/* * dmi-sysfs.c * * This module exports the DMI tables read-only to userspace through the * sysfs file system. * * Data is currently found below * /sys/firmware/dmi/... * * DMI attributes are presented in attribute files with names * formatted using %d-%d, so that the first integer indicates the * structure type (0-255), and the second field is the instance of that * entry. * * Copyright 2011 Google, Inc. */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/types.h> #include <linux/kobject.h> #include <linux/dmi.h> #include <linux/capability.h> #include <linux/slab.h> #include <linux/list.h> #include <linux/io.h> #define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider the top entry type is only 8 bits */ struct dmi_sysfs_entry { struct dmi_header dh; struct kobject kobj; int instance; int position; struct list_head list; struct kobject *child; }; /* * Global list of dmi_sysfs_entry. Even though this should only be * manipulated at setup and teardown, the lazy nature of the kobject * system means we get lazy removes. */ static LIST_HEAD(entry_list); static DEFINE_SPINLOCK(entry_list_lock); /* dmi_sysfs_attribute - Top level attribute. used by all entries. */ struct dmi_sysfs_attribute { struct attribute attr; ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf); }; #define DMI_SYSFS_ATTR(_entry, _name) \ struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \ .attr = {.name = __stringify(_name), .mode = 0400}, \ .show = dmi_sysfs_##_entry##_##_name, \ } /* * dmi_sysfs_mapped_attribute - Attribute where we require the entry be * mapped in. Use in conjunction with dmi_sysfs_specialize_attr_ops. */ struct dmi_sysfs_mapped_attribute { struct attribute attr; ssize_t (*show)(struct dmi_sysfs_entry *entry, const struct dmi_header *dh, char *buf); }; #define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \ struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \ .attr = {.name = __stringify(_name), .mode = 0400}, \ .show = dmi_sysfs_##_entry##_##_name, \ } /************************************************* * Generic DMI entry support. *************************************************/ static void dmi_entry_free(struct kobject *kobj) { kfree(kobj); } static struct dmi_sysfs_entry *to_entry(struct kobject *kobj) { return container_of(kobj, struct dmi_sysfs_entry, kobj); } static struct dmi_sysfs_attribute *to_attr(struct attribute *attr) { return container_of(attr, struct dmi_sysfs_attribute, attr); } static ssize_t dmi_sysfs_attr_show(struct kobject *kobj, struct attribute *_attr, char *buf) { struct dmi_sysfs_entry *entry = to_entry(kobj); struct dmi_sysfs_attribute *attr = to_attr(_attr); /* DMI stuff is only ever admin visible */ if (!capable(CAP_SYS_ADMIN)) return -EACCES; return attr->show(entry, buf); } static const struct sysfs_ops dmi_sysfs_attr_ops = { .show = dmi_sysfs_attr_show, }; typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *, const struct dmi_header *dh, void *); struct find_dmi_data { struct dmi_sysfs_entry *entry; dmi_callback callback; void *private; int instance_countdown; ssize_t ret; }; static void find_dmi_entry_helper(const struct dmi_header *dh, void *_data) { struct find_dmi_data *data = _data; struct dmi_sysfs_entry *entry = data->entry; /* Is this the entry we want? */ if (dh->type != entry->dh.type) return; if (data->instance_countdown != 0) { /* try the next instance? */ data->instance_countdown--; return; } /* * Don't ever revisit the instance. Short circuit later * instances by letting the instance_countdown run negative */ data->instance_countdown--; /* Found the entry */ data->ret = data->callback(entry, dh, data->private); } /* State for passing the read parameters through dmi_find_entry() */ struct dmi_read_state { char *buf; loff_t pos; size_t count; }; static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry, dmi_callback callback, void *private) { struct find_dmi_data data = { .entry = entry, .callback = callback, .private = private, .instance_countdown = entry->instance, .ret = -EIO, /* To signal the entry disappeared */ }; int ret; ret = dmi_walk(find_dmi_entry_helper, &data); /* This shouldn't happen, but just in case. */ if (ret) return -EINVAL; return data.ret; } /* * Calculate and return the byte length of the dmi entry identified by * dh. This includes both the formatted portion as well as the * unformatted string space, including the two trailing nul characters. */ static size_t dmi_entry_length(const struct dmi_header *dh) { const char *p = (const char *)dh; p += dh->length; while (p[0] || p[1]) p++; return 2 + p - (const char *)dh; } /************************************************* * Support bits for specialized DMI entry support *************************************************/ struct dmi_entry_attr_show_data { struct attribute *attr; char *buf; }; static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry, const struct dmi_header *dh, void *_data) { struct dmi_entry_attr_show_data *data = _data; struct dmi_sysfs_mapped_attribute *attr; attr = container_of(data->attr, struct dmi_sysfs_mapped_attribute, attr); return attr->show(entry, dh, data->buf); } static ssize_t dmi_entry_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct dmi_entry_attr_show_data data = { .attr = attr, .buf = buf, }; /* Find the entry according to our parent and call the * normalized show method hanging off of the attribute */ return find_dmi_entry(to_entry(kobj->parent), dmi_entry_attr_show_helper, &data); } static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = { .show = dmi_entry_attr_show, }; /************************************************* * Specialized DMI entry support. *************************************************/ /*** Type 15 - System Event Table ***/ #define DMI_SEL_ACCESS_METHOD_IO8 0x00 #define DMI_SEL_ACCESS_METHOD_IO2x8 0x01 #define DMI_SEL_ACCESS_METHOD_IO16 0x02 #define DMI_SEL_ACCESS_METHOD_PHYS32 0x03 #define DMI_SEL_ACCESS_METHOD_GPNV 0x04 struct dmi_system_event_log { struct dmi_header header; u16 area_length; u16 header_start_offset; u16 data_start_offset; u8 access_method; u8 status; u32 change_token; union { struct { u16 index_addr; u16 data_addr; } io; u32 phys_addr32; u16 gpnv_handle; u32 access_method_address; }; u8 header_format; u8 type_descriptors_supported_count; u8 per_log_type_descriptor_length; u8 supported_log_type_descriptos[0]; } __packed; #define DMI_SYSFS_SEL_FIELD(_field) \ static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \ const struct dmi_header *dh, \ char *buf) \ { \ struct dmi_system_event_log sel; \ if (sizeof(sel) > dmi_entry_length(dh)) \ return -EIO; \ memcpy(&sel, dh, sizeof(sel)); \ return sprintf(buf, "%u\n", sel._field); \ } \ static DMI_SYSFS_MAPPED_ATTR(sel, _field) DMI_SYSFS_SEL_FIELD(area_length); DMI_SYSFS_SEL_FIELD(header_start_offset); DMI_SYSFS_SEL_FIELD(data_start_offset); DMI_SYSFS_SEL_FIELD(access_method); DMI_SYSFS_SEL_FIELD(status); DMI_SYSFS_SEL_FIELD(change_token); DMI_SYSFS_SEL_FIELD(access_method_address); DMI_SYSFS_SEL_FIELD(header_format); DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count); DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length); static struct attribute *dmi_sysfs_sel_attrs[] = { &dmi_sysfs_attr_sel_area_length.attr, &dmi_sysfs_attr_sel_header_start_offset.attr, &dmi_sysfs_attr_sel_data_start_offset.attr, &dmi_sysfs_attr_sel_access_method.attr, &dmi_sysfs_attr_sel_status.attr, &dmi_sysfs_attr_sel_change_token.attr, &dmi_sysfs_attr_sel_access_method_address.attr, &dmi_sysfs_attr_sel_header_format.attr, &dmi_sysfs_attr_sel_type_descriptors_supported_count.attr, &dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr, NULL, }; static struct kobj_type dmi_system_event_log_ktype = { .release = dmi_entry_free, .sysfs_ops = &dmi_sysfs_specialize_attr_ops, .default_attrs = dmi_sysfs_sel_attrs, }; typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel, loff_t offset); static DEFINE_MUTEX(io_port_lock); static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel, loff_t offset) { u8 