arch/x86/kernel/ksysfs.c

   1 /*
   2  * Architecture specific sysfs attributes in /sys/kernel
   3  *
   4  * Copyright (C) 2007, Intel Corp.
   5  *      Huang Ying <ying.huang@intel.com>
   6  * Copyright (C) 2013, 2013 Red Hat, Inc.
   7  *      Dave Young <dyoung@redhat.com>
   8  *
   9  * This file is released under the GPLv2
  10  */
  11
  12 #include <linux/kobject.h>
  13 #include <linux/string.h>
  14 #include <linux/sysfs.h>
  15 #include <linux/init.h>
  16 #include <linux/stat.h>
  17 #include <linux/slab.h>
  18 #include <linux/mm.h>
  19 #include <linux/io.h>
  20
  21 #include <asm/setup.h>
  22
  23 static ssize_t version_show(struct kobject *kobj,
  24                             struct kobj_attribute *attr, char *buf)
  25 {
  26         return sprintf(buf, "0x%04x\n", boot_params.hdr.version);
  27 }
  28
  29 static struct kobj_attribute boot_params_version_attr = __ATTR_RO(version);
  30
  31 static ssize_t boot_params_data_read(struct file *fp, struct kobject *kobj,
  32                                      struct bin_attribute *bin_attr,
  33                                      char *buf, loff_t off, size_t count)
  34 {
  35         memcpy(buf, (void *)&boot_params + off, count);
  36         return count;
  37 }
  38
  39 static struct bin_attribute boot_params_data_attr = {
  40         .attr = {
  41                 .name = "data",
  42                 .mode = S_IRUGO,
  43         },
  44         .read = boot_params_data_read,
  45         .size = sizeof(boot_params),
  46 };
  47
  48 static struct attribute *boot_params_version_attrs[] = {
  49         &boot_params_version_attr.attr,
  50         NULL,
  51 };
  52
  53 static struct bin_attribute *boot_params_data_attrs[] = {
  54         &boot_params_data_attr,
  55         NULL,
  56 };
  57
  58 static const struct attribute_group boot_params_attr_group = {
  59         .attrs = boot_params_version_attrs,
  60         .bin_attrs = boot_params_data_attrs,
  61 };
  62
  63 static int kobj_to_setup_data_nr(struct kobject *kobj, int *nr)
  64 {
  65         const char *name;
  66
  67         name = kobject_name(kobj);
  68         return kstrtoint(name, 10, nr);
  69 }
  70
  71 static int get_setup_data_paddr(int nr, u64 *paddr)
  72 {
  73         int i = 0;
  74         struct setup_data *data;
  75         u64 pa_data = boot_params.hdr.setup_data;
  76
  77         while (pa_data) {
  78                 if (nr == i) {
  79                         *paddr = pa_data;
  80                         return 0;
  81                 }
  82                 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
  83                 if (!data)
  84                         return -ENOMEM;
  85
  86                 pa_data = data->next;
  87                 memunmap(data);
  88                 i++;
  89         }
  90         return -EINVAL;
  91 }
  92
  93 static int __init get_setup_data_size(int nr, size_t *size)
  94 {
  95         int i = 0;
  96         struct setup_data *data;
  97         u64 pa_data = boot_params.hdr.setup_data;
  98
  99         while (pa_data) {
 100                 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 101                 if (!data)
 102                         return -ENOMEM;
 103                 if (nr == i) {
 104                         *size = data->len;
 105                         memunmap(data);
 106                         return 0;
 107                 }
 108
 109                 pa_data = data->next;
 110                 memunmap(data);
 111                 i++;
 112         }
 113         return -EINVAL;
 114 }
 115
 116 static ssize_t type_show(struct kobject *kobj,
 117                          struct kobj_attribute *attr, char *buf)
 118 {
 119         int nr, ret;
 120         u64 paddr;
 121         struct setup_data *data;
 122
 123         ret = kobj_to_setup_data_nr(kobj, &nr);
 124         if (ret)
 125                 return ret;
 126
 127         ret = get_setup_data_paddr(nr, &paddr);
 128         if (ret)
 129                 return ret;
 130         data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
 131         if (!data)
 132                 return -ENOMEM;
 133
 134         ret = sprintf(buf, "0x%x\n", data->type);
 135         memunmap(data);
 136         return ret;
 137 }
 138
 139 static ssize_t setup_data_data_read(struct file *fp,
 140                                     struct kobject *kobj,
 141                                     struct bin_attribute *bin_attr,
 142                                     char *buf,
 143                                     loff_t off, size_t count)
 144 {
 145         int nr, ret = 0;
 146         u64 paddr;
 147         struct setup_data *data;
 148         void *p;
 149
 150         ret = kobj_to_setup_data_nr(kobj, &nr);
 151         if (ret)
 152                 return ret;
 153
 154         ret = get_setup_data_paddr(nr, &paddr);
 155         if (ret)
 156                 return ret;
 157         data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
 158         if (!data)
 159                 return -ENOMEM;
 160
 161         if (off > data->len) {
 162                 ret = -EINVAL;
 163                 goto out;
 164         }
 165
