blob: 4793fc594549742389fd8b420215b2cd76fd914d [file] [log] [blame]
Isaku Yamahatab15993f2008-04-02 10:54:01 -07001/*
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
Joe Perches283c0972013-06-28 03:21:41 -070021#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
Isaku Yamahatab15993f2008-04-02 10:54:01 -070023#include <linux/mm.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090024#include <linux/slab.h>
Isaku Yamahatab15993f2008-04-02 10:54:01 -070025#include <asm/page.h>
26#include <xen/xencomm.h>
27#include <xen/interface/xen.h>
Isaku Yamahata75909fd2008-10-14 17:50:41 -070028#include <asm/xen/xencomm.h> /* for xencomm_is_phys_contiguous() */
Isaku Yamahatab15993f2008-04-02 10:54:01 -070029
30static int xencomm_init(struct xencomm_desc *desc,
31 void *buffer, unsigned long bytes)
32{
33 unsigned long recorded = 0;
34 int i = 0;
35
36 while ((recorded < bytes) && (i < desc->nr_addrs)) {
37 unsigned long vaddr = (unsigned long)buffer + recorded;
38 unsigned long paddr;
39 int offset;
40 int chunksz;
41
42 offset = vaddr % PAGE_SIZE; /* handle partial pages */
43 chunksz = min(PAGE_SIZE - offset, bytes - recorded);
44
45 paddr = xencomm_vtop(vaddr);
46 if (paddr == ~0UL) {
47 printk(KERN_DEBUG "%s: couldn't translate vaddr %lx\n",
48 __func__, vaddr);
49 return -EINVAL;
50 }
51
52 desc->address[i++] = paddr;
53 recorded += chunksz;
54 }
55
56 if (recorded < bytes) {
57 printk(KERN_DEBUG
58 "%s: could only translate %ld of %ld bytes\n",
59 __func__, recorded, bytes);
60 return -ENOSPC;
61 }
62
63 /* mark remaining addresses invalid (just for safety) */
64 while (i < desc->nr_addrs)
65 desc->address[i++] = XENCOMM_INVALID;
66
67 desc->magic = XENCOMM_MAGIC;
68
69 return 0;
70}
71
72static struct xencomm_desc *xencomm_alloc(gfp_t gfp_mask,
73 void *buffer, unsigned long bytes)
74{
75 struct xencomm_desc *desc;
76 unsigned long buffer_ulong = (unsigned long)buffer;
77 unsigned long start = buffer_ulong & PAGE_MASK;
78 unsigned long end = (buffer_ulong + bytes) | ~PAGE_MASK;
79 unsigned long nr_addrs = (end - start + 1) >> PAGE_SHIFT;
80 unsigned long size = sizeof(*desc) +
81 sizeof(desc->address[0]) * nr_addrs;
82
83 /*
84 * slab allocator returns at least sizeof(void*) aligned pointer.
85 * When sizeof(*desc) > sizeof(void*), struct xencomm_desc might
86 * cross page boundary.