ret; mutex_lock(&io_port_lock); outb((u8)offset, sel->io.index_addr); ret = inb(sel->io.data_addr); mutex_unlock(&io_port_lock); return ret; } static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel, loff_t offset) { u8 ret; mutex_lock(&io_port_lock); outb((u8)offset, sel->io.index_addr); outb((u8)(offset >> 8), sel->io.index_addr + 1); ret = inb(sel->io.data_addr); mutex_unlock(&io_port_lock); return ret; } static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel, loff_t offset) { u8 ret; mutex_lock(&io_port_lock); outw((u16)offset, sel->io.index_addr); ret = inb(sel->io.data_addr); mutex_unlock(&io_port_lock); return ret; } static sel_io_reader sel_io_readers[] = { [DMI_SEL_ACCESS_METHOD_IO8] = read_sel_8bit_indexed_io, [DMI_SEL_ACCESS_METHOD_IO2x8] = read_sel_2x8bit_indexed_io, [DMI_SEL_ACCESS_METHOD_IO16] = read_sel_16bit_indexed_io, }; static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry, const struct dmi_system_event_log *sel, char *buf, loff_t pos, size_t count) { ssize_t wrote = 0; sel_io_reader io_reader = sel_io_readers[sel->access_method]; while (count && pos < sel->area_length) { count--; *(buf++) = io_reader(sel, pos++); wrote++; } return wrote; } static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry, const struct dmi_system_event_log *sel, char *buf, loff_t pos, size_t count) { u8 __iomem *mapped; ssize_t wrote = 0; mapped = ioremap(sel->access_method_address, sel->area_length); if (!mapped) return -EIO; while (count && pos < sel->area_length) { count--; *(buf++) = readb(mapped + pos++); wrote++; } iounmap(mapped); return wrote; } static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry, const struct dmi_header *dh, void *_state) { struct dmi_read_state *state = _state; struct dmi_system_event_log sel; if (sizeof(sel) > dmi_entry_length(dh)) return -EIO; memcpy(&sel, dh, sizeof(sel)); switch (sel.access_method) { case DMI_SEL_ACCESS_METHOD_IO8: case DMI_SEL_ACCESS_METHOD_IO2x8: case DMI_SEL_ACCESS_METHOD_IO16: return dmi_sel_raw_read_io(entry, &sel, state->buf, state->pos, state->count); case DMI_SEL_ACCESS_METHOD_PHYS32: return dmi_sel_raw_read_phys32(entry, &sel, state->buf, state->pos, state->count); case DMI_SEL_ACCESS_METHOD_GPNV: pr_info("dmi-sysfs: GPNV support missing.\n"); return -EIO; default: pr_info("dmi-sysfs: Unknown access method %02x\n", sel.access_method); return -EIO; } } static ssize_t dmi_sel_raw_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t pos, size_t count) { struct dmi_sysfs_entry *entry = to_entry(kobj->parent); struct dmi_read_state state = { .buf = buf, .pos = pos, .count = count, }; return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state); } static struct bin_attribute dmi_sel_raw_attr = { .attr = {.name = "raw_event_log", .mode = 0400}, .read = dmi_sel_raw_read, }; static int dmi_system_event_log(struct dmi_sysfs_entry *entry) { int ret; entry->child = kzalloc(sizeof(*entry->child), GFP_KERNEL); if (!entry->child) return -ENOMEM; ret = kobject_init_and_add(entry->child, &dmi_system_event_log_ktype, &entry->kobj, "system_event_log"); if (ret) goto out_free; ret = sysfs_create_bin_file(entry->child, &dmi_sel_raw_attr); if (ret) goto out_del; return 0; out_del: kobject_del(entry->child); out_free: kfree(entry->child); return ret; } /************************************************* * Generic DMI entry support. *************************************************/ static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf) { return sprintf(buf, "%d\n", entry->dh.length); } static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf) { return sprintf(buf, "%d\n", entry->dh.handle); } static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf) { return sprintf(buf, "%d\n", entry->dh.type); } static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry, char *buf) { return sprintf(buf, "%d\n", entry->instance); } static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry, char *buf) { return sprintf(buf, "%d\n", entry->position); } static DMI_SYSFS_ATTR(entry, length); static