includecheck fix: drivers/xen, evtchn.c
[linux-2.6.git] / drivers / xen / xencomm.c
1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 2 of the License, or
5  * (at your option) any later version.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * along with this program; if not, write to the Free Software
14  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
15  *
16  * Copyright (C) IBM Corp. 2006
17  *
18  * Authors: Hollis Blanchard <hollisb@us.ibm.com>
19  */
20
21 #include <linux/gfp.h>
22 #include <linux/mm.h>
23 #include <asm/page.h>
24 #include <xen/xencomm.h>
25 #include <xen/interface/xen.h>
26 #include <asm/xen/xencomm.h>    /* for xencomm_is_phys_contiguous() */
27
28 static int xencomm_init(struct xencomm_desc *desc,
29                         void *buffer, unsigned long bytes)
30 {
31         unsigned long recorded = 0;
32         int i = 0;
33
34         while ((recorded < bytes) && (i < desc->nr_addrs)) {
35                 unsigned long vaddr = (unsigned long)buffer + recorded;
36                 unsigned long paddr;
37                 int offset;
38                 int chunksz;
39
40                 offset = vaddr % PAGE_SIZE; /* handle partial pages */
41                 chunksz = min(PAGE_SIZE - offset, bytes - recorded);
42
43                 paddr = xencomm_vtop(vaddr);
44                 if (paddr == ~0UL) {
45                         printk(KERN_DEBUG "%s: couldn't translate vaddr %lx\n",
46                                __func__, vaddr);
47                         return -EINVAL;
48                 }
49
50                 desc->address[i++] = paddr;
51                 recorded += chunksz;
52         }
53
54         if (recorded < bytes) {
55                 printk(KERN_DEBUG
56                        "%s: could only translate %ld of %ld bytes\n",
57                        __func__, recorded, bytes);
58                 return -ENOSPC;
59         }
60
61         /* mark remaining addresses invalid (just for safety) */
62         while (i < desc->nr_addrs)
63                 desc->address[i++] = XENCOMM_INVALID;
64
65         desc->magic = XENCOMM_MAGIC;
66
67         return 0;
68 }
69
70 static struct xencomm_desc *xencomm_alloc(gfp_t gfp_mask,
71                                           void *buffer, unsigned long bytes)
72 {
73         struct xencomm_desc *desc;
74         unsigned long buffer_ulong = (unsigned long)buffer;
75         unsigned long start = buffer_ulong & PAGE_MASK;
76         unsigned long end = (buffer_ulong + bytes) | ~PAGE_MASK;
77         unsigned long nr_addrs = (end - start + 1) >> PAGE_SHIFT;
78         unsigned long size = sizeof(*desc) +
79                 sizeof(desc->address[0]) * nr_addrs;
80
81         /*
82          * slab allocator returns at least sizeof(void*) aligned pointer.
83          * When sizeof(*desc) > sizeof(void*), struct xencomm_desc might
84          * cross page boundary.
85          */
86         if (sizeof(*desc) > sizeof(void *)) {
87                 unsigned long order = get_order(size);
88                 desc = (struct xencomm_desc *)__get_free_pages(gfp_mask,
89                                                                order);
90                 if (desc == NULL)
91                         return NULL;
92
93                 desc->nr_addrs =
94                         ((PAGE_SIZE << order) - sizeof(struct xencomm_desc)) /
95                         sizeof(*desc->address);
96         } else {
97                 desc = kmalloc(size, gfp_mask);
98                 if (desc == NULL)
99                         return NULL;
100
101                 desc->nr_addrs = nr_addrs;
102         }
103         return desc;
104 }
105
106 void xencomm_free(struct xencomm_handle *desc)
107 {
108         if (desc && !((ulong)desc & XENCOMM_INLINE_FLAG)) {
109                 struct xencomm_desc *desc__ = (struct xencomm_desc *)desc;
110                 if (sizeof(*desc__) > sizeof(void *)) {
111                         unsigned long size = sizeof(*desc__) +
112                                 sizeof(desc__->address[0]) * desc__->nr_addrs;
113                         unsigned long order = get_order(size);
114                         free_pages((unsigned long)__va(desc), order);
115                 } else
116                         kfree(__va(desc));
117         }
118 }
119
120 static int xencomm_create(void *buffer, unsigned long bytes,
121                           struct xencomm_desc **ret, gfp_t gfp_mask)
122 {
123         struct xencomm_desc *desc;
124         int rc;
125
126         pr_debug("%s: %p[%ld]\n", __func__, buffer, bytes);
127
128         if (bytes == 0) {
129                 /* don't create a descriptor; Xen recognizes NULL. */
130                 BUG_ON(buffer != NULL);
131                 *ret = NULL;
132                 return 0;
133         }
134
135         BUG_ON(buffer == NULL); /* 'bytes' is non-zero */
136
137         desc = xencomm_alloc(gfp_mask, buffer, bytes);
138         if (!desc) {
139                 printk(KERN_DEBUG "%s failure\n", "xencomm_alloc");
140                 return -ENOMEM;
141         }
142
143         rc = xencomm_init(desc, buffer, bytes);
144         if (rc) {
145                 printk(KERN_DEBUG "%s failure: %d\n", "xencomm_init", rc);
146                 xencomm_free((struct xencomm_handle *)__pa(desc));
147                 return rc;
148         }
149
150         *ret = desc;
151         return 0;
152 }
153
154 static struct xencomm_handle *xencomm_create_inline(void *ptr)
155 {
156         unsigned long paddr;
157
158         BUG_ON(!xencomm_is_phys_contiguous((unsigned long)ptr));
159
160         paddr = (unsigned long)xencomm_pa(ptr);
161         BUG_ON(paddr & XENCOMM_INLINE_FLAG);
162         return (struct xencomm_handle *)(paddr | XENCOMM_INLINE_FLAG);
163 }
164
165 /* "mini" routine, for stack-based communications: */
166 static int xencomm_create_mini(void *buffer,
167         unsigned long bytes, struct xencomm_mini *xc_desc,
168         struct xencomm_desc **ret)
169 {
170         int rc = 0;
171         struct xencomm_desc *desc;
172         BUG_ON(((unsigned long)xc_desc) % sizeof(*xc_desc) != 0);
173
174         desc = (void *)xc_desc;
175
176         desc->nr_addrs = XENCOMM_MINI_ADDRS;
177
178         rc = xencomm_init(desc, buffer, bytes);
179         if (!rc)
180                 *ret = desc;
181
182         return rc;
183 }
184
185 struct xencomm_handle *xencomm_map(void *ptr, unsigned long bytes)
186 {
187         int rc;
188         struct xencomm_desc *desc;
189
190         if (xencomm_is_phys_contiguous((unsigned long)ptr))
191                 return xencomm_create_inline(ptr);
192
193         rc = xencomm_create(ptr, bytes, &desc, GFP_KERNEL);
194
195         if (rc || desc == NULL)
196                 return NULL;
197
198         return xencomm_pa(desc);
199 }
200
201 struct xencomm_handle *__xencomm_map_no_alloc(void *ptr, unsigned long bytes,
202                         struct xencomm_mini *xc_desc)
203 {
204         int rc;
205         struct xencomm_desc *desc = NULL;
206
207         if (xencomm_is_phys_contiguous((unsigned long)ptr))
208                 return xencomm_create_inline(ptr);
209
210         rc = xencomm_create_mini(ptr, bytes, xc_desc,
211                                 &desc);
212
213         if (rc)
214                 return NULL;
215
216         return xencomm_pa(desc);
217 }