[process] Include process name in debug messages
[ipxe.git] / src / core / iobuf.c
1 /*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <stdint.h>
27 #include <strings.h>
28 #include <errno.h>
29 #include <ipxe/malloc.h>
30 #include <ipxe/iobuf.h>
31
32 /** @file
33 *
34 * I/O buffers
35 *
36 */
37
38 /**
39 * Allocate I/O buffer with specified alignment and offset
40 *
41 * @v len Required length of buffer
42 * @v align Physical alignment
43 * @v offset Offset from physical alignment
44 * @ret iobuf I/O buffer, or NULL if none available
45 *
46 * @c align will be rounded up to the nearest power of two.
47 */
48 struct io_buffer * alloc_iob_raw ( size_t len, size_t align, size_t offset ) {
49 struct io_buffer *iobuf;
50 size_t padding;
51 size_t threshold;
52 unsigned int align_log2;
53 void *data;
54
55 /* Calculate padding required below alignment boundary to
56 * ensure that a correctly aligned inline struct io_buffer
57 * could fit (regardless of the requested offset).
58 */
59 padding = ( sizeof ( *iobuf ) + __alignof__ ( *iobuf ) - 1 );
60
61 /* Round up requested alignment to at least the size of the
62 * padding, to simplify subsequent calculations.
63 */
64 if ( align < padding )
65 align = padding;
66
67 /* Round up alignment to the nearest power of two, avoiding
68 * a potentially undefined shift operation.
69 */
70 align_log2 = fls ( align - 1 );
71 if ( align_log2 >= ( 8 * sizeof ( align ) ) )
72 return NULL;
73 align = ( 1UL << align_log2 );
74
75 /* Calculate length threshold */
76 assert ( align >= padding );
77 threshold = ( align - padding );
78
79 /* Allocate buffer plus an inline descriptor as a single unit,
80 * unless doing so would push the total size over the
81 * alignment boundary.
82 */
83 if ( len <= threshold ) {
84
85 /* Round up buffer length to ensure that struct
86 * io_buffer is aligned.
87 */
88 len += ( ( - len - offset ) & ( __alignof__ ( *iobuf ) - 1 ) );
89
90 /* Allocate memory for buffer plus descriptor */
91 data = malloc_dma_offset ( len + sizeof ( *iobuf ), align,
92 offset );
93 if ( ! data )
94 return NULL;
95 iobuf = ( data + len );
96
97 } else {
98
99 /* Allocate memory for buffer */
100 data = malloc_dma_offset ( len, align, offset );
101 if ( ! data )
102 return NULL;
103
104 /* Allocate memory for descriptor */
105 iobuf = malloc ( sizeof ( *iobuf ) );
106 if ( ! iobuf ) {
107 free_dma ( data, len );
108 return NULL;
109 }
110 }
111
112 /* Populate descriptor */
113 iobuf->head = iobuf->data = iobuf->tail = data;
114 iobuf->end = ( data + len );
115
116 return iobuf;
117 }
118
119 /**
120 * Allocate I/O buffer
121 *
122 * @v len Required length of buffer
123 * @ret iobuf I/O buffer, or NULL if none available
124 *
125 * The I/O buffer will be physically aligned on its own size (rounded
126 * up to the nearest power of two).
127 */
128 struct io_buffer * alloc_iob ( size_t len ) {
129
130 /* Pad to minimum length */
131 if ( len < IOB_ZLEN )
132 len = IOB_ZLEN;
133
134 /* Align buffer on its own size to avoid potential problems
135 * with boundary-crossing DMA.
136 */
137 return alloc_iob_raw ( len, len, 0 );
138 }
139
140 /**
141 * Free I/O buffer
142 *
143 * @v iobuf I/O buffer
144 */
145 void free_iob ( struct io_buffer *iobuf ) {
146 size_t len;
147
148 /* Allow free_iob(NULL) to be valid */
149 if ( ! iobuf )
150 return;
151
152 /* Sanity checks */
153 assert ( iobuf->head <= iobuf->data );
154 assert ( iobuf->data <= iobuf->tail );
155 assert ( iobuf->tail <= iobuf->end );
156
157 /* Free buffer */
158 len = ( iobuf->end - iobuf->head );
159 if ( iobuf->end == iobuf ) {
160
161 /* Descriptor is inline */
162 free_dma ( iobuf->head, ( len + sizeof ( *iobuf ) ) );
163
164 } else {
165
166 /* Descriptor is detached */
167 free_dma ( iobuf->head, len );
168 free ( iobuf );
169 }
170 }
171
172 /**
173 * Ensure I/O buffer has sufficient headroom
174 *
175 * @v iobuf I/O buffer
176 * @v len Required headroom
177 *
178 * This function currently only checks for the required headroom; it
179 * does not reallocate the I/O buffer if required. If we ever have a
180 * code path that requires this functionality, it's a fairly trivial
181 * change to make.
182 */
183 int iob_ensure_headroom ( struct io_buffer *iobuf, size_t len ) {
184
185 if ( iob_headroom ( iobuf ) >= len )
186 return 0;
187 return -ENOBUFS;
188 }
189
190 /**
191 * Concatenate I/O buffers into a single buffer
192 *
193 * @v list List of I/O buffers
194 * @ret iobuf Concatenated I/O buffer, or NULL on allocation failure
195 *
196 * After a successful concatenation, the list will be empty.
197 */
198 struct io_buffer * iob_concatenate ( struct list_head *list ) {
199 struct io_buffer *iobuf;
200 struct io_buffer *tmp;
201 struct io_buffer *concatenated;
202 size_t len = 0;
203
204 /* If the list contains only a single entry, avoid an
205 * unnecessary additional allocation.
206 */
207 if ( list_is_singular ( list ) ) {
208 iobuf = list_first_entry ( list, struct io_buffer, list );
209 INIT_LIST_HEAD ( list );
210 return iobuf;
211 }
212
213 /* Calculate total length */
214 list_for_each_entry ( iobuf, list, list )
215 len += iob_len ( iobuf );
216
217 /* Allocate new I/O buffer */
218 concatenated = alloc_iob_raw ( len, __alignof__ ( *iobuf ), 0 );
219 if ( ! concatenated )
220 return NULL;
221
222 /* Move data to new I/O buffer */
223 list_for_each_entry_safe ( iobuf, tmp, list, list ) {
224 list_del ( &iobuf->list );
225 memcpy ( iob_put ( concatenated, iob_len ( iobuf ) ),
226 iobuf->data, iob_len ( iobuf ) );
227 free_iob ( iobuf );
228 }
229
230 return concatenated;
231 }
232
233 /**
234 * Split I/O buffer
235 *
236 * @v iobuf I/O buffer
237 * @v len Length to split into a new I/O buffer
238 * @ret split New I/O buffer, or NULL on allocation failure
239 *
240 * Split the first @c len bytes of the existing I/O buffer into a
241 * separate I/O buffer. The resulting buffers are likely to have no
242 * headroom or tailroom.
243 *
244 * If this call fails, then the original buffer will be unmodified.
245 */
246 struct io_buffer * iob_split ( struct io_buffer *iobuf, size_t len ) {
247 struct io_buffer *split;
248
249 /* Sanity checks */
250 assert ( len <= iob_len ( iobuf ) );
251
252 /* Allocate new I/O buffer */
253 split = alloc_iob ( len );
254 if ( ! split )
255 return NULL;
256
257 /* Copy in data */
258 memcpy ( iob_put ( split, len ), iobuf->data, len );
259 iob_pull ( iobuf, len );
260 return split;
261 }