DMI_SYSFS_ATTR(entry, handle); static DMI_SYSFS_ATTR(entry, type); static DMI_SYSFS_ATTR(entry, instance); static DMI_SYSFS_ATTR(entry, position); static struct attribute *dmi_sysfs_entry_attrs[] = { &dmi_sysfs_attr_entry_length.attr, &dmi_sysfs_attr_entry_handle.attr, &dmi_sysfs_attr_entry_type.attr, &dmi_sysfs_attr_entry_instance.attr, &dmi_sysfs_attr_entry_position.attr, NULL, }; static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry, const struct dmi_header *dh, void *_state) { struct dmi_read_state *state = _state; size_t entry_length; entry_length = dmi_entry_length(dh); return memory_read_from_buffer(state->buf, state->count, &state->pos, dh, entry_length); } static ssize_t dmi_entry_raw_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t pos, size_t count) { struct dmi_sysfs_entry *entry = to_entry(kobj); struct dmi_read_state state = { .buf = buf, .pos = pos, .count = count, }; return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state); } static const struct bin_attribute dmi_entry_raw_attr = { .attr = {.name = "raw", .mode = 0400}, .read = dmi_entry_raw_read, }; static void dmi_sysfs_entry_release(struct kobject *kobj) { struct dmi_sysfs_entry *entry = to_entry(kobj); spin_lock(&entry_list_lock); list_del(&entry->list); spin_unlock(&entry_list_lock); kfree(entry); } static struct kobj_type dmi_sysfs_entry_ktype = { .release = dmi_sysfs_entry_release, .sysfs_ops = &dmi_sysfs_attr_ops, .default_attrs = dmi_sysfs_entry_attrs, }; static struct kset *dmi_kset; /* Global count of all instances seen. Only for setup */ static int __initdata instance_counts[MAX_ENTRY_TYPE + 1]; /* Global positional count of all entries seen. Only for setup */ static int __initdata position_count; static void __init dmi_sysfs_register_handle(const struct dmi_header *dh, void *_ret) { struct dmi_sysfs_entry *entry; int *ret = _ret; /* If a previous entry saw an error, short circuit */ if (*ret) return; /* Allocate and register a new entry into the entries set */ entry = kzalloc(sizeof(*entry), GFP_KERNEL); if (!entry) { *ret = -ENOMEM; return; } /* Set the key */ memcpy(&entry->dh, dh, sizeof(*dh)); entry->instance = instance_counts[dh->type]++; entry->position = position_count++; entry->kobj.kset = dmi_kset; *ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL, "%d-%d", dh->type, entry->instance); if (*ret) { kfree(entry); return; } /* Thread on the global list for cleanup */ spin_lock(&entry_list_lock); list_add_tail(&entry->list, &entry_list); spin_unlock(&entry_list_lock); /* Handle specializations by type */ switch (dh->type) { case DMI_ENTRY_SYSTEM_EVENT_LOG: *ret = dmi_system_event_log(entry); break; default: /* No specialization */ break; } if (*ret) goto out_err; /* Create the raw binary file to access the entry */ *ret = sysfs_create_bin_file(&entry->kobj, &dmi_entry_raw_attr); if (*ret) goto out_err; return; out_err: kobject_put(entry->child); kobject_put(&entry->kobj); return; } static void cleanup_entry_list(void) { struct dmi_sysfs_entry *entry, *next; /* No locks, we are on our way out */ list_for_each_entry_safe(entry, next, &entry_list, list) { kobject_put(entry->child); kobject_put(&entry->kobj); } } static int __init dmi_sysfs_init(void) { int error; int val; if (!dmi_kobj) { pr_err("dmi-sysfs: dmi entry is absent.\n"); error = -ENODATA; goto err; } dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj); if (!dmi_kset) { error = -ENOMEM; goto err; } val = 0; error = dmi_walk(dmi_sysfs_register_handle, &val); if (error) goto err; if (val) { error = val; goto err; } pr_debug("dmi-sysfs: loaded.\n"); return 0; err: cleanup_entry_list(); kset_unregister(dmi_kset); return error; } /* clean up everything. */ static void __exit dmi_sysfs_exit(void) { pr_debug("dmi-sysfs: unloading.\n"); cleanup_entry_list(); kset_unregister(dmi_kset); } module_init(dmi_sysfs_init); module_exit(dmi_sysfs_exit); MODULE_AUTHOR("Mike Waychison <mikew@google.com>"); MODULE_DESCRIPTION("DMI sysfs support"); MODULE_LICENSE("GPL");