 166         if (count > data->len - off)
 167                 count = data->len - off;
 168
 169         if (!count)
 170                 goto out;
 171
 172         ret = count;
 173         p = memremap(paddr + sizeof(*data), data->len, MEMREMAP_WB);
 174         if (!p) {
 175                 ret = -ENOMEM;
 176                 goto out;
 177         }
 178         memcpy(buf, p + off, count);
 179         memunmap(p);
 180 out:
 181         memunmap(data);
 182         return ret;
 183 }
 184
 185 static struct kobj_attribute type_attr = __ATTR_RO(type);
 186
 187 static struct bin_attribute data_attr __ro_after_init = {
 188         .attr = {
 189                 .name = "data",
 190                 .mode = S_IRUGO,
 191         },
 192         .read = setup_data_data_read,
 193 };
 194
 195 static struct attribute *setup_data_type_attrs[] = {
 196         &type_attr.attr,
 197         NULL,
 198 };
 199
 200 static struct bin_attribute *setup_data_data_attrs[] = {
 201         &data_attr,
 202         NULL,
 203 };
 204
 205 static const struct attribute_group setup_data_attr_group = {
 206         .attrs = setup_data_type_attrs,
 207         .bin_attrs = setup_data_data_attrs,
 208 };
 209
 210 static int __init create_setup_data_node(struct kobject *parent,
 211                                          struct kobject **kobjp, int nr)
 212 {
 213         int ret = 0;
 214         size_t size;
 215         struct kobject *kobj;
 216         char name[16]; /* should be enough for setup_data nodes numbers */
 217         snprintf(name, 16, "%d", nr);
 218
 219         kobj = kobject_create_and_add(name, parent);
 220         if (!kobj)
 221                 return -ENOMEM;
 222
 223         ret = get_setup_data_size(nr, &size);
 224         if (ret)
 225                 goto out_kobj;
 226
 227         data_attr.size = size;
 228         ret = sysfs_create_group(kobj, &setup_data_attr_group);
 229         if (ret)
 230                 goto out_kobj;
 231         *kobjp = kobj;
 232
 233         return 0;
 234 out_kobj:
 235         kobject_put(kobj);
 236         return ret;
 237 }
 238
 239 static void __init cleanup_setup_data_node(struct kobject *kobj)
 240 {
 241         sysfs_remove_group(kobj, &setup_data_attr_group);
 242         kobject_put(kobj);
 243 }
 244
 245 static int __init get_setup_data_total_num(u64 pa_data, int *nr)
 246 {
 247         int ret = 0;
 248         struct setup_data *data;
 249
 250         *nr = 0;
 251         while (pa_data) {
 252                 *nr += 1;
 253                 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
 254                 if (!data) {
 255                         ret = -ENOMEM;
 256                         goto out;
 257                 }
 258                 pa_data = data->next;
 259                 memunmap(data);
 260         }
 261
 262 out:
 263         return ret;
 264 }
 265
 266 static int __init create_setup_data_nodes(struct kobject *parent)
 267 {
 268         struct kobject *setup_data_kobj, **kobjp;
 269         u64 pa_data;
 270         int i, j, nr, ret = 0;
 271
 272         pa_data = boot_params.hdr.setup_data;
 273         if (!pa_data)
 274                 return 0;
 275
 276         setup_data_kobj = kobject_create_and_add("setup_data", parent);
 277         if (!setup_data_kobj) {
 278                 ret = -ENOMEM;
 279                 goto out;
 280         }
 281
 282         ret = get_setup_data_total_num(pa_data, &nr);
 283         if (ret)
 284                 goto out_setup_data_kobj;
 285
 286         kobjp = kmalloc_array(nr, sizeof(*kobjp), GFP_KERNEL);
 287         if (!kobjp) {
 288                 ret = -ENOMEM;
 289                 goto out_setup_data_kobj;
 290         }
 291
 292         for (i = 0; i < nr; i++) {
 293                 ret = create_setup_data_node(setup_data_kobj, kobjp + i, i);
 294                 if (ret)
 295                         goto out_clean_nodes;
 296         }
 297
 298         kfree(kobjp);
 299         return 0;
 300
 301 out_clean_nodes:
 302         for (j = i - 1; j >= 0; j--)
 303                 cleanup_setup_data_node(*(kobjp + j));
 304         kfree(kobjp);
 305 out_setup_data_kobj:
 306         kobject_put(setup_data_kobj);
 307 out:
 308         return ret;
 309 }
 310
 311 static int __init boot_params_ksysfs_init(void)
 312 {
 313         int ret;
 314         struct kobject *boot_params_kobj;
 315
 316         boot_params_kobj = kobject_create_and_add("boot_params",
 317                                                   kernel_kobj);
 318         if (!boot_params_kobj) {
 319                 ret = -ENOMEM;
 320                 goto out;
 321         }
 322
 323         ret = sysfs_create_group(boot_params_kobj, &boot_params_attr_group);
 324         if (ret)
 325                 goto out_boot_params_kobj;
 326
 327         ret = create_setup_data_nodes(boot_params_kobj);
 328         if (ret)
 329                 goto out_create_group;
 330
 331         return 0;
 332 out_create_group:
 333         sysfs_remove_group(boot_params_kobj, &boot_params_attr_group);
 334 out_boot_params_kobj:
 335         kobject_put(boot_params_kobj);
 336 out:
 337         return ret;
 338 }
 339
 340 arch_initcall(boot_params_ksysfs_init);