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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 | #ifdef __ia64__ | |
27 | #include <asm/xen/xencomm.h> /* for is_kern_addr() */ | |
28 | #endif | |
29 | ||
30 | #ifdef HAVE_XEN_PLATFORM_COMPAT_H | |
31 | #include <xen/platform-compat.h> | |
32 | #endif | |
33 | ||
34 | static int xencomm_init(struct xencomm_desc *desc, | |
35 | void *buffer, unsigned long bytes) | |
36 | { | |
37 | unsigned long recorded = 0; | |
38 | int i = 0; | |
39 | ||
40 | while ((recorded < bytes) && (i < desc->nr_addrs)) { | |
41 | unsigned long vaddr = (unsigned long)buffer + recorded; | |
42 | unsigned long paddr; | |
43 | int offset; | |
44 | int chunksz; | |
45 | ||
46 | offset = vaddr % PAGE_SIZE; /* handle partial pages */ | |
47 | chunksz = min(PAGE_SIZE - offset, bytes - recorded); | |
48 | ||
49 | paddr = xencomm_vtop(vaddr); | |
50 | if (paddr == ~0UL) { | |
51 | printk(KERN_DEBUG "%s: couldn't translate vaddr %lx\n", | |
52 | __func__, vaddr); | |
53 | return -EINVAL; | |
54 | } | |
55 | ||
56 | desc->address[i++] = paddr; | |
57 | recorded += chunksz; | |
58 | } | |
59 | ||
60 | if (recorded < bytes) { | |
61 | printk(KERN_DEBUG | |
62 | "%s: could only translate %ld of %ld bytes\n", | |
63 | __func__, recorded, bytes); | |
64 | return -ENOSPC; | |
65 | } | |
66 | ||
67 | /* mark remaining addresses invalid (just for safety) */ | |
68 | while (i < desc->nr_addrs) | |
69 | desc->address[i++] = XENCOMM_INVALID; | |
70 | ||
71 | desc->magic = XENCOMM_MAGIC; | |
72 | ||
73 | return 0; | |
74 | } | |
75 | ||
76 | static struct xencomm_desc *xencomm_alloc(gfp_t gfp_mask, | |
77 | void *buffer, unsigned long bytes) | |
78 | { | |
79 | struct xencomm_desc *desc; | |
80 | unsigned long buffer_ulong = (unsigned long)buffer; | |
81 | unsigned long start = buffer_ulong & PAGE_MASK; | |
82 | unsigned long end = (buffer_ulong + bytes) | ~PAGE_MASK; | |
83 | unsigned long nr_addrs = (end - start + 1) >> PAGE_SHIFT; | |
84 | unsigned long size = sizeof(*desc) + | |
85 | sizeof(desc->address[0]) * nr_addrs; | |
86 | ||
87 | /* | |
88 | * slab allocator returns at least sizeof(void*) aligned pointer. | |
89 | * When sizeof(*desc) > sizeof(void*), struct xencomm_desc might | |
90 | * cross page boundary. | |
91 | */ | |
92 | if (sizeof(*desc) > sizeof(void *)) { | |
93 | unsigned long order = get_order(size); | |
94 | desc = (struct xencomm_desc *)__get_free_pages(gfp_mask, | |
95 | order); | |
96 | if (desc == NULL) | |
97 | return NULL; | |
98 | ||
99 | desc->nr_addrs = | |
100 | ((PAGE_SIZE << order) - sizeof(struct xencomm_desc)) / | |
101 | sizeof(*desc->address); | |
102 | } else { | |
103 | desc = kmalloc(size, gfp_mask); | |
104 | if (desc == NULL) | |
105 | return NULL; | |
106 | ||
107 | desc->nr_addrs = nr_addrs; | |
108 | } | |
109 | return desc; | |
110 | } | |
111 | ||
112 | void xencomm_free(struct xencomm_handle *desc) | |
113 | { | |
114 | if (desc && !((ulong)desc & XENCOMM_INLINE_FLAG)) { | |
115 | struct xencomm_desc *desc__ = (struct xencomm_desc *)desc; | |
116 | if (sizeof(*desc__) > sizeof(void *)) { | |
117 | unsigned long size = sizeof(*desc__) + | |
118 | sizeof(desc__->address[0]) * desc__->nr_addrs; | |
119 | unsigned long order = get_order(size); | |
120 | free_pages((unsigned long)__va(desc), order); | |
