*95b482a8SLen Brown 			break;
378*95b482a8SLen Brown 
379*95b482a8SLen Brown 		case 0:
380*95b482a8SLen Brown 
381*95b482a8SLen Brown 			/* null_name valid as of 8-12-98 ASL/AML Grammar Update */
382*95b482a8SLen Brown 
383*95b482a8SLen Brown 			if (prefix_count == ACPI_UINT32_MAX) {
384*95b482a8SLen Brown 				ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
385*95b482a8SLen Brown 						  "NameSeg is \"\\\" followed by NULL\n"));
386*95b482a8SLen Brown 			}
387*95b482a8SLen Brown 
388*95b482a8SLen Brown 			/* Consume the NULL byte */
389*95b482a8SLen Brown 
390*95b482a8SLen Brown 			aml_address++;
391*95b482a8SLen Brown 			name_string =
392*95b482a8SLen Brown 			    acpi_ex_allocate_name_string(prefix_count, 0);
393*95b482a8SLen Brown 			if (!name_string) {
394*95b482a8SLen Brown 				status = AE_NO_MEMORY;
395*95b482a8SLen Brown 				break;
396*95b482a8SLen Brown 			}
397*95b482a8SLen Brown 
398*95b482a8SLen Brown 			break;
399*95b482a8SLen Brown 
400*95b482a8SLen Brown 		default:
401*95b482a8SLen Brown 
402*95b482a8SLen Brown 			/* Name segment string */
403*95b482a8SLen Brown 
404*95b482a8SLen Brown 			name_string =
405*95b482a8SLen Brown 			    acpi_ex_allocate_name_string(prefix_count, 1);
406*95b482a8SLen Brown 			if (!name_string) {
407*95b482a8SLen Brown 				status = AE_NO_MEMORY;
408*95b482a8SLen Brown 				break;
409*95b482a8SLen Brown 			}
410*95b482a8SLen Brown 
411*95b482a8SLen Brown 			status =
412*95b482a8SLen Brown 			    acpi_ex_name_segment(&aml_address, name_string);
413*95b482a8SLen Brown 			break;
414*95b482a8SLen Brown 		}
415*95b482a8SLen Brown 	}
416*95b482a8SLen Brown 
417*95b482a8SLen Brown 	if (AE_CTRL_PENDING == status && has_prefix) {
418*95b482a8SLen Brown 
419*95b482a8SLen Brown 		/* Ran out of segments after processing a prefix */
420*95b482a8SLen Brown 
421*95b482a8SLen Brown 		ACPI_ERROR((AE_INFO, "Malformed Name at %p", name_string));
422*95b482a8SLen Brown 		status = AE_AML_BAD_NAME;
423*95b482a8SLen Brown 	}
424*95b482a8SLen Brown 
425*95b482a8SLen Brown 	if (ACPI_FAILURE(status)) {
426*95b482a8SLen Brown 		if (name_string) {
427*95b482a8SLen Brown 			ACPI_FREE(name_string);
428*95b482a8SLen Brown 		}
429*95b482a8SLen Brown 		return_ACPI_STATUS(status);
430*95b482a8SLen Brown 	}
431*95b482a8SLen Brown 
432*95b482a8SLen Brown 	*out_name_string = name_string;
433*95b482a8SLen Brown 	*out_name_length = (u32) (aml_address - in_aml_address);
434*95b482a8SLen Brown 
435*95b482a8SLen Brown 	return_ACPI_STATUS(status);
436*95b482a8SLen Brown }
437