87 */
88 if (sizeof(*desc) > sizeof(void *)) {
89 unsigned long order = get_order(size);
90 desc = (struct xencomm_desc *)__get_free_pages(gfp_mask,
91 order);
92 if (desc == NULL)
93 return NULL;
94
95 desc->nr_addrs =
96 ((PAGE_SIZE << order) - sizeof(struct xencomm_desc)) /
97 sizeof(*desc->address);
98 } else {
99 desc = kmalloc(size, gfp_mask);
100 if (desc == NULL)
101 return NULL;
102
103 desc->nr_addrs = nr_addrs;
104 }
105 return desc;
106}
107
108void xencomm_free(struct xencomm_handle *desc)
109{
110 if (desc && !((ulong)desc & XENCOMM_INLINE_FLAG)) {
111 struct xencomm_desc *desc__ = (struct xencomm_desc *)desc;
112 if (sizeof(*desc__) > sizeof(void *)) {
113 unsigned long size = sizeof(*desc__) +
114 sizeof(desc__->address[0]) * desc__->nr_addrs;
115 unsigned long order = get_order(size);
116 free_pages((unsigned long)__va(desc), order);
117 } else
118 kfree(__va(desc));
119 }
120}
121
122static int xencomm_create(void *buffer, unsigned long bytes,
123 struct xencomm_desc **ret, gfp_t gfp_mask)
124{
125 struct xencomm_desc *desc;
126 int rc;
127
128 pr_debug("%s: %p[%ld]\n", __func__, buffer, bytes);
129
130 if (bytes == 0) {
131 /* don't create a descriptor; Xen recognizes NULL. */
132 BUG_ON(buffer != NULL);
133 *ret = NULL;
134 return 0;
135 }
136
137 BUG_ON(buffer == NULL); /* 'bytes' is non-zero */
138
139 desc = xencomm_alloc(gfp_mask, buffer, bytes);
140 if (!desc) {
141 printk(KERN_DEBUG "%s failure\n", "xencomm_alloc");
142 return -ENOMEM;
143 }
144
145 rc = xencomm_init(desc, buffer, bytes);
146 if (rc) {
147 printk(KERN_DEBUG "%s failure: %d\n", "xencomm_init", rc);
148 xencomm_free((struct xencomm_handle *)__pa(desc));
149 return rc;
150 }
151
152 *ret = desc;
153 return 0;
154}
155
Isaku Yamahatab15993f2008-04-02 10:54:01 -0700156static struct xencomm_handle *xencomm_create_inline(void *ptr)
157{
158 unsigned long paddr;
159
Isaku Yamahata75909fd2008-10-14 17:50:41 -0700160 BUG_ON(!xencomm_is_phys_contiguous((unsigned long)ptr));
Isaku Yamahatab15993f2008-04-02 10:54:01 -0700161
162 paddr = (unsigned long)xencomm_pa(ptr);
163 BUG_ON(paddr & XENCOMM_INLINE_FLAG);
164 return (struct xencomm_handle *)(paddr | XENCOMM_INLINE_FLAG);
165}
166
167/* "mini" routine, for stack-based communications: */
168static int xencomm_create_mini(void *buffer,
169 unsigned long bytes, struct xencomm_mini *xc_desc,
170 struct xencomm_desc **ret)
171{
172 int rc = 0;
173 struct xencomm_desc *desc;
174 BUG_ON(((unsigned long)xc_desc) % sizeof(*xc_desc) != 0);
175
176 desc = (void *)xc_desc;
177
178 desc->nr_addrs = XENCOMM_MINI_ADDRS;
179
180 rc = xencomm_init(desc, buffer, bytes);
181 if (!rc)
182 *ret = desc;
183
184 return rc;
185}
186
187struct xencomm_handle *xencomm_map(void *ptr, unsigned long bytes)
188{
189 int rc;
190 struct xencomm_desc *desc;
191
Isaku Yamahata75909fd2008-10-14 17:50:41 -0700192 if (xencomm_is_phys_contiguous((unsigned long)ptr))
Isaku Yamahatab15993f2008-04-02 10:54:01 -0700193 return xencomm_create_inline(ptr);
194
195 rc = xencomm_create(ptr, bytes, &desc, GFP_KERNEL);
196
197 if (rc || desc == NULL)
198 return NULL;
199
200 return xencomm_pa(desc);
201}
202
203struct xencomm_handle *__xencomm_map_no_alloc(void *ptr, unsigned long bytes,
204 struct xencomm_mini *xc_desc)
205{
206 int rc;
207 struct xencomm_desc *desc = NULL;
208
Isaku Yamahata75909fd2008-10-14 17:50:41 -0700209 if (xencomm_is_phys_contiguous((unsigned long)ptr))
Isaku Yamahatab15993f2008-04-02 10:54:01 -0700210 return xencomm_create_inline(ptr);
211
212 rc = xencomm_create_mini(ptr, bytes, xc_desc,
213 &desc);
214
215 if (rc)
216 return NULL;
217
218 return xencomm_pa(desc);
219}