Isaku Yamahata | b15993f | 2008-04-02 10:54:01 -0700 | [diff] [blame^] | 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 | } |