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Viewing changes to drivers/xen/xencomm.c

  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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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,
 
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 * 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
 *
 
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 * Authors: Hollis Blanchard <hollisb@us.ibm.com>
 
19
 */
 
20
 
 
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#include <linux/mm.h>
 
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#include <linux/slab.h>
 
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#include <asm/page.h>
 
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#include <xen/xencomm.h>
 
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#include <xen/interface/xen.h>
 
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#include <asm/xen/xencomm.h>    /* for xencomm_is_phys_contiguous() */
 
27
 
 
28
static int xencomm_init(struct xencomm_desc *desc,
 
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                        void *buffer, unsigned long bytes)
 
30
{
 
31
        unsigned long recorded = 0;
 
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        int i = 0;
 
33
 
 
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        while ((recorded < bytes) && (i < desc->nr_addrs)) {
 
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                unsigned long vaddr = (unsigned long)buffer + recorded;
 
36
                unsigned long paddr;
 
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                int offset;
 
38
                int chunksz;
 
39
 
 
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                offset = vaddr % PAGE_SIZE; /* handle partial pages */
 
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                chunksz = min(PAGE_SIZE - offset, bytes - recorded);
 
42
 
 
43
                paddr = xencomm_vtop(vaddr);
 
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                if (paddr == ~0UL) {
 
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                        printk(KERN_DEBUG "%s: couldn't translate vaddr %lx\n",
 
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                               __func__, vaddr);
 
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                        return -EINVAL;
 
48
                }
 
49
 
 
50
                desc->address[i++] = paddr;
 
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                recorded += chunksz;
 
52
        }
 
53
 
 
54
        if (recorded < bytes) {
 
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                printk(KERN_DEBUG
 
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                       "%s: could only translate %ld of %ld bytes\n",
 
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                       __func__, recorded, bytes);
 
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                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,
 
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                                          void *buffer, unsigned long bytes)
 
72
{
 
73
        struct xencomm_desc *desc;
 
74
        unsigned long buffer_ulong = (unsigned long)buffer;
 
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        unsigned long start = buffer_ulong & PAGE_MASK;
 
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        unsigned long end = (buffer_ulong + bytes) | ~PAGE_MASK;
 
77
        unsigned long nr_addrs = (end - start + 1) >> PAGE_SHIFT;
 
78
        unsigned long size = sizeof(*desc) +
 
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                sizeof(desc->address[0]) * nr_addrs;
 
80
 
 
81
        /*
 
82
         * slab allocator returns at least sizeof(void*) aligned pointer.
 
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         * When sizeof(*desc) > sizeof(void*), struct xencomm_desc might
 
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         * cross page boundary.
 
85
         */
 
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        if (sizeof(*desc) > sizeof(void *)) {
 
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                unsigned long order = get_order(size);
 
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                desc = (struct xencomm_desc *)__get_free_pages(gfp_mask,
 
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                                                               order);
 
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                if (desc == NULL)
 
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                        return NULL;
 
92
 
 
93
                desc->nr_addrs =
 
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                        ((PAGE_SIZE << order) - sizeof(struct xencomm_desc)) /
 
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                        sizeof(*desc->address);
 
96
        } else {
 
97
                desc = kmalloc(size, gfp_mask);
 
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                if (desc == NULL)
 
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                        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;
 
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                if (sizeof(*desc__) > sizeof(void *)) {
 
111
                        unsigned long size = sizeof(*desc__) +
 
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                                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
}