x86/kernel/ksysfs.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Architecture specific sysfs attributes in /sys/kernel
0004  *
0005  * Copyright (C) 2007, Intel Corp.
0006  *      Huang Ying <ying.huang@intel.com>
0007  * Copyright (C) 2013, 2013 Red Hat, Inc.
0008  *      Dave Young <dyoung@redhat.com>
0009  */
0010
0011 #include <linux/kobject.h>
0012 #include <linux/string.h>
0013 #include <linux/sysfs.h>
0014 #include <linux/init.h>
0015 #include <linux/stat.h>
0016 #include <linux/slab.h>
0017 #include <linux/mm.h>
0018 #include <linux/io.h>
0019
0020 #include <asm/setup.h>
0021
0022 static ssize_t version_show(struct kobject *kobj,
0023                 struct kobj_attribute *attr, char *buf)
0024 {
0025     return sprintf(buf, "0x%04x\n", boot_params.hdr.version);
0026 }
0027
0028 static struct kobj_attribute boot_params_version_attr = __ATTR_RO(version);
0029
0030 static ssize_t boot_params_data_read(struct file *fp, struct kobject *kobj,
0031                      struct bin_attribute *bin_attr,
0032                      char *buf, loff_t off, size_t count)
0033 {
0034     memcpy(buf, (void *)&boot_params + off, count);
0035     return count;
0036 }
0037
0038 static struct bin_attribute boot_params_data_attr = {
0039     .attr = {
0040         .name = "data",
0041         .mode = S_IRUGO,
0042     },
0043     .read = boot_params_data_read,
0044     .size = sizeof(boot_params),
0045 };
0046
0047 static struct attribute *boot_params_version_attrs[] = {
0048     &boot_params_version_attr.attr,
0049     NULL,
0050 };
0051
0052 static struct bin_attribute *boot_params_data_attrs[] = {
0053     &boot_params_data_attr,
0054     NULL,
0055 };
0056
0057 static const struct attribute_group boot_params_attr_group = {
0058     .attrs = boot_params_version_attrs,
0059     .bin_attrs = boot_params_data_attrs,
0060 };
0061
0062 static int kobj_to_setup_data_nr(struct kobject *kobj, int *nr)
0063 {
0064     const char *name;
0065
0066     name = kobject_name(kobj);
0067     return kstrtoint(name, 10, nr);
0068 }
0069
0070 static int get_setup_data_paddr(int nr, u64 *paddr)
0071 {
0072     int i = 0;
0073     struct setup_data *data;
0074     u64 pa_data = boot_params.hdr.setup_data;
0075
0076     while (pa_data) {
0077         if (nr == i) {
0078             *paddr = pa_data;
0079             return 0;
0080         }
0081         data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
0082         if (!data)
0083             return -ENOMEM;
0084
0085         pa_data = data->next;
0086         memunmap(data);
0087         i++;
0088     }
0089     return -EINVAL;
0090 }
0091
0092 static int __init get_setup_data_size(int nr, size_t *size)
0093 {
0094     u64 pa_data = boot_params.hdr.setup_data, pa_next;
0095     struct setup_indirect *indirect;
0096     struct setup_data *data;
0097     int i = 0;
0098     u32 len;
0099
0100     while (pa_data) {
0101         data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
0102         if (!data)
0103             return -ENOMEM;
0104         pa_next = data->next;
0105
0106         if (nr == i) {
0107             if (data->type == SETUP_INDIRECT) {
0108                 len = sizeof(*data) + data->len;
0109                 memunmap(data);
0110                 data = memremap(pa_data, len, MEMREMAP_WB);
0111                 if (!data)
0112                     return -ENOMEM;
0113
0114                 indirect = (struct setup_indirect *)data->data;
0115
0116                 if (indirect->type != SETUP_INDIRECT)
0117                     *size = indirect->len;
0118                 else
0119                     *size = data->len;
0120             } else {
0121                 *size = data->len;
0122             }
0123
0124             memunmap(data);
0125             return 0;
0126         }
0127
0128         pa_data = pa_next;
0129         memunmap(data);
0130         i++;
0131     }
0132     return -EINVAL;
0133 }
0134
0135 static ssize_t type_show(struct kobject *kobj,
0136              struct kobj_attribute *attr, char *buf)
0137 {
0138     struct setup_indirect *indirect;
0139     struct setup_data *data;
0140     int nr, ret;
0141     u64 paddr;
0142     u32 len;
0143
0144     ret = kobj_to_setup_data_nr(kobj, &nr);
0145     if (ret)
0146         return ret;
0147
0148     ret = get_setup_data_paddr(nr, &paddr);
0149     if (ret)
0150         return ret;
0151     data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
0152     if (!data)
0153         return -ENOMEM;
0154
0155     if (data->type == SETUP_INDIRECT) {
0156         len = sizeof(*data) + data->len;
0157         memunmap(data);
0158         data = memremap(paddr, len, MEMREMAP_WB);
0159         if (!data)
0160             return -ENOMEM;
0161
0162         indirect = (struct setup_indirect *)data->data;
0163
0164         ret = sprintf(buf, "0x%x\n", indirect->type);
0165     } else {
0166         ret = sprintf(buf, "0x%x\n", data->type);
0167     }
0168
0169     memunmap(data);
0170     return ret;
0171 }
0172
0173 static ssize_t setup_data_data_read(struct file *fp,
0174                     struct kobject *kobj,
0175                     struct bin_attribute *bin_attr,
0176                     char *buf,
0177                     loff_t off, size_t count)
0178 {
0179     struct setup_indirect *indirect;
0180     struct setup_data *data;
0181     int nr, ret = 0;
0182     u64 paddr, len;
0183     void *p;
0184
0185     ret = kobj_to_setup_data_nr(kobj, &nr);
0186     if (ret)
0187         return ret;
0188
0189     ret = get_setup_data_paddr(nr, &paddr);
0190     if (ret)
0191         return ret;
0192     data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
0193     if (!data)
0194         return -ENOMEM;
0195
0196     if (data->type == SETUP_INDIRECT) {
0197         len = sizeof(*data) + data->len;
0198         memunmap(data);
0199         data = memremap(paddr, len, MEMREMAP_WB);
0200         if (!data)
0201             return -ENOMEM;
0202
0203         indirect = (struct setup_indirect *)data->data;
0204
0205         if (indirect->type != SETUP_INDIRECT) {
0206             paddr = indirect->addr;
0207             len = indirect->len;
0208         } else {
0209             /*
0210              * Even though this is technically undefined, return
0211              * the data as though it is a normal setup_data struct.
0212              * This will at least allow it to be inspected.
0213              */
0214             paddr += sizeof(*data);
0215             len = data->len;
0216         }
0217     } else {
0218         paddr += sizeof(*data);
0219         len = data->len;
0220     }
0221
0222     if (off > len) {
0223         ret = -EINVAL;
0224         goto out;
0225     }
0226
0227     if (count > len - off)
0228         count = len - off;
0229
0230     if (!count)
0231         goto out;
0232
0233     ret = count;
0234     p = memremap(paddr, len, MEMREMAP_WB);
0235     if (!p) {
0236         ret = -ENOMEM;
0237         goto out;
0238     }
0239     memcpy(buf, p + off, count);
0240     memunmap(p);
0241 out:
0242     memunmap(data);
0243     return ret;
0244 }
0245
0246 static struct kobj_attribute type_attr = __ATTR_RO(type);
0247
0248 static struct bin_attribute data_attr __ro_after_init = {
0249     .attr = {
0250         .name = "data",
0251         .mode = S_IRUGO,
0252     },
0253     .read = setup_data_data_read,
0254 };
0255
0256 static struct attribute *setup_data_type_attrs[] = {
0257     &type_attr.attr,
0258     NULL,
0259 };
0260
0261 static struct bin_attribute *setup_data_data_attrs[] = {
0262     &data_attr,
0263     NULL,
0264 };
0265
0266 static const struct attribute_group setup_data_attr_group = {
0267     .attrs = setup_data_type_attrs,
0268     .bin_attrs = setup_data_data_attrs,
0269 };
0270
0271 static int __init create_setup_data_node(struct kobject *parent,
0272                      struct kobject **kobjp, int nr)
0273 {
0274     int ret = 0;
0275     size_t size;
0276     struct kobject *kobj;
0277     char name[16]; /* should be enough for setup_data nodes numbers */
0278     snprintf(name, 16, "%d", nr);
0279
0280     kobj = kobject_create_and_add(name, parent);
0281     if (!kobj)
0282         return -ENOMEM;
0283
0284     ret = get_setup_data_size(nr, &size);
0285     if (ret)
0286         goto out_kobj;
0287
0288     data_attr.size = size;
0289     ret = sysfs_create_group(kobj, &setup_data_attr_group);
0290     if (ret)
0291         goto out_kobj;
0292     *kobjp = kobj;
0293
0294     return 0;
0295 out_kobj:
0296     kobject_put(kobj);
0297     return ret;
0298 }
0299
0300 static void __init cleanup_setup_data_node(struct kobject *kobj)
0301 {
0302     sysfs_remove_group(kobj, &setup_data_attr_group);
0303     kobject_put(kobj);
0304 }
0305
0306 static int __init get_setup_data_total_num(u64 pa_data, int *nr)
0307 {
0308     int ret = 0;
0309     struct setup_data *data;
0310
0311     *nr = 0;
0312     while (pa_data) {
0313         *nr += 1;
0314         data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
0315         if (!data) {
0316             ret = -ENOMEM;
0317             goto out;
0318         }
0319         pa_data = data->next;
0320         memunmap(data);
0321     }
0322
0323 out:
0324     return ret;
0325 }
0326
0327 static int __init create_setup_data_nodes(struct kobject *parent)
0328 {
0329     struct kobject *setup_data_kobj, **kobjp;
0330     u64 pa_data;
0331     int i, j, nr, ret = 0;
0332
0333     pa_data = boot_params.hdr.setup_data;
0334     if (!pa_data)
0335         return 0;
0336
0337     setup_data_kobj = kobject_create_and_add("setup_data", parent);
0338     if (!setup_data_kobj) {
0339         ret = -ENOMEM;
0340         goto out;
0341     }
0342
0343     ret = get_setup_data_total_num(pa_data, &nr);
0344     if (ret)
0345         goto out_setup_data_kobj;
0346
0347     kobjp = kmalloc_array(nr, sizeof(*kobjp), GFP_KERNEL);
0348     if (!kobjp) {
0349         ret = -ENOMEM;
0350         goto out_setup_data_kobj;
0351     }
0352
0353     for (i = 0; i < nr; i++) {
0354         ret = create_setup_data_node(setup_data_kobj, kobjp + i, i);
0355         if (ret)
0356             goto out_clean_nodes;
0357     }
0358
0359     kfree(kobjp);
0360     return 0;
0361
0362 out_clean_nodes:
0363     for (j = i - 1; j >= 0; j--)
0364         cleanup_setup_data_node(*(kobjp + j));
0365     kfree(kobjp);
0366 out_setup_data_kobj:
0367     kobject_put(setup_data_kobj);
0368 out:
0369     return ret;
0370 }
0371
0372 static int __init boot_params_ksysfs_init(void)
0373 {
0374     int ret;
0375     struct kobject *boot_params_kobj;
0376
0377     boot_params_kobj = kobject_create_and_add("boot_params",
0378                           kernel_kobj);
0379     if (!boot_params_kobj) {
0380         ret = -ENOMEM;
0381         goto out;
0382     }
0383
0384     ret = sysfs_create_group(boot_params_kobj, &boot_params_attr_group);
0385     if (ret)
0386         goto out_boot_params_kobj;
0387
0388     ret = create_setup_data_nodes(boot_params_kobj);
0389     if (ret)
0390         goto out_create_group;
0391
0392     return 0;
0393 out_create_group:
0394     sysfs_remove_group(boot_params_kobj, &boot_params_attr_group);
0395 out_boot_params_kobj:
0396     kobject_put(boot_params_kobj);
0397 out:
0398     return ret;
0399 }
0400
0401 arch_initcall(boot_params_ksysfs_init);