121 | } else | |
122 | kfree(__va(desc)); | |
123 | } | |
124 | } | |
125 | ||
126 | static int xencomm_create(void *buffer, unsigned long bytes, | |
127 | struct xencomm_desc **ret, gfp_t gfp_mask) | |
128 | { | |
129 | struct xencomm_desc *desc; | |
130 | int rc; | |
131 | ||
132 | pr_debug("%s: %p[%ld]\n", __func__, buffer, bytes); | |
133 | ||
134 | if (bytes == 0) { | |
135 | /* don't create a descriptor; Xen recognizes NULL. */ | |
136 | BUG_ON(buffer != NULL); | |
137 | *ret = NULL; | |
138 | return 0; | |
139 | } | |
140 | ||
141 | BUG_ON(buffer == NULL); /* 'bytes' is non-zero */ | |
142 | ||
143 | desc = xencomm_alloc(gfp_mask, buffer, bytes); | |
144 | if (!desc) { | |
145 | printk(KERN_DEBUG "%s failure\n", "xencomm_alloc"); | |
146 | return -ENOMEM; | |
147 | } | |
148 | ||
149 | rc = xencomm_init(desc, buffer, bytes); | |
150 | if (rc) { | |
151 | printk(KERN_DEBUG "%s failure: %d\n", "xencomm_init", rc); | |
152 | xencomm_free((struct xencomm_handle *)__pa(desc)); | |
153 | return rc; | |
154 | } | |
155 | ||
156 | *ret = desc; | |
157 | return 0; | |
158 | } | |
159 | ||
160 | /* check if memory address is within VMALLOC region */ | |
161 | static int is_phys_contiguous(unsigned long addr) | |
162 | { | |
163 | if (!is_kernel_addr(addr)) | |
164 | return 0; | |
165 | ||
166 | return (addr < VMALLOC_START) || (addr >= VMALLOC_END); | |
167 | } | |
168 | ||
169 | static struct xencomm_handle *xencomm_create_inline(void *ptr) | |
170 | { | |
171 | unsigned long paddr; | |
172 | ||
173 | BUG_ON(!is_phys_contiguous((unsigned long)ptr)); | |
174 | ||
175 | paddr = (unsigned long)xencomm_pa(ptr); | |
176 | BUG_ON(paddr & XENCOMM_INLINE_FLAG); | |
177 | return (struct xencomm_handle *)(paddr | XENCOMM_INLINE_FLAG); | |
178 | } | |
179 | ||
180 | /* "mini" routine, for stack-based communications: */ | |
181 | static int xencomm_create_mini(void *buffer, | |
182 | unsigned long bytes, struct xencomm_mini *xc_desc, | |
183 | struct xencomm_desc **ret) | |
184 | { | |
185 | int rc = 0; | |
186 | struct xencomm_desc *desc; | |
187 | BUG_ON(((unsigned long)xc_desc) % sizeof(*xc_desc) != 0); | |
188 | ||
189 | desc = (void *)xc_desc; | |
190 | ||
191 | desc->nr_addrs = XENCOMM_MINI_ADDRS; | |
192 | ||
193 | rc = xencomm_init(desc, buffer, bytes); | |
194 | if (!rc) | |
195 | *ret = desc; | |
196 | ||
197 | return rc; | |
198 | } | |
199 | ||
200 | struct xencomm_handle *xencomm_map(void *ptr, unsigned long bytes) | |
201 | { | |
202 | int rc; | |
203 | struct xencomm_desc *desc; | |
204 | ||
205 | if (is_phys_contiguous((unsigned long)ptr)) | |
206 | return xencomm_create_inline(ptr); | |
207 | ||
208 | rc = xencomm_create(ptr, bytes, &desc, GFP_KERNEL); | |
209 | ||
210 | if (rc || desc == NULL) | |
211 | return NULL; | |
212 | ||
213 | return xencomm_pa(desc); | |
214 | } | |
215 | ||
216 | struct xencomm_handle *__xencomm_map_no_alloc(void *ptr, unsigned long bytes, | |
217 | struct xencomm_mini *xc_desc) | |
218 | { | |
219 | int rc; | |
220 | struct xencomm_desc *desc = NULL; | |
221 | ||
222 | if (is_phys_contiguous((unsigned long)ptr)) | |
223 | return xencomm_create_inline(ptr); | |
224 | ||
225 | rc = xencomm_create_mini(ptr, bytes, xc_desc, | |
226 | &desc); | |
227 | ||
228 | if (rc) | |
229 | return NULL; | |
230 | ||
231 | return xencomm_pa(desc); | |
232